Wear behaviour of carbon implanted hard chromium coatings

Recent results are reported from a systematic study of the wear behaviour of carbon implanted hard chromium coatings. After carbon implantation to various doses, samples were characterised using ion beam analysis techniques and grazing incidence X-ray diffraction. A nanoindentation technique was utilised to measure near surface hardness and wear tests were carried out in a pin on disc configuration under various conditions; SEM was employed to examine the worn surfaces. Wear behaviour changed significantly and new phases formed as a result of high dose carbon implantation. Wear damage and friction coefficient were dependent on implantation doses as well as on test conditions. Only very high dose (4 x 1017 C cm-2) implantation could significantly improve wear resistance under mild wear conditions. The implications of these findings are discussed. (author)