Mechanical properties and simulated thermal conductivity of biomimetic structured PS-PVD (Gd0.9Yb0.1)2Zr2O7 thermal barrier coatings

Abstract

Plasma spray physical vapor deposition (PS-PVD) (Gd0.9Yb0.1)2Zr2O7 (GYbZ) thermal barrier coatings (TBCs) exhibited better silicate-phobicity than coatings produced by electron beam physical vapor deposition. In combination with PS-PVD and ultrafast laser direct writing technology, biomimetic structured GYbZ TBCs, with a triple-scale micro/nano surface microstructure, were obtained. Laser ablating on the PS-PVD GYbZ coating enhanced the surface roughness, improving its wear resistance without increasing the surface hardness. Furthermore, during the laser ablation processing, numerous nanoparticles were deposited in-situ in the gaps between columns of the coating, reducing the coating Young's modulus. The simulated temperature field and heat flux field demonstrated that the presence of numerous interfaces between small columns of the PS-PVD coatings is beneficial to thermal insulation. However, laser ablation decreased the coating thickness, reducing the thermal insulation by around 20%–30% as compared to its PS-PVD counterpart, suggesting that a moderate increase in the coating thickness should be considered when designing an efficient TBC system.