Corrosion behaviour of Ti alloy TA8-1, Cu alloy B19 and Cu as candidate materials for nuclear waste containers under early deep geological conditions

Abstract

The corrosion behaviour of Ti alloy TA8-1, Cu alloy B19 and Cu are studied under simulated early deep geological conditions of Beishan, China. In the short-term experiment, the influence of temperature on the corrosion properties of the studied materials is investigated by electrochemical impedance spectroscopy (EIS), potentiodynamic polarisation and cyclic polarisation. In the long-term immersion tests, the evolution of corrosion behaviour is investigated by EIS, in combination with SEM, XPS and Raman analysis. The results show that Ti alloy TA8-1 has the minimum corrosion current density (10 −7 A cm −2 ) and low pitting susceptibility, attributed to the formation of a thin passive film. Cu has the relatively high corrosion current density (∼10 −5 A cm −2 ) and low pitting susceptibility. The corrosion resistance of the Cu 2 O/Cu 2 (OH) 3 Cl deposit layer is maintained during the two-month immersion test at 50°C. Severe localised corrosion occurs on the surface of B19 and the corrosion resistance deteriorates obviously during the immersion test.