Regional characteristic of 7YSZ coatings prepared by plasma spray-physical vapor deposition technique

Abstract

7YSZ coating was prepared by plasma spray-physical vapor deposition (PS-PVD) technique based on a specific experimental design. The microstructure and deposition properties of 7YSZ coating along the radius of plasma jet were investigated in detail. Results show that the coating presents regional characteristic in the radial direction, which could be divided into three typical zones: In Zone I, the coating is all composed of columnar structures with cauliflower structure, and the coating properties including the surface roughness and deposition efficiency (DE) are almost stable; in Zone III, the coating is made up of solid particles, droplet and gas phase mixed without columnar structures; Zone II is between Zone I and Zone III, in which there are columns with domed top and small particles. Based on experiment results, a model on the state and distribution of particles in plasma jet was proposed to clarify the regional characteristic. This study is helpful to comprehend and control coatings deposition by PS-PVD technique.