Evaluation of four commercially produced surface treatments

The paper reports the results of characterization of four commercial surface treatments on M2 tool steel substrates. The treatments characterized were (a) TiN deposited by physical vapor deposition (PVD), (b) TiCN/TiN multilayer also deposited by PVD, (c) diamond-like carbon (DLC) deposited by an ion-assisted technique, and (d) vanadium carbide (VC) produced by a thermal diffusion process. The surface treatments were evaluated for characteristics relevant to their tribological performance, such as thickness, roughness, chemical composition, micro- and nanohardness, coating-substrate adhesion, and wear resistance. In addition, a hardness model developed at the University of Newcastle upon Tyne (United Kingdom) to correct for substrate effects was successfully applied. Nanohardness tests also yielded the elastic modulus values of the surface treatments, while scratch testing used for determining coating-substrate adhesion provided qualitative information on their ductility.