Marine corrosion: A widespread, underestimated and poorly understood phenomenon

Seawater is a universal fluid – it is the medium where oceanographic moorings, ships, harbour installations and offshore platforms spend their life. Seawater is also widely used in industrial applications: for cooling and for use against fire in ships and platforms, and in coastal installations such as refineries, chemical/petrochemical plants, desalination plants and power stations. By nature, seawater is very corrosive to metallic materials; it contains, for example, dissolved oxygen, micro-organisms, and high concentrations of chloride ions and other chemical species deleterious to the integrity of metallic materials, such as hydrogen sulphide and ammonia compounds. Therefore, when designing any equipment or industrial plant that will be in contact with seawater, it is important to know about, and to take into account, the behaviour of metallic materials in seawater. It is also absolutely essential to evaluate not only the effects of corrosion, but also the environmental effects of measures taken to counteract it.