Bonded Terfenol-D composites with low eddy current loss and high magnetostriction

Abstract

Bonded Terfenol-D composites, with high electrical resistivity and low eddy current loss, can be used in an alternating magnetic field with high frequency. However, the nonmagnetic binder impairs the magnetostriction of the composites. To achieve high magnetostriction and low eddy current loss, the mixture of the alloy powder and binder was compressed at low pressure in an oriented magnetic field. After this, the aligned samples were recompressed by cold isostatic pressing (CIP). Besides, the effect of particle size on the magnetostriction of the bonded Terfenol-D composites was also studied. The results showed that the bonded Terfenol-D composites had excellent magnetostriction when the particle size was 50–80 μm. The oriented magnetic field and CIP could improve the magnetostriction of the bonded composites, which reaches 1020×10−6. The bonded Terfenol-D composites had good compact structure and high density (7.24 g/cm3). The magnetic loss of the bonded Terfenol-D composites was 192 mW/cm3 at a frequency of 100 kHz in a magnetic field of 960 A/m, which was about one third of that of casting Terfenol-D alloys.