X-ray Path Length Research Articles

X-ray examination of diffused films

X-ray diffraction has been used to provide a non-destructive measurement of composition profiles in diffused films, as well as simultaneous measurements of those structural changes associated with diffusion processes. Two methods are discussed which are capable of giving composition profiles in thick diffused films. The first makes use of differences in X-ray path lengths for two orders of reflection from planes of the same composition, while the second makes use of computer simulations of X-ray intensity bands using known solutions of the diffusion equation. The ease of data collection and reduction varies considerably with the texture of the material under study. Single-crystal substrates greatly simplify the overall X-ray approach. Considerable broadening is observed within the X-ray bands, which may be analyzed for both subgrain tilt and size. The results suggest that for those cases examined the diffusion-induced damage is comparable with that of highly deformed metals. Since the broadening is time dependent and diffusion is structure sensitive, one would expect to find a time dependence associated with diffusion coefficients.