Abstract
The effects of Be content (0∼1.7 wt%) and Fe content (5∼20 wt%) on properties in semihard magnetic alloys in the Co-Fe-Be system were investigated. Magnetic properties, resistivity, X-ray diffraction and tensile strength were measured in the specimens annealed at 400∼1000°C after cold drawing by 90% reduction in area.
The results obtained are as follows:
(1) In the wire involving Be, the coercive force is raised to a maximum value by the annealing near 600°C. The maximum value increases with the increase in Be content and reaches about 35 Oe at 1.7 wt%Be. In this case, the squareness ratio is higher than 0.90 and the magnetization is about 14000 G. Moreover, the coercive force tends to increase with the increase in Fe content.
(2) The transformation of the γ phase (fcc) to the α phase (bcc) by cold drawing becomes larger in scale with the increase in Be or Fe content. The α phase, however, is again transformed into the γ phase by the high-temperature annealing.
(3) The high value of coercive force and the high value of squareness ratio even after the high-temperature annealing in Be-involving alloys are attributed to the precipitation of the intermetallic compound CoBe.
