AC permeability of Fe-Co-Ge/WC/phenol magnetostrictive composites

Polymer-bonded magnetostrictive composites of flake-type Fe-Co-Ge powder were fabricated and their complex permeability were characterized in the frequency range of 100-100 kHz using the modified ferrite core method. This alternating current (ac) permeability measurement method is firstly proposed in this study, and has some merits, such as easy handling and stress-free measuring. The WC powder, as a highly elastic material, with various amount of 0 wt%-30 wt% was added to form magnetostrictive composite to investigate high-frequency magnetic properties with measured permeability. The real part of permeability is almost constant with frequency varying. Also, the imaginary part of permeability increases exponentially with frequency increase. Both real and imaginary parts of permeability decrease with WC content increase to 20 wt%, but the composite of 30 wt% WC has larger permeability than that of 20 wt%. Index Terms--Alternating current (ac) permeability, magnetostrictive composite, stress-free measurement.