Abstract
We developed a new sample holder for small-angle neutron scattering (SANS) experiments under controlled atmospheres. Using this new sample holder, SANS profiles of conventional hydrogen-absorbing alloy LaNi5 under a deuterium atmosphere were measured. Changes in the SANS profile of LaNi5 were clearly observed during absorption and desorption. It was found that there is reversibility in the surface morphology of LaNi5; it changed from being markedly rough (fractal dimension of particle surface DS = 2.8, before deuteration) to smoother (DS = 2.5 at 1.05 D/M, i.e., LaNi5D6.3) during absorption (up to 1 MPa), and then reverted to being rough (DS = 2.8) during desorption (under vacuum <5 Pa), where D/M is the deuterium-to-metal ratio.
