Гидрирование порошка Ti-Ni, подвергнутого механохимическому легированию титаном

Abstract

The paper studies the structure and phase composition of Ti-Ni alloy of near-equiatomic composition after its mechanochemical alloying with titanium in a planetary ball mill and subsequent heat treatment and hydrogen sorption during hydrogenation. The content of titanium in powder mixtures varied from 7 to 25 wt.%. It is shown that the phase composition of the Ti-Ni powder before mechanochemical alloying consisted of TiNi ( B 2, B 19'), Ti2Ni and Ni3Ti phases. The (Ti-Ni) - Ti powders consisted of TiNi ( B 2, B 19') and Ti2Ni phases after mechanochemical alloying and subsequent heat treatment. It was revealed that the Ti2Ni phase had a different genesis. The Ti2Ni (I) phase existed in the Ti-Ni powder before mechanochemical alloying, the lattice parameter the Ti2Ni (I) did not change and was equal to 1.1283± 5∙10-4 nm. Phase Ti2Ni (II) is formed in the process of mechanochemical alloying and subsequent heat treatment, the lattice parameter of Ti2Ni (II) decreased with increasing titanium content added into the Ti-Ni powder during alloying. It was revealed that the composition Ti-Ni (85 wt.%) - Ti (15 wt.%) has the maximum content of the Ti2Ni phase. It is shown that the average particle size increased with an increasing of titanium content added into the Ti-Ni powder during alloying and subsequent heat treatment due to the process of particle consolidation. Hydrogenation of a Ti-Ni (85 wt.%) - Ti (15wt.%) powder during 90 min leads to a change in the Ti2Ni (II) lattice parameter, which corresponds to the Ti2NiH1.9 hydride parameter, and during 360 min, to Ti2NiH2.8.