| Research Abstract |
The pressure-composition isotherms of dihydride formation in (V_<1-x>Ti_x)_<1-y>M_y (x=0.1-0.2 ; M=A1, si, Zr, Cr, Fe, Co, Ni, y=0.01 - 0.1) alloys were determined at temepe-ratures between 273 K and 433 K and hydrogen pressures up to 3MPa. The effect of absorption-desorption cycles on the hydriding properties were also examined, together with an evaluation of the pulverization resistance. It was found from the experiments on hydriding cycles that the V_<0.9>Ti_<0.1> alloys with chromium showed a good pulverization resistance and no significant deterioration of the effective hydrogen content, although the hysteresis factor was relatively large. The hydrogen absorption rate increases markedly with titanium content and the rate is reduced by the addition of silicon and iron. The enthalpy change :DELTAH:for gamma-dihydride formation and decomposition decraeses slightly by alloying with silicon, aluminium, iron, cobalt and nickel. The addition of chromium does not affect the DELTAH value in the case of the low titanium alloy as zirconium does, but reduces it for the high titanium alloys.
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