Failure Analysis and Life Prediction for 3PE Anticorrosion Layer

To study the failure problems of 3PE anticorrosion layer,testing on the spot,lab analysis and simulated experiments were used to study the disbondment of 3PE anticorrosion layer and predict its life.The results show that the bad processing control in the production such as surface treatment and fusion bonded epoxy (FBE) spray and the environmental factors such as coating damage and too negative cathodic protection potential caused the disbondment of 3PE anticorrosion layer.At the same current density,cathodic disbondment distance increased as the test period increased.The increase rate of cathodic disbondment distance was high at the early stage of test and was low at the late stage of test.In the same testing period,cathodic disbondment distance increased with the increase of current density and the characteristic life of the 3PE anticorrosion layer had exponent relationship with the reciprocal of current density.