Gm Global Technolgoy Operations, Inc.

General Motors LLC

John J Croat

Robert W Lee

Andrew Roman Chraplyvy

Viswanathan Panchanathan

Jan F Herbst

Gregory P Meisner

Earl G Brewer

A method is provided for forming a high energy product, anisotropic, hot pressed iron-rare earth metal permanent magnet without the requirement for magnetic alignment during pressing or additional hot working steps. The method of this invention includes providing a quantity of anisotropic iron-rare earth metal particles and hot pressing the particles so as to form a substantially anisotropic permanent magnet. The pressed permanent magnet of this invention permits a greater variety of shapes as compared to conventional hot worked anisotropic permanent magnets. As a result, the magnetic properties and shape of the permanent magnet of this invention can be tailored to meet the particular needs of a given application.

Hot pressed magnets formed from anisotropic powders

A method is disclosed for producing a rapidly solidified, fine grained, magnetically anisotropic powder of the RE-Fe-B type. The rapidly solidified material is optimally quenched or slightly overquenched and is subjected to a hydrogen absorption-hydrogen desorption process that produces a fine grained material containing the essential magnetic phase RE.sub.2 TM.sub.14 B and an intergranular phase and is magnetically anisotropic.

Fine grained anisotropic powder from melt-spun ribbons

The hard magnetic properties, including intrinsic coercivity, remanence and energy product of rapidly quenched, rare earth-transition metal alloys has been substantially increased by the addition of suitable amounts of the element boron. The preferred rare earth constituent elements are neodymium and praseodymium, and the preferred transition metal element is iron.

High-energy product rare earth-iron magnet alloys

Magnetically hard compositions having high values of coercivity, remanence and energy product contain rare earth elements, transition metal elements and boron in suitable proportions. The preferred rare earth elements are neodymium and praseodymium, and the preferred transition metal element is iron. The magnetic alloys have characteristic very finely crystalline microstructures.

High energy product rare earth-iron magnet alloys

This invention relates to permanent bonded magnets of very finely crystalline, melt-spun, rare earth-iron alloys. The compacts are magnetically isotropic.

Bonded rare earth-iron magnets

A method to produce rare earth (RE), iron, boron type anisotropic permanently magnetic material includes forming magnetically isotropic coarse powder particles of melt-spun alloy with a very fine grain RE.sub.2 FE.sub.14 B phase. The particles are mixed with inert particles of a size and of a weight percentage of the mixture to separate the powder particles for preventing hot work bonding therebetween. The mixture is hot pressed to cause the magnetically isotropic particles to be compressed in a direction parallel to the press direction so as to strain the particles to cause crystallites to be oriented along a crystallographically preferred magnetic axis resulting in particles of anisotropic permanently magnetic material.

Method for producing anisotropic RE-FE-B type magnetically aligned

Ferromagnetic compositions having intrinsic magnetic coercivities at room temperature of at least 1,000 Oersteds are formed by the controlled quench of molten rare earth-transition metal alloys. Hard magnets may be inexpensively formed from the lower atomic weight lanthanide elements and iron.

High coercivity rare earth-iron magnets

An amorphous rare-earth transition metal body is provided that has integral, predetermined regions of hard and soft magnetism. A method is provided for heating portions of an amorphous rare-earth transition metal alloy body, in situ, to transform predetermined portions from a state of low magnetic coercivity to a highly magnetically coercive state.

Selective magnetization of rare-earth transition metal alloys

A portion of a nonmagnetic body of manganese-aluminum based alloy is tempered in situ to a state of high magnetic coercivity. The magnetically coercive portion may be used, e.g., to store magnetically readable information or to provide a tailored permanent magnetic field for an electrical device.

Selective magnetization of manganese-aluminum alloys

In a preferred embodiment thin layers of rare earth metal-cobalt powder comprising an outer layer of RCo.sub.5 and a discrete transitional layer of R.sub.2 Co.sub.17 are compressed against an adjacent thicker layer of iron powder to form a laminated green compact, with the rare earth-cobalt powdered material being magnetically aligned. The green laminate body is then sintered to densify the rare earth-cobalt material layer to a body wherein the pores are substantially noninterconnecting. The laminate structure is then magnetized. By this method a strong rare earth-cobalt (RCo.sub.5) permanent magnet body is produced in which the rare earth-cobalt layer may be very thin (of the order of 1 to 2 millimeters) but of relatively large surface area and supported by a strong iron layer so as to be durable in handling, manufacturing and use. It is possible to press an RCo.sub.5 layer directly onto a powdered iron layer when the oxygen content of the iron is suitably low. The method will also produce an R.sub.2 Co.sub.17 -iron composite.

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Sterling Heights, MI, United States of America

John J Croat