ГИДРИРОВАНИЕ СПЛАВА Ti 80 Fe 20

We investigated the interaction of alloy of composition 80 at. % of Ti + 20 at. % of Fe (Ti 80 Fe 20 ) with ammonia under pressure of 0.6 ÷ 0.8 MPa at the temperatures 100 ÷ 500 oC: the phase transformations in the Ti 80 Fe 20 –NH 3 system were defined; the composition of products was established; the formation conditions of the hydride and nitride phases were found; the formation temperatures of the hydride phases with the greatest possible content of hydrogen for use of alloy in the metal hydride accumulators of hydrogen were determined. The study shows the dependence of the reaction direction of alloy with ammonia, taking place in presence of NH 4 Cl (the 10 wt. % of alloy quantity) as activator, on temperature. One of the products of the reaction, which is carried out at 100 oC, is the hydride phase of composition Ti 4 FeH 8.3 . With further a slight increase in temperature of reaction, this phase decomposes on hydride phases of the titanium and of the intermetallic compound TiFe. At interaction temperature of 200 oC and above, insignificant amount of nitrogen is introduced into a metal lattice of hydride of an intermetallide of TiFeH -2 with formation of the phase TiFeH -2 N x . At temperature of 350 oC and above, the titanium nitride TiN appears as a part of reaction product. The interaction of alloy and ammonia at 500 oC leads to mixture of titanium nitride and metallic - Fe. The sharp increase in a specific surface area of reaction products at increase in process temperature from 250 oC to 400 oC (from 0.2 m 2 /g to 46.4 m 2 /g) is shown to demonstrate the formation of mixture of high-disperse powders. The metal hydride accumulator of hydrogen on the basis of the studied alloy can work in a temperature range of room temperature to 600 oC and allocate up to 3 wt. % of hydrogen.