Planar-flow spin-casting of molten metals : process behaviour

An experimental study of the planar-flow melt-spinning process was performed to gain a better understanding of the steady-state production of microcrystalline and amorphous ribbons. The dependence of the thickness of the ribbon product, T, on process parameters (wheel speed, U, nozzle/wheel gap, G, overpressure, Delta P, nozzle-slot breadth, R, and nozzle-slot width, W) was determined using an apparatus designed to deliver reproducible results. Thicknesses were reproducible to within 5-8%. Guided by dimensional analysis, the non-dimensional thickness (T/G) was found to depend, within the experimental error, only on a non-dimensional pressure drop ( Delta P/ rho exp U2 ) and slot breadth (R/G) for fixed thermal conditions. Data from the literature and the experimental data, which considerably extend the range, correlate consistently on the basis. In contrast to the steady behaviour, the limits within which a uniform ribbon can be formed depend on a larger set of parameters; this dependence is sketched with the available data. Finally, a variety of observed ribbon (Al) surface textures (free meniscus side) is catalogued.