The crack-healing behavior and corrosion resistance of SiC ceramics were investigated. Heat treatment was carried out from 1173 K to 1573 K. The corrosion test of SiC was carried out in acid solution and alkaline solution under KSL1607. Results showed that heat treatment in air could significantly increase the strength. The heat-treatment temperature has a profound influence on the extent of crack healing, and the degree of strength recovery. The optimum heat-treatment temperature had one hour at an atmospheric level of 1373 K. In the two kinds of solution, the cracks of cracked specimen were dimmed with increasing time, and the surface of the crack healed specimen showed increased black and white spots. The strength of the corroded cracked specimen was similar to that of the cracked specimen. The strength of the corroded crack healed specimen decreased 47 and 75% over that of the crack healed specimen in acid and alkaline solution, respectively. Therefore, the corrosion of SiC ceramics is faster in alkaline solution, than in acid solution.

Keywords: Crack-healing; Corrosion; Strength of corroded specimen; Alkaline solution; Acid solution