中文摘要：

利用热重分析法、SEM和X射线仪研究了30％TiC—TiB2增强MoSi2复合材料在800、1000℃和1200℃空气中的氧化行为。结果表明，30％TiC—TiB2／MoSi2复合材料在各温度下氧化192h时，均表现为增重，温度越高，材料氧化增重越大。在初始氧化阶段，氧化速率较大，随后逐渐进人钝氧化阶段。TiC—TiB2的引入在一定程度上降低了MoSi2的抗氧化性能。复合材料中的TiB2优先与氧发生反应生成TiO2和B2O3，然后是TiC与氧反应生成TiO2、CO或CO2，最后才是MoSi2发生氧化。氧化层中没有发现低熔点的B2O3，而TiO2和SiO2形成的氧化膜使材料具有较好的抗氧化性。

英文摘要：

The oxidation behaviors of MoSi2 composites reinforced by 30% TiC-TiB2 at 800 ℃, 1 000 ℃ and 1 200 ℃ were investigated by TGA, SEM and X-ray. Results showed that the composites exhibited continuous weight gain during the course of 192 hours＇ oxidation at each of the above temperatures. The higher the temperature, the more the weight gain. The oxidation rate is much higher during the initial oxidation stage, followed by passivation stage. The oxidation resistance properties of MoSi2 composites was weaken by adding TiC-TiB2 particles. The TiB2 phase of the composites was firstly oxidized and formed TiO2 and B2O3 phases, then the TiC phase reacted with oxygen and formed TiO2, CO or CO/phases. The oxidation of MoSi2 matrix occurred after all that. B203 with low melting point was not found in the oxidized layer,but TiO2 and SiO2 in the oxidation layer made TiC-TiB2/MoSi2 composites being of good oxidation resistance.