Reaction products of Sm_(2)Zr_(2)O_(7) 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 Sm_(2)Zr_(2)O_(7))have good CMAS resistance properties.The reaction products of Sm_(2)Zr_(2)O_(7) and CMAS and their subsequent changes were studied by the reaction of Sm_(2)Zr_(2)O_(7) and excess CMAS at 1350℃.After 1 h of reaction,Sm_(2)Zr_(2)O_(7) powders were not completely corroded.The reaction products were Sm-apatite and c-Zr0_(2) solid solution.After 4h of reaction,all Sm_(2)Zr_(2)O_(7) powders were completely corroded.After 24 h of reaction,Sm-apatite disappeared,and the c-Zr02 solid solution remained.