Surface modification of cemented carbide using plasma nitriding and metal ion implantation

Cemented carbide has good miscibility, high hardness and toughness, as well as good resistance to wear, abrasion, and infusibility. The surface mechanical properties of the cermets can be improved if nitrogen or heavy metals, such as Mo and W, are embedded into the cermet surface. In this work, WC–TiC–Co samples were plasma-implanted with nitrogen, Mo, as well as Mo and W. Our results show that the surface hardness and wear can be enhanced to different degrees according to the treatment processes. X-ray photoelectron spectroscopy (XPS) was used to determine the concentration and chemical states of the elements present in the implanted cermets. The results show that high-energy ion bombardment can lead to the formation of ternary or quaternary carbides through mixed crystal hardening within the implanted zone. Our results indicate that tungsten nitride, titanium nitride, and molybdenum carbide are embedded or precipitated in the WC–TiC grains, and as a result, the surface stress in the cubic carbide is altered to better absorb the impact energy from external loads.