Some new aspects in X-ray stress analysis of thin layers

Due to their influence on the mechanical properties, residual stresses in t hin hard coatings and their non-destructive analysis by X-ray diffraction h ave become an important topic in materials science. Because it is possible today to achieve defined internal stress gradients with respect to the laye r thickness by appropriate variation of the deposition parameters, the appl ied diffraction methods have to meet the demand for a depth-resolved stress evaluation. By the example of thin PVD coatings of Ti1-xCrxN with a marked [111] fibre texture, the paper compares several methods in X-ray stress an alysis (XSA) concerning their suitability for the detection of stress gradi ents in thin layers. The best results are obtained by means of the scatteri ng vector method, where the lattice spacing depth profiles, d(phi psi)(hkl, tau), are measured after stepwise rotation of the sample around the scatte ring vector g(phi psi) near the intensity poles of the texture. (C) 1999 El sevier Science S.A. All rights reserved.