Corrosion behavior and strength degradation of Ti3SiC2 exposed to a eutectic K2CO3 and Li2CO3 mixture

The corrosion of polycrystalline Ti3SiC2 was studied in the eutectic Li2CO3 (68 at.%) and K2CO3 (32 at.%) mixture at 650–850 °C. Ti3SiC2 exhibited better corrosion resistance at 650 °C. However, the mass loss was fast when temperature was above 700 °C. It was demonstrated that the surface chemical reaction-controlled shrinking core model could be applied to describe the relationship between the degree of the corrosion and reaction time for the corrosion of Ti3SiC2 in the 700–850 °C temperature range. The corresponding apparent activation energy was 206 kJ/mol. Corrosion resulted in roughness of specimen surface. The fracture strength of the corroded samples was evaluated by a three-point bending test. The results showed that the degradation of the fracture strength was about 25% of the original values for the corroded specimens up to 10% weight loss. The mechanism of the strength degradation was discussed based on the analysis of the microstructure and composition of the corroded sample.