The effect of the hydrogenation process on the production of lattice defects in Pd

Abstract: The effect of the hydrogen absorption and desorption process on the production of lattice defects in pure Pd was studied by means of positron lifetime spectroscopy. Pd hydrogenated and dehydrogenated at 623K contains some dislocations but few metal vacancies. In contrast, a remarkable vacancy production was observed in Pd hydrogenated at 623K and subsequently electrochemically dehydrogenated at ambient temperature. This result shows that vacancies are formed during the hydrogen desorption process at RT, and suggests that the vacancy formation is caused by the effect of stresses accompanied by the phase separation. [Copyright &y& Elsevier]