Calcium–magnesium aluminosilicate corrosion of barium–strontium aluminosilicates with different strontium content

In this study, the hot corrosion of barium–strontium aluminosilicate (B_1−xS_xAS) attacked by calcium–magnesium aluminosilicate (CMAS) was investigated at temperatures in the 1200–1400 °C range. Moreover, a corrosion mechanism based on the interdiffusion of Ba/Sr and Ca cations was also proposed. The proposed corrosion mechanism indicated the diffusion of Ba/Sr cations into the CMAS, and Ca cations into the B_1−xS_xAS during the hot corrosion process. At 1200 °C, a thin corrosion zone was formed at the interface of B_1−xS_xAS and CMAS due to weak diffusion of Ba/Sr and Ca cations. Further increase in the temperature led to an enhancement in the interdiffusion of Ba/Sr and Ca cations, thus significantly widening the corrosion zone. Moreover, oriental dendrites, identified as monoclinic B_1−xS_xAS, were found to precipitate in the molten CMAS. Attributed to the faster diffusion rate of Sr cations compared to that of the Ba cations, B_1−xS_xAS with a higher Sr content was found to be more prone to CMAS-induced corrosion due to the rapid loss of Sr.