The reductive diffusion process was studied on the basis of the depth profiling. The phase and element depth profiling of mm grade Nd-Ni alloy were determine in the preparation of H absorption material by the reductive-diffusion process. Relative content of Ni, Nd, and Ca at different depths were studied using chem. anal., x-ray diffraction anal., x-ray photoelectronic spectroscopy, and SEM. The surface phase in Nd-Ni alloy was nearly pure Nd when the temperature was just 1000? At the depth >100 ? the presence of Ni and Ca were observed Nd and Ni diffuse into each other, but rate of diffusion of Nd is faster than that of Ni. When the temperature is 1000? the relative content of Ni and Ca increases but Nd decreases with increasing depth. When the reduction- is carred out at constant temperature, the Ca content in the products decreased with increasing time, and at 1000?for 4 h, the phase of the product is NdNi5 with Ca content of 0.3%.

Key words: NICKEL ALLOYS, DISTRIBUTION OF ELEMENT, HYDROGEN, X-RAY DIFFRACTION ANALYSIS, X-RAY PHOTOELECTRON SPECTROMETRY, X-RAY PHOTOELECTRON SPECTROMETRY, DEPTH, NEODYMIUM ALLOYS, STORAGE, CRYSTALLOCHEMICAL ANALYSIS