Depth-resolved X-ray analysis of residual stresses in graded PVD coatings of Ti(C,N)

Thin hard coatings are widely employed in order to improve the efficiency o f cutting and forging processes by increasing wear and corrosion resistance of the tools. Recent investigations have shown that PVD-gradient coatings of Ti(C,N) on cutting edges of cemented carbide exhibit a significantly gre ater wear resistance than conventional TiC or TiN coatings. However, beside the microstructure and composition the residual stress state in the coatin gs strongly influence the in-service performance. In addition to TEM and SE M investigation on the microstructure, X-ray residual stress analyses on Ti (C,N)-gradient coatings were performed. The special approach employed for t he non-destructive depth-resolved determination of the residual stress stat es and stress-free lattice parameters in the gradient coatings is presented together with results obtained from selected Ti(C,N)-gradient coatings.