Flow-accelerated corrosion of Ti64 and surface-nitrided Ti64 in pressurised water at 300 °C

ABSTRACT At 300°C, in purified simulated primary water flowing at 7 m·s -1 , surface-nitrided and untreated Ti64 samples were oxidised to a continuous layer of TiO 2 containing anatase grains, while rutile grains formed only on nitrided Ti64. Between 9 and 36 days, their surface was covered by a protective layer of FeTiO 3 , which ultimately dissolved. Afterwards, their average corrosion rate was approximately 5 µm·year -1 . A flow-accelerated corrosion model was adapted to these conditions. It predicts that the corrosion rate of both materials would increase with fluid speed and stabilize once the fluid speed reaches 5 to 10 m·s -1 .