Effect of SiO₂ coating layer morphology on TiH₂ gas release characteristic

In this study, a uniform and compact SiO₂ film-coating layer was prepared on the surface of TiH₂ particles by sol-gel method using inexpensive raw materials. The preparation process of SiO₂-coated TiH₂ particles and the effect of the coating layer morphology on the gas release characteristic were investigated in detail. When the pH value of TiH₂ suspending solution is about 4.0 and the concentration of silicic acid is more than 0.5 mol/L, the coating layer shows a SiO₂ particle-coating morphology. While a homogeneous and dense film-coating layer can be obtained when the solution pH value and concentration of silicic acid are about 4.0 and 0.5 mol/L. The results of gas release at 700°C show that TiH₂ particles coated with silicon dioxide layers can efficiently delay the starting time of gas release of TiH₂ powders to 60-100 s. Comparing the particle-coating layer, the SiO₂ film-coating layer has a better delaying effect on gas release of TiH₂ particles.