Measurements of the Temperature Coefficient of Electric Resistivity of Hydrogen Overloaded Pd

As reported in previous papers, we performed many electrolytic loading tests using thin Pd wires, achieving loading ratios of H/Pd ≥ 0.95 (H/Pd over-loading). In particular, we defined a reproducible "loading protocol" suitable for achieving such an over-loading level, based on the use of very diluted acid electrolytic solutions (with additions of tenths of micro-moles of Ca or Sr or Li cations and some hundred nano-moles of Hg ions) and operating with electrolytic current cycles from a few mA up to one hundred mA. By observing the day/night cyclic fluctuations of electrical resistance, as a function of the corresponding temperature variations, of stable, long term, H/Pd loadings we were able to calculate the temperature coefficient of resistivity (K_0) of the Pd-H system at very high H/Pd loadings. Many years ago (on 1998) we reported an unexpected value showing that the K_0 parameter values increase when H/Pd exceeds 0.75 (i.e. after that R/Ro goes beyond the 1.8 peak value, i.e. to the right side of the R/Ro / H/Pd curve). This fact was confirmed by the ISR-Stanford Group (McKubre and Tripodi) and Pirelli-Research Group (Gamberale and Garbelli). In this paper we show several measurements of K_0 at different overloading values of H/Pd up to ≅ 1 (corresponding at R/Ro=1.12) where K_0 =(13±1) * 10^-3 K^-1 , i.e. more than six times higher than the minimum value achieved at the R/Ro=1.8 peak value. This result can corroborate the hypothesis that a new Pd-H phase (full β-phase or the beginning of β+α phase) could occur after the H/Pd=0.75 loading ratio (at the end of β+α phase), as claimed by many authors as the necessary condition for excess (anomalous) heat from Pd-D system (at D/Pd ≥ 1).