Oxide formation on titanium alloys in primary water of nuclear pressurised water reactor

Abstract

Three titanium alloys were exposed to primary water at 300 °C. Oxides of the three alloys consisted of a dense layer and surface crystallites. The dense oxide layer of Ti CP was made of TiO2 rutile whereas it was made of TiO2 anatase for both Ti 64 and Ti10-2-3. Surface crystallites of the three alloys were composed of TiO2 anatase and FeTiO3 ilmenite. Oxide dissolution and precipitation phenomenon were found to play a key role in the corrosion mechanisms. Oxygen vacancies were identified as the main point defect responsible for the growth of the dense oxide layer.