Non-destructive cathodic disbondment testing of pipewrap coatings

Abstract

A method and apparatus herein is disclosed that consists of establishing and equilibrating a circuit path through a working test pipe electrode and a counter electrode in an electrolyte fluid in which said test pipe electrode achieves a state of cathodic protection. Disconnecting said cathodically protected working test pipe electrode from said counter electrode. Then re-establishing a circuit path through said working test pipe electrode, said counter electrode, and a reference electrode, in said electrolyte fluid along with an electronic control and measuring means. Subsequently causing a measured known voltage step to be applied to said working test pipe electrode. Then measuring the current flowing after application of said measured applied voltage step. Finally, then analyzing said current flow data and thereby determining the double layer capacitance at the interface between said working test pipe electrode and said electrolyte fluid as a measure of disbonded area thereon.