Abstract
The corrosion behaviour and mechanism of solid-state sintered silicon carbide ceramics in the mixed HF–HNO3 acid solution were investigated in this paper. The corrosion results of SiC in different corrosion medium demonstrated that the corrosion of ceramic was affected by the coefficient of HF and HNO3. In addition, the results of different corrosion time showed that the corrosion process can be divided into three stages: 0–6, 6–24, 24–96 h, which was also proved by the strength degradation of SiC after being corroded for different time. Because the relationship between mass loss and corrosion time was linear, the corrosion of first two stages was controlled by chemical reaction. Owing to the scattered data of mass loss in the third stage, the apparent activation is introduced to investigate the control mechanism. The corrosion results at different corrosion temperatures demonstrated that the corrosion mechanism was diffusion control in the third stage, and the apparent activation energy was 198.47 ± 13.97 kJ mol−1.
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