dency to adsorb hydrogen involves heavy plastic deformation under pressure and subsequent complete or partial
dehydrogenation. The formation of a nanocrystalline structure in the palladium–hydrogen system was studied.
The coarse-grained disklike palladium specimens 6 mm in diameter and 0.3 mm in thickness were electrolyti-
cally hydrogenated to a level ensuring the formation of
hydride PdH0.7. Then the palladium specimens and the specimens containing
-PdHx (x = 0.01) + -PdH0.7 were deformed by shear under pressure to 
= 7–8 at 20 and –196°C. The deformation of the initial palladium specimens to
= 7 decreases their grain size to 50–100 nm, and the deformation of the specimens containing hydrides to
= 7–8 both at 20 and at –196°C decreases their grain size to 15–20 nm and, in some regions, to 3–5 nm. Annealing at 180°C for 1 h or holding
at room temperature for more than seven days causes partial dehydrogenation of the hydrogenated deformed
nanocrystalline palladium specimens (n-Pd). The grain size of n-Pd was shown by electron microscopy to be
unaffected by dehydrogenation, remaining unchanged at 3–20 nm.