中文摘要：

利用热重分析法和SEM，X射线衍射考察了不同致密度的MoSi2材料在1200℃的循环氧化行为。研究结果表明：不同致密度的MoSi2均未发生“Pesting”现象，致密度和“Pesting”现象无本质关系。低致密度MoSi2材料在0-1h和1～480h阶段，氧化动力学曲线基本呈直线，而高致密度的材料氧化动力学曲线近似抛物线。氧化480h后，最小致密度（78．6％）试样和最高致密度（94．8％）试样增质分别为10．39mg／cm^2和0．135mg／cm^2。高致密度MoSi2材料优异的抗氧化主要归因于其生成了连续致密的保护膜，阻止了氧化的进一步发生。氧化层相组成由表至里按照SiO2→Mo5Si3→MoSi2逐渐演化。

英文摘要：

The oxidation behaviors of different density MoSi2 at 1 200 ℃ has been investigated by TGA, SEM and X-ray. Results show that the ＂pesting＂ is not found in all MoSi2 materials oxidized after 480 h. It is found that the density has no essential relation to the＂ pesting＂. The oxidation cure of lower density sample shows two-step oxidation kinetics. Both the first stage （0 - 1 h） and the second stage （1 -480 h） nearly obey linear kinetics cure with different oxidation rate. The oxidation kinetics of higher dense MoSi2 nearly follows parabolic kinetics cure. The mass gain of the lowest density （78.6%） and the highest density （94.8%） of MoSi2 is 10.39 mg/cm^2 and 0. 135 mg/cm^2 respectively. The better oxidation resistance of relatively high density material is resulted from the formation of a compact and continuous oxidation film, which hinder the diffusion of oxygen. The phase distribution of oxidation layer from outer to inward is SiO2→ Mo5 Si3→MoSi2.