coating thickness determination

by x-ray  fluorescence spectrometry

Ljubica Totovski

Military Technical Institute, Belgrade, totovski@sezampro.rs

Abstract: X-ray fluorescence spectrometry is a powerful and nondestructive analytical technique for chemical composition analysis of various materials. Its application for determination of coating thickness is based on variations of characteristic spectral lines intensity with thickness. With increasing thickness of a coating or thin film, intensity of characteristic lines of the coating increases and the intensity of the base metal characteristic spectral lines decreases. Consequently, two methods can be applied, which are based on: a) measuring the characteristic line intensity of the coating and b) measuring the attenuation of substrate characteristic lines intensity. Both methods were applied using calibration standards with different combinations of coating and base material and experimental calibration curves were obtained. Also, for the same combinations of elements, calculated calibration curves were simulated and compared with those experimentally obtained. Good agreement of experimentally obtained and calculated curves has shown that it is possible to predict the parameters of calibration curves for any combination of coating and substrate element and to determine thickness without calibration standards