Abstract

The effects of hydrogen insertion by electrolytic charging in pure nickel were investigated by scanning electron microscopy (SEM) and X-ray diffraction. The hydrogenated simples (thin foils of 0,02mm) contained at least 50% of NiH0.68 hydride just after charging. The NiH0.68 hydride and the alpha-Ni phase were distinguished by scanning electrón microscopy (SEM) operating in the backscattered electrons mode. The difference of density or an average atomic number between the two phases was enough to obtain a contrast between them. The instability of the nickel hydride at room temperature was observed by X-ray diffractíon and by SEM. Interesting features about the intergranular cracks developed during and after charging are discussed.