Effect of spinning condition on non-crystallinity of Fe_77.5Si_7.5B₁₅ (at%) wire produced by in-rotating-water spinning method

The effect of spinning condition on the quality of Fe_77.5Si_7.5B₁₅ (at%) wires produced by the In-Rotating-Water Spinning Method was examined experimentally. The diameter of the injection nozzle was 0.25 mm. Long continuous wires with round cross section were obtained when the molten-jet velocity ν_j was a little higher than the drum velocity ν_d, whereas the wire became meanderous with the increase in ν_j/ν_d. The heat of crystallization ΔH, which expresses the degree of non-crystallinity of the wire, remained almost constant for 0.77 < ν_j/ν_d < 1. For this case the wires were estimated to be almost amorphous judged from the X-ray diffraction pattern and the scanning electron micrograph. For 1 < ν_j/ν_d < 1.32, however, ΔH decreased with increasing ν_j/ν_d. The temperature distribution of the jet was measured by the photo-calorimetric method. For the water temperature of 10°C, the average cooling rate of the jet between 1470 to 1200 K, was found to be 6 × 10⁴ to 9 × 10⁴ K/s. The measured cooling rate did not show any correlation with ΔH. This indicated that the quality of the wire was determined by the cooling rate in the downstream region with a lower temperature.