Mechanical and microstructural characterization of microwave post processed Alloy-718 coating

Abstract

High Velocity Oxy-fuel (HVOF) sprayed coatings are preferred for depositing almost all materials in numerous industries due to their ease of operation. However, the presence of heterogenous microstructure along with the presence of considerable porosity requires a suitable post processing of as-sprayed coatings. In the present work, the principles of microwave hybrid heating (MHH) were successfully applied for the post processing of HVOF sprayed Alloy-718 coating. The as-sprayed and post-processed coatings were characterised in terms of their microstructure, microhardness, fracture toughness and surface roughness. Pin-on-disc tribometer was used to analyse the abrasive wear behaviour of as-sprayed and post-processed coatings. The post processed coating resulted in significant improvement in mechanical properties of the as-sprayed coatings due to healing of micro-cracks and pores during microwave exposure.