In situ measurement of elastic properties of PdHx, PdDx, and PdTx

The Young's modulus E of palladium hydride PdHx, deuteride PdDx and tritide PdTx were measured for studying the effect of both hydrogen stoichiometry x and isotope nature. A special technique based on optical detection of flexural modes of a palladium cylindrical microcantilever was adapted to in situ measurements to guarantee the sample homogeneity during the hydriding process. A 10% decrease in E was found between pure polycrystalline palladium and hydride phases. The non linear dependence observed with the H content was discussed in terms of lattice expansion, phonons and electronic properties. Sensitivity of the technique enables to distinguish an isotope effect on E. (C) 2003 Elsevier B.V. All rights reserved.