Non-isothermal and isothermal hydrogen desorption kinetics of zirconium hydride

Thermal desorption behaviors of zirconium hydride powder under non-isothermal and isothermal heat treatment conditions were studied using simultaneous TG-TDS. The phase transformation sequences were established by correlating the observed peaks of H-2 release and mass loss. The origins of the peaks or shoulders in the TDS spectra were described as the equilibrium hydrogen pressures of a number of consecutive phase regions that decomposition reaction passed through. Effect of held temperature on the isothermal desorption behavior was taken into consideration, which was shown to be essential for the phase transformation sequence during ZrH2 decomposition. The zirconium monohydride gamma ZrH was observed at ambient conditions, which has been supposed to be metastable for a long time. (C) 2015 Elsevier B.V. All rights reserved.