| 摘要 |
<p><PICT:0899287/III/1> In a method of heat-treating, e.g. zonerefining, a fusible material, e.g. silicon, germanium, titanium or nickel, the material is placed in one or more crucibles cooled by circulating fluid, and a direct or low-frequency alternating current is passed through the material between two crucibles, or between a crucible and an auxiliary electrode, each of which is in contact with the fusible material. The crucibles and electrode are of material having thermal and electrical conductivities not less than those of aluminium. As shown, a silver electrode 15, cooled by circulating fluid, is movably mounted above a hollow, silver crucible 10 containing silicon 13. In a further arrangement, a series of U-shaped crucibles are separated by gaps wide enough to prevent arcing but narrow enough for surface tension to prevent spillage of molten material. These crucibles may be used in conjunction with one or more electrodes 15 or alternate crucibles may be arranged to be connected to one terminal of the supply voltage and the remainder to the other terminal, so that a silicon rod may be zone-melted by connecting up adjacent crucibles in turn. Specification 827,676 is referred to.</p> |
