Influence of binder materials on the properties of low power plasma sprayed cermet coatings

Thermal spraying of cermet coatings is widely used for protection of machined parts against wear and corrosion. These coatings consist of WC particles in metal binders such as Co, Cr, and Ni. In this study, three kinds of WC powders with different metal binders (Co, NiCr and CoCr) were sprayed by low power plasma spray system on Al-Si-Cu alloy substrate. Fundamental aspects of sprayed cermet coatings, including (i) the effects of binder type on the coating structure, (ii) the microhardness properties and (iii) the microstructure were investigated. All the cermet coatings had the same phase structure such as WC and W2C. However, the phase intensities of these phases are different in each coating, mainly due to the different in solidification rate in each case. Moreover, the microhardness measurements were found to be different in each coating. The results show that the binder type has a significance effect of the physical and mechanical properties of the sprayed coatings.