Reaction products of Sm₂Zr₂O₇ with calcium-magnesium-aluminum-silicate (CMAS) and their evolution

During flight, many silicates (sand, dust, debris, fly ash, etc.) are ingested by an engine. They melt at high operating temperatures on the surface of thermal barrier coatings (TBCs) to form calcium-magnesium-aluminum-silicate (CMAS) amorphous settling. CMAS corrodes TBCs and causes many problems, such as composition segregation, degradation, cracking, and disbanding. As a new generation of TBC candidate materials, rare-earth zirconates (such as Sm₂Zr₂O₇) have good CMAS resistance properties. The reaction products of Sm₂Zr₂O₇ and CMAS and their subsequent changes were studied by the reaction of Sm₂Zr₂O₇ and excess CMAS at 1350 °C. After 1 h of reaction, Sm₂Zr₂O₇ powders were not completely corroded. The reaction products were Sm-apatite and c-ZrO₂ solid solution. After 4 h of reaction, all Sm₂Zr₂O₇ powders were completely corroded. After 24 h of reaction, Sm-apatite disappeared, and the c-ZrO₂ solid solution remained. [Figure not available: see fulltext.]