CHANGES IN LINEAR DIMENSIONS OF FLAT PALLADIUM SAMPLES DURING ABSORPTION AND DESORPTION OF HYDROGEN

Kinetic regularities pertaining to changes in linear dimensions of fla t palladium samples in the course of electrochemical hydrogen absorpti on and subsequent electrochemical or thermal hydrogen desorption are s tudied. Heat quantities generated during thermal hydrogen desorption f rom palladium are measured at temperatures of 400 and 600 degrees C in air and vacuum. The hydrogen absorption-desorption cycle is shown to give rise to irreversible changes in the crystalline lattice of pallad ium, the nature of the changes depending on the manner in which the hy drogen is desorbed. The electrochemical desorption leads to an increas e in the sample length, compared with the initial value. Conversely, t he thermal desorption results in the length decrease, which is presuma bly associated with the pulsed heating of the surface palladium layers during the thermal desorption of hydrogen from palladium.