Study of the microstructure and tribological properties of Mo plus C-implanted TiN coatings on cemented carbide substrates

Ion implantation with Metal Vacuum Vapor Arc (MEVVA) source has been investigated on several types of steels and the practical industrial results have proved that it could effectively improve wear resistance, hardness and solid lubrication of materials. In this paper, the microstructure and tribological properties of TiN coatings implanted with Mo and Mo + C ion at different doses and acceleration energies by MEVVA ion source were studied. The microstructure of Mo and Mo + C ion implanted TiN coatings was investigated by High-resolution Transmission Electron Microscope (HRTEM) and EDS, and the micro-hardness of the coatings was examined. The tribological properties of implanted TiN coatings were tested by SRV friction and wear tester. The results showed that the nano fiber phases were found in the surface of TiN coatings within the depth of 50 nm after Mo ion was implanted. The diameter of the fiber phases was 2-10 nm and it dispersed uniformly in the TiN coating surface. The nano fiber phases were rich in molybdenum, the content of which reached to 17%-25%. The micro-hardness of TiN coatings increased after ion implantation and the effect of Mo + C dual ion implantation was much better than the single ion implantation of Mo. It was found that the wear loss of the coatings in SRV tests was significantly reduced after ion implantation and the friction coefficient of TiN coating implanted by Mo + C was remarkably lower than that of the coating implanted by single Mo. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.