Studies on Microstructure and Microhardness of plasma sprayed NiCrBSi/Flyash/TiO2/Cr2O3/Mo composite coatings

Abstract

In a wide variety of applications, mechanical components are subjected to severe conditions, such as high load, speed or temperature and hostile chemical environment. Thus, their surface modification is necessary in order to protect them against various types of degradation. Thermal spraying has emerged as an important tool of increasingly sophisticated surface engineering technology. Plasma spraying is a rather simple process from a practical point of view. In the present investigation, NiCrBSi along flyash, Cr2O3, Mo and TiO2 composite coating were obtained by atmospheric plasma spray process on Super Ni 76. The coating was characterized using scanning electron microscope to study the surface morphology and cross section to study the nature of coatings deposited. All the composite coatings had good bonding with substrate material and continuous interface without any porosity. The microhardness studies showed that the composite coatings had higher microhardness values than that of substrate material.