Deposition and characterization of thermal barrier coatings of ZrO2–4 mol.% Y2O3–1 mol.% Gd2O3–1 mol.% Yb2O3

• TBC systems of ZrO2–4 mol.% Y2O3–1 mol.% Gd2O3–1 mol.% Yb2O3 were produced.
• A highly porous microstructure with a porosity of 34% was realized.
• This microstructure led to a lower thermal diffusivity than a conventional TBC.
• It resulted in a better thermal shock behavior than the conventional TBC.

Multicomponent oxide-doped zirconia based thermal barrier coatings (TBCs) have been found to possess significantly lower thermal conductivity and better sintering resistance at high temperatures than current state of the art ZrO2–(7–8) wt.% Y2O3 TBCs. In this study, two TBC systems of multicomponent oxide-doped zirconia (ZrO2–4 mol.% Y2O3–1 mol.% Gd2O3–1 mol.% Yb2O3) were produced with a three-cathode plasma generator Triplex Pro-210. The first TBC system was deposited using a conventional fused and crushed spray powder. This powder was further processed by high energy ball milling to get a highly porous second TBC system. The two TBC systems were characterized in terms of their microstructures, phase compositions, mechanical properties and thermo-physical properties. Their thermal shock behavior was evaluated using thermal cyclic tests at 1150 °C. The results showed that the second TBC system had a significantly lower thermal diffusivity and better thermal shock behavior compared to the first TBC system due to its highly porous microstructure.