NANOINDENTATION AND MICROINDENTATION STUDIES OF HARD CARBON ON 304 STAINLESS-STEEL

Microhardness and nanoindentation techniques have been used to probe the surface and near surface mechanical properties of hard carbon (a:C-H) coatings (0.1-1 mum thick) deposited by_an ion beam method on 304 stainless steel substrates. At low loads, nanoindentation experiments clearly delineate the differing elastic and plastic properties of the coatings as a function of thickness and allow the fine-scale indentation-induced deformation and damage mechanisms to be assessed. By contrast, microindentation experiments have been used to show the cracking and deformation behaviour at larger contact loads where the behaviour of the substrate is important. The experimental techniques will be described, the results compared and the implications presented and discussed.