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研究了不同SiC体积分数原位合成MoSi2-SiC复合材料在700℃空气中1000h的长期氧化行为。结果表明:复合材料氧化1000h后,均未发生pest现象。复合材料的氧化抗力明显好于单一MoSi2,原位合成复合材料的氧化抗力好于传统的热压商用MoSi2粉末和SiC粉末混合物制备的复合材料(外加复合材料)。复合材料氧化膜相组成仅为非晶SiO2,材料的氧化过程主要是O2与MoSi2的作用,SiC未发生氧化。材料在700℃下仍发生硅、钼的同时氧化,因MoO3的挥发较快没有晶须形成,因而在材料表面快速形成一薄层连续、致密的非晶SiO2保护膜,使材料表现出优异的长期抗氧化性。
The long-term oxidation behavior of MoSi2-SiC composites synthesized in-situ at 700 ℃ for 1000 h in different volume fraction of SiC was investigated. The results show that the pest phenomenon did not occur after the composite was oxidized for 1000 hours. The oxidation resistance of the composites is obviously better than that of the single MoSi2. The in-situ composites have better oxidation resistance than that of the composites prepared by traditional hot-pressed commercial MoSi2 powders and SiC powders. The phase composition of the composite oxide film is only amorphous SiO2, the oxidation process of the material is mainly the role of O2 and MoSi2, SiC is not oxidized. The material is still silicon and molybdenum at 700 ℃ oxidation occurs at the same time, due to the rapid evaporation of MoO3 no whisker formation, thus rapidly forming a thin layer of continuous, dense amorphous SiO2 protective film on the material surface, the material showed excellent Long-term antioxidant.