NMR study of hydrogen diffusion in the three different phases of the titanium-hydrogen system

摘要: Abstract The proton spin lattice relaxation time T 1 has been measured by an NMR pulse technique at 19.00 MHz as a function of temperature in the range 25°–500°C for series samples α, β and γ phases titanium hydride. mechanism α was governed primarily hydrogen diffusion over most range. diffusional activation energy phase found to be constant with respect concentration, having value 11.77 ± 0.4 kcal mole , attempt jump frequency proportional available local vacancies. behavior is discussed relation previously proposed model compared data on optical mode vibrations. Evidence uniform distribution when ratio titanium, x greater than 1.6 while clustering takes place lower ratios. low transition concentration = related electronic structure from ( ) e data. conduction electrons were primary cause near room contribution this rate increased increase concentration. ranged 190 4sec-°K 62.5 2 sec −°K (the atoms) varied 1.55 1.90. + gg, boundary between 25° 100°C. Diffusion parameters gradual region observed. observed heating-cooling hysteresis effect displayed. 450°C TiH 0.78 mainly of( 58±5 −° K found.