(Ti,Cr)N and Ti/TiN PVD Coatings on 304 Stainelss Steel Substrates: texture and Residual Stress

Growth texture and residual stress were determined by X-ray Diffraction (XRD) methods in three different nitride coating systems (TiN or (Ti,Cr)N single-layers and TiN/Ti two-layers) deposited by reactive sputtering on AISI 304 stainless steel. All samples exhibited the fibre texture typical of many PVD layers grown under non-epitaxial conditions, and the nitride layer had the well-known fcc structure of δ-TiN. The main growth direction in TiN coatings (independently of the presence of the Ti buffer) was [111], even if a secondary [211] grain fraction was produced by a twin growth mechanism that partially relaxed the intense compressive stress (≈ −8 GPa). The Ti buffer layer, also in a compressive state, contributed to a further reduction of the in-plane compression in the TiN top coat. The residual stress in the (Ti,Cr)N coatings was very high (≈ −17 GPa), probably due to the different growth texture (nearly [h00]) and the absence of suitable stress relaxation mechanisms.