Effects of Plasma Current on the Microstructure of Solution Precursor Plasma Spray YSZ Coatings

The investigations have been carried out for the effects of processing parameter (plasma current) in the SPPS and to understand their implications and improving of this process. Thermal spraying is an advanced materials processing technique which has found wide acceptance in many high technology industries. High temperature, high velocity flame is produced to heat, melt and spray material introduced into the flame. The Solution Precursor Plasma Spray (SPPS) process has been used for obtaining Zirconia coatings asThermal Barrier Coatings (TBCs). The solution precursor Plasma Spray (SPPS) was carried out using a robotic plasma spray system equipped with a liquid spray unit. The gun was connected to a 6 axis ABB robot for precession maneuvering. In this study an in house developed Zirconyle nitratesolution precursor plasma spray setup has been used. In this process the coating is built up by horizontal and vertical passes of the plasma torch across the substrate. The microstructural characterizations of coatings were carried out by scanning electron microscope (SEM) and X-ray diffraction (XRD). Significant effect of plasma current has been observed on the zirconia coatings.