Self-crystallization characteristics of calcium-magnesium-alumina- silicate (CMAS) glass under simulated conditions for thermal barrier coating applications

Abstract Understanding self-crystallization characteristics of calcium-magnesium-alumina- silicate (CMAS) glass is of great significance for seeking for solution to its corrosion to thermal barrier coatings (TBCs). Here, we design a series of experiments to investigate the relationship between CMAS self-crystallization behavior and cooling/heating rates and dwell temperature, and emphasize the potential influence of self-crystallization on CMAS corrosion behavior to TBCs. With the cooling rate decreasing, crystalline phases formed in a sequence of diopside, wollastonite and anorthite, and the thickness of the crystalline layer increased. During the heating process, diopside and melilite phases formed when the temperature was lower than 1050 °C; while at higher temperatures, melilite transformed to anorthite and wollastonite, independent on the heating rate. Although self-crystallization can slow molten CMAS penetration, the function on protecting TBCs from damage is limited, and other strategies alleviating CMAS corrosion are necessitated to be developed.