Isotope effects in alpha-PdH(D) as an instrument for diagnosing bulk defects

Protium and deuterium sorption in the alpha -phase region is studied for hi ghly defective palladium electrodeposits fabricated under controllable pote ntiostatic modest particularly in the region of concentrated hydride format ion. An anomalously high hydrogen content is observed for these samples in both alpha- and beta -hydrides. On the basis of coulometry in the course of anodic hydrogen extraction, the nan-linear sorption isotherms are plotted and their specific features are considered under an assumption of simultane ous equilibrium sorption of hydrogen by several types of lattice positions with a certain degree of defectiveness. Less defective palladium samples de posited in the absence of bulk hydridization are studied for comparison. Th e approach is proposed to estimate the fraction of defective regions. The p rocedure of analyzing the low-pressure limit is used for the first time for determining the specific values of the isotope effect, and also H and D Si evert's constants. The isotope effect is demonstrated to be extremely sensi tive to the type of defectiveness.