Magnetic and electric properties of glass-coated Co-beased amorphous alloy microwires with field annealing

Modified Taylor-Ulitovsky process was developed for continuous fabrication of glass-coated Co-based amorphous alloy microwires with controlled size. Effects of different annealing processes (conventional thermal annealing, horizontal and longitudinal field annealing) on microstructures and magnetic and electric properties of the microwires were investigated. Phase transformations of the wires were evaluated by X-ray diffraction (XRD) and scanning electron microscope (SEM) measurements, while magnetic properties were tested by vibration sample magnetometer (VSM). The results suggested that precipitated phases depended on the annealing process significantly, leading to distinct changes in their electric and magnetic properties. Particularly, excellent soft magnetic properties with much enhanced saturation and initial permeability and high conductivity could be achieved by longitudinal magnetic field annealing. Compared with as-spun samples, the saturation magnetization increased by 225%, the initial permeability increased by 214%, and the electrical conductivity increased by 26%. In addition, the saturation magnetization, the initial permeability and the electrical conductivity of the longitudinal field-annealed microwires increased by 110%, 79%, 45%, respectively, compared with the best ribbons with the same composition and annealed at the same condition.