{"title":"Effects of N sub 2 gas pressure sintering on the surface and strength of Si sub 3 N sub 4","authors":"N. Hirosaki, A. Okada","doi":"10.1111/J.1551-2916.1988.TB00268.X","DOIUrl":null,"url":null,"abstract":"The flexural strength of Si{sub 3}N{sub 4} having an as-sintered surface was measured to investigate the effects of the sintering atmosphere on the surface. The as-sintered strength of Si{sub 3}N{sub 4} fires in 0.1 MPa N{sub 2} (pressureless sintering) degraded to 39% of its ground strength as a result of near-surface voids formed by thermal decomposition reactions between Si{sub 3}N{sub 4} and additive oxides. The as-sintered strength of Si{sub 3}N{sub 4} fired at 70 MPa N{sub 2} (gas pressure sintering), however, was shown to retain as much as 76% of its ground strength. This result seems to indicate that high-pressure N{sub 2} gas suppressed the void formation by reducing the decomposition reactions. Gas pressure sintering was effective in avoiding thermal decomposition and in maintaining a higher as-sintered strength.","PeriodicalId":7260,"journal":{"name":"Advanced Ceramic Materials","volume":"16 1","pages":"515-516"},"PeriodicalIF":0.0000,"publicationDate":"1988-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"7","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Advanced Ceramic Materials","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1111/J.1551-2916.1988.TB00268.X","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 7
Abstract
The flexural strength of Si{sub 3}N{sub 4} having an as-sintered surface was measured to investigate the effects of the sintering atmosphere on the surface. The as-sintered strength of Si{sub 3}N{sub 4} fires in 0.1 MPa N{sub 2} (pressureless sintering) degraded to 39% of its ground strength as a result of near-surface voids formed by thermal decomposition reactions between Si{sub 3}N{sub 4} and additive oxides. The as-sintered strength of Si{sub 3}N{sub 4} fired at 70 MPa N{sub 2} (gas pressure sintering), however, was shown to retain as much as 76% of its ground strength. This result seems to indicate that high-pressure N{sub 2} gas suppressed the void formation by reducing the decomposition reactions. Gas pressure sintering was effective in avoiding thermal decomposition and in maintaining a higher as-sintered strength.