Sliding wear of a-C:H coatings against alumina in corrosive media

Abstract

This paper reports the results obtained fromthe study of friction and sliding wear in two corrosive solutions of an a-C:H coating deposited on 316L stainless against an alumina ball, employed as static counterpart. Calculations of the values of the vonMises stresses developed at the coating–substrate interface, as soon as the ball touches the coated sample, and how this state of stress influences the response of the coated system under the corrosion environment, are presented and discussed. The results obtained from these calculations, as well as from the experiments conducted in the present research, are compared with other experiments published in the literature, where a-C:H coatings deposited on different substrates and with different coating architectureswere tested in similar corrosive media. It has been determined that in those systems, where the vonMises stress in the coating, found in the vicinity of the interface, exceeds the threshold value of approximately 370 MPa, coating failure with spallation will take place, regardless of the substrate nature onwhich this coating has been deposited. From this analysis it has been concluded that the coating yield strength is of utmost importance in conferring the a-C:H coated system the required stability in a corrosive solution.