Preparation and characteristics of three-layer YSZ-(YSZ/A1_2O_3)-YSZ TBCs

摘要

Novel three-layer YSZ-(YSZ/A1_2O_3)-YSZ (6 wt.% Y_2O_3 partially stabilized ZrO_2) thermal barrier coatings (TBCs) were successfully prepared on Ni-based superalloy substrate using composite sol-gel and pressure filtration microwave sintering (PFMS) techniques. The coatings were evaluated for the cyclic oxidation resistance, thermal barrier effect and the presences of phases and microstructures. FE-SEM results indicate that the coatings were dense and crack-free. The coatings maintained their structural integrity when they were exposed at 1100 for 100 h. They exhibited superior oxidation resistance, spallation resistance and thermal insulation property compared with single-layer YSZ coatings. Moreover, the detailed mechanisms were discussed in order to understand the improved performance of the three-layer TBCs.