Integrating APS TBCs with a built-in Al2O3 protection network for superior CMAS resistance

Abstract

Calcium–magnesium–alumina–silicate (CMAS) attack poses a great threat to the durability of thermal barrier coatings (TBCs). We introduce a novel Al2O3-modified TBC architecture to counter this threat. The architecture integrates an Al2O3 protection network into the microstructure of an atmospheric plasma sprayed (APS) TBC by drip coating method, which modifies the vulnerable infiltration pathway of CMAS melt and promotes the self-crystallization of CMAS at the infiltration front. Moreover, during sintering, the built-in Al2O3 can inhibit inter-splat crack healing. This innovative TBC design achieves robust CMAS resistance and strain tolerance, while also offering advantages during sintering.