Oxidation behavior of a pressureless sintered ZrB_2–MoSi_2 ceramic composite
Oxidation behavior of a pressureless sintered ZrB_2–MoSi_2 ceramic composite
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DOI：
10.1557/jmr.2005.0111
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发表时间：
2005-04
影响因子：
2.7
通讯作者：
D. Sciti;Mylène Brach;A. Bellosi
中科院分区：
文献类型：
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作者：
D. Sciti;Mylène Brach;A. Bellosi
在1830℃、Ar气氛下无压烧结制备了组成为(5~20)体积%MoSi2的超耐火陶瓷复合材料。烧结循环和显微组织分析表明，要获得致密的材料，至少需要20%的二硅化钼。在此基础上，用80体积%的ZrB_2+20体积%的MoSi_2来测试复合材料在氧化环境下的热稳定性。氧化试验在700~1400℃的流动合成空气中进行，暴露时间为30h，在低温范围内(700~1000℃)，复合材料的氧化过程类似于单块的ZrB_2陶瓷，在&1200℃时，二硅化钼氧化产生的二氧化硅封闭了样品表面，防止了二硼化锆的快速降解。
Ultra-refractory ceramic composites of composition ZrB_2 + (5 to 20) vol% MoSi_2 were produced by pressureless sintering at 1830 °C under argon atmosphere. Sintering cycles and microstructural analysis point out that at least 20 vol% molybdenum disilicide is necessary for obtaining a dense material. Thereafter, the composite 80 vol% ZrB_2 + 20 vol% MoSi_2 was used to test the thermal stability under oxidizing environment. Oxidation tests were carried out in flowing synthetic air in a thermogravimetric analyzer from 700 to 1400 °C with exposure time of 30 h. In the low-temperature range (700–1000 °C), the oxidation of the composite resembles that of monolithic ZrB_2 ceramics, for temperatures >1200 °C the silica resulting from oxidation of molybdenum disilicide seals the sample surface, preventing zirconium diboride from fast degradation.