Correlation between sulphur content and corrosion resistance of nickel alloys

Abstract

Corrosion tests were carried out in specially selected environments, i.e. NaCl solution and a highly concentrated inhibited HCI solution, on nickel alloys (32–39%Ni, 22–27%Cr, 3·3–4·1%Mo, bal. Fe) nominally belonging to the same class. Differences in the corrosion behaviour occurred both in tests conducted in passive conditions (NaCl solution) and in active conditions (HCl solution). The differences in corrosion behaviour were attributed to the variations in sulphur content, although this content was very low for all three alloys investigated. The importance of an effective desulphurisation process for this class of alloys is thus demonstrated.