Synthesis of the dihydride phase of vanadium

Abstract

There are two constituents that determine success in synthesizing vanadium hydride: activation and supply of hydrogen to vanadium at an appropriate pressure. The most efficient activation has been found to occur, depending on the vacuum produced in a facility, in temperature ranges between 550 and 750 K or above 850 K. Dependencies of equilibrium sorption pressures of protium and deuterium over respective dihydride phases of vanadium are provided. At an atomic ratio of 0.85 ≤ X/V ≤ 1.5 (X is protium or deuterium), they take the following form, respectively, log P ( Pa ) = − 2160 / T + 12.8 and log P ( Pa ) = − 2480 / T + 13.6 . At higher hydrogen concentrations, coefficients in the Van’t Hoff equation are observed to depend on the hydrogen content. Based on the obtained experimental data on equilibrium sorption pressures and available literature data on isotopic effects, the same dependence of sorption pressure has been calculated for vanadium ditritide. For T/V = 0.85 , it is expressed as: log P ( Pa ) = − 2490 / T + 13.4 . Dependencies of equilibrium sorption pressures for all the three hydrogen isotopes at temperatures between 273 and 323 K and ratios of 0.85 ≤ ( H, D or X ) / V ≤ 1.9 are presented in the form of diagrams.