HYDROGEN PRESSURE HYDROGEN CONTENT AND ELECTRICAL-RESISTANCE HYDROGENCONTENT RELATIONSHIPS OF PALLADIUM AND PALLADIUM ALLOY HYDROGEN SYSTEMS

Increasingly detailed findings of hydrogen pressure-hydrogen content-t emperature [p-c(n)-T] relationships of the palladium-hydrogen system h ave continued to be reported and there have also been very substantial increases in pc(n)-T information for palladium alloy-hydrogen systems , extending to a very wide range of alloy composition. One convenient technique for obtaining pc(n)-T relationships at near 25 degrees C has involved derivations from electrode potential measurements using spec imens with which sensitive changes of electrical resistance could be m easured in conjunction. Discussion continues in regard to origins of h ysteretic differences between forms of relationships obtained in cours es of increases or decreases of hydrogen content, respectively. Associ ated discussion also continues concerning critical points defined with reference to suppression of hysteresis effects. In these regards ther e has been recent research interest in the hydrogen systems of palladi um alternatively allied with either of pairs of elements in the same s ubgroup of transition metals, namely Ti, Zr; V, Nb and Sc, Y. Results have emphasized the key role of relative atomic dimensional and electr onegative differences between the alloying elements in determining the ir modifying influences on p-c(n)-T relationships.