27 / 2025-04-22 16:28:56

Structural evolutions and failure mechanisms of APS tantalate high-entropy ceramics coatings response to thermal cycle up to 1500 ºC

TBCs,Rare-earth tantalates,Thermal cycle,High-entropy ceramics,Failure mechanisms

Thermal barrier coatings (TBCs) are widely used in gas turbine engines to provide thermal insulation for high-temperature alloy blades, and rare-earth tantalates are extensively studied and applied in recent years. To further boost the service performance of tantalate TBCs, high-entropy ceramic coatings of tantalates (HECs tantalates) are designed and synthesized via air plasma spraying (APS) in this work. The typical microstructures and failure mechanisms of HECs tantalates coatings are analyzed after thermal cycle at temperatures up to 1500 ºC, and it is found that the formation and thickening of thermal growth oxides (TGO) lead to the failure of HECs tantalates coatings. The evolutions of crystal structure, microstructures, and interfacial thermal stress of the synthesized HECs tantalates TBC systems are investigated in detail, which are used to further reveal the failure mechanisms. It is believed that the service life of HECs tantalates coatings can be further optimized by improving the APS parameters and designing novel bond coat (BC) compositions. In summary, HECs tantalates coatings can be used at temperatures up to 1500 ºC, and they can provide excellent thermal insulation for high-temperature components.