Study of localized corrosion of 304 stainless steel under chloride solution droplets using the wire beam electrode

Localized corrosion of 304 stainless steel under droplets of 1 M sodium chloride solution was investigated by the wire beam electrode (WBE) method. It was found that the current distributions were heterogeneous with isolated anodic current peaks mostly located near the edge of the droplet. During the corrosion process, the stainless steel WBE exhibited the stochastic characteristics with the disappearance of some anodic sites. In addition, stainless steel suffered more serious localized corrosion with the increase of the droplet size. The increase of the cathodic area and the three-phase boundary (TPB) length was believed to be the reason.

► The galvanic current distributions of localized corrosion of stainless steel under NaCl droplet were studied.
► Serious corrosion sites were preferentially located near the three-phase boundary (TPB) zone.
► Stainless steel suffered more severe localized corrosion with the increase of the size of droplets.