Assessment of different X-ray stress measuring techniques for thin titanium nitride coatings

Abstract

Three different X-ray stress measuring techniques have been applied to thin titanium nitride coatings: the classical d-sin(2)psi method, a low incident-beam-angle method and the crystallite-group method. The results are used for a comparison of the three methods. The influence of the crystallographic texture is studied by considering a set of coatings with a strong (111) fibre texture and another set with a weaker and mixed fibre texture. It is shown that no significant differences in the stresses in the latter coatings are found using the three methods, whereas the coatings with strong (111) fibre texture exhibit compressive stresses that are significantly higher when the crystallite-group method is used. This is explained by the fact that (111)-oriented grains sustain stresses that are about 30% higher than those of the grains that show a deviation of 10 degrees from this orientation. Non-linearities in the d-sin(2)psi curves are reported that cannot be explained by means of linear elastic theories. (C) 2000 International Union of Crystallography Printed in Great Britain - all rights reserved.