Conductivity Measurement of Solid Metal Rods Using High-Frequency Eddy Current Method

Conductivity is an essential parameter for solid metal rods, which can be applied to assess quality. In this article, an eddy current testing (ECT) method is investigated to measure the conductivity of solid metal rods. Above all, the simplified theoretical model is derived for a coil encircling a cylindrical sample. According to the proposed model, the real part of the coil impedance variation at high frequency (∼ MHz) is closely related to the reciprocal of root of the rod conductivity. Therefore, a simple and effective conductivity measurement method for solid rod conductivity measurement is investigated based on the relationship between the impedance variation and the solid rod conductivity. Moreover, the effect of metal rods and coils parameters on the proposed method is also analyzed. Finally, the proposed method is verified with measurements of conductive materials. The results demonstrate the investigated simplified theoretical model is accurate and reasonable, and the relative error of the solid rod conductivity measurement is 2.2%.