Penetration depths of hydride phases in cylindrical Ni samples and in Ni-rich Pd–Ni alloys

The penetration depths of the hydride phases at 298 K and 6.8 kbar of gaseous hydrogen have been determined for cylindrical samples of Ni and Pd–Ni alloys, consisting of equal or more than 94 at.% of nickel. For PdxNi1−x ( x = 0.04 , 0.06) alloys, a linear dependence between thickness of the hydride ring and the wire radius has been found. The analogous function for Ni–1% Pd and Ni–1.94% Pd exhibits a parabolic course, revealing limitation in penetration depths. The maximum penetration depth of nickel hydride is about 50 μm. The general trend in the maximal penetration depths is that an increase of Pd concentration causes an increase of the maximal penetration depth.