Preparation and electrochemical behavior of amorphous Co-Mo coating with high content of Mo

Preparation and electrochemical behavior of amorphous Co-Mo coating with high content of Mo | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Preparation and electrochemical behavior of amorphous Co-Mo coating with high content of Mo Ya Tian, Liwen Ma, Xiaoli Xi, Zuoren Nie This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-1437984/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 27 May, 2022 Read the published version in Coatings → Version 1 posted You are reading this latest preprint version Abstract At present, alloy materials have been widely used as wear-resistant coatings due to good mechanical properties. In this paper, electrodeposition was used to prepare the Co-Mo coating. The electrochemical behavior of the deposition of alloy and the phase composition, morphology, composition and property of the coating have been studied. The study of process parameters found that when the concentration of Na 2 Mo 4 is 0.05mol/L, the concentration of C 6 H 5 Na 3 O 7 is 0.15mol/L, the pH of the solution is 7, and the temperature is 50℃, the content of Mo in Co-Mo coating is 39.56%, and the microhardness reaches the maximum value of 503HV. The study of electrochemical behavior found that when the concentration of Na 2 Mo 4 is 0.05mol/L, the concentration of C 6 H 5 Na 3 O 7 is 0.15mol/L, the pH of the solution is 7 and the temperature is 50℃, the most positive deposition potential, maximum exchange current density and minimum charge transfer impedance were obtained, which explained why the best performance coating can be obtained under this condition. Electrodeposition Amorphous Co-Mo coating Microhardness Electrochemical mechanism Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16 Figure 17 1. Introduction Alloy materials have been widely used due to their good mechanical properties. The traditional method of preparing alloy materials is mainly powder metallurgy, but the electrodeposition can be used to prepare alloy coatings on the substrate in a salt solution to improve the property of the substrate materials. Currently, the more widely used alloy coatings mainly include Ni-Co alloy, Ni-W alloy [ 1 , 2 ] , Co-W alloy [ 3 – 5 ] , Ni-Mo alloy [ 6 – 9 ] , Co-Mo alloy [ 10 – 12 ] , Ni-Co-Mo alloy [ 13 ] and other iron group element alloys [ 14 – 17 ] . Among them, the content of W [ 18 , 19 ] and Mo [ 20 , 21 ] is critical to the performance of the coating. Due to its good mechanical properties and catalytic hydrogen evolution performance, the molybdenum-containing coating have been used as wear-resistant coating and catalytic hydrogen evolution material in the field of metal protection and water electrolysis. N. P. Wasekar et al. [ 8 ] prepared a Ni-Mo alloy coating and found that the increase in molybdenum content improved the microhardness, wear resistance and corrosion resistance of the coating. C. Y. Lee et al. [ 21 ] studied the corrosion behavior of Ni-Mo coating in NaCl solution, found that the corrosion film was not passivated under high overpotential, and the synergistic effect of wear and corrosion on the weight loss of this Ni-Mo alloy coating was less obvious than that of other Ni alloy coatings. Some researchers have studied the principle of electrodeposition and electrochemical behavior of molybdenum-containing alloys. Elvira Go´mezet al. [ 11 ] used voltammetry to study the influence of process parameters on co-deposition of cobalt and molybdenum. At present, most of the Co-Mo coatings show crystalline structure, while the amorphous Co-Mo coating with high Mo content possess better property. And the relationship between the electrochemical behavior of the alloy and the structure, composition, morphology and property of the coating has not been deeply studied. Therefore, in this paper, the amorphous Co-Mo coating with high Mo content was prepared by optimization of process electrodeposition and the effect of different process parameters on the electrochemical behavior, structure, morphology, composition and property of coating was studied. 2. Experimental 2.1 Coating preparation The Co-Mo coating was prepared by electrodeposition in a citrate bath. The composition of the bath and process parameters are shown in Table 1 . All reagents are analytically pure, using anionic surfactant C 12 H 25 SO 4 N as the dispersant. Use dilute sulfuric acid and sodium hydroxide solution to adjust the pH of the solution. Electrodeposition was carried out in a 200 mL beaker. The anode of the double graphite plate was inserted into the electroplating solution in parallel, and the copper sheet was used as the cathode, suspended in the middle of the double graphite plate. The substrate is pretreated before deposition, using 600#, 800#, 2000# sandpaper for mechanical polishing, and 6µm, 3µm polishing liquid for polishing. Then use sodium hydroxide for chemical degreasing, dilute sulfuric acid for activation, and use alcohol to clean in an ultrasonic cleaning machine, finally wash with distilled water and dry. Table 1 Bath composition and electroplating parameters for deposition of coatings. Bath composition Electrodeposition conditions CoSO 4 0.1mol/L pH 6 ~ 9 Na 2 MoO 4 0.05 ~ 0.15mol/L Temperature 40 ~ 60℃ Na 3 C 6 H 5 O 7 0.1 ~ 0.3mol/L Current density 1A·dm − 2 C 12 H 25 SO 4 Na 1g/L Deposition time 2h The current efficiency is calculated according to Eq. ( 1 ): $${\eta }=（\frac{\text{{\rm M}}\times {\text{f}}_{\text{C}\text{o}}}{{\text{C}}_{\text{C}\text{o}}\times \text{I}\times \text{t}}+\frac{\text{{\rm M}}\times {\text{f}}_{\text{M}\text{o}}}{{\text{C}}_{\text{M}\text{o}}\times \text{I}\times \text{t}})\times 100\text{\%}$$ 1 Where, M is the quality of the obtained alloy coating, f is the mass fraction of each metal in the coating, C is the electrochemical equivalent of each metal in the coating, I is the current intensity, and t is the electrodeposition time. 2.2 Coating characterization The surface morphology of the coating was characterized by scanning electron microscope (SEM-2100) and the composition of the coating was studied using an energy dispersive X-ray spectrometer (EDS) coupled with SEM. The structure was analyzed by X-ray diffraction method (XRD-7000) under copper Kα1 radiation, and the measurement was carried out in the range of 2θ from 10° to 90°. 2.3 Coating performance test The Microhardness of the coating was examined by HXD-100TMC/LCD micro-hardness tester. The applied force is 0.05mm/s, the applied load is 100g, and the holding time is 10s. Each sample was tested for the hardness value of 10 points and find the average. 2.4 Electrochemical behavior test A three-electrode system was used for electrochemical testing in a 200ml beaker containing electroplating solution. The glassy carbon electrode and copper electrode were used as the working electrode, the platinum electrode was used as the auxiliary electrode, and the saturated calomel electrode was used as the reference electrode. The cyclic voltammetry(CV) was performed at a scan rate of 50mV/s within the potential range of -1.2V~-0.5V, the linear scan voltammetry(LSV) was performed at a scan rate of 50mV/s within the potential range of -1.2V ~ 0V, and the electrochemical impedance spectroscopy(EIS) was performed in the range of 0.1 Hz-10k Hz with the potential of -1.2V. 3 Results And Discussion 3.1 The structure, composition, morphology and property of Co-Mo coating 3.1.1 Effect of the concentration of Na 2 MoO 4 The XRD spectra of the Co-Mo coatings at different concentrations of Na 2 MoO 4 are shown in Fig. 1(a). The XRD spectra of the coatings with different concentrations of Na 2 MoO 4 showed a broad diffraction peak around 2θ = 43°, indicating that the Co-Mo coating is an alloy with an amorphous structure. The XRD spectra of the coatings prepared with the concentration of Na 2 MoO 4 at 0.075 mol/L, 0.1 mol/L, 0.125 mol/L and 0.15 mol/L show the diffraction peak of copper at 2θ = 50° and 2θ = 74°, and a less obvious broadened diffraction peak is shown near 2θ = 43°. Combined with electrochemical test of different concentrations of Na 2 MoO 4 , it was shown that as the concentration of Na 2 MoO 4 increases, the deposition of alloy becomes more and more difficult, so the coating becomes thin, causing X-rays to hit the copper substrate. Figure 1(b) shows the influence of the concentration of Na 2 MoO 4 in the plating solution on the composition and current efficiency of the Co-Mo coatings. As the concentration of Na 2 MoO 4 increases, the mass fraction of molybdenum in the coating shows a trend of first decreasing and then increasing. When the concentration of Na 2 MoO 4 in the plating solution is 0.05mol/L, the content of molybdenum reaches the maximum value of 37.25%. It is reported that the greater the concentration of Na 2 MoO 4 in the plating solution in a certain range, the higher the content of molybdenum in the coating. However, the electrochemical test results of different sodium molybdate concentrations shows that as the concentration of Na 2 MoO 4 increases, the exchange current density i 0 decreases, the charge transfer resistance Rct increases, which is conducive to the separate deposition of cobalt and hinders the co-deposition of cobalt and molybdenum. At the same time, as the concentration of Na 2 MoO 4 increases, the thickness of the coating becomes thinner, resulting in the determination of the mass fraction of coating components, the copper matrix also occupies a certain mass fraction. As the concentration of Na 2 MoO 4 in the plating solution increases, the current efficiency decreases. This is because as the concentration of Na 2 MoO 4 increases, the deposition of alloy becomes difficult and the coating quality decreases. According to the Eq. (2 − 1), the current efficiency decreases. The surface morphology of the Co-Mo coating under different concentrations of Na 2 MoO 4 is shown in Fig. 2. When the concentration of Na 2 MoO 4 is 0.05 mol/L, the Co-Mo coating has the characteristics of the surface morphology of nodular shape, the surface is flat and smooth, and the crystal grains are small and uniform. This is due to the higher content of molybdenum in the coating. When the concentration of Na 2 MoO 4 increases, the surface quality of the coating is reduced, the surface becomes uneven, and the crystal grains become coarse. Figure 3 shows the comparison of the microhardness of the Co-Mo coating with different concentrations of Na 2 MoO 4 . As the concentration of Na 2 MoO 4 in the plating solution increases, the microhardness of the Co-Mo coating is reduced. When the concentration of Na 2 MoO 4 is 0.075 mol/L, 0.1 mol/L, 0.125 mol/L and 0.15 mol/L, The microhardness of Co-Mo coating are 289.486HV、268.462 HV、240.938 HV、207.722 HV. When the concentration of Na 2 MoO 4 is 0.05 mol/L, the microhardness of the Co-Mo coating reaches the maximum value of 331HV. From the perspective of the structure of coating, the coating is an amorphous alloy, indicating that molybdenum enters the cobalt lattice, causing lattice distortion, which hinders the movement of dislocations and improves the microhardness of the coating. Therefore, the higher the content of molybdenum in the coating, the higher the microhardness. Moreover, as the concentration of Na 2 MoO 4 increases, the thickness of the coating decreases. During the microhardness test, the diamond probe may release the copper matrix. The microhardness of copper is about 200HV, which makes the microhardness of the coating low. 3.1.2 Effect of the concentration of C 6 H 5 Na 3 O 7 The XRD spectra of the Co-Mo coatings at different concentrations of C 6 H 5 Na 3 O 7 are shown in Fig. 4(a). The XRD spectra of the coatings with different concentrations of C 6 H 5 Na 3 O 7 showed a broad diffraction peak around 2θ = 43°. The XRD spectra of the coatings prepared with the concentration of C 6 H 5 Na 3 O 7 at 0.2 mol/L, 0.25 mol/L and 0.3 mol/L show the diffraction peak of copper at 2θ = 50° and 2θ = 74°, and a less obvious broadened diffraction peak is shown near 2θ = 43°. Combined with electrochemical test of different s concentrations of C 6 H 5 Na 3 O 7 , it was shown that when the concentration of C 6 H 5 Na 3 O 7 is too high, the deposition of alloy becomes difficult, so the coating becomes thin, causing X-rays to hit the copper substrate. Figure 4(b) shows the influence of the concentration of C 6 H 5 Na 3 O 7 in the plating solution on the composition and current efficiency of the Co-Mo coatings. As the concentration of C 6 H 5 Na 3 O 7 increases, the mass fraction of molybdenum in the coating shows a trend of first increasing and then decreasing. When the concentration of C 6 H 5 Na 3 O 7 in the plating solution is 0.15mol/L, the content of molybdenum reaches the maximum value of 37.25%. The deposition of molybdenum mainly depends on the formation of cobalt-molybdenum complex ions. Combined with the electrochemical test results, when the concentration of C 6 H 5 Na 3 O 7 in the solution is too low, the optimal concentration for forming complex ions cannot be achieved, which is not conducive to the deposition of molybdenum. When the concentration of C 6 H 5 Na 3 O 7 increases to 0.15 mol/L, the exchange current density reaches the maximum value and the charge transfer resistance reaches the minimum value. At this time, the deposition of alloy is easier, and the content of molybdenum in the coating reaches the maximum value. With the further increase of the C 6 H 5 Na 3 O 7 concentration, excessive ions hinder the movement of complex ions to the cathode, the exchange current density begins to decrease, the charge transfer resistance begins to increase, alloy deposition becomes difficult, and the molybdenum content in the coating decreases. As the concentration of C 6 H 5 Na 3 O 7 in the plating solution increases, the current efficiency increases first and then decreases. This is because as the concentration of C 6 H 5 Na 3 O 7 increases, the deposition of alloy becomes easy and the coating quality increases, according to the Eq. (2 − 1), the current efficiency increases. However, as the concentration of C 6 H 5 Na 3 O 7 further increases, the deposition of the alloy is hindered, and the quality of the coating decreases. According to the Eq. (2 − 1), the current efficiency decreases. The surface morphology of the Co-Mo coating under different concentrations of C 6 H 5 Na 3 O 7 is shown in Fig. 5. When the concentration of C 6 H 5 Na 3 O 7 is 0.1 mol/L, the Co-Mo coating has the characteristics of the surface morphology of irregular polygonal flakes. When the concentration of C 6 H 5 Na 3 O 7 is 0.15 mol/L, the surface is flat and smooth, and the crystal grains are small and uniform. This is due to the higher content of molybdenum in the coating. When the concentration of C 6 H 5 Na 3 O 7 continue to increase, the surface becomes uneven, and the crystal grains become coarse. Figure 6 shows the comparison of the microhardness of the Co-Mo coating with different concentrations of C 6 H 5 Na 3 O 7 . As the concentration of Na 2 MoO 4 in the plating solution increases, the microhardness of the Co-Mo coating increases first and then decreases. When the concentration of C 6 H 5 Na 3 O 7 is 0.1mol/L, 0.2 mol/L, 0.25mol/L and 0.3mol/L, the microhardness of Co-Mo coating is 314HV, 284.4HV, 270.2HV and 251.6HV, respectively. When the concentration of C 6 H 5 Na 3 O 7 is 0.15 mol/L, the microhardness of the Co-Mo coating reaches the maximum value of 331HV. As the concentration of C 6 H 5 Na 3 O 7 increases, the content of molybdenum in the coating first increases and then decreases, and the degree of lattice distortion caused first increases and then decreases. Therefore, the microhardness of the coating first increases and then decreases. 3.1.3 Effect of the pH value The XRD spectra of the Co-Mo coatings under different pH are shown in Fig. 7(a). The XRD spectra of the coatings under different temperature showed a broad diffraction peak around 2θ = 43°. The XRD spectra of the coatings prepared with the pH at 6 and 9 show the diffraction peak of copper at 2θ = 50° and 2θ = 74°, and a less obvious broadened diffraction peak is shown near 2θ = 43°. Combined with electrochemical test of different temperature, it was shown that as the pH rises, the deposition of alloys becomes more difficult, but when the pH is 6, the alloy deposition rate is too fast, and the hydrogen evolution reaction is violent due to the high concentration of H + in the electroplating solution, causing the coating surface to fall off causing the coating surface to peel off, which makes the coating thinner causing X-rays to hit the copper substrate. Figure 7(b) shows the influence of the pH on the composition and current efficiency of the Co-Mo coatings. As the pH increases, the mass fraction of molybdenum in the coating shows a trend of decreasing. When the pH is 6, the content of molybdenum reaches the maximum value of 38.98%. Combined with the electrochemical test results, as the pH increases, the exchange current density decreases, and the charge transfer resistance increases, which makes the deposition of alloy more difficult, so the content of molybdenum in the coating decreases. As the pH increases, the current efficiency increases first and then decreases. When the pH is 7, the current efficiency reaches the maximum value. The low current efficiency is due to the high content of molybdenum. The deposition of MoO 4 2− is not a one-step reduction to Mo. The first stage is the reduction of MoO 4 2− to low-valent molybdenum oxides, such as MoO 2 , under the action of CoCit − . At this stage, there is a hydrogen evolution reaction, so this leads to a decrease in current efficiency [22] . Therefore, when the pH is 6, the current efficiency is low. However, when the pH is too high, the deposition quality is reduced, resulting in a decrease in current efficiency. The surface morphology of the Co-Mo coating under different pH is shown in Fig. 8. As the pH rises, the surface of the coating becomes smoother and the crystal grains are smaller. When the pH is 8 and 9, the Co-Mo coating has the characteristics of the surface morphology of irregular polygonal flakes. This is due to the lower content of molybdenum in the coating. Figure 9 shows the comparison of the microhardness of the Co-Mo coating under different pH. As the pH increases, the microhardness of the Co-Mo coating increases first and then decreases. When the pH is 6, 8 and 9, the microhardness of Co-Mo coating are 276 HV、269.46 HV、245.93 HV. When the pH is 7, the microhardness of the Co-Mo coating reaches the maximum value of 331HV. The higher the content of molybdenum in the coating, the greater the hardness of the coating. When the pH is 6, although the content of molybdenum in the coating is high, the surface of the coating falls off, causing the diamond probe to contact the copper substrate during the microhardness test, which makes the microhardness of the coating lower. 3.1.4 Effect of the temperature The XRD spectra of the Co-Mo coatings under different temperature are shown in Fig. 10(a). The XRD spectra of the coatings under different temperature showed a broad diffraction peak around 2θ = 43°. The XRD spectra of the coatings prepared with the temperature at 40℃, 55℃and 60℃ show the diffraction peak of copper at 2θ = 50° and 2θ = 74°, and a less obvious broadened diffraction peak is shown near 2θ = 43°. Combined with electrochemical test of different temperature, it was shown that as the temperature rises, the deposition of the alloy becomes easier, but when the temperature is too high, the deposition rate is too fast, causing the coating surface to peel off, which makes the coating thinner causing X-rays to hit the copper substrate. Figure 10(b) shows the influence of the temperature on the composition and current efficiency of the Co-Mo coatings. As the temperature increases, the mass fraction of molybdenum in the coating shows a trend of first increasing and then decreasing. When the temperature is 50℃, the content of molybdenum reaches the maximum value of 39.56%. The deposition of molybdenum mainly depends on the formation of cobalt-molybdenum complex ions. Combined with the electrochemical test results, as the temperature increases, the migration rate of complex ions to the cathode increases, the exchange current density increases, and the charge transfer resistance decreases, which makes the deposition of alloy easier, so the content of molybdenum in the coating increases. However, when the temperature is too high, it will affect the stability of the complex ions, which is not conducive to the deposition of molybdenum, resulting in a decrease in the content of molybdenum in the coating. As the temperature increases, the current efficiency increases first and then decreases. When the temperature is 50℃, the current efficiency reaches the maximum value of 63%. This is because as the temperature increases, the deposition of alloy becomes easy and the coating quality increases, according to the Eq. (1), the current efficiency increases. However, as the temperature further increases, the deposition rate is too fast, causing the coating surface to fall off and reduce the quality, according to the Eq. (2 − 1), the current efficiency decreases. The surface morphology of the Co-Mo coating under different temperature is shown in Fig. 11. When the temperature is 40℃, the Co-Mo coating has the characteristics of the surface morphology of irregular polygonal flakes. As the temperature rises, the surface of the coating becomes smoother and the crystal grains are smaller. This is due to the higher content of molybdenum in the coating. When the temperature is too high, the surface becomes uneven, and the crystal grains become coarse. Figure 12 shows the comparison of the microhardness of the Co-Mo coating under different temperature. As the temperature increases, the microhardness of the Co-Mo coating increases first and then decreases. When the temperature is 40℃, 45℃, 55℃ and 60℃, the microhardness of Co-Mo coating are 320HV, 314HV, 397HV and 376HV. When the temperature is 50℃, the microhardness of the Co-Mo coating reaches the maximum value of 503HV. As the temperature increases, the content of molybdenum in the coating first increases and then decreases. The thickness of the coating also increases first and then decreases. Therefore, the microhardness of the coating first increases and then decreases. 3.1.5 Characterization of coating surface elements XPS was used to test the composition and chemical valence state of the Co-Mo coating. XPS pattern of (a) full spectrum of elements, (b) Co2p, (c) O1s and (d) Mo3d of Co-Mo coating is shown in Fig. 13. As shown in Fig. 13 (a), the peaks of O, Co and Mo appear in the spectrum. As shown in Fig. 13 (b), the Co 2p1/2 XPS has two split peaks, belonging to Co (799.3 eV), Cobalt Oxides (804.1 eV). The Co 2p3/2 XPS has two split peaks, belonging to Co (779.1 eV), Cobalt Oxides (781.7 eV). Coating surface formed an oxide film when exposed to air. As shown in Fig. 8 (c), the O 1s XPS has one split peaks at 532.3 eV, which is related to the Er 2 O 3 and the metal oxide. As shown in Fig. 8 (d), the Mo 3d XPS has three split peaks, belonging to Mo 6+ (235.5 eV), Mo 3+ (228.9 eV and 232.3 eV). The existence of Mo 6+ is due to the oxidation of Mo to MoO 3 and the existence of Mo 3+ is due to the oxidation of Mo to Mo 2 O 3 .As shown in Fig. 14, it can be seen that the distribution of Co and Mo elements is very uniform. Figure 14(b) shows the EDS spectrum and the composition of the Co-Mo coating, the peaks of Co and Mo appear on the EDS pattern. 3.2 The electrochemical behavior of the deposition of Co-Mo alloy 3.2.1 Deposition potential Figure 15(a) shows the cyclic voltammetry curves of cobalt-molybdenum plating solutions with different concentrations Na 2 MoO 4 on glassy carbon electrodes. When the concentration of Na 2 MoO 4 is 0.05 mol/L, 0.075mol/L, 0.1 mol/L, 0.125mol/L and 0.15 mol/L, the reduction peak appears at -0.85V, -0.9V, -0.95V, -1V and − 1.05V during the negative scan, and the oxidation peak appears at -0.25V, -0.3V,-0.33V and − 0.35V during the positive scan. Figure 15(b) shows the cyclic voltammetry curves of cobalt-molybdenum plating solutions with different concentration of C 6 H 5 Na 3 O 7 on glassy carbon electrodes. When the concentration of C 6 H 5 Na 3 O 7 is 0.1 mol/L, 0.15 mol/L, 0.2mol/L, 0.25mol/L and 0.3mol/L, the reduction peak appears at -0.85V, -0.75V, -0.9V, -0.95V and − 1V during the negative scan, and the oxidation peak appears at -0.25V, -0.1V, -0.3V, -0.35V and − 0.38V during the positive scan. Figure 15(c) shows the cyclic voltammetry curves of cobalt-molybdenum baths with different pH on glassy carbon electrodes. When the pH is 5, 6, 7 and 8, the reduction peak appears at -0.75V, -0.8V, -0.9V and − 1V when scanning in the negative direction, and the oxidation peak appears at -0.15V, -0.25V, -0.3V and − 0.35V when scanning in the forward direction. When the pH is 9, there is almost no redox peak. Figure 15(d) shows the cyclic voltammetry curves of cobalt-molybdenum baths with different temperature on glassy carbon electrodes. When the temperature is 40℃, 45℃, 50℃, 55℃ and 60℃, the reduction peak appears at -0.89V, -0.87V, -0.85V, -0.84V and − 0.82V when scanning in the negative direction, and the oxidation peak appears at -0.25V, -0.26V, -0.27V, -0.29V and − 0.32V when scanning in the forward direction. It can be seen from the CV graph that as the concentration of Na 2 MoO 4 increases, the deposition potential of the cobalt-molybdenum alloy moves in a negative direction. The reason for this trend is that when the concentration of Na 2 MoO 4 increases, too much molybdate ions make the migration rate of complex ions slow, and the precipitation potential shifts in the negative direction; as the concentration of C 6 H 5 Na 3 O 7 increases, the deposition potential of the cobalt-molybdenum alloy first shifts to a positive direction and then to a negative direction. The reason for this trend is that when the concentration of C 6 H 5 Na 3 O 7 increases, the number of cobalt-molybdenum complex ions formed increases, which facilitates the deposition of cobalt-molybdenum complex ions, thereby shifting the precipitation potential to the positive direction. When the concentration of C 6 H 5 Na 3 O 7 is high, the ionization equilibrium is destroyed, resulting in the pH of the plating solution; as the pH increases, the deposition potential of the cobalt-molybdenum alloy shifts in the negative direction. The reason for this trend is that when the pH value is high, Co(Ⅱ) exists in the form of CoCit − , and molybdenum exists in the form of MoO 4 2− ; when the pH value is low, Co(Ⅱ) exists in the form of HCoCit, molybdenum exists in the form of HrMoO4Cit [5−r] [11] ; as the temperature rises, the deposition potential of the cobalt-molybdenum alloy shifts in the positive direction. This is because as the temperature rises, the migration rate of ions increases, and the stability of complex ions is destroyed, so it is more conducive to the deposition of cobalt, and the deposition potential moves forward. 3.2.2 Exchange current density The exchange current density is an important kinetic parameter to evaluate the electrode reaction: The higher the exchange current density, the easier the electrode reaction. Therefore, the exchange current density i 0 on the glassy carbon electrode in the bath was studied by LSV. The Butler-Volmer [23, 24] equation was applied at very low cathode overpotential, which can be simplified to Eq. (2), Take the logarithm of both sides of Eq. (2) to obtain Eq. (3). $$i={i}_{0}\left\{-exp\left[\frac{-\alpha nF}{RT}\eta \right]\right\}$$ 2 $$\text{l}\text{o}\text{g}\left|i\right|=\text{l}\text{o}\text{g}\left|{i}_{0}\right|-\frac{\alpha nF}{RT}\eta$$ 3 where i is the current density (mA·cm − 2 ), i 0 is the exchange current density (mA·cm − 2 ), α is the charge transfer coefficient in the cathode direction, ƞ is over-potential. Based on the Eq. (3), it can be found that under a small overpotential, i and ƞ are linearly related. When the overpotential exceeds − 0.1 V, the current contribution of anode polarization is negligible. Therefore, the value of i 0 can be measured by the slope of the i - ƞ curve in a narrow potential range close to the equilibrium potential. Figure 16 shows the LSV curve on glassy carbon electrode in the bath, where when ŋ is between − 0.15 V and − 0.1 V, the polarization curve presents a straight line. Table 2 shows the value of exchange current density i 0 on glassy carbon electrode in the bath, it can be found that as the concentration of Na 2 MoO 4 increases, the exchange current density i 0 decreases; as the concentration of C 6 H 5 Na 3 O 7 increases, the exchange current density i 0 increases first and decreases then, when the concentration of C 6 H 5 Na 3 O 7 is 0.05mol/L, i 0 reaches a maximum; as the pH increases, the exchange current density i 0 decreases; as the temperature increases, the exchange current density i 0 increases. Table 2 The value of exchange current density i 0 on glassy carbon electrode in the bath C Na2MoO4 (mol/L) i 0 (mA·cm − 2 ) C C6H5Na3O7 (mol/L) i 0 pH i 0 Temperature (℃) i 0 0.05 0.0703 0.1 0.0661 5 0.1296 40 0.1975 0.075 0.0702 0.15 0.0703 6 0.0703 45 0.2306 0.1 0.0687 0.2 0.0523 7 0.0458 50 0.2413 0.125 0.0534 0.25 0.0313 8 0.0314 55 0.2452 0.15 0.0385 0.3 0.0150 9 0.0158 60 0.2458 3.2.3 Charge transfer impedance Figure 17 shows Nyquist plots at -1.2 V potential in the bath. It is observed that there is only one EIS spectrum composed of a semicircular arc, which indicates that the deposition of alloy is only controlled by charge transfer [25] . According to the impedance results, Zview software was used to fit the equivalent circuit, and the result is shown as Fig. 17(e). In the circuit, Rs is the resistance of the solution, Rct is the charge transfer resistance, CPE is a constant phase element used to establish a more accurate fit. As shown in Table 3, as the concentration of Na 2 MoO 4 increases, the charge transfer resistance Rct increases; as the concentration of C 6 H 5 Na 3 O 7 increases, the charge transfer resistance Rct decreases first and then increases; as the pH increases, the charge transfer resistance Rct increase; as the temperature increases, the charge transfer resistance Rct decreases. Table 3 The value of Rs and Rct on copper electrode in the bath C Na2MoO4 (mol/L) Rct (ohms·cm 2 ) C C6H5Na3O7 (mol/L) Rct pH Rct temperature Rct 0.05 13.9000 0.1 15.4158 5 11.0002 40℃ 9.6225 0.075 20.5874 0.15 13.9000 6 13.9000 45℃ 8.5698 0.1 23.9291 0.2 16.7228 7 14.2071 50℃ 8.4991 0.125 30.9588 0.25 16.8429 8 15.4511 55℃ 8.3437 0.15 47.9219 0.3 19.2591 9 30.5490 60℃ 8.0187 4. Conclusion In this paper, Co-Mo coating was prepared on the copper substrate by electrodeposition. The influence of different process parameters on the kinetics of deposition of alloy and structure, morphology, composition and mechanical properties of coating was studied. The conclusions are as follows: By studying the effects of different factors on the structure, composition, morphology and properties of the coating, it is determined that the optimum process conditions for electrodeposition of Co-Mo coating are as follows: the concentration of Na 2 MoO 4 is 0.05mol/L, the concentration of C 6 H 5 Na 3 O 7 is 0.15mol/L, the pH of the plating solution is 7 and the temperature is 50℃. Under these conditions, the coating is an amorphous alloy with dense nodular morphology, the content of Mo is 39.56% and the microhardness is 503HV. Through the study of electrodeposition behavior of Co-Mo alloy under different factors, it is found that smaller concentration of Na 2 MoO 4 , appropriate concentration of C 6 H 5 Na 3 O 7 , smaller plating solution pH and higher temperature made the reduction potential move forward, the exchange current increase and the charge transfer impedance decrease. Declarations Acknowledgements This work was supported by National Key R&D Program of China (2018YFC1901700), National Natural Science Foundation of China (52025042, 51621003). Author contribution statements Ya Tian wrote the main manuscript text, Liwen Ma and Xiaoli Xi revised the language ,overall structure of the manuscript and provided research funding, and Zuoren Nie provided research funding. Data Availability Statement The data used to support the findings of this study are included within the article. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-1437984","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":92364578,"identity":"6f9c1594-cc0f-4087-8d0a-9e33c148745a","order_by":0,"name":"Ya Tian","email":"","orcid":"","institution":"Beijing University of Technology","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Ya","middleName":"","lastName":"Tian","suffix":""},{"id":92364579,"identity":"9e390a3e-6f64-4c00-a860-d38cd78d9ea2","order_by":1,"name":"Liwen Ma","email":"","orcid":"","institution":"Beijing University of Technology","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Liwen","middleName":"","lastName":"Ma","suffix":""},{"id":92364580,"identity":"54a8b4dd-3c58-41ff-ad06-f037c48dd1e5","order_by":2,"name":"Xiaoli Xi","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA3klEQVRIie3RsQrCMBCA4ZNAXCJdT9R3iATUoeirVASfoWNBcBJnxZfoI5x06FJwLejg1MlBNxfRpC5OMaNg/i2QL8cRAJ/vF2MABDASAUJkzo3EkaBobzQhJ/IOQZYAbkTmok/3GLvqmFSdK4S9lFh1tpH2gkf7VYFicKI5EsxVSnwobSRgjKi11KSMDMmmKQmONsJZI9k/NFGbmjy/EzMlM1Mk1oS+E7NL1tW74Ilmo0LO1DbjAyuRh0LdLnE4CXaraRnH4946X1RW8pGI9AtQf65rTXK/6/P5fH/VC3hkRznBt3IBAAAAAElFTkSuQmCC","orcid":"","institution":"Beijing University of Technology","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Xiaoli","middleName":"","lastName":"Xi","suffix":""},{"id":92364581,"identity":"932ece84-bf06-44ca-8da9-fc606463b053","order_by":3,"name":"Zuoren Nie","email":"","orcid":"","institution":"Beijing University of Technology","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Zuoren","middleName":"","lastName":"Nie","suffix":""}],"badges":[],"createdAt":"2022-03-10 10:29:14","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-1437984/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-1437984/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.3390/coatings12060739","type":"published","date":"2022-05-27T12:18:48+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":19581702,"identity":"0314e4d2-52fc-4408-8b59-5507c7116a65","added_by":"auto","created_at":"2022-03-24 18:37:19","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":163373,"visible":true,"origin":"","legend":"\u003cp\u003e(a) XRD of Co-Mo coatings under different concentrations of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e;(b) The effect of the concentration of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e on the composition and current efficiency of the Co-Mo coating\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-1437984/v1/0cf7befdb370f1dc74cec6ad.png"},{"id":19581744,"identity":"56a0a08f-0c97-4108-9689-8491d2bd588d","added_by":"auto","created_at":"2022-03-24 18:37:53","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":217107,"visible":true,"origin":"","legend":"\u003cp\u003eSEM of Co-Mo coatings under different concentrations of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e (a) 0.05 mol/L; (b) 0.075 mol/L;(c) 0.1 mol/L;(d) 0.125 mol/L\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-1437984/v1/e5b6689da79e5d4877406de7.png"},{"id":19581729,"identity":"951f989d-bf2c-4c13-bb7b-f52964f7819b","added_by":"auto","created_at":"2022-03-24 18:37:31","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":47934,"visible":true,"origin":"","legend":"\u003cp\u003eThe microhardness of Co-Mo coatings with different concentrations of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-1437984/v1/6e2e4b050352108e67231a15.png"},{"id":19581901,"identity":"f0ade7d6-7a23-4c5e-9568-0694a2361a97","added_by":"auto","created_at":"2022-03-24 18:41:36","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":225315,"visible":true,"origin":"","legend":"\u003cp\u003e(a) XRD of Co-Mo coatings under different concentrations of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e;(b) The effect of the concentration of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e on the composition and current efficiency of the Co-Mo coatings\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-1437984/v1/ef8bc38f2e4c19aeb42ab4fe.png"},{"id":19581742,"identity":"cd63364e-546c-44ed-b233-0867af45ada9","added_by":"auto","created_at":"2022-03-24 18:37:51","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":207972,"visible":true,"origin":"","legend":"\u003cp\u003eSEM of Co-Mo coatings under different concentrations of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e (a) 0.1 mol/L; (b) 0.15mol/L;(c) 0.2mol/L;(d) 0.25mol/L\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-1437984/v1/76520238bc166412d21cf814.png"},{"id":19581746,"identity":"2c1d5353-29ec-48ff-80da-98ff653a9031","added_by":"auto","created_at":"2022-03-24 18:38:15","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":47905,"visible":true,"origin":"","legend":"\u003cp\u003eThe microhardness of Co-Mo coatings with different concentrations of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-1437984/v1/ecd39b345cdca6030a2cba03.png"},{"id":19581745,"identity":"776c5c83-944d-4a53-b4b6-7c1227c88bf1","added_by":"auto","created_at":"2022-03-24 18:37:53","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":224773,"visible":true,"origin":"","legend":"\u003cp\u003e(a) XRD of Co-Mo coatings under different pH;(b) The effect of pH on the composition and current efficiency of the Co-Mo coatings\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-1437984/v1/e59499e90773cd72bc4a61c9.png"},{"id":19581733,"identity":"7ef31836-e2a1-4945-b77a-a9409c9db182","added_by":"auto","created_at":"2022-03-24 18:37:35","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":153595,"visible":true,"origin":"","legend":"\u003cp\u003eSEM of Co-Mo coatings under different pH (a) pH=6; (b) pH=7;(c) pH=8;(d) pH=9\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"8.png","url":"https://assets-eu.researchsquare.com/files/rs-1437984/v1/37f3720c0cfed1a7770f0a53.png"},{"id":19581732,"identity":"ec7f58ce-e8a8-4883-98d3-acb91bcf2f46","added_by":"auto","created_at":"2022-03-24 18:37:34","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":44072,"visible":true,"origin":"","legend":"\u003cp\u003eThe microhardness of Co-Mo coatings under different pH\u003c/p\u003e","description":"","filename":"9.png","url":"https://assets-eu.researchsquare.com/files/rs-1437984/v1/046155173d744cf5ad7b7272.png"},{"id":19581713,"identity":"f1a607e4-9630-42b4-b215-51ea418e94da","added_by":"auto","created_at":"2022-03-24 18:37:24","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":217185,"visible":true,"origin":"","legend":"\u003cp\u003e(a) XRD of Co-Mo coatings under different temperature;(b) The effect of temperature on the composition and current efficiency of the Co-Mo coatings\u003c/p\u003e","description":"","filename":"10.png","url":"https://assets-eu.researchsquare.com/files/rs-1437984/v1/f811d1abea8e48f9ae079ed9.png"},{"id":19581709,"identity":"3fb66b46-a1fa-4ebf-990c-359ee9726243","added_by":"auto","created_at":"2022-03-24 18:37:22","extension":"png","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":171653,"visible":true,"origin":"","legend":"\u003cp\u003eSEM of Co-Mo coatings under different temperature (a) 40℃; (b) 45℃;(c) 50℃;(d) 55℃\u003c/p\u003e","description":"","filename":"11.png","url":"https://assets-eu.researchsquare.com/files/rs-1437984/v1/4e585edab4a00ab9acc638dd.png"},{"id":19581717,"identity":"38902736-0a9e-4050-b04e-ff8e91b3702d","added_by":"auto","created_at":"2022-03-24 18:37:26","extension":"png","order_by":12,"title":"Figure 12","display":"","copyAsset":false,"role":"figure","size":51453,"visible":true,"origin":"","legend":"\u003cp\u003eThe microhardness of Co-Mo coatings under different temperature\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"12.png","url":"https://assets-eu.researchsquare.com/files/rs-1437984/v1/58a38a55dc9dc512919a8d0e.png"},{"id":19581698,"identity":"d7da17f5-52e8-46b0-a73b-b7c1b00c7661","added_by":"auto","created_at":"2022-03-24 18:37:17","extension":"png","order_by":13,"title":"Figure 13","display":"","copyAsset":false,"role":"figure","size":133076,"visible":true,"origin":"","legend":"\u003cp\u003eXPS spectra of Co-Mo coating (a)full spectrum of elements, (b) Co2p, (c) O1s, (d) Mo3d\u0026nbsp;\u003c/p\u003e","description":"","filename":"13.png","url":"https://assets-eu.researchsquare.com/files/rs-1437984/v1/ce984d85ca94365912929b2f.png"},{"id":19581752,"identity":"c0adfb86-fe60-4530-9059-c18a71bd1909","added_by":"auto","created_at":"2022-03-24 18:38:55","extension":"png","order_by":14,"title":"Figure 14","display":"","copyAsset":false,"role":"figure","size":257768,"visible":true,"origin":"","legend":"\u003cp\u003eSEM (a), element distribution (a-1)-(a-2) and EDS spectrum (b) of Co-Mo coating\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"14.png","url":"https://assets-eu.researchsquare.com/files/rs-1437984/v1/a65d95eae0dcaecb605115f1.png"},{"id":19581711,"identity":"769f9d26-9686-439d-a3ef-83c7a6dbfd98","added_by":"auto","created_at":"2022-03-24 18:37:23","extension":"png","order_by":15,"title":"Figure 15","display":"","copyAsset":false,"role":"figure","size":166513,"visible":true,"origin":"","legend":"\u003cp\u003eCV curves obtained on glassy carbon electrode in the bath with different(a) concentration of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e ;(b) concentration of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e ;(c) pH;(d) temperature\u003c/p\u003e","description":"","filename":"15.png","url":"https://assets-eu.researchsquare.com/files/rs-1437984/v1/3db95e0d06e4b6f30acaa1a8.png"},{"id":19581731,"identity":"29b35ebc-cada-42ca-bf94-8b4593ca6956","added_by":"auto","created_at":"2022-03-24 18:37:32","extension":"png","order_by":16,"title":"Figure 16","display":"","copyAsset":false,"role":"figure","size":154083,"visible":true,"origin":"","legend":"\u003cp\u003eLSV curves obtained on glassy carbon electrode in the bath with different(a) concentration of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e ;(b) concentration of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e ;(c) pH;(d) temperature\u003c/p\u003e","description":"","filename":"16.png","url":"https://assets-eu.researchsquare.com/files/rs-1437984/v1/0ac1864deb99f89bd1daf18d.png"},{"id":19581734,"identity":"cc72d32f-7c04-4287-86f0-5c649455ba51","added_by":"auto","created_at":"2022-03-24 18:37:35","extension":"png","order_by":17,"title":"Figure 17","display":"","copyAsset":false,"role":"figure","size":252040,"visible":true,"origin":"","legend":"\u003cp\u003eNyquist plots at -1.2 V potential in the bath with different (a) concentration of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e ;(b) concentration of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e ;(c) pH;(d) temperature;(e) equivalent circuit\u003c/p\u003e","description":"","filename":"17.png","url":"https://assets-eu.researchsquare.com/files/rs-1437984/v1/caaddf0cba449e9a56ce0d65.png"},{"id":61412794,"identity":"8be09b7d-43d7-452e-8718-8fa9ed7d3f96","added_by":"auto","created_at":"2024-07-30 12:18:55","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3295168,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-1437984/v1/5c818b22-737e-4841-9f27-360d7bf46583.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Preparation and electrochemical behavior of amorphous Co-Mo coating with high content of Mo","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eAlloy materials have been widely used due to their good mechanical properties. The traditional method of preparing alloy materials is mainly powder metallurgy, but the electrodeposition can be used to prepare alloy coatings on the substrate in a salt solution to improve the property of the substrate materials.\u003c/p\u003e \u003cp\u003eCurrently, the more widely used alloy coatings mainly include Ni-Co alloy, Ni-W alloy \u003csup\u003e[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]\u003c/sup\u003e, Co-W alloy \u003csup\u003e[\u003cspan additionalcitationids=\"CR4\" citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]\u003c/sup\u003e, Ni-Mo alloy \u003csup\u003e[\u003cspan additionalcitationids=\"CR7 CR8\" citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]\u003c/sup\u003e, Co-Mo alloy \u003csup\u003e[\u003cspan additionalcitationids=\"CR11\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]\u003c/sup\u003e, Ni-Co-Mo alloy \u003csup\u003e[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]\u003c/sup\u003e and other iron group element alloys\u003csup\u003e[\u003cspan additionalcitationids=\"CR15 CR16\" citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]\u003c/sup\u003e. Among them, the content of W \u003csup\u003e[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]\u003c/sup\u003e and Mo \u003csup\u003e[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]\u003c/sup\u003e is critical to the performance of the coating. Due to its good mechanical properties and catalytic hydrogen evolution performance, the molybdenum-containing coating have been used as wear-resistant coating and catalytic hydrogen evolution material in the field of metal protection and water electrolysis. N. P. Wasekar et al. \u003csup\u003e[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/sup\u003e prepared a Ni-Mo alloy coating and found that the increase in molybdenum content improved the microhardness, wear resistance and corrosion resistance of the coating. C. Y. Lee et al.\u003csup\u003e[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]\u003c/sup\u003e studied the corrosion behavior of Ni-Mo coating in NaCl solution, found that the corrosion film was not passivated under high overpotential, and the synergistic effect of wear and corrosion on the weight loss of this Ni-Mo alloy coating was less obvious than that of other Ni alloy coatings. Some researchers have studied the principle of electrodeposition and electrochemical behavior of molybdenum-containing alloys. Elvira Go\u0026acute;mezet al.\u003csup\u003e[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]\u003c/sup\u003e used voltammetry to study the influence of process parameters on co-deposition of cobalt and molybdenum. At present, most of the Co-Mo coatings show crystalline structure, while the amorphous Co-Mo coating with high Mo content possess better property. And the relationship between the electrochemical behavior of the alloy and the structure, composition, morphology and property of the coating has not been deeply studied. Therefore, in this paper, the amorphous Co-Mo coating with high Mo content was prepared by optimization of process electrodeposition and the effect of different process parameters on the electrochemical behavior, structure, morphology, composition and property of coating was studied.\u003c/p\u003e"},{"header":"2. Experimental","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Coating preparation\u003c/h2\u003e \u003cp\u003eThe Co-Mo coating was prepared by electrodeposition in a citrate bath. The composition of the bath and process parameters are shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. All reagents are analytically pure, using anionic surfactant C\u003csub\u003e12\u003c/sub\u003eH\u003csub\u003e25\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003eN as the dispersant. Use dilute sulfuric acid and sodium hydroxide solution to adjust the pH of the solution. Electrodeposition was carried out in a 200 mL beaker. The anode of the double graphite plate was inserted into the electroplating solution in parallel, and the copper sheet was used as the cathode, suspended in the middle of the double graphite plate. The substrate is pretreated before deposition, using 600#, 800#, 2000# sandpaper for mechanical polishing, and 6\u0026micro;m, 3\u0026micro;m polishing liquid for polishing. Then use sodium hydroxide for chemical degreasing, dilute sulfuric acid for activation, and use alcohol to clean in an ultrasonic cleaning machine, finally wash with distilled water and dry.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eBath composition and electroplating parameters for deposition of coatings.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eBath composition\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003eElectrodeposition conditions\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCoSO\u003csub\u003e4\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.1mol/L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003epH\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6\u0026thinsp;~\u0026thinsp;9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNa\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.05\u0026thinsp;~\u0026thinsp;0.15mol/L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eTemperature\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e40\u0026thinsp;~\u0026thinsp;60℃\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNa\u003csub\u003e3\u003c/sub\u003eC\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.1\u0026thinsp;~\u0026thinsp;0.3mol/L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eCurrent density\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1A\u0026middot;dm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eC\u003csub\u003e12\u003c/sub\u003eH\u003csub\u003e25\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003eNa\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1g/L\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eDeposition time\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2h\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThe current efficiency is calculated according to Eq.\u0026nbsp;(\u003cspan refid=\"Equ1\" class=\"InternalRef\"\u003e1\u003c/span\u003e):\u003cdiv id=\"Equ1\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ1\" name=\"EquationSource\"\u003e\n$${\\eta }=（\\frac{\\text{{\\rm M}}\\times {\\text{f}}_{\\text{C}\\text{o}}}{{\\text{C}}_{\\text{C}\\text{o}}\\times \\text{I}\\times \\text{t}}+\\frac{\\text{{\\rm M}}\\times {\\text{f}}_{\\text{M}\\text{o}}}{{\\text{C}}_{\\text{M}\\text{o}}\\times \\text{I}\\times \\text{t}})\\times 100\\text{\\%}$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e1\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eWhere, M is the quality of the obtained alloy coating, f is the mass fraction of each metal in the coating, C is the electrochemical equivalent of each metal in the coating, I is the current intensity, and t is the electrodeposition time.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Coating characterization\u003c/h2\u003e \u003cp\u003eThe surface morphology of the coating was characterized by scanning electron microscope (SEM-2100) and the composition of the coating was studied using an energy dispersive X-ray spectrometer (EDS) coupled with SEM. The structure was analyzed by X-ray diffraction method (XRD-7000) under copper Kα1 radiation, and the measurement was carried out in the range of 2θ from 10\u0026deg; to 90\u0026deg;.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3 Coating performance test\u003c/h2\u003e \u003cp\u003eThe Microhardness of the coating was examined by HXD-100TMC/LCD micro-hardness tester. The applied force is 0.05mm/s, the applied load is 100g, and the holding time is 10s. Each sample was tested for the hardness value of 10 points and find the average.\u003c/p\u003e \u003ch2\u003e2.4 Electrochemical behavior test\u003c/h2\u003e \u003cp\u003eA three-electrode system was used for electrochemical testing in a 200ml beaker containing electroplating solution. The glassy carbon electrode and copper electrode were used as the working electrode, the platinum electrode was used as the auxiliary electrode, and the saturated calomel electrode was used as the reference electrode. The cyclic voltammetry(CV) was performed at a scan rate of 50mV/s within the potential range of -1.2V~-0.5V, the linear scan voltammetry(LSV) was performed at a scan rate of 50mV/s within the potential range of -1.2V\u0026thinsp;~\u0026thinsp;0V, and the electrochemical impedance spectroscopy(EIS) was performed in the range of 0.1 Hz-10k Hz with the potential of -1.2V.\u003c/p\u003e"},{"header":"3 Results And Discussion","content":"\u003ch2\u003e3.1 The structure, composition, morphology and property of Co-Mo coating\u003c/h2\u003e\n\u003ch2\u003e3.1.1 Effect of the concentration of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e\u003c/h2\u003e\n\u003cp\u003eThe XRD spectra of the Co-Mo coatings at different concentrations of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e are shown in Fig. 1(a). The XRD spectra of the coatings with different concentrations of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e showed a broad diffraction peak around 2\u0026theta;\u0026thinsp;=\u0026thinsp;43\u0026deg;, indicating that the Co-Mo coating is an alloy with an amorphous structure. The XRD spectra of the coatings prepared with the concentration of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e at 0.075 mol/L, 0.1 mol/L, 0.125 mol/L and 0.15 mol/L show the diffraction peak of copper at 2\u0026theta;\u0026thinsp;=\u0026thinsp;50\u0026deg; and 2\u0026theta;\u0026thinsp;=\u0026thinsp;74\u0026deg;, and a less obvious broadened diffraction peak is shown near 2\u0026theta;\u0026thinsp;=\u0026thinsp;43\u0026deg;. Combined with electrochemical test of different concentrations of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e, it was shown that as the concentration of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e increases, the deposition of alloy becomes more and more difficult, so the coating becomes thin, causing X-rays to hit the copper substrate.\u003c/p\u003e\n\u003cp\u003eFigure\u0026nbsp;1(b) shows the influence of the concentration of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e in the plating solution on the composition and current efficiency of the Co-Mo coatings. As the concentration of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e increases, the mass fraction of molybdenum in the coating shows a trend of first decreasing and then increasing. When the concentration of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e in the plating solution is 0.05mol/L, the content of molybdenum reaches the maximum value of 37.25%. It is reported that the greater the concentration of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e in the plating solution in a certain range, the higher the content of molybdenum in the coating. However, the electrochemical test results of different sodium molybdate concentrations shows that as the concentration of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e increases, the exchange current density \u003cem\u003ei\u003c/em\u003e\u003csub\u003e0\u003c/sub\u003e decreases, the charge transfer resistance \u003cem\u003eRct\u003c/em\u003e increases, which is conducive to the separate deposition of cobalt and hinders the co-deposition of cobalt and molybdenum. At the same time, as the concentration of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e increases, the thickness of the coating becomes thinner, resulting in the determination of the mass fraction of coating components, the copper matrix also occupies a certain mass fraction.\u003c/p\u003e\n\u003cp\u003eAs the concentration of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e in the plating solution increases, the current efficiency decreases. This is because as the concentration of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e increases, the deposition of alloy becomes difficult and the coating quality decreases. According to the Eq. (2\u0026thinsp;\u0026minus;\u0026thinsp;1), the current efficiency decreases.\u003c/p\u003e\n\u003cp\u003eThe surface morphology of the Co-Mo coating under different concentrations of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e is shown in Fig. 2. When the concentration of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e is 0.05 mol/L, the Co-Mo coating has the characteristics of the surface morphology of nodular shape, the surface is flat and smooth, and the crystal grains are small and uniform. This is due to the higher content of molybdenum in the coating. When the concentration of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e increases, the surface quality of the coating is reduced, the surface becomes uneven, and the crystal grains become coarse.\u003c/p\u003e\n\u003cp\u003eFigure\u0026nbsp;3 shows the comparison of the microhardness of the Co-Mo coating with different concentrations of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e. As the concentration of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e in the plating solution increases, the microhardness of the Co-Mo coating is reduced. When the concentration of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e is 0.075 mol/L, 0.1 mol/L, 0.125 mol/L and 0.15 mol/L, The microhardness of Co-Mo coating are 289.486HV、268.462 HV、240.938 HV、207.722 HV. When the concentration of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e is 0.05 mol/L, the microhardness of the Co-Mo coating reaches the maximum value of 331HV.\u003c/p\u003e\n\u003cp\u003eFrom the perspective of the structure of coating, the coating is an amorphous alloy, indicating that molybdenum enters the cobalt lattice, causing lattice distortion, which hinders the movement of dislocations and improves the microhardness of the coating. Therefore, the higher the content of molybdenum in the coating, the higher the microhardness. Moreover, as the concentration of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e increases, the thickness of the coating decreases. During the microhardness test, the diamond probe may release the copper matrix. The microhardness of copper is about 200HV, which makes the microhardness of the coating low.\u003c/p\u003e\n\u003ch2\u003e3.1.2 Effect of the concentration of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e\u003c/h2\u003e\n\u003cp\u003eThe XRD spectra of the Co-Mo coatings at different concentrations of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e are shown in Fig. 4(a). The XRD spectra of the coatings with different concentrations of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e showed a broad diffraction peak around 2\u0026theta;\u0026thinsp;=\u0026thinsp;43\u0026deg;. The XRD spectra of the coatings prepared with the concentration of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e at 0.2 mol/L, 0.25 mol/L and 0.3 mol/L show the diffraction peak of copper at 2\u0026theta;\u0026thinsp;=\u0026thinsp;50\u0026deg; and 2\u0026theta;\u0026thinsp;=\u0026thinsp;74\u0026deg;, and a less obvious broadened diffraction peak is shown near 2\u0026theta;\u0026thinsp;=\u0026thinsp;43\u0026deg;. Combined with electrochemical test of different s concentrations of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e, it was shown that when the concentration of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e is too high, the deposition of alloy becomes difficult, so the coating becomes thin, causing X-rays to hit the copper substrate.\u003c/p\u003e\n\u003cp\u003eFigure\u0026nbsp;4(b) shows the influence of the concentration of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e in the plating solution on the composition and current efficiency of the Co-Mo coatings. As the concentration of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e increases, the mass fraction of molybdenum in the coating shows a trend of first increasing and then decreasing. When the concentration of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e in the plating solution is 0.15mol/L, the content of molybdenum reaches the maximum value of 37.25%. The deposition of molybdenum mainly depends on the formation of cobalt-molybdenum complex ions. Combined with the electrochemical test results, when the concentration of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e in the solution is too low, the optimal concentration for forming complex ions cannot be achieved, which is not conducive to the deposition of molybdenum. When the concentration of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e increases to 0.15 mol/L, the exchange current density reaches the maximum value and the charge transfer resistance reaches the minimum value. At this time, the deposition of alloy is easier, and the content of molybdenum in the coating reaches the maximum value. With the further increase of the C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e concentration, excessive ions hinder the movement of complex ions to the cathode, the exchange current density begins to decrease, the charge transfer resistance begins to increase, alloy deposition becomes difficult, and the molybdenum content in the coating decreases.\u003c/p\u003e\n\u003cp\u003eAs the concentration of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e in the plating solution increases, the current efficiency increases first and then decreases. This is because as the concentration of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e increases, the deposition of alloy becomes easy and the coating quality increases, according to the Eq. (2\u0026thinsp;\u0026minus;\u0026thinsp;1), the current efficiency increases. However, as the concentration of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e further increases, the deposition of the alloy is hindered, and the quality of the coating decreases. According to the Eq. (2\u0026thinsp;\u0026minus;\u0026thinsp;1), the current efficiency decreases.\u003c/p\u003e\n\u003cp\u003eThe surface morphology of the Co-Mo coating under different concentrations of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e is shown in Fig. 5. When the concentration of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e is 0.1 mol/L, the Co-Mo coating has the characteristics of the surface morphology of irregular polygonal flakes. When the concentration of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e is 0.15 mol/L, the surface is flat and smooth, and the crystal grains are small and uniform. This is due to the higher content of molybdenum in the coating. When the concentration of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e continue to increase, the surface becomes uneven, and the crystal grains become coarse.\u003c/p\u003e\n\u003cp\u003eFigure\u0026nbsp;6 shows the comparison of the microhardness of the Co-Mo coating with different concentrations of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e. As the concentration of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e in the plating solution increases, the microhardness of the Co-Mo coating increases first and then decreases. When the concentration of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e is 0.1mol/L, 0.2 mol/L, 0.25mol/L and 0.3mol/L, the microhardness of Co-Mo coating is 314HV, 284.4HV, 270.2HV and 251.6HV, respectively. When the concentration of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e is 0.15 mol/L, the microhardness of the Co-Mo coating reaches the maximum value of 331HV. As the concentration of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e increases, the content of molybdenum in the coating first increases and then decreases, and the degree of lattice distortion caused first increases and then decreases. Therefore, the microhardness of the coating first increases and then decreases.\u003c/p\u003e\n\u003ch2\u003e3.1.3 Effect of the pH value\u003c/h2\u003e\n\u003cp\u003eThe XRD spectra of the Co-Mo coatings under different pH are shown in Fig.\u0026nbsp;7(a). The XRD spectra of the coatings under different temperature showed a broad diffraction peak around 2\u0026theta;\u0026thinsp;=\u0026thinsp;43\u0026deg;. The XRD spectra of the coatings prepared with the pH at 6 and 9 show the diffraction peak of copper at 2\u0026theta;\u0026thinsp;=\u0026thinsp;50\u0026deg; and 2\u0026theta;\u0026thinsp;=\u0026thinsp;74\u0026deg;, and a less obvious broadened diffraction peak is shown near 2\u0026theta;\u0026thinsp;=\u0026thinsp;43\u0026deg;. Combined with electrochemical test of different temperature, it was shown that as the pH rises, the deposition of alloys becomes more difficult, but when the pH is 6, the alloy deposition rate is too fast, and the hydrogen evolution reaction is violent due to the high concentration of H\u003csup\u003e+\u003c/sup\u003e in the electroplating solution, causing the coating surface to fall off causing the coating surface to peel off, which makes the coating thinner causing X-rays to hit the copper substrate.\u003c/p\u003e\n\u003cp\u003eFigure\u0026nbsp;7(b) shows the influence of the pH on the composition and current efficiency of the Co-Mo coatings. As the pH increases, the mass fraction of molybdenum in the coating shows a trend of decreasing. When the pH is 6, the content of molybdenum reaches the maximum value of 38.98%. Combined with the electrochemical test results, as the pH increases, the exchange current density decreases, and the charge transfer resistance increases, which makes the deposition of alloy more difficult, so the content of molybdenum in the coating decreases.\u003c/p\u003e\n\u003cp\u003eAs the pH increases, the current efficiency increases first and then decreases. When the pH is 7, the current efficiency reaches the maximum value. The low current efficiency is due to the high content of molybdenum. The deposition of MoO\u003csub\u003e4\u003c/sub\u003e\u003csup\u003e2\u0026minus;\u003c/sup\u003e is not a one-step reduction to Mo. The first stage is the reduction of MoO\u003csub\u003e4\u003c/sub\u003e\u003csup\u003e2\u0026minus;\u003c/sup\u003e to low-valent molybdenum oxides, such as MoO\u003csub\u003e2\u003c/sub\u003e, under the action of CoCit\u003csup\u003e\u0026minus;\u003c/sup\u003e. At this stage, there is a hydrogen evolution reaction, so this leads to a decrease in current efficiency\u003csup\u003e[22]\u003c/sup\u003e. Therefore, when the pH is 6, the current efficiency is low. However, when the pH is too high, the deposition quality is reduced, resulting in a decrease in current efficiency.\u003c/p\u003e\n\u003cp\u003eThe surface morphology of the Co-Mo coating under different pH is shown in Fig. 8. As the pH rises, the surface of the coating becomes smoother and the crystal grains are smaller. When the pH is 8 and 9, the Co-Mo coating has the characteristics of the surface morphology of irregular polygonal flakes. This is due to the lower content of molybdenum in the coating.\u003c/p\u003e\n\u003cp\u003eFigure 9 shows the comparison of the microhardness of the Co-Mo coating under different pH. As the pH increases, the microhardness of the Co-Mo coating increases first and then decreases. When the pH is 6, 8 and 9, the microhardness of Co-Mo coating are 276 HV、269.46 HV、245.93 HV. When the pH is 7, the microhardness of the Co-Mo coating reaches the maximum value of 331HV. The higher the content of molybdenum in the coating, the greater the hardness of the coating. When the pH is 6, although the content of molybdenum in the coating is high, the surface of the coating falls off, causing the diamond probe to contact the copper substrate during the microhardness test, which makes the microhardness of the coating lower.\u003c/p\u003e\n\u003ch2\u003e3.1.4 Effect of the temperature\u003c/h2\u003e\n\u003cp\u003eThe XRD spectra of the Co-Mo coatings under different temperature are shown in Fig. 10(a). The XRD spectra of the coatings under different temperature showed a broad diffraction peak around 2\u0026theta;\u0026thinsp;=\u0026thinsp;43\u0026deg;. The XRD spectra of the coatings prepared with the temperature at 40℃, 55℃and 60℃ show the diffraction peak of copper at 2\u0026theta;\u0026thinsp;=\u0026thinsp;50\u0026deg; and 2\u0026theta;\u0026thinsp;=\u0026thinsp;74\u0026deg;, and a less obvious broadened diffraction peak is shown near 2\u0026theta;\u0026thinsp;=\u0026thinsp;43\u0026deg;. Combined with electrochemical test of different temperature, it was shown that as the temperature rises, the deposition of the alloy becomes easier, but when the temperature is too high, the deposition rate is too fast, causing the coating surface to peel off, which makes the coating thinner causing X-rays to hit the copper substrate.\u003c/p\u003e\n\u003cp\u003eFigure\u0026nbsp;10(b) shows the influence of the temperature on the composition and current efficiency of the Co-Mo coatings. As the temperature increases, the mass fraction of molybdenum in the coating shows a trend of first increasing and then decreasing. When the temperature is 50℃, the content of molybdenum reaches the maximum value of 39.56%. The deposition of molybdenum mainly depends on the formation of cobalt-molybdenum complex ions. Combined with the electrochemical test results, as the temperature increases, the migration rate of complex ions to the cathode increases, the exchange current density increases, and the charge transfer resistance decreases, which makes the deposition of alloy easier, so the content of molybdenum in the coating increases. However, when the temperature is too high, it will affect the stability of the complex ions, which is not conducive to the deposition of molybdenum, resulting in a decrease in the content of molybdenum in the coating.\u003c/p\u003e\n\u003cp\u003eAs the temperature increases, the current efficiency increases first and then decreases. When the temperature is 50℃, the current efficiency reaches the maximum value of 63%. This is because as the temperature increases, the deposition of alloy becomes easy and the coating quality increases, according to the Eq.\u0026nbsp;(1), the current efficiency increases. However, as the temperature further increases, the deposition rate is too fast, causing the coating surface to fall off and reduce the quality, according to the Eq.\u0026nbsp;(2\u0026thinsp;\u0026minus;\u0026thinsp;1), the current efficiency decreases.\u003c/p\u003e\n\u003cp\u003eThe surface morphology of the Co-Mo coating under different temperature is shown in Fig. 11. When the temperature is 40℃, the Co-Mo coating has the characteristics of the surface morphology of irregular polygonal flakes. As the temperature rises, the surface of the coating becomes smoother and the crystal grains are smaller. This is due to the higher content of molybdenum in the coating. When the temperature is too high, the surface becomes uneven, and the crystal grains become coarse.\u003c/p\u003e\n\u003cp\u003eFigure 12 shows the comparison of the microhardness of the Co-Mo coating under different temperature. As the temperature increases, the microhardness of the Co-Mo coating increases first and then decreases. When the temperature is 40℃, 45℃, 55℃ and 60℃, the microhardness of Co-Mo coating are 320HV, 314HV, 397HV and 376HV. When the temperature is 50℃, the microhardness of the Co-Mo coating reaches the maximum value of 503HV. As the temperature increases, the content of molybdenum in the coating first increases and then decreases. The thickness of the coating also increases first and then decreases. Therefore, the microhardness of the coating first increases and then decreases.\u003c/p\u003e\n\u003ch2\u003e3.1.5 Characterization of coating surface elements\u003c/h2\u003e\n\u003cp\u003eXPS was used to test the composition and chemical valence state of the Co-Mo coating. XPS pattern of (a) full spectrum of elements, (b) Co2p, (c) O1s and (d) Mo3d of Co-Mo coating is shown in Fig.\u0026nbsp;13. As shown in Fig.\u0026nbsp;13 (a), the peaks of O, Co and Mo appear in the spectrum. As shown in Fig.\u0026nbsp;13 (b), the Co 2p1/2 XPS has two split peaks, belonging to Co (799.3 eV), Cobalt Oxides (804.1 eV). The Co 2p3/2 XPS has two split peaks, belonging to Co (779.1 eV), Cobalt Oxides (781.7 eV). Coating surface formed an oxide film when exposed to air. As shown in Fig.\u0026nbsp;8 (c), the O 1s XPS has one split peaks at 532.3 eV, which is related to the Er\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e and the metal oxide. As shown in Fig. 8 (d), the Mo 3d XPS has three split peaks, belonging to Mo\u003csup\u003e6+\u003c/sup\u003e (235.5 eV), Mo\u003csup\u003e3+\u003c/sup\u003e (228.9 eV and 232.3 eV). The existence of Mo\u003csup\u003e6+\u003c/sup\u003e is due to the oxidation of Mo to MoO\u003csub\u003e3\u003c/sub\u003e and the existence of Mo\u003csup\u003e3+\u003c/sup\u003e is due to the oxidation of Mo to Mo\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e.As shown in Fig. 14, it can be seen that the distribution of Co and Mo elements is very uniform. Figure 14(b) shows the EDS spectrum and the composition of the Co-Mo coating, the peaks of Co and Mo appear on the EDS pattern.\u003c/p\u003e\n\u003ch2\u003e3.2 The electrochemical behavior of the deposition of Co-Mo alloy\u003c/h2\u003e\n\u003ch2\u003e3.2.1 Deposition potential\u003c/h2\u003e\n\u003cp\u003eFigure\u0026nbsp;15(a) shows the cyclic voltammetry curves of cobalt-molybdenum plating solutions with different concentrations Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e on glassy carbon electrodes. When the concentration of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e is 0.05 mol/L, 0.075mol/L, 0.1 mol/L, 0.125mol/L and 0.15 mol/L, the reduction peak appears at -0.85V, -0.9V, -0.95V, -1V and \u0026minus;\u0026thinsp;1.05V during the negative scan, and the oxidation peak appears at -0.25V, -0.3V,-0.33V and \u0026minus;\u0026thinsp;0.35V during the positive scan. Figure 15(b) shows the cyclic voltammetry curves of cobalt-molybdenum plating solutions with different concentration of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e on glassy carbon electrodes. When the concentration of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e is 0.1 mol/L, 0.15 mol/L, 0.2mol/L, 0.25mol/L and 0.3mol/L, the reduction peak appears at -0.85V, -0.75V, -0.9V, -0.95V and \u0026minus;\u0026thinsp;1V during the negative scan, and the oxidation peak appears at -0.25V, -0.1V, -0.3V, -0.35V and \u0026minus;\u0026thinsp;0.38V during the positive scan. Figure 15(c) shows the cyclic voltammetry curves of cobalt-molybdenum baths with different pH on glassy carbon electrodes. When the pH is 5, 6, 7 and 8, the reduction peak appears at -0.75V, -0.8V, -0.9V and \u0026minus;\u0026thinsp;1V when scanning in the negative direction, and the oxidation peak appears at -0.15V, -0.25V, -0.3V and \u0026minus;\u0026thinsp;0.35V when scanning in the forward direction. When the pH is 9, there is almost no redox peak. Figure 15(d) shows the cyclic voltammetry curves of cobalt-molybdenum baths with different temperature on glassy carbon electrodes. When the temperature is 40℃, 45℃, 50℃, 55℃ and 60℃, the reduction peak appears at -0.89V, -0.87V, -0.85V, -0.84V and \u0026minus;\u0026thinsp;0.82V when scanning in the negative direction, and the oxidation peak appears at -0.25V, -0.26V, -0.27V, -0.29V and \u0026minus;\u0026thinsp;0.32V when scanning in the forward direction.\u003c/p\u003e\n\u003cp\u003eIt can be seen from the CV graph that as the concentration of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e increases, the deposition potential of the cobalt-molybdenum alloy moves in a negative direction. The reason for this trend is that when the concentration of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e increases, too much molybdate ions make the migration rate of complex ions slow, and the precipitation potential shifts in the negative direction; as the concentration of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e increases, the deposition potential of the cobalt-molybdenum alloy first shifts to a positive direction and then to a negative direction. The reason for this trend is that when the concentration of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e increases, the number of cobalt-molybdenum complex ions formed increases, which facilitates the deposition of cobalt-molybdenum complex ions, thereby shifting the precipitation potential to the positive direction. When the concentration of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e is high, the ionization equilibrium is destroyed, resulting in the pH of the plating solution; as the pH increases, the deposition potential of the cobalt-molybdenum alloy shifts in the negative direction. The reason for this trend is that when the pH value is high, Co(Ⅱ) exists in the form of CoCit\u003csup\u003e\u0026minus;\u003c/sup\u003e, and molybdenum exists in the form of MoO\u003csub\u003e4\u003c/sub\u003e\u003csup\u003e2\u0026minus;\u003c/sup\u003e; when the pH value is low, Co(Ⅱ) exists in the form of HCoCit, molybdenum exists in the form of HrMoO4Cit\u003csup\u003e[5\u0026minus;r] [11]\u003c/sup\u003e; as the temperature rises, the deposition potential of the cobalt-molybdenum alloy shifts in the positive direction. This is because as the temperature rises, the migration rate of ions increases, and the stability of complex ions is destroyed, so it is more conducive to the deposition of cobalt, and the deposition potential moves forward.\u003c/p\u003e\n\u003ch2\u003e3.2.2 Exchange current density\u003c/h2\u003e\n\u003cp\u003eThe exchange current density is an important kinetic parameter to evaluate the electrode reaction: The higher the exchange current density, the easier the electrode reaction. Therefore, the exchange current density \u003cem\u003ei\u003c/em\u003e\u003csub\u003e0\u003c/sub\u003e on the glassy carbon electrode in the bath was studied by LSV. The Butler-Volmer\u003csup\u003e[23, 24]\u003c/sup\u003e equation was applied at very low cathode overpotential, which can be simplified to Eq. (2), Take the logarithm of both sides of Eq. (2) to obtain Eq. (3).\u003c/p\u003e\n\u003cdiv id=\"Equ2\"\u003e\n \u003cdiv id=\"FileID_Equ2\" name=\"EquationSource\"\u003e$$i={i}_{0}\\left\\{-exp\\left[\\frac{-\\alpha nF}{RT}\\eta \\right]\\right\\}$$\u003c/div\u003e\n \u003cdiv\u003e2\u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Equ3\"\u003e\n \u003cdiv id=\"FileID_Equ3\" name=\"EquationSource\"\u003e$$\\text{l}\\text{o}\\text{g}\\left|i\\right|=\\text{l}\\text{o}\\text{g}\\left|{i}_{0}\\right|-\\frac{\\alpha nF}{RT}\\eta$$\u003c/div\u003e\n \u003cdiv\u003e3\u003c/div\u003e\n\u003c/div\u003e\n\u003cp\u003ewhere \u003cem\u003ei\u003c/em\u003e is the current density (mA\u0026middot;cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e), \u003cem\u003ei\u003c/em\u003e\u003csub\u003e0\u003c/sub\u003e is the exchange current density (mA\u0026middot;cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e), \u0026alpha; is the charge transfer coefficient in the cathode direction, \u003cem\u003eƞ\u003c/em\u003e is over-potential.\u003c/p\u003e\n\u003cp\u003eBased on the Eq. (3), it can be found that under a small overpotential, \u003cem\u003ei\u003c/em\u003e and \u003cem\u003eƞ\u003c/em\u003e are linearly related. When the overpotential exceeds \u0026minus;\u0026thinsp;0.1 V, the current contribution of anode polarization is negligible. Therefore, the value of \u003cem\u003ei\u003c/em\u003e\u003csub\u003e\u003cem\u003e0\u003c/em\u003e\u003c/sub\u003e can be measured by the slope of the \u003cem\u003ei\u003c/em\u003e-\u003cem\u003eƞ\u003c/em\u003e curve in a narrow potential range close to the equilibrium potential.\u003c/p\u003e\n\u003cp\u003eFigure 16 shows the LSV curve on glassy carbon electrode in the bath, where when \u003cem\u003eŋ\u003c/em\u003e is between \u0026minus;\u0026thinsp;0.15 V and \u0026minus;\u0026thinsp;0.1 V, the polarization curve presents a straight line.\u003c/p\u003e\n\u003cp\u003eTable 2 shows the value of exchange current density \u003cem\u003ei\u003c/em\u003e\u003csub\u003e0\u003c/sub\u003e on glassy carbon electrode in the bath, it can be found that as the concentration of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e increases, the exchange current density \u003cem\u003ei\u003c/em\u003e\u003csub\u003e0\u003c/sub\u003e decreases; as the concentration of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e increases, the exchange current density \u003cem\u003ei\u003c/em\u003e\u003csub\u003e0\u003c/sub\u003e increases first and decreases then, when the concentration of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e is 0.05mol/L, \u003cem\u003ei\u003c/em\u003e\u003csub\u003e0\u003c/sub\u003e reaches a maximum; as the pH increases, the exchange current density \u003cem\u003ei\u003c/em\u003e\u003csub\u003e0\u003c/sub\u003e decreases; as the temperature increases, the exchange current density \u003cem\u003ei\u003c/em\u003e\u003csub\u003e0\u003c/sub\u003e increases.\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"1\" id=\"Tab2\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv\u003eTable 2\u003c/div\u003e\n \u003cdiv\u003e\n \u003cp\u003eThe value of exchange current density \u003cem\u003ei\u003c/em\u003e\u003csub\u003e0\u003c/sub\u003e on glassy carbon electrode in the bath\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eC\u003csub\u003eNa2MoO4\u003c/sub\u003e\u003c/p\u003e\n \u003cp\u003e(mol/L)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003ei\u003c/em\u003e\u003csub\u003e\u003cem\u003e0\u003c/em\u003e\u003c/sub\u003e\u003c/p\u003e\n \u003cp\u003e(mA\u0026middot;cm\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eC\u003csub\u003eC6H5Na3O7\u003c/sub\u003e(mol/L)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003ei\u003c/em\u003e\u003csub\u003e\u003cem\u003e0\u003c/em\u003e\u003c/sub\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003epH\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003ei\u003c/em\u003e\u003csub\u003e\u003cem\u003e0\u003c/em\u003e\u003c/sub\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eTemperature\u003c/p\u003e\n \u003cp\u003e(℃)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003ei\u003c/em\u003e\u003csub\u003e\u003cem\u003e0\u003c/em\u003e\u003c/sub\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.05\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.0703\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.0661\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.1296\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.1975\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.075\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.0702\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.0703\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.0703\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.2306\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.0687\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.0523\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.0458\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.2413\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.125\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.0534\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.0313\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.0314\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e55\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.2452\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.0385\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.0150\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.0158\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.2458\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n\u003ch2\u003e3.2.3 Charge transfer impedance\u003c/h2\u003e\n\u003cp\u003eFigure\u0026nbsp;17 shows Nyquist plots at -1.2 V potential in the bath. It is observed that there is only one EIS spectrum composed of a semicircular arc, which indicates that the deposition of alloy is only controlled by charge transfer\u003csup\u003e[25]\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eAccording to the impedance results, Zview software was used to fit the equivalent circuit, and the result is shown as Fig. 17(e). In the circuit, \u003cem\u003eRs\u003c/em\u003e is the resistance of the solution, \u003cem\u003eRct\u003c/em\u003e is the charge transfer resistance, CPE is a constant phase element used to establish a more accurate fit.\u003c/p\u003e\n\u003cp\u003eAs shown in Table\u0026nbsp;3, as the concentration of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e increases, the charge transfer resistance \u003cem\u003eRct\u003c/em\u003e increases; as the concentration of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e increases, the charge transfer resistance \u003cem\u003eRct\u003c/em\u003e decreases first and then increases; as the pH increases, the charge transfer resistance \u003cem\u003eRct\u003c/em\u003e increase; as the temperature increases, the charge transfer resistance \u003cem\u003eRct\u003c/em\u003e decreases.\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"1\" id=\"Tab3\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv\u003eTable 3\u003c/div\u003e\n \u003cdiv\u003e\n \u003cp\u003eThe value of \u003cem\u003eRs\u003c/em\u003e and \u003cem\u003eRct\u003c/em\u003e on copper electrode in the bath\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eC\u003csub\u003eNa2MoO4\u003c/sub\u003e\u003c/p\u003e\n \u003cp\u003e(mol/L)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eRct\u003c/p\u003e\n \u003cp\u003e(ohms\u0026middot;cm\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eC\u003csub\u003eC6H5Na3O7\u003c/sub\u003e\u003c/p\u003e\n \u003cp\u003e(mol/L)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eRct\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003epH\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eRct\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003etemperature\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eRct\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.05\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e13.9000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e15.4158\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e11.0002\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e40℃\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e9.6225\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.075\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e20.5874\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e13.9000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e13.9000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e45℃\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e8.5698\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e23.9291\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e16.7228\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e14.2071\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e50℃\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e8.4991\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.125\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e30.9588\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e16.8429\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e15.4511\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e55℃\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e8.3437\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0.15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e47.9219\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e19.2591\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e30.5490\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e60℃\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e8.0187\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"},{"header":"4. Conclusion","content":"\u003cp\u003eIn this paper, Co-Mo coating was prepared on the copper substrate by electrodeposition. The influence of different process parameters on the kinetics of deposition of alloy and structure, morphology, composition and mechanical properties of coating was studied. The conclusions are as follows:\u003c/p\u003e\n\u003cp\u003eBy studying the effects of different factors on the structure, composition, morphology and properties of the coating, it is determined that the optimum process conditions for electrodeposition of Co-Mo coating are as follows: the concentration of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e is 0.05mol/L, the concentration of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e is 0.15mol/L, the pH of the plating solution is 7 and the temperature is 50℃. Under these conditions, the coating is an amorphous alloy with dense nodular morphology, the content of Mo is 39.56% and the microhardness is 503HV.\u003c/p\u003e\n\u003cp\u003eThrough the study of electrodeposition behavior of Co-Mo alloy under different factors, it is found that smaller concentration of Na\u003csub\u003e2\u003c/sub\u003eMoO\u003csub\u003e4\u003c/sub\u003e, appropriate concentration of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e, smaller plating solution pH and higher temperature made the reduction potential move forward, the exchange current increase and the charge transfer impedance decrease.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work was supported by National Key R\u0026amp;D Program of China\u0026nbsp;(2018YFC1901700),\u0026nbsp;National Natural Science Foundation of China (52025042, 51621003).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contribution statements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eYa Tian wrote the main manuscript text, Liwen Ma and Xiaoli Xi revised the language ,overall structure of the manuscript and provided research funding, and Zuoren Nie \u0026nbsp;provided research funding.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData Availability Statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe data used to support the findings of this study are included within the article.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDeclaration of interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eElias L.\u0026amp; Chitharanjan A. 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Acta 227,170\u0026ndash;179(2017). \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.electacta.2017.01.011\u003c/span\u003e\u003cspan address=\"10.1016/j.electacta.2017.01.011\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Electrodeposition, Amorphous Co-Mo coating, Microhardness, Electrochemical mechanism","lastPublishedDoi":"10.21203/rs.3.rs-1437984/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-1437984/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eAt present, alloy materials have been widely used as wear-resistant coatings due to good mechanical properties. In this paper, electrodeposition was used to prepare the Co-Mo coating. The electrochemical behavior of the deposition of alloy and the phase composition, morphology, composition and property of the coating have been studied. The study of process parameters found that when the concentration of Na\u003csub\u003e2\u003c/sub\u003eMo\u003csub\u003e4\u003c/sub\u003e is 0.05mol/L, the concentration of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e is 0.15mol/L, the pH of the solution is 7, and the temperature is 50℃, the content of Mo in Co-Mo coating is 39.56%, and the microhardness reaches the maximum value of 503HV. The study of electrochemical behavior found that when the concentration of Na\u003csub\u003e2\u003c/sub\u003eMo\u003csub\u003e4\u003c/sub\u003e is 0.05mol/L, the concentration of C\u003csub\u003e6\u003c/sub\u003eH\u003csub\u003e5\u003c/sub\u003eNa\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e is 0.15mol/L, the pH of the solution is 7 and the temperature is 50℃, the most positive deposition potential, maximum exchange current density and minimum charge transfer impedance were obtained, which explained why the best performance coating can be obtained under this condition.\u003c/p\u003e","manuscriptTitle":"Preparation and electrochemical behavior of amorphous Co-Mo coating with high content of Mo","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2022-03-24 15:27:35","doi":"10.21203/rs.3.rs-1437984/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"01c70138-9fb2-4eaf-89f2-6ed4b4156a00","owner":[],"postedDate":"March 24th, 2022","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2024-07-30T12:18:48+00:00","versionOfRecord":{"articleIdentity":"rs-1437984","link":"https://doi.org/10.3390/coatings12060739","journal":{"identity":"coatings","isVorOnly":true,"title":"Coatings"},"publishedOn":"2022-05-27 12:18:48","publishedOnDateReadable":"May 27th, 2022"},"versionCreatedAt":"2022-03-24 15:27:35","video":"","vorDoi":"10.3390/coatings12060739","vorDoiUrl":"https://doi.org/10.3390/coatings12060739","workflowStages":[]},"version":"v1","identity":"rs-1437984","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-1437984","identity":"rs-1437984","version":["v1"]},"buildId":"WrCJVZZCHTDjtuVLN7oU0","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}