ES395450A3 - A procedure for the manufacture of permanent magnets. (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

A process for the manufacture of permanent magnets, characterized by a first phase in which fine particles of the anisotropic magnetic substance are dispersed in a support material which may be a plastic or resinous composition, an elastomer semi-solid or a viscous liquid. The magnetic particles are of small size, constituting small elementary magnets. This reduction has been obtained by grinding in two phases with thermal treatment. The support material may be rubber, plasticized vinyl chloride or a thermoplastic material, generally thermosetting, and the anisotropic magnetic material may be barium ferrite, lead ferrite, strontium ferrite or a binary or ternary mixture of both. The particles of magnetic material do not exceed 70% by volume of the dispersion. In a second phase the mixture or dispersion is subjected to a shearing to align the particles of magnetic material and then the support material hardens to preserve the alignment. The shearing is obtained by the passage of the mixture between two rollers that go at different speeds, or by the passage of the mixture through the orifice of an extrusion die. The magnetizable material obtained in the preceding phases is subjected in a third phase to the action of a magnetic field substantially perpendicular to the surfaces of the sheets. This operation is after shearing. As the support material is thermosetting, after subjecting the assembly to the magnetic field, it is passed to the fourth phase in which it is heated to vulcanize the support material. In a fifth phase the laminated mixture is stacked in the form of thin sheets of magnetizable material. The leaf assemblies are subjected in a final phase, to the action of pressure and heat to form the magnet. (Machine-translation by Google Translate, not legally binding)