Microstructure and tribological properties of W-implanted PVD TiN coatings on 316L stainless steel

In order to further enhance the tribological properties of TiN coatings used on mechanical parts, W ion implantation with Metal Vapor Vacuum Arc (MEVVA) source was carried out on PVD TiN coatings at the implantation dose as high as 9 × 1017 ions/cm2. The microstructures of the TiN coatings were investigated by Scanning Auger microprobe (SAM), X-ray diffraction (XRD), and X-ray photoelectron spectroscope (XPS). The surface morphology and Nano-hardness were examined by an optical profilometer and Nano Indenter System, respectively. Also, the tribological properties were investigated on a ball-on-disc friction and wear tester. The results demonstrated that TiN coating with W-implantation at 9 × 1017 ions/cm2 showed remarkably sputtering effects on the surfaces, and sharply decreased the friction coefficient and wear rate by 63.74% and 56.55% respectively. Based on the hard phases of TiN, Ti2N and WN, the existence of soft tungsten, lubricious tungsten oxides and titanium oxides resulted in the remarkable reducing of the friction coefficient of TiN coatings with W-implantation.