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Amorphous ribbons of an alloy with the composition (Tb0.33Fe0.67)0.98B0.02, which exhibit good magnetostrictive properties at low magnetic fields, are bonded with a phenol-based binder to fabricate bulk composites. Efforts to determine optimum fabrication parameters are made by examining magnetic and mechanical properties of bulk compacts obtained at various fabrication conditions. From the binder content dependence of magnetostriction and compressive strength, the optimum binder content is estimated to be about 4.3 wt %, taking into account magnetostrictive and mechanical properties and the necessity of reducing nonmagnetic binder content. The two properties of magnetostriction and compressive strength vary nearly linearly with the compaction pressure; as the compaction pressure varies from 0.25 to 1.0 GPa, magnetostriction decreases but compressive strength increases, making it difficult to determine the optimum compaction pressure. A magnetostriction of 493 ppm (at 1.1 kOe) is achieved from the present bulk composites, together with a high dλ/dH (sensitivity of magnetostriction with applied magnetic field) of 1 ppm/Oe.

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325ues of x,y,z chosen for minimum magnetic anisotropy and easy magnetization axis rotation near room temperature. As holmium replaces terbium and dysprosium in these compounds, this minimum anisotropy decreases until at a value of 2~0 . 5 8 both K, and K,=zero.' An important objective of this work is to determine how the width of the hysteresis loop depends upon holmium concentration and then compare this dependence with the decrease in magnetostriction as z is increased. Table I shows the fractional reduction in the width of the hysteresis curve, AHh/Hh, with 15% holmium substituted for Tb and Dy. (The reduction in AHh/Hh for a drive field of 72 kA/m is given for a wide range of compressive stresses, U ) . Clearly for all U, the hysteresis is reduced substantially, whereas only a small fraction reduction in magnetostriction ( AXIX) occurs using the same drive field. As z is increased, both the hysteresis and magnetosuiction are still further reduced.