Conductivity and Thickness Layer Measurements of Conductive Layers on Conductive Base Materials Using Calibrated Apparent Conductivity Measurements

An eddy current technique for the simultaneous determination of the layer thickness and conductivity of a uniform conductive layer on a conductive base material is presented. The technique uses apparent conductivities measured on the surface of the sample at several frequencies and a calibration-based methodology that compares measured apparent conductivities to a three-dimensional calibration volume. The use of a calibration methodology is advantageous in that it avoids the need for forward or inverse modeling of the layered eddy current problem. Experimental results are presented that support the validity of the technique.

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