Plasma and gaseous nitrocarburizing of C60W steel for tribological applications

A comparison has been made between plasma and gas nitrocarburizing processes for C60W steel in terms of structural features of the layers and the tribological properties of the specimens. Gaseous treatments were performed in a sealed quench industrial furnace in optimized process cycles. A semi – industrial size unit was operated at a range of process parameters for plasma nitrocarburizing. Experimental results indicate that increasing the treatment time increases the thickness of the compound layer but lowers the wear resistance. Plasma treatment produced a more effective case depth compared with gaseous process, providing a better uniformity. Analysis of X-ray diffraction patterns indicated that the compound layer in gas nitrocarburizing and plasma nitrocarburizing consisted of both ɛ and γ′ phases.