Life time of new SYSZ thermal barrier coatings produced by plasma spraying method under thermal shock test and high temperature treatment

Nanostructured scandia (4.6 mol%), yttria (0.4 mol%) doped zirconia (5SYSZ) and 7 wt% yttria stabilized zirconia (7YSZ) thermal barrier coatings (TBCs) were produced by plasma spraying on nickel-based superalloy substrates with NiCrAlY as the bond coat. The thermal shock behavior of the two as-sprayed TBCs at 1000 °C was investigated. The results indicated that the thermal cycling lifetime of 7YSZ TBCs was longer than the 5SYSZ TBCs due to the lower thermal mismatch stress between the ceramic layer and the metallic layer at high temperature. However, the nanostructured 5SYSZ coating had higher thermal stability than 7YSZ TBC.