The passivation of Ti-2 by Fe(III) and Cu(II) species in acidic chloride solutions was investigated by electrochemical techniques. It was found that the critical concentrations of Fe (III) and Cu(II) species required to induce passivation of Ti-2 increased from 1.0 +/- 0 to 6.0 +/- 0 mM and from 0.25 +/- 0 to 1.15 +/- 0.23 mM, respectively, when the temperature was increased from 30 degrees C to 80 degrees C. The mechanism associated with the passivation was the acceleration of the cathodic reactions due to the introduction of oxidants for Ti-2. Cu(II) was more effective than Fe(III) at inducing the passivation of Ti-2 for the conditions investigated here. (C) 2019 The Electrochemical Society.