Plasma and HVOF sprayed WC–Co coatings as hard chrome replacement solution

Abstract

In the present study, WC-12Co coating has been deposited using plasma spray and high velocity oxyfuel spraying (HVOF) and wear performances of these coatings have been compared with electroplated hard chrome. Bearing steel and WC-Co balls have been used as rubbing counterparts. The wear is predominantly adhesive for the atmospheric plasma spray (APS) and the electroplated coating. For HVOF coating, wear has been found to occur by localised microfracture. A careful choice of plasma spray parameters yields a coating more wear resistant than the electroplated hard chrome. However, the HVOF coating has always offered the highest wear resistance.

The effect of parametric variation on the mullite content of plasma sprayed zircon-alumina powder mixture

“…As stated earlier, with an increase in SOD up to 125 mm, possibly the melting condition of the particles improve and well molten particles deform appreciably on impact with the substrate. Hazra et al [24] reported that a coating consisting of well deformed splats showed less porosity. Pores develop in the vicinity of unmelted or ill-formed particles.…”

Effect of Waveform and Heat Treatment Processes on the Performance of Electrodeposited Co-P Coating

“…Since the environmental factor has become a prior consideration in both technology and industry, hard chromium deposition has been banned in some developed countries, due to the fact that Cr (VI) in chromic acid solution used for chromium deposition is known to be carcinogenic and detrimental to the environment [1]. In order to solve this problem, researchers are looking for promising materials such as Ni-P, Ni-Co-P, and Co-P to replace hard chromium [2][3][4][5][6]. Among which, cobalt-phosphorus (Co-P) alloy coatings have received much attention due to their high hardness, good wear resistance, low friction coefficient and high thermal stability [1,7].…”

Carbide Spray Coating Influence on Wear Behavior of Carburized Steel against Two Counter-Rollers

“…10,11) WC-Co surface coatings are deposited by thermal spraying or high velocity oxy-fuel (HVOF) process that bonds WC-Co coatings to the substrate with minimal porosity on the surface. Several factors such as carbide grain size, cobalt and carbon content play important roles in determining the wear performance of sintered cermets.…”