Vacuumschmelze Gmbh

Netzsch Trockenmahltechnik Gmbh

Technische Universitat Darmstadt

Wilhelm Fernengel

Frank Winter

Matthias Katter

Lothar Zapf

Oliver Gutfleisch

Konstantin Skokov

Boris Wall

Werner Rodewald

Konrad Löwe

Sergej Antochin

Klaus Rehbein

A method and a plant for the production of a powdery starting material, which is provided for the manufacture of rare earth magnets, are disclosed. First of all, at least one magnetic material, which is comminuted into a powdery intermediate product with a possibly increased concentration of impurities, and/or at least one alloy including rare earth metal are provided, which includes a low concentration of impurities. A classification of the powdery intermediate product to at least one criterion takes place subsequently, wherein, for the classification of the powdery intermediate product with the increased concentration of impurities, at least one dynamic classifier is provided, which divides the powdery intermediate product with impurities into at least two fractions based on the at least one criterion, wherein at least a high concentration of impurities accumulates in a first fraction and no impurities or at least a lower concentration of impurities than in the case of the first fraction accumulate in a second fraction, and wherein the fraction without impurities or with a low concentration of impurities forms the starting material for the manufacture of rare earth magnets.

Method and plant for the production of a starting material for the production of rare earth magnets

A method and a plant for the production of a powdery material, which is provided for the manufacture of rare earth magnets. First of all, at least one magnetic or magnetizable raw material, respectively, is provided and is comminuted into a powdery intermediate product, which includes powder particles including corners and edges, by means of conventional comminuting methods. The sharp-edged powder particles are chamfered subsequently. The optimized powdery product including the chamfered powder particles is used for the manufacture of rare earth magnets.

A method is provided for producing an artificial permanent magnet, in a powder preparation step a main phase powder, which includes a rare-earth transition metal compound with permanently magnetic properties and has a first average particle size, is prepared and an anisotropic powder, which has a higher anisotropy field strength than the main phase powder and has a second average particle size, is prepared, wherein the second average particle size is smaller than the first average particle size. In a subsequent powder mixing step, the main phase powder and the anisotropic powder are mixed together to form a powder mixture and, in a subsequent heat treatment step, this powder mixture with the main phase powder of the first average particle size and with the anisotropic powder of the second average particle size is sintered to form an artificial permanent magnet.

Artificial permanent magnet and method for producing the artificial permanent magnet

The invention relates to hard magnetic films made of a polymer matrix and hard magnetic powder particles distributed therein. The films have a thickness of preferably 100 to 500 &mgr;m and are flexible. They can be produced by using a casting method and are suited, for example, as hard magnetic components in miniature motors, polarized relays or sensors.

Magnetic film and a method for the production thereof

In the manufacture of magnetic data carriers, such for example, hard-disk storages, it must be assured that neither the data carrier itself nor component parts of the data carrier system situated in the proximity has magnetic contaminants. An improved measuring method allows the determination of the magnetic contaminants which were attached to an adhesive tape applied to the surface being examined. The improvement is that a magnetized soft-magnetic measuring substrate has a surface provided with a parting agent which is then brought into contact with the magnetic contaminants adhering to the adhesive tape. A reduction of the remanent field that is produced by this contact represents a criterion for the magnetic contamination of the surface under examination.

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Kleinostheim, Germany

Wilhelm Fernengel