Tribological behaviour of N- or O-doped austenitic stainless-steel magnetron sputter-deposited coatings

N-, O- and N-O-doped stainless-steel coatings (SSN, SSO, SSNO) were deposited via reactive magnetron sputtering. Vickers indentation as well as single pass and triboscopic multipass scratch testing were carried out on these coatings in order to establish a relation between their brittleness and their tribological behaviour, These tests clearly demonstrate a structure-brittleness relationship. Contact interface chemistry influences the coating-substrate-composite damage behaviour. Despite a low friction coefficient, SSo brittleness is 'catastrophic' for tribological applications. SSN ductility is associated with rapid adhesive transfer layer formation and high friction-but moderate wear. SSNO sequenced treatment yields the best behaviour: low friction, low coating wear and low adhesive material pick-up on the pin as well as negligible plastic deformation of the substrate. (C) 1999 Elsevier Science S.A. All rights reserved.