Pourbaix diagrams for titanium in concentrated aqueous lithium bromide solutions at 25 °C

Pourbaix diagrams (electrode potential-pH diagrams) for Ti–Br−–H2O system at 25 °C in the absence and presence of titanium hydrides were developed in 400, 700, 850, and 992 g/L LiBr solutions. The diagrams were compared with the simple Ti–H2O system at 25 °C. Comparison of the simple Ti–H2O system with the diagrams of the Ti–Br−–H2O system at 25 °C showed that the titanium solubility range in the acid, neutral, and weak alkaline areas of the diagrams extended slightly to both higher pH values and potentials with increasing bromide ion activity and decreasing water activity.

Research highlights
► The titanium solubility range increases slightly with increasing Br− activity.
► The passivation area decreases slightly with increasing Br− activity.
► Immunity area increases slightly with increasing Br− activity.
► The titanium immunity disappears in the presence of titanium hydrides.
► TiH2 is the stable species at low potentials in the presence of titanium hydrides.