The formation of hydrides and their propagation into the matrix for grade 2 titanium in 3.5%NaCl solution were examined in this paper. The critical potential for hydride formation increased with decreasing pH and increasing temperature. The pH had a more significant effect than the temperature. A surface film could significantly lower the critical potential for hydride formation. The hydride formation was controlled by the critical current density, which was constant for one material, regardless of
environmental conditions. The applied stress did not change the critical potential under the testing conditions used in this study. The microstructure of the hydride and its growth also strongly depended
on pH. Key words: titanium, polarization, XRD, hydrogen absorption, hydrides