Stable region of ZrCo under hydrogen atmosphere at high temperature

In this work, the unusual reproportionation phenomenon, which occurs under hydrogen atmosphere, has been studied for the first time by combing temperature-programmed dehydrogenation and XRD characterization. The phase transition from ZrCo2 ZrH2 to ZrCo for reproportionation was clearly observed without vacuum pumping. It was shown that the reproportionation could take place even under hydrogen pressure of 0.65 bar at 640 degrees C. In addition, the reproportionation behaviors under different initial hydrogen pressures were investigated and the onset boundary for reproportionation was successfully established. The original insight into the unusual reproportionation phenomenon reveals that there is a stable region for ZrCo under hydrogen atmosphere at high temperature. On the basis of this work, it is hopeful that the application of ZrCo at high temperature will be substantially broadened. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.