Hydrogen Absorption of Palladium Thin Films Observed by in Situ Transmission Electron Microscopy with an
Tengfei Zhang1, Yuki Nakagawa1, Takenobu Wakasugi1
1Graduate School of Engineering, Hokkaido University , N-13, W-8, Sapporo 060-8628, Japan.
Abstract:
A window type of the environmental cell system for a high-voltage electron microscope was developed and applied to in situ observation of a palladium (Pd) thin film. For in situ hydrogenation of Pd thin films, the distances of the lattice fringes were 0.20 and 0.23 nm, which correspond to the lattice d spacings of β-phase (200) and (111) planes. Expansion of the Pd lattice happened as a result of phase transformation from the α phase to the β phase. In particular, the lattice fringes were clearly distinguished, and the dislocation behavior during Pd hydrogenation was easily recognized according to the corresponding inverse fast fourier transform images. Furthermore, significant growth in the number of dislocations was observed at the grain boundary during increasing hydrogen pressure in the cell.
