Effect of Ti substitution on hydrogen storage properties of Zr1−xTixCo (x = 0, 0.1, 0.2, 0.3) alloys

Zr_1−xTi_xCo (x = 0, 0.1, 0.2, 0.3) alloys were prepared by arc-melting method and the effect of Ti substitution on hydrogen storage properties was studied systematically. Hydrogen desorption pressure-composition-temperature (PCT) measurements were carried out using Sievert's type volumetric apparatus for ZrCo (at 473 K, 573 K and 673 K) and Zr_1−xTi_xCo alloys (at 673 K), respectively. Products after dehydrogenation were characterized by X-ray diffraction (XRD). In addition, the kinetics of Zr_1−xTi_xCo hydride was investigated at 473 K and 673 K, respectively, under hydrogen pressure of 5 MPa. Results showed that Ti substitution for Zr did not change the crystal structure of ZrCo phase. With the increase of temperature from 473 K to 673 K, the extent of disproportionation for ZrCo alloy increased. With Ti content increasing at 673 K, the desorption equilibrium pressure of Zr_1−xTi_xCo-H₂ systems elevated and the disproportionation reaction of Zr_1−xTi_xCo alloys was inhibited effectively. Ti substitution decreased the kinetics rate and the effective hydrogen storage capacity of Zr_1−xTi_xCo alloys slightly. Generally speaking, it was found that Zr_0.8Ti_0.2Co alloy had better anti-disproportionation property with less decrease of effective hydrogen storage capacity which was beneficial to tritium application in the International Thermonuclear Experimental Reactor (ITER).