Microstructure and magnetostrictive properties of epoxy-bonded Tb_(1?x)Nd_x(Fe_(0.8)Co_(0.2))_(1.93)(0.20 ≤ x ≤ 0.75) composites

摘要

An epoxy-resin bonding route was used to produce composite rods of the highly magnetostrictive alloys Tb_(1?x)Nd_x(Fe_(0.8)Co_(0.2))_(1.93) (0.20 ≤ x ≤ 0.75). The structure, spin configuration, magnetostriction and particle size are investigated by means of X-ray diffraction (XRD), a standard strain technique and scanning electron microscope (SEM). The epoxy-bonded 0–3 type and pseudo 1–3 type composites are successfully fabricated, respectively. XRD analysis shows that the easy magnetization direction (EMD) for the alloy of x = 0.20 lies along h111i axis. The magnetic curing field makes the particles align as a particulate chain and also causes the particles rotating along its EMD direction. The pseudo 1–3 type epoxy-bonded composite has a larger magnetostriction than that of the 0–3 type composite, which can be attributed to the larger magnetostriction coefficient λ_(111), EMD lying along <111> direction, the <111>-textured orientation and the chain structure. A large saturation magnetostriction (λ_(0S) ～ 570 ppm) is achieved for the 1–3 type epoxy/Tb_(0.35)Nd_(0.65)(Fe_(0.8)Co_(0.2))_(1.93) composite (about 150–250 μm, 10 kOe), which approaches 70% of its monolithic alloy. Furthermore, it only contains 27 vol.% alloy particles in the insulating epoxy matrix and performs a low magnetic anisotropy, which could make it technologically interesting for the field of Nd-containing magnetostrictive materials.