Pd-Ag electrical resistivity in hydrogen and deuterium: Temperature effect

Abstract

The electrical resistivity of Pd-Ag (silver 21 wt.%) in hydrogen and deuterium atmosphere at 100 kPa has been investigated via electrochemical impedance spectroscopy. The electrical resistivity of Pd-Ag vs. the temperature presents the characteristic S-shaped curve with a minimum and a maximum of the resistivity in different positions for the tests in hydrogen and deuterium. The results have been related to: (1) the different isotope ratios, H/Mand D/M, and (2) their position in the Pd-Ag lattice. The behavior of the electrical resistivity is discussed in details by considering the hydrogen and deuterium uploading into the alloy, its effect on the conduction electrons, and the scattering of the isotopes atoms into the metal lattice. Measurements carried out in hydrogen with slow temperature ramping between 25-250 °C evidenced a hysteresis effect that can be explained by the different energy levels of isotopes in O-sites and T-sites.