The effect of electrode surface area on corrosion initiation monitoring of X65 steel in soil

Abstract

This work examines the effect of electrode surface area on the monitoring of corrosion initiation on X65 steel buried in soil under the scenario that cathodic protection (CP) was disrupted, mimicking a corrosion issue frequently observed on underground steel pipelines. Current mapping using an electrochemically integrated multi-electrode array has been performed in conjunction with electrode potential monitoring to visualise dynamic early corrosion initiation process. After CP was disrupted, corrosion was found to initiate earlier on smaller sized electrodes. The prior CP induced steel surface pH was found to play a decisive role in determining the pitting susceptibility. Results suggest that electrode size needs to be carefully considered when corrosion monitoring is performed.