The coating process of TiH2 particles with SiO2 layers, and the effect of the coating layer on hydrogen release characteristic of TiH2 powders were studied experimentally. The gelation rate of silicic acid is an important factor for controlling the surface morphologies of coating layers. When the concentration of SiO2-3 is about 0.5 mol/L, the condensation rate of silicic acid is appropriate for the formation of a homogeneous and dense coating membrane. The results of hydrogen release at 700 ℃ show that TiH2 particles coated with silicon dioxide layers can efficiently delay the starting time of hydrogen release of TiH2 powders to 60100 s.
Cu(NO3)2 and (NH4)6H2W12O40?4H2O were used to prepare W/Cu nanosized composite powder by sol-gel tech-nique. The influences of heat treatment process, pH value of the solution and the amount of an addition agent on particle size were investigated by DSC, XRD and TEM. The results show that, at a certain heat treatment temperature, the W/Cu nanoparticle size increases with the pH value or the amount of the addition agent increasing.
