• 作者： Sabde, G.; Gan, F.; Chin, D.T.
• 中文摘要： 地下管線廣泛應用於石油和天然氣的輸送。通常聯合使用塗層和陰極保護技術來防止地下管線的外腐蝕。當塗層老化形成針孔和龜裂時會發生縫隙腐蝕。破損的塗層失去附著力而與管道剝離,在管道外表面與剝離的塗層之間形成縫隙。由於剝離塗層對電流的絕緣屏障作用,在高電阻率的土壤中,陰極保護效果會下降。這是因為陰極電流必須經塗層的裂口處流入縫隙深處,當泥水電阻率很高時,將產生很高的歐姆電位降,使管道-溶液界面的極化減小,其真實極化電位達不到-0.85V(相對於銅-飽和硫酸銅參考電極)的保護電位,導致腐蝕不能完全停止。本文綜述有關地下管線塗層和陰極保護方面的文獻,並對陰極保護參數、剝離塗層下縫隙內的電位分布、傳輸過程和陰極保護機制進行討論。
• 英文摘要： Underground pipelines are used for the transportation of oil and natural gas. The pipelines are protected from external corrosion by the combined application of coating and cathodic protection. Crevice corrosion occurs when coating develops pinholes and ruptures through aging process. The coatings surrounding the damaged areas loss adhesion and are disbonded from the pipe, forming a crevice between the exterior pipe surface and disbonded coatings. In high resistivity soils, the effectiveness of cathodic protection is reduced because disbonded coatings function as a shield against the flow of cathodic current to the pipe surface. To protect the pipe against corrosion, the current must flow through ruptured openings on the coating into the crevice, and the excess ohmic potential drop across the soil water within the crevice reduces the pipe-to-solution potential from a protected value of -0.85V vs. CSE to a less negative value where corrosion may not be completely mitigated. This paper presents a review of the coatings and cathodic protection of underground pipelines. The cathodic protection criteria, potential distribution inside the crevice of disbonded coating, transport processes occurring in the crevice, and mechanism of cathodic protection are discussed.
• 中文關鍵字： 陰極防護; 外腐蝕; 剝離塗層; 質量傳遞; 地下管線
• 英文關鍵字： Cathodic Protection; Crevice Corrosion; Disbonded Coating; Mass Transport; Underground Pipeline