Journal of Inorganic Materials

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Oxidation Behaviors of the Pressureless Sintered ZrB2-SiC Composites

YAN Yong-Jie1, ZHANG Hui1,2, HUANG Zheng-Ren1, LIU Xue-Jian1   

  1. 1. Shanghai Institute of Ceramics, Chinese Academic of Sciences, Shanghai 200050, China; 2. Graduate University of the Chinese Academy of Sciences, Beijing 100049, China)
  • Received:2008-09-16 Revised:2008-11-23 Online:2009-05-20 Published:2009-05-20
  • Contact: HUANG Zheng-Ren E-mail:zhrhuang@mail.sic.ac.cn

Abstract:

The pressureless sintering process of ZrB2-SiC composite ceramics was studied. The ceramic samples was prepared by using sol-gel synthesized ultra-fine ZrB2 powders as sources and different contents of Mo and/or B4C as sintering aids. The static oxidation behaviors of the sintered ZrB2-20wt%SiC composite ceramics using 4wt%Mo and 4wt%Mo-2wt%B4C additives were systemically analyzed. The results show that the composite ceramics oxidized quickly with visible ZrO2 particles on the surface above 1300℃/30min with pure Mo additive. While Mo-B4C additive is added, the protective liquid layer appears at 1300℃ and becomes thicker and uniform with the temperature rising. The composite ceramics present good oxidation resistance of which the flexural strength retains 86% of the value in room temperature after oxidiation at 1500℃ for 30min.

Key words: ultra-high temperature ceramics, pressureless sintering, oxidation resistance

CLC Number: 

  • TB335