DIFFUSION OF HYDROGEN IN NICKEL.

Abstract

The diffusivity and solubility of hydrogen in both the annealed and cold worked polycrystalline nickel were determined in the temperature range from 10 to 60 degree C by an electrochemical permeation technique. The diffusivity was found to increase slightly with the increase in grain size, whereas there is an enhanced solubility of hydrogen at grain boundaries. The cold working of nickel results in a lower value of diffusivity, producing not only an increase in the solubility of hydrogen but also a change in the mode of absorption from endothermic to exothermic.