Usage of Conductive Polymer Composite as the Object Film of Eddy Current Gap Sensor

To realize the noncontact gap measurement based on eddy current effect when the object is not conductive, we fabricate a film made of conductive polymer composite and cover it on the surface of the nonconductive object. The experimental results on the lift-off effect show that the impedance of the coil with alternating current changes regularly with the variations in the distance between the coil and the composite object. This phenomenon indicates that there exists an eddy current composed of the tunneling current and the conduction current in the composite object. The results indicate that conductive polymer composite has the potential to replace metal as an object of an eddy current sensor system.