Hydrogen absorption behavior of TC4 compacts

The relation of equilibrium hydrogen pressure with temperature and the hydrogen absorption kinetic behavior of TC4 compacts were investigated with a tubular hydrogen treatment furnace. The rate constant, reaction mechanisms and activation energy of hydrogen absorption at different temperatures were also determined. It is found that the time to reach equilibrium decreases with increasing temperature, but the equilibrium hydrogen pressure increases with increasing temperature. The hydrogen absorption process at 350℃ is controlled by the nucleation and growth, power law and three-dimensional diffusion, the hydrogen absorption process at 400℃ is controlled by the power law and three-dimensional diffusion, while the hydrogen absorption process from 450 to 750℃ is only controlled by the three-dimensional diffusion. The activation energy for hydrogen absorption by TC4 compacts is found to be 14.55 kJ·mol^-1.