Fight chloride corrosion in aqueous systems

In iron-based alloys like carbon steel or stainless steel, the chloride ion increases corrosion by increasing the water's conductivity and by penetrating the alloy's protective oxides. It can increase overall or general corrosion, and can cause localized corrosion such as pitting and stress corrosion cracking. The chloride ion occurs naturally in seawater, in ground waters, in potable water, in condensate after incinerating waste materials such as polyvinyl chloride, and from the hydrolysis or decomposition of chlorinated hydrocarbons such as carbon tetrachloride or trichloroethane. Chlorides can also occur as trace impurities in bulk chemicals where they are neither expected nor analyzed for, but nonetheless can cause serious corrosion. This trace effect is worsened by the tendency of chlorides to concentrate in pits and crevices, especially on heated or intermittently wet and dry surfaces, to amounts that can be orders of magnitude greater than the percentage of chlorides in the bulk liquid. In this article the effects of chloride corrosion, as well as corrosion resistance are discussed.