| 摘要 |
810,448. Zone melting; alloys. WESTERN ELECTRIC CO. Inc. June 15, 1956 [June 17 1955], No. 18591/56. Class 82(1) [Also in Group XXXV] , In a method of treating a body of material in which a portion of the body is liquid and wets an adjacent solid portion of the body, the liquid portion being subjected to a force tending to displace it from a desired position, an electric current is passed through at least the liquid portion and a magnetic field is impressed across this portion so that the electric current and magnetic field co-act to provide a sustaining force which opposes the said displacing force. The method may be applied in zonemelting particularly of semi-conductor materials such as silicon or germanium, in alloying processes by adding a solid or gaseous addition agent to the molten portion or in refining by evaporation of a volatile constituent or reaction of an impurity in the melt with an agent in the surrounding atmosphere. Fig. 2B illustrates the application of the method to a zone melting process, the rod 10, enclosed in quartz tube 11, is clamped at its ends in supports 12 and 13. Electric current is passed along the rod and a magnetic field is set up between magnet faces of opposite polarity, one 25 being shown. Coaction of the current and field produces an upward force which counteracts the effect of gravity on the molten zone 27 produced by induction heater 28. Any suitable atmosphere or a vacuum may be maintained in tube 11 by means of inlet and outlets 19 and 20. The invention may be used for fusing and solidifying in rod form a sintered body or, as shown in Fig. 6, for melting and solidifying in rod form a powdered material. In the latter application a rod 123 is clamped at one end in support 121 the other end being clamped in a moveable support 120 which is moved to the left as powdered material is added from hopper 134 to the molten zone 128. The pole faces of the magnets may be suitably shaped to provide a more uniform field in the region of the molten portion or to provide a graded field decreasing an intensity in the upward direction to improve the stability of the molten zone. A non-uniform magnetic field may also be used to modify the configuration of the molten portion. Specification 769,673 is referred to.
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