Residual stress, surface defects and corrosion resistance of CrN hard coatings

Metallic components like moulds, dies and machinery are subjected to degradation during plastic transformation processes, namely when working with abrasive fillers and corrosive components combined with relatively high processing temperatures. This degradation reduces the lifetime of the components considerably and has a direct impact on process productivity and surface finish of the final products. Nitride based hard coatings have proven their capability in increasing tool lifetime when being exposed to abrasive and corrosive environments. Within the aim of this article CrN hard coatings were deposited on steel substrates by magnetron sputtering. The growth process of the coatings generated compressive internal stresses of the order of -10 GPa. The mechanical and corrosion behaviour of the coated samples are influenced, among other factors, by these stresses and by the defects of the coatings. (C) 1999 Published by Elsevier Science S.A. All rights reserved.