Improving the durability and investing failure behavior of TBCs under thermal cycling-CMAS test by Yb2O3 and Y2O3 co-stabilized ZrO2 materials and different processes

Abstract

Under extremely complex conditions, extending the lifetime of thermal barrier coatings (TBCs) is a challenge. In the present study, optimization of the coating structure and selection of coating materials are beneficial for improving the lifetime of TBCs under thermal cycling-CMAS (calcium-magnesium-alumina-silicate) test. It is efficient to obtain different layer thicknesses of multi-layer coating, including the micro-nano dual-scale layer, the dense YbYSZ layer (4.0 mol % Yb₂O₃ and 0.5 mol% Y₂O₃ co-stabilized ZrO₂), the porous YbYSZ layer and the laser 3D texturing layer, using the computational model under thermal load. Based on the corresponding coating structure and YbYSZ material, bond strength and thermal cycling-CMAS lifetime are evaluated, and compared with those of YSZ (4.5 mol % Y₂O₃ stabilized ZrO₂) coating. The results reveal that TBCs with porous embedded particle cluster (PEPC) structure is lower than that of YSZ coating. In addition, the original defects in multi-layer coating with grid texture reduce the bond strength. The lifetime of multi-layer coatings with a punctate texture are significantly improved in the thermal cycling-CMAS test, and their failure behavior includes fragmented and bulk-like exfoliation. This study emphasizes that combination of materials modification and structure optimization are a promising strategy to extend lifetime of TBCs.