Eddy current measurements of surface roughness

The paper proposes a method for simultaneous measurements of the material conductivity and its surface roughness for non-ferromagnetic materials. The method takes advantage of the effect exercised by eddy currents onto impedance of a contact coil. The essence of the method is to eliminate the influence of the surface unevenness onto measurements of conductivity by the calculation of a correcting factor that serves as a specific equivalent of the surface roughness. (© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)