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用 XPS、BET 和 EPR 方法对五种 SiC 晶须的表面成分、比表面、Si 悬挂键进行了测定。用TG-DTA 方法研究了表面涂层和未涂层的 SiC 晶须的抗氧化性能。结果表明:SiC 晶须的抗氧化性主要取决于起始表面氧含量;在表面涂覆 Al_2O_3,SiO_2和 Mullite 后,SiC 晶须无论是表面抗氧化性和体积抗氧化性均得到显著改善。表面抗氧化性的改善是由于涂层使 SiC 表面 Si 悬挂键减少,而体积抗氧化性改善是由于涂层增加了氧扩散阻力。
The surface composition, surface area and Si dangling bonds of five SiC whiskers were determined by XPS, BET and EPR methods. The oxidation resistance of surface-coated and uncoated SiC whiskers was investigated by TG-DTA method. The results show that the oxidation resistance of SiC whiskers mainly depends on the oxygen content of the starting surface. After the surface coating of Al 2 O 3, SiO 2 and Mullite, the SiC whiskers are significantly improved both in surface oxidation resistance and volume oxidation resistance. The improvement in surface oxidation resistance is due to the coating reducing the Si dangling bonds on the SiC surface and the improvement in volumetric oxidation resistance due to the increased oxygen diffusion resistance of the coating.