Galvanic Series in Seawater as a Function of Temperature, Oxygen Content, and Chlorination

Abstract

The open-circuit potential is one of the main driving forces of galvanic corrosion when two dissimilar metals are in electrical continuity in an electrolyte. From the existing literature, the galvanic series which provides averaged potential of metallic materials in seawater is generally restricted to ambient/standard conditions or to a limited number of alloys. However, advanced materials have been developed in the last decade and the corrosion potential of any alloy immersed in seawater may be strongly affected by environmental factors. There is a lack of information on these purposes (e.g., effect of dissolved oxygen content, temperatures, chlorination at different levels, or recently developed alloys, etc.). In this work, the open-circuit potential of different stainless steel grades, as well as nickel-based and copper-based alloys, has been systematically measured in seawater under different experimental conditions. In particular, the effect of temperature (from 30°C to 70°C), oxygen content (from 10 ppb to saturation), and chlorination level (from 0 ppm to 0.5 ppm) have been studied. The work can also be used for material selection in terms of risk of bi-metallic corrosion when coupling two materials under these conditions.