Effect of ball-milling with Ni and Raney Ni on surface structural characteristics of TiV2.1Ni0.3 alloy

Surface structural characteristics of TiV2.1Ni0.3-Ni and TiV2.1Ni0.3-Raney Ni composites, which were prepared by ball-milling a TiV2.1Ni0.3 alloy with Ni or Raney Ni under an Ar atmosphere, were investigated by X-ray diffract ometry, Auger electron spectrometric analysis (AES) and so on. The ball-mil ling with Ni or Raney Ni did not influence the bulk crystal structure of th e TiV2.1Ni0.3 alloy. The mutual diffusion layer, which was presumed to be r esponsible for retarding the progress of the corrosion, was found to be for med in the interface region between Ni and alloy components during the ball -milling with Ni or Raney Ni. The AES depth profile of the constituent elem ents for the TiV2.1Ni0.3-Ni composite, however, was different from the TiV2 .1Ni0.3-Raney Ni composite due to the difference in the coverage and the ho mogeneity of the surface modification, which also influenced the time cours e of the rest potential. The ball-milling with Ni and Raney Ni greatly decr eased the onset temperature of weight loss assigned to dehydriding from dih ydride to monohydride and from monohydride to alloy. (C) 2001 Elsevier Scie nce B.V. All rights reserved.