Effect of pH on corrosion and monotonic loading behaviour of 90Cu–10Ni in 3·5% sodium chloride solution

Abstract

Polarisation studies were performed on 90Cu–10Ni (alloy UNS C70600, hot rolled and annealed) in 3·5% NaCl solutions over a range of initial pH levels. It was found that film formation was dependent on the applied current and the relative concentrations of the ionic species H⁺, (OH)⁻, and Cl⁻ in solution which ultimately influenced the formation of the corrosion products. Constant extension rate tests at different applied currents and pH levels suggested that a higher pH level increased the time to failure although no evidence of stress corrosion cracking was found. These observations are rationalised through surface film formation mechanisms.