Stress corrosion of pipeline steel under occluded coating disbondment in a red soil environment

A crevice cell with a multi-sample loading frame was constructed to study stress corrosion initiation of pipeline steel under an occluded shielding plate simulating coating disbondment under free corrosion condition in a red soil environment. The local potential and pH under the shielding were monitored by microelectrodes. Results show that intensive anodic dissolution and initiation of microcrack were preferential at the open holiday, whereas the corrosion attack was markedly mitigated under the occluded shielding. Species gradient and internal polarization were proposed for the corrosion scenarios of pipeline steel under disbanded coating. (C) 2015 Elsevier Ltd. All rights reserved.