Raman microscopic studies of PVD hard coatings

A series of PVD ceramic hard coatings (TiN, 21 N, TiAlN, TiZrN and TiCN) we re deposited on steel substrates using the cathodic arc/unbalanced magnetro n deposition technique. These coatings were characterised using Raman micro scopy to elucidate the behaviour of the optic and acoustic phonon modes of the (cubic) crystalline lattices. Defect-induced first- (and second-) order spectra have been observed in the 200-300 and 500-800 cm(-1) regions and t hese have been assigned and correlated with coating composition. Changes in the position, intensity and shape of the principal TO band (640-560 cm(-1) ) have been interpreted. Raman microscopy has been shown to be a very useful non-destructive complem entary technique to XRD for the characterisation of PVD hard coatings. (C) 1999 Elsevier Science S.A. All rights reserved.