The role of iron content on the corrosion behavior of 90Cu‐10Ni alloys in 3.5% NaCl solutions

Abstract

PurposeThe purpose of this paper is to investigate the effect of iron content (2% and up to 6% Fe) on the corrosion behavior of 90Cu‐10Ni alloys in 3.5% NaCl at different temperatures (23, 50 and 80°C) under stagnant conditions and fluid flow (with an agitation speed of 350 and 900 RPM). The laboratory study was conducted following a failure of high iron content (up to 6%) 90Cu‐10Ni heat exchanger tubes in a desalination plant.Design/methodology/approachPotentiodynamic polarization measurement (DC) was used to estimate the corrosion rate of the 90Cu‐10Ni alloys in NaCl solutions under stagnant and fluid flow conditions.FindingsIt was found that the higher iron content cupronickel material suffered higher corrosion rates in all tests. The intensity of the corrosion attack of both materials was increased significantly with increasing experimental temperature or flow velocity. The results support a previous prediction that the presence of excess iron (well above 2%) has played a major role in corrosion failure of 90Cu‐10Ni heat exchanger tubing material in seawater.Originality/valueThis paper explains the role of iron content on the corrosion behavior of 90Cu‐10Ni alloys in 3.5% NaCl under stagnant and fluid flow conditions.