| 摘要 |
1,029,805. Zone-melting. SIEMENSSCHUCKERTWERKE AG. Nov. 21,1963 [Dec. 24, 1962], No. 46103/63. Heading B1S. In a process of zone-melting or crystal pulling, the molten zone is surrounded by inner and outer shields,the inner shield being of heat transmitting material and the outer shield being of heat reflecting material. The inner shield, which may be of molybdenum, tungsten, tantallum, or graphite, is roughened on the inside by sand blasting. An inner metal shield may be coated with carbon black on the outside. The outer shield may be of silver or have a silver coating. Using induction heating, the shields are in the form of incompletely closed rings to prevent formation of induction currents. As shown, a molten zone 5 is formed in a rod 4 held between holders 7 and 8 in an evacuated vessel 2 having a viewing window 15, by means of an induction coil 6 carried by a rod 14. Also carried by rod 14 are inner and outer shields 17 and 16 separated by distance pieces of mica or porcelain, outer shield 16 being cooled by water coils 18. |
