Study of the tribological modifications induced by nitrogen implantation on Cr, Mo and W

This article reports the study of the changes in the surface properties of metals of group VIa after their implantation with atomic nitrogen. Doses of 1E17 N+, 5E17 N+ and 1E18 N+ ions/cm2 were implanted on polished samples of chromium, molybdenum and tungsten, in order to investigate the tribological effects due to implantation. This work is the continuation of the study carried out on groups IVb and Va, where the effects of nitrogen implantation were also evaluated. Microindentation hardness at low loads, friction and wear tests have been carried out on the different materials and doses in an attempt to relate surface modifications with the implanted dose. Microindentation hardness tests at low loads showed increases of at least a factor 2 in all the cases. Friction tests against Co–WC were performed, finding the higher friction reductions for molybdenum. AES and GDS profiles have also been performed to determine the nitrogen distribution after the implantation experiments.