Surface properties of Mo-implanted PVD TiN coatings using MEVVA source

To further improve the tribological properties of TiN coatings used on mechanical parts, Mo ions were implanted into PVD TiN coatings with Metal Vapor Vacuum Arc (MEVVA) source at the implantation dose as high as 1 × 1018 ions/cm2. Surface morphology, microstructures, and nano-hardness of TiN coatings were investigated by optical profilometer, X-ray diffraction (XRD), X-ray photoelectron spectroscope (XPS), and Nano Indenter System. The tribological properties were investigated on a ball-on-disk friction and wear tester. The XRD results demonstrated that the diffraction peak of Ti2N appeared in the Mo-implanted TiN coatings. However, there was obvious decrease of nano-hardness due to the soft Molybdenum phase and its oxides. It was approved that Mo-implanted TiN coatings could greatly improve their tribological properties and that the implantation at dose of 1 × 1018 ions/cm2 could result in much lower friction coefficient. The existence of soft molybdenum, lubricious molybdenum oxides and titanium oxides resulted in the remarkable reducing of the friction coefficient of TiN coatings with Mo-implantation.