An explanation of hysteresis of electrical resistance–composition relationship in the Pd–H(D) and Pd alloy–H(D) systems measured by a gas phase method

Hysteresis of electrical resistance–hydrogen (deuterium) content relationship in the α + β two-phase region of the Pd–H(D) system measured by a gas phase method was found by Sakamoto et al. [20,21], and subsequently verified and extended to Pd alloy–H(D) systems by Kibria et al. [22–28]. However, the evidence of this phenomenon is not reliable because the resistance was measured from one sample and the hydrogen content was determined from other samples in the same vessel. In this paper, it is proposed that the ‘hysteresis’ is attributed to the inequality of plateau pressures between these two sorts of samples during the α ↔ β phase transitions of the Pd–H(D) and Pd alloy–H(D) systems. Some phenomena accompanied are also discussed on this basis.