A Reaction Rate Study in Hydrofluoric Acid of the Dissolution of Titanium and the Alpha Solid Solution of Oxygen in Titanium

Studies were conducted into the mechanism of dissolution in hydrofluoric-hydrochloric acid mixtures of titanium and of alpha solid solution specimens of oxygen in titanium. Special precautions were taken to preserve the trivalent state of titanium. For titanium a rate order of 0.76 and an activation energy of 6.9 ± 0.5 kcal was found and for titanium in TiO x a rate order of 0.83 and an activation energy of 6.6 ± 0.5 kcal. Furthermore, the oxygen content of TiO x, within the range studied, had no effect on the rate of hydrogen evolution; all specimens evolved hydrogen at the same fixed rate per unit area for a given temperature. It is concluded that a diffusionally controlled reaction can best explain the results. © 1961