Determination of coating thickness of a copper-plated steel wire by measurement of the internal wire impedance

A measurement of the internal impedance of a copper-cladded steel wire by a quote measurement of the voltage across and current through the wire can be used as a method to determine the cladding thickness. An electromagnetic model accounting for the internal impedance with different values of the coating thickness on a steel wire is described. Numerical calculations based on this model have been carried out and compared with measurements. An example shows how the method can be used to model a steel wire with a coating of copper to find the expected impedance as a function of coating thickness.