Corrosion of sintered SiC ceramics in mixed acid solution: temperature and time dependences

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.

Keywords:

• SiC
• Acid corrosion
• Time
• Temperature

Additional information

Funding

The authors gratefully acknowledge the funding provided by the National Natural Science Foundation of China (51202270); Strategic Pilot of Science and Technology of Chinese Academy of Sciences (Class A: XDA02040206)