Preparation and Characterization of Thermal Spray Coating of Glass Microspheres on Metal Substrate

Abstract

Plasma spray technology utilizes the exotic properties of the plasma medium to effect physical, chemical or metallurgical reactions to produce new materials or impart new functional properties to conventional materials. It is in fact a process that includes melting, rapid solidification and quenching taking place simultaneously. As for the coating materials, it is well understood that for a number of unique application, spherical particles are preferred over irregular ones due to low surface area to volume ratio, high density, free flowing ability and close sizing etc. In view of this, the present paper reports on the preparation of glass microspheres coatings on mild steel substrate using plasma spray technology. An 80 kW atmospheric plasma spray set up is used for spraying purpose. Solid glass micro-spheres of average sized 100 micron are used as the coating materials which are deposited at four different power levels on mild steel substrate. The coatings are characterized in terms of their thickness, hardness, density and porosity. The coatability of glass micro-spheres on mild steel is assessed by evaluating the coating deposition efficiency. Different phases present in the coating are ascertained using X-ray diffractography.