Study of the tribological modifications induced by nitrogen implantation on metals of the Va group

This paper reports a comparative study of the modifications induced by Nitrogen implantation on metals of the Va group. Doses of 1.25 X 10(17), and 7 X 10(17) of atomic (N+) and of 3.5 X 10(17), and 6 X 10(17) molecular (N-2(+)) Nitrogen at 150 keV energy were implanted on vanadium, niobium and tantalum polished samples, to investigate the tribological effects due to their reactivity with nitrogen. Microhardness at low loads (2 mN), friction and wear tests have been carried out on the different materials and doses in an attempt to relate the superficial modifications with the implanted dose. In addition, XPS analysis and AES profiles have been performed to investigate the nitrogen distribution and binding state after the different implantation experiments, in order to describe the relationship between the implanted dose, the surface mechanical modifications and the spectroscopic results. (C) 2002 Elsevier Science B.V. All rights reserved.