Production of amorphous alloy ribbons and effects of apparatus parameters on ribbon dimensions

An apparatus for the production of amorphous alloy ribbon is described. The alloy is induction-melted in a small quartz crucible and ejected by argon gas pressure through a small orifice in the bottom of the crucible. The liquid jet impinges at a small angle with respect to a radius of a copper disk rotating at several thousand rev/min, flattens while rapidly cooling and solidifying, and leaves the circumferential surface of the disk as a result of centrifugal force. The resulting ribbon geometry for an alloy of Fe 40 Ni 40 B 20 has been studied as a function of orifice sizes between 340 and 480 μm in diameter, of disk speeds between 5 and 10 \times 10^{3} rev/min (20 and 40 m/sec), and of ejection pressures between 4 and 10 psig (28 and 70 kPa). The cross-sectional area of the ribbon can be predicted quite accurately from the disk speed, the orifice diameter, and the velocity of the liquid jet as given by the Bernoulli equation. Experimental data are in the form of ribbon thicknesses, ranging between 10 and 40 μm, and mass/ length, ranging between 0.05 and 0.24 mg/mm. None of the ribbons produced showed any signs of crystallinity, as determined by X-ray diffraction.