Comparative Investigation on Thermally Sprayed Al2O3, Al2O3-13%(TiO2) and Al2O3-40%(TiO2) Composite Coatings from Room to 400 °C Temperature

Abstract The aim of this research is to study the comparative wear behaviour of pure Al2O3 with varying TiO2 content due to the high demand in the industry for high temperature applications such as the automotive industry (piston ring and liner), petrochemicals industry (pump sleeves) and textile industry tools which require the hard bearing surface, abrasion resistance and particle corrosion at the temperature of up to 400 °C. In the present study, three coatings of Al2O3, Al2O3-13%(TiO2) and Al2O3-40%(TiO2) composite coatings were deposited by the thermally flame spray process. The comparative wear behaviour of the Al2O3-TiO2 coatings has been studied under high temperature of up to 400°C using a high temperature tribometer at a constant load of 40N. Before the wear test, the mechanical properties of the coated samples such as microhardness and surface roughness were studied. The morphological analysis was determined by field emission scanning electron microscope, elemental dispersion spectroscopy and X-ray powder diffraction techniques. The results reveal that specific wear rate decreases with a rise in temperature for all the deposited coating except Al2O3 coating at 400°C. The friction coefficient of deposited three alumina based coatings is decreasing with the increasing temperature. The research reveals that the Al2O3-40%TiO2 coating has the highest wear resistance properties as well as a low coefficient of friction due to its low hardness and high adhesion properties. For Al2O3-40%TiO2 coating the measured values of specific wear rate varying from 0.034567*10-3 mm3/Nm to 0.014581*10-3 mm3/Nm and the average values of coefficient friction ranging from 0.7284 to 0.3901 as temperature varying from room temperature to 400°C. In the worn out surface of deposited coatings, brittle fracture and abrasive wear behaviour were observed from room temperature to 400°C.