SiC高温氧化行为及Al基复合材料界面研究

Research on High Temperature Oxidation Behavior of SiC and Interface of Al Based Composite

将SiC颗粒在空气中进行850~1100℃高温氧化增重试验。研究了氧化时间、氧化温度对SiC颗粒表面氧化行为和氧化层结构的影响。采用烧结温度500℃压力30MPa保压时间30min的热压烧结工艺,制备出体积分数为20%的SiCP/Al复合材料。研究了SiC氧化过程对SiCP/Al复合材料界面的影响。结果表明SiC在850℃以上,随氧化时间延长或温度升高,氧化层从非晶态向晶态转变。1100℃氧化4h后,SiO2氧化层厚度为252nm。本文优化的正四面体模型计算厚度约190nm,传统球形模型计算厚度约110nm。氧化层中SiO2主要为高温型方石英晶型;SiC颗粒氧化后与Al基体形成了SiC/SiO2和Al2O3/Al复合界面组织。

High temperature oxidation weight gain experiment of SiC particles was carried out at 850℃-1100℃ in air atmosphere, and the effects of oxidation time and oxidation temperature on the surface oxidation behavior of SiC particle and oxide layer structure were studied. 20vo1% SiCp/A1 composite was prepared by hot pressing sintering process with 30 MPa pressure at 500 ℃ for 30 min. The effects of SiC oxidation process on SiCp/Al composite interface were studied.The results show that, when SiC at above 850℃, with the increase of oxidation time or temperature, the oxide layer changes from amorphous to crystalline. After oxidation at 1100℃for 4 h, the thickness of SiO2 oxide layer is about 250 nm. The calculated result of the thickness of the oxide layer obtained by optimized regular tetrahedron model is about 190nm. Whereas, the thickness is about 110 nm according to the traditional spherical model calculation. The SiO2 in the oxide layer is mainly high temperature typecristobalite. The compound interface microstrueture of SiC/SiO2 and AI2O3/Al is formed by the oxidized SiC particle and Al matrix.