The preparation of LaNi4.8A10.2 enwrapped by SiO2 sol

SiO2 sol was used to enwrap LaNi4.8Al0.2 to improve its hydrating performance. The sol viscosity was reduced gradually with the increase of water and time. In the SEM image of the dried solid it was found that many metal particles were embedded into the silica. The hydrating performance was studied at different parameters including the ratios of water, silica and LaNi4.8Al0.2, the granularity of the alloy, and the drying techniques. When the ratio of water and silica was 8:1, the hydrating speed of the solid was the fastest. The hydrogen absorption capacity per unit weight solid was increased with the decrease of LaNi4.8Al0.2. It was easier for the paste enwrapping metal when the granularity of metal particle was smaller, while the hydride capability of the solid was better. Furthermore, the hydrogen absorption capacity and absorption speed of the solid heated and dried in Ar was worse than that heated and dried in air. Thus the solid hydrating performance was not much relevant with the drying techniques. (authors)