The fabrication of nickel-graphite coatings on mild steel using plasma-spray techniques

Ni-graphite coatings, due to their high hardness and chemical inertness, are often used as protective coatings against friction and corrosion. In this paper, the preparation of a nickel-graphite coating on mild steel substrates using plasma spraying technique and the properties of the coatings are presented. The microstructural characterization of the coatings was examined by optical microscope and image analyzer. Hardness and elastic modulus measurements were applied to the fabricated coatings through a dynamic ultra-microhardness machine. Also, phase analysis of the coatings was determined by XRD techniques. It has been found that, samples produced by plasma spray technique possess oxide, unmelted and semimelted particles, inclusions and porosity.