Fabrication and Characterization of Melt-Extracted Co-Based Amorphous Wires

Amorphous Co(68.15)Fe(4.35)Si(12.25)B(15.25) wires with smooth surface and circular cross section were fabricated by melt extraction technology using a copper wheel with a knife-edge cross section angle of 60 deg. The effect of some process parameters such as wheel circumference velocity, molten alloy feed rate, and temperature on the geometry and weight, i.e., melt extracted layer thickness, of wire was examined carefully. An optimum process parameter to produce high-quality circular wires was presented. A high resolution CCD video camera recorder was used to monitor the changing of the surface shape of molten alloy contacting the wheel tip under different conditions. It was found that the mechanism of the wire formation during the optimum process condition was controlled by the momentum mechanism, while in the low wheel speed region, heat transfer turned out to be a dominant factor. Some characteristics of the circular wires such as amorphous nature and tensile strength were also studied.