A new method of studying buried steel corrosion and its inhibition using the wire beam electrode

An electrochemically integrated multi-electrode system namely the wire beam electrode (WBE) has been applied for the first time to study corrosion of mild steel buried in sand, with and without the presence of corrosion inhibitor potassium dichromate (K2Cr2O7)- Measurements of galvanic current distribution maps have been carried out during the exposure of the WBE to dry, damp and chlorinated sand environments. Characteristic changes in galvanic current distribution maps have been observed during the initiation and propagation of localised corrosion. Specifically, during corrosion initiation in damped sand, new anodes were found to initiate and corrosion appeared to be in general form. When the WBE was later exposed to chlorinated sand, massive disappearance of anodic sites was found to occur, resulting in accelerated anodic dissolution of a small number of remaining anodic sites. Addition of corrosion inhibitor K2Cr2O7 to the sand environment was found to significantly reduce galvanic current only after an initial increase in galvanic current. This result suggests that KICI-107 behaved as an anodic inhibitor. (C) 2004 Elsevier Ltd. All rights reserved.