Effect of Ni content on the hydrogen storage behavior of ZrGo_(1-x)Ni_x alloys

摘要

ZrGo_(1-x)Ni_x (x = 0,0.1,0.2 and 0.3) alloys were prepared and their hydrogen storage behavior were studied. ZrGo_(1-x)Ni_x alloys of compositions with x = 0,0.1,0.2 and 0.3 prepared by arc-melting method and characterized by X-ray diffraction analysis. XRD analysis showed that the alloys of composition with x = 0,0.1, 0.2 and 0.3 forms cubic phase similar to ZrCo with traces of ZrCo_2 phase. A trace amount of an additional phase similar to ZrNi was found for the alloy with composition x = 0.3. Hydrogen desorption pressure-composition-temperature (PCT) measurements were carried out using Sievert's type volumetric apparatus and the hydrogen desorption pressure-composition isotherms (PCIs) were generated for all the alloys in the temperature range of 523-603 K. A single sloping plateau was observed for each isotherm and the plateau pressure was found to increase with increasing Ni content in ZrGo_(1-x)Ni_x alloys at the same experimental temperature. A van't Hoff plot was constructed using plateau pressure data of each pressure-composition isotherm and the thermody-namic parameters were calculated for desorption of hydrogen in the ZrGo_(1-x)Ni_x-H_2 systems. The enthalpy and entropy change for desorption of hydrogen were calculated. In addition, the hydrogen absorption-desorption cyclic life studies were performed on ZrGo_(1-x)Ni_x alloys at 583 K up to 50 cycles. It was observed that with increasing Ni content the durability against disproportionation of alloys increases.