Effect of Residual Phase and Grain Size on Corrosion Resistance of SiC Ceramics in Mixed HF-HNO$lt;inf$gt;3$lt;/inf$gt; Acid Solution

Effect of residual phase and grain size the corrosion resistance of SiC ceramics in mixed HF-HNO 3 acid solution was investigated. Three kinds of fabrication methods (SSiC-solid state sintered SiC, LPS SiC-liquid phase sintered SiC and RB SiC-reaction bonded SiC) were adopted to prepare SiC ceramics. Besides, the grain size in SiC ceramics was adjusted under different sinter temperatures. Compared to RB SiC and LPS SiC ceramics, SSiC ceramics showed a better corrosion resistance for the good corrosion resistance of residual graphite and 'island' structure of residual phase in ceramics. The grain size of SiC ceramics sintered at temperature between 2100 and 2160 increase from 2 m to 6 m, and the absolute values of Y intercept, which reflect the corrosion of SSiC ceramics with none residual phase, are 9.22 g/cm 2 (2100), 5.81 g/cm 2 (2130) and 0.29 g/cm 2 (2160), which demonstrate that large grain size is beneficial to the corrosion resistance of SiC ceramics.