Kinetic study on nonisothermal dehydrogenation of TiH2 powders

The nonisothermal dehydrogenation of TiH2 powders was studied using thermogravimetry and differential scanning calorimetry. The reaction model was established by estimating the activation energy. The results show the nonisothermal dehydrogenation occurred in a four-step process. The hydrogen released from the TiH1.5∼2TiH1.5∼2 phase in the first step, which led to the decrease of activation energy. The second step was derived from the formation of βHβH in δδ phase and the reaction model was Phase boundary reaction. In the third step, the hydrogen started to release from the βHβH phase, and then the βH→αHβH→αH phase transformation happened. So the activation energy EαEα underwent a decrease followed by a quick increase. The fourth step corresponded to the formation of αHαH in βHβH phase, and the slight oxidation resulted in the small fluctuation of activation energy.