Hydride Formation at Cathodic Charging of α-Ti

The hydrogen absorption and the formation of the hydride phase at cathodic polarization of annealed α-Ti have been studied by the kinetic hydrogen extraction and by the X-ray diffraction methods. The electrochemical parameters of cathodic hydrogen charging have been selected in order to obtain the hydrogen present in the solid solution of α-Ti lattice and the hydride phase to be formed. In 2M NaOH solution, the hydride phase has been already formed at cathodic polarization lower than 1 mA/cm². In the case of 0.1M NaOH, the polarization regions (i) of hydrogen dissolution in the solid phase (ii) of hydride precipitation and (iii) of formation the increased amount of hydride phase have been distinguished in the course of application of increased cathodic polarization. Hydrogen dissolved in the metal lattice produces its dilatation, whereas presence of hydride phase causes the contraction of Ti lattice. Increased cathodic polarization causes the increase it the amount of hydride phase and the increase in the hydrogen content in TiH_x phase as well.