A nondestructive x-ray diffraction technique has been developed to analyze small diffusion zones. This technique constitutes a new approach to the study of one-dimensional volume diffusion and only requires intensity measurements from two different reflections. It has the distinct advantages of permitting a determination of both the concentration profile and the atomic arrangements associated with the diffusion zone. Data for the Cu–Ni system is presented to provide an example of the technique. The composition profile resulting from the interdiffusion of an 8-μ Ni deposit and a Cu single crystal at 900°C for 45 min was determined. Good agreement was found between these experimental results and a composition curve calculated from DaSilva-Mehl diffusion coefficients. It has also been found that volume diffusion significantly increases the degree of crystalline misorientation along the diffusion zone. The structure of the as-plated Ni deposits on a Cu single crystal was found to undergo a large misorientation change, initially, but maintained a relatively constant degree of epitaxy for longer diffusion times.
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