Estimating volume fractions of superabundant vacancy phases and their potential roles in low energy nuclear reactions and high conductivity in the palladium – isotopic hydrogen system

Highlights

• Superabundant vacancy SAV phase (δ) plays role in Low Energy Nuclear Reactions LENR.

• Long strings of Pd-vacancies form tubes in δ phase supporting resonance and LENR.

• SAV phase (δ′) has very low electrical resistance with volume fraction near 5%.

• SAV (δ) is nuclear active environment NEA for LENR with volume fraction only 0.03%.

• SAV (δ′) Fraction estimated from resistivity in multiphase Pd-D using rule of mixture.

Abstract

The addition of three superabundant vacancy (SAV) phases, γ (Pd₇VacD_6–8), δ (Pd₃VacD₄ – octahedral), and δ′ (Pd₃VacD₄ – tetrahedral) to the palladium – isotopic hydrogen phase diagram was recently reported [1]. Also, in that study, production of excess heat from a nuclear source during electrolysis in heavy water indicated portions of the palladium (Pd) – deuterium (D) specimen were in the ordered δ phase, while a drop in resistance of the Pd during excess heat, with an increase in temperature, indicated portions of the specimen had shifted to the ordered δ′ phase. Both δ and δ′, create intersecting channels along the edges of the unit cells which are in effect long strings of Pd lattice vacancies for fast electron transport or a deuteron resonance condition. At high D/Pd ratio, the Pd-D alloy can be multiphase. An estimate of the volume fraction (f_v) of δ phase is made from the amount of nuclear energy measured. An estimate of f_v of δ′ is made from the measurement of the change in resistivity of the overall multiphase Pd-D alloy using the rule of mixtures. Both δ and δ′ have low volume fractions with f_v(δ) ≈ 0.03% and f_v(δ′) ≈ 5%. These experimental measurements suggest that δ is the nuclear active environment (NAE) for low energy nuclear reactions (LENR) while δ′ is likely a high conducting state (phase). Which interstitial site (octahedral or tetrahedral) is occupied by isotopic hydrogen would determine whether the phase is nuclear active or highly conductive. These two phases are distinct and can coexist as minor volumetric components (phases) because they are both of low volume fractions, share the same composition (arrangement of Pd and lattice vacancy sites, and can also share the same D/Pd ratio), and result from hydrogen-induced vacancy formation. Thus, portions of the specimen can be producing nuclear energy (excess heat) while other portions can be highly conductive.