Vorrichtung zur Herstellung kugelförmiger Teilchen

Spherical particles of high melting materials, e.g. a metal or a carbide or oxide of molybdenum, tungsten, uranium, thorium, titanium, zirconium, hafnium, tantalum, or boron, are manufactured by passing powder or grains through a high current electric arc discharge in an inert atmosphere, e.g. argon, to a cool region so that the particles are heated above their melting point and immediately cooled before they adhere to each other. Superatmospheric pressure may be used. Cylindrical vessel 1, made of metal, e.g. nickel steel, with conical base, and having inert gas inlet pipes 6 and inspection port 7, contains three movable electrodes 2 of very pure graphite or high melting metal, e.g. tungsten, which receive the three phases of current mains supply, for maintaining the arc. Material (of grain size 40-260m ) is inserted by means of an electro-magnetic station (not shown) through guide 3 and nozzle 4, preferably of graphite, which projects almost to the boundary of the arc. Inlet and outlet pipes 8 supply water to the double jacket for cooling, and the solidified spheres are removed at 5. An example specifies molybdenum carbide.ALSO: Spherical particles of high melting materials, e.g. carbides or oxides of molybdenum, tungsten, uranium, thorium, titanium, zirconium, hafnium, tantalum or boron, are manufactured by passing powder or grains through a high current electric arc discharge to a cool region so that the particles are heated above their melting point and immediately cooled before they adhere to each other. The process is carried out in an inert atmosphere e.g. argon, preferably at super-atmospheric pressure. Cylindrical vessel 1, made of metal, e.g. nickel steel, with conical base, and having inert gas inlet pipes 6 and inspection port 7, contains three movable electrodes 2, of very pure graphite or high melting metal, e.g. tungsten, which receive the three phases of current mains supply, for maintaining the arc. Material (of grain size 40-260 m ) is inserted by means of an electromagnetic shaker (not shown) through guide 3 and nozzle 4, preferably of graphite, which projects almost to the boundary of the arc. Inlet and outlet pipes 8 supply water to the double jacket for cooling, and the solidified spheres are removed at 5. An example specifies molybdenum carbide.