Investigations of the Thermoelectric Power at High Hydrogen Pressure in the NiH and PdH Systems

The thermoelectric powers of NiH and PdH systems have been investigated at high hydrogen pressures (up to 14000 at) at 303 °K. It was found that in the case of the NiH system, the β-phase formed at about 7000 at has an nearly stoichiometric composition (H/Ni = 0.97). The nearly linear dependence of the absolute thermoelectric power of the NiH system on the atomic ratio can be explained in terms of a two-phase structure of the sample in a wide range of composition. In the pure β-phase the PdH system shows a linear dependence of the absolute thermoelectric power on the logarithm of the hydrogen fugacity.