Absolute measurement of the electrical conductivity and of the magnetic permeability without calibration standards

To characterize the material properties of a test object, the electrical conductivity and the magnetic permeability are utilised which are determined from the measured impedance of a test coil by means of an eddy-current test. The aim is to achieve an absolute and mutually independent determination of the conductivity and of the permeability even in the case of highly permeable materials, without calibration standards. For this purpose, the permeability of the material is reduced by premagnetisation at a low test frequency of, for example,