Mechanical properties of ion-plated TiN films on AISI D2 steel

TiN films were deposited on AISI D2 steel substrates without and with a tit anium intermediate layer using a hollow cathode discharge (HCD) ion plating technique. The structure of the him was determined by X-ray diffraction (X RD) and the composition was measured by X-ray photoelectron spectroscopy (X PS). The microhardness and adhesive strength of the as-deposited coatings w ere measured as well. The results of X-ray diffraction and X-say rocking cu rves showed that the TiN film exhibited a (111) preferred orientation. The hardness of coatings was found to be related to the N/Ti composition ratio and the porosity in the TiN films. The results of scratch test show that th e high critical load is a measure of the adhesion of the TiN film, while th e low critical load can be used as a qualitative measure of the toughness o f the TiN film. The interfacial diffusion depth increased with the average substrate temperature during the ion plating process. From the results of s cratch test and the depth profiles of secondary ion mass spectrometry (SIMS ), the adhesive strength of the coating/substrate interface increased with increasing interdiffusion depth. Moreover, the results indicated that the T i interlayer can enhance the adhesion strength of the coatings. (C) 1998 El sevier Science S.A. All rights reserved.