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 deposit ed via reactive magnetron sputtering. Vickers indentation as well as single pass and triboscopic multipass scratch testing were carried out on these c oatings in order to establish a relation between their brittleness and thei r tribological behaviour, These tests clearly demonstrate a structure-britt leness relationship. Contact interface chemistry influences the coating-sub strate-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 frictio n-but moderate wear. SSNO sequenced treatment yields the best behaviour: lo w friction, low coating wear and low adhesive material pick-up on the pin a s well as negligible plastic deformation of the substrate. (C) 1999 Elsevie r Science S.A. All rights reserved.