SiC 晶须表面成分和涂层对抗氧化性的影响

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。

EFFECTS OF SURFACE COMPOSITION AND COATINGS ON OXIDATION RESISTANCE FOR SiC WHISKER

The surface compositions,silicon dangling bonds and specific areas of five kindsof SiC whiskers were measured by XPS,EPR and BET respectively.The oxidation behaviour ofthe SiC whiskers containing and not containing coatings were studied by using of TG-DTA.The experimental results showed that the oxidation resistance predominantly depended on theinital silica content on the surface of SiC whiskers.After Al_2O_3,SiO_2 and mullite were coatedon the SiC whisker,the surface and bulk oxidation resistance had been much improved,whichwere contributed to the decrease of the silicon dangling bonds on the SiC whiskers and to the in-crease of oxygen diffusion obstacle resulted from the coatings.