Analyses of Cathodic Disbonding Products of 3PE Coating on Buried Pipelines

Using electrochemical method, the product of cathodic disbonding of 3PE coating on buried pipelines was studied. Scanning electron microscopy, infrared spectrometer and comprehensive thermal analyzer were used to analyze the cathodic stripping area and the product of the sample. The results show that when the disbonding of 3PE anticorrosive layer disintegration occurred, white products were found in stripping area. The product was a mixture of inorganic salt and organics. The products of 3PE anticorrosive coating layer or epoxy primer under alkaline conditions constituted the organics, and the inorganic salt was composed of calcium, magnesium ions.