Effect of Mn/Mg co-substitution on the phase composition, microstructure, and microwave dielectric properties of SrAl 2-x (Mn 0.5 Mg 0.5 ) x Si 2 O 8 ceramics

Effect of Mn/Mg co-substitution on the phase composition, microstructure, and microwave dielectric properties of SrAl 2-x (Mn 0.5 Mg 0.5 ) x Si 2 O 8 ceramics | 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 Research Article Effect of Mn/Mg co-substitution on the phase composition, microstructure, and microwave dielectric properties of SrAl 2-x (Mn 0.5 Mg 0.5 ) x Si 2 O 8 ceramics Jie Xu, Yang Lu, Heng Miao, Huangping Yang, Hongqing Zhou, Huifen Lu, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8681089/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 13 Apr, 2026 Read the published version in Journal of Materials Science: Materials in Electronics → Version 1 posted You are reading this latest preprint version Abstract SrAl 2−x (Mn 0.5 Mg 0.5 ) x Si 2 O 8 (x = 0–0.06) microwave dielectric ceramics were synthesized via a solid-state reaction route. The sintering behavior, phase composition, microstructure, and microwave dielectric properties were systematically investigated by X-ray diffraction (XRD) with Rietveld refinement and scanning electron microscopy/energy-dispersive spectroscopy (SEM/EDS), together with microwave dielectric measurements. XRD–Rietveld refinement confirms that a single-phase monoclinic SrAl 2 Si 2 O 8 solid solution is maintained for x ≤ 0.02, whereas a Sr 2 MgSi 2 O 7 secondary phase appears for x ≥ 0.03 and increases with substitution, indicating the solubility limit of Mn/Mg co-substitution. The introduction of Mn/Mg effectively lowers the optimum densification temperature from 1500°C (x = 0) to 1350°C (x = 0.06). The composition x = 0.02 sintered at 1400°C for 5 h exhibits the highest relative density (98.7%) and achieves ε r = 7.112, Q×f = 43569 GHz, and τ f = − 37.8 ppm/°C. When x > 0.02, secondary-phase precipitation and microstructural inhomogeneity (as evidenced by SEM/EDS) reduce densification and lead to degraded dielectric performance, with Q×f decreasing to 28800 GHz at x = 0.06. These results clarify the solid-solution window and provide a feasible compositional strategy for lowering firing temperature while maintaining low-permittivity and low-loss performance in SrAl 2 Si 2 O 8 -based microwave dielectrics. SrAl2Si2O8 Mn/Mg co-substitution solid solution secondary phase densification Full Text Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 13 Apr, 2026 Read the published version in Journal of Materials Science: Materials in Electronics → Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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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-8681089","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":588483088,"identity":"463d7043-ac6c-400f-87b0-509f0d9e4d44","order_by":0,"name":"Jie Xu","email":"","orcid":"","institution":"Nanjing Tech University","correspondingAuthor":false,"prefix":"","firstName":"Jie","middleName":"","lastName":"Xu","suffix":""},{"id":588483090,"identity":"f6cd036e-eb52-40ac-a3db-90e346e5c2e3","order_by":1,"name":"Yang Lu","email":"","orcid":"","institution":"Nanjing Tech University","correspondingAuthor":false,"prefix":"","firstName":"Yang","middleName":"","lastName":"Lu","suffix":""},{"id":588483092,"identity":"09a30ebb-6200-44a0-bd52-19036b94cad7","order_by":2,"name":"Heng Miao","email":"","orcid":"","institution":"Nanjing Tech University","correspondingAuthor":false,"prefix":"","firstName":"Heng","middleName":"","lastName":"Miao","suffix":""},{"id":588483096,"identity":"5b6091de-f65c-4748-babd-bd7ae49f08a3","order_by":3,"name":"Huangping Yang","email":"","orcid":"","institution":"Nanjing Tech University","correspondingAuthor":false,"prefix":"","firstName":"Huangping","middleName":"","lastName":"Yang","suffix":""},{"id":588483098,"identity":"0d495f09-4f90-435d-8d91-54526ade4d62","order_by":4,"name":"Hongqing 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Zhang","email":"","orcid":"","institution":"JCET Semiconductor (Suqian) Co., Ltd.,","correspondingAuthor":false,"prefix":"","firstName":"Bo","middleName":"","lastName":"Zhang","suffix":""}],"badges":[],"createdAt":"2026-01-23 16:23:20","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8681089/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8681089/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s10854-026-17149-4","type":"published","date":"2026-04-13T15:57:43+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":107350849,"identity":"69959514-5d3f-415a-8a07-baccd16c185f","added_by":"auto","created_at":"2026-04-20 16:05:52","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":734181,"visible":true,"origin":"","legend":"","description":"","filename":"EffectofMnMgcosubstitutiononthephasecompositionmicrostructureandmicrowavedielectricpropertiesofSrAl2xMn0.5Mg0.5xSi2O8ceramics.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8681089/v1_covered_fe3c509c-89ba-4657-8e1c-dde9e2f200a9.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Effect of Mn/Mg co-substitution on the phase composition, microstructure, and microwave dielectric properties of SrAl 2-x (Mn 0.5 Mg 0.5 ) x Si 2 O 8 ceramics","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"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":"SrAl2Si2O8, Mn/Mg co-substitution, solid solution, secondary phase, densification","lastPublishedDoi":"10.21203/rs.3.rs-8681089/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8681089/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eSrAl\u003csub\u003e2\u0026minus;x\u003c/sub\u003e(Mn\u003csub\u003e0.5\u003c/sub\u003eMg\u003csub\u003e0.5\u003c/sub\u003e)\u003csub\u003ex\u003c/sub\u003eSi\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e8\u003c/sub\u003e (x\u0026thinsp;=\u0026thinsp;0\u0026ndash;0.06) microwave dielectric ceramics were synthesized via a solid-state reaction route. The sintering behavior, phase composition, microstructure, and microwave dielectric properties were systematically investigated by X-ray diffraction (XRD) with Rietveld refinement and scanning electron microscopy/energy-dispersive spectroscopy (SEM/EDS), together with microwave dielectric measurements. XRD\u0026ndash;Rietveld refinement confirms that a single-phase monoclinic SrAl\u003csub\u003e2\u003c/sub\u003eSi\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e8\u003c/sub\u003e solid solution is maintained for x\u0026thinsp;\u0026le;\u0026thinsp;0.02, whereas a Sr\u003csub\u003e2\u003c/sub\u003eMgSi\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e secondary phase appears for x\u0026thinsp;\u0026ge;\u0026thinsp;0.03 and increases with substitution, indicating the solubility limit of Mn/Mg co-substitution. The introduction of Mn/Mg effectively lowers the optimum densification temperature from 1500\u0026deg;C (x\u0026thinsp;=\u0026thinsp;0) to 1350\u0026deg;C (x\u0026thinsp;=\u0026thinsp;0.06). The composition x\u0026thinsp;=\u0026thinsp;0.02 sintered at 1400\u0026deg;C for 5 h exhibits the highest relative density (98.7%) and achieves \u003cem\u003eε\u003c/em\u003e\u003csub\u003e\u003cem\u003er\u003c/em\u003e\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;7.112, \u003cem\u003eQ\u0026times;f\u003c/em\u003e\u0026thinsp;=\u0026thinsp;43569 GHz, and \u003cem\u003eτ\u003c/em\u003e\u003csub\u003e\u003cem\u003ef\u003c/em\u003e\u003c/sub\u003e\u0026thinsp;=\u0026thinsp;\u0026minus;\u0026thinsp;37.8 ppm/\u0026deg;C. When x\u0026thinsp;\u0026gt;\u0026thinsp;0.02, secondary-phase precipitation and microstructural inhomogeneity (as evidenced by SEM/EDS) reduce densification and lead to degraded dielectric performance, with \u003cem\u003eQ\u0026times;f\u003c/em\u003e decreasing to 28800 GHz at x\u0026thinsp;=\u0026thinsp;0.06. These results clarify the solid-solution window and provide a feasible compositional strategy for lowering firing temperature while maintaining low-permittivity and low-loss performance in SrAl\u003csub\u003e2\u003c/sub\u003eSi\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e8\u003c/sub\u003e-based microwave dielectrics.\u003c/p\u003e","manuscriptTitle":"Effect of Mn/Mg co-substitution on the phase composition, microstructure, and microwave dielectric properties of SrAl 2-x (Mn 0.5 Mg 0.5 ) x Si 2 O 8 ceramics","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-02-10 18:34:00","doi":"10.21203/rs.3.rs-8681089/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":"0ae9ccd7-a858-49b2-be8c-aa29d47eaf77","owner":[],"postedDate":"February 10th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-04-20T16:03:01+00:00","versionOfRecord":{"articleIdentity":"rs-8681089","link":"https://doi.org/10.1007/s10854-026-17149-4","journal":{"identity":"journal-of-materials-science-materials-in-electronics","isVorOnly":false,"title":"Journal of Materials Science: Materials in Electronics"},"publishedOn":"2026-04-13 15:57:43","publishedOnDateReadable":"April 13th, 2026"},"versionCreatedAt":"2026-02-10 18:34:00","video":"","vorDoi":"10.1007/s10854-026-17149-4","vorDoiUrl":"https://doi.org/10.1007/s10854-026-17149-4","workflowStages":[]},"version":"v1","identity":"rs-8681089","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8681089","identity":"rs-8681089","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}