A device for in situ X-ray diffraction measurements during cathodic hydroge
n charging has been developed. The lattice change on Pd before and after hy
drogen charging has been clearly demonstrated. The results of Delta a/a for
Pd and Ni during increasing hydrogen concentration have been shown. The de
vice is effective for understanding metal-hydrogen systems under various co
nstrained hydrogen environments. (C) 1999 Elsevier Science S.A. All rights
reserved.