Abstract
The influences of electric potential at defect and NaCl concentration in aqueous solution for cathodic delamination were investigated in polyethylene coated steel pipe. The cathodic delamination kinetics and incubation time of cathodic delamination were calculated by using time dependability of cathodic delamination. The cathodic delamination kinetics became so large when electric potential at defects became disnoble and was proportional to electric potential at defect. That became so large when NaCl concentration in aqueous solution became higher and was proportional to the 0.15th power of NaCl concentration. The incubation time of cathodic delamination was greatly dependent on electric potential at defect. The cathodic delamination model was proposed by for polyethylene coated-steel.
