EFFECTS OF THE CRYSTAL-STRUCTURE ON THE INTERNAL STRAIN IN NICKEL PLATED COPPER ELECTRODE DURING CATHODIC HYDROGEN EVOLUTION

The variation during hydrogen evolution of the internal strain with th e absorption and desorption of hydrogen was measured in situ for thin nickel films plated from Watts-type baths using a resistance wire-type strain gauge placed on the reverse side of the copper substrate. Plat ed bright nickel films with a (220) preferred orientation or a disorde red orientation tend to absorb hydrogen. Especially, the internal stra in in the former sharply changes to a compressive strain during the ab sorption of hydrogen and then returns quickly to the initial value dur ing its desorption after the current is turned off. On the other hand, the variation in the internal strain of plated mat nickel films with a (200) preferred orientation is minor during hydrogen evolution, and films of this orientation seem to absorb little hydrogen.