The University of Birmingham

The Secretary of State for Defence in Her Britannic Majesty's Government

Johnson Matthey Public Limited Company

Lucas Industries Public Limited Company

Institut Fuer Festkoerper- Und Werkstofforschung Dresden E.v.

Ivor Rex Harris

Allan Walton

John D Speight

Brian Cockayne

Nigel A Smith

William R MacEwan

Allin Sidney Pratt

Ludwig Schultz

Clive B Ponton

Mark Laurence Doyle

Axel Handstein

Karl-Hartmut Mueller

Oliver Gutfleisch

Andrew Williams

Abolghasem Ataie

Oliver Peter Brooks

Malcolm J Wootton

Bernhard Gebel

Michael Kubis

David Benjamin Willey

Syed H Safi

John Speight

A process is provided for the production of rare earth magnets comprising the steps of exposing a rare earth alloy to hydrogen gas at an elevated temperature so as to effect hydrogenation and disproportionation of the alloy, mechanically processing the disproportionated alloy, and degassing the processed alloy so as to effect hydrogen desorption and recombination of the alloy. The process of the invention finds use in the production and shaping of rare earth magnets, and may be particularly applicable to the production of thin magnetic sheets.

Magnet production

The present invention discloses a method for recovering rare earth particulate material from an assembly comprising a rare earth magnet and comprises the steps of exposing the assembly to hydrogen gas to effect hydrogen decrepitation of the rare earth magnet to produce a rare earth particulate material, and separating the rare earth particulate material from the rest of the assembly. The invention also resides in an apparatus for separating rare earth particulate material from an assembly comprising a rare earth magnet. The apparatus comprises a reaction vessel having an opening which can be closed to form a gas-tight seal, a separator for separating the rare earth particulate material from the assembly, and a collector for collecting the rare earth particulate material. The reaction vessel is connected to a vacuum pump and a gas control system, and the gas control system controls the supply of hydrogen gas to the reaction vessel.

Magnet recycling

The present invention discloses a method for recovering rare earth particulate material from an assembly comprising a rare earth magnet and comprises the steps of exposing the assembly to hydrogen gas to effect hydrogen decrepitation of the rare earth magnet to produce a rare earth particulate material, and separating the rare earth particulate material from the rest of the assembly. The invention also resides in an apparatus for separating rare earth particulate material from an assembly comprising a rare earth magnet. The apparatus comprises a reaction vessel having an opening which can be closed to form a gas-tight seal, a separation means for separating the rare earth particulate material from the assembly, and a collection means for collecting the rare earth particulate material. The reaction vessel is connected to a vacuum pump and a gas control system, and the gas control system controls the supply of hydrogen gas to the reaction vessel.

This invention, in one aspect, relates to a method of applying a corrosion-resistant coating on an article and is particularly, but not exclusively, concerned with a method of applying a corrosion-resistant coating on an Nd&mdash;Fe&mdash;B magnet. In another aspect, the present invention relates to a method of applying a coherent coating on the surfaces of the particles of a powder. Such powder may be one which is susceptible to oxidative corrosion and/or one which is used to form a magnet (e.g Nd&mdash;Fe&mdash;B powder).

Method of applying a corrosion-resistant coating

A method is disclosed enabling a technologically controllable and economical production of a hard-magnetic powder composed of a samarium-cobalt base alloy for highly coercive permanent magnets. The method is based on a HDDR treatment in which a starting powder is subjected to hydrogenation with disproportionation of the alloy in a first method step under hydrogen and, in a subsequent, second method step under vacuum conditions, a hydrogen desorption with recombination of the alloy. A starting powder containing samarium and cobalt is treated in the first method step either at a high temperature in the range of 500&deg; C. to 900&deg; C. and with a high hydrogen pressure of >0.5 MPa or by applying an intensive fine grinding at a low temperature in the range of 50&deg; C. to 500&deg; C. and with a hydrogen pressure of >0.15 MPa. By means of the method of the invention, magnetic alloy powders can be produced from samarium-cobalt base alloys; highly coercive permanent magnets can be produced from these magnetic alloy powders, particularly by hot compacting or plastic bonding.

Method for producing a magnetic alloy powder

Hydrogen storage materials

Hexaferrite materials

Ferromagnetic materials

A non-sintered permanent magnet is formed by a cold compacting technique or by resin bonding using particles of a stoichiometric alloy (e.g. R.sub.2 Fe.sub.14 B where R is at least one rare earth and/or yttrium, particularly La, Ce, Pr, ND or Y or a mixture thereof) which have been coated with a reaction product of the alloy or a non-magnetic metal such as Sn, Ga, Zn, Al, or Cu. The use of a stoichiometric alloy avoids the presence of a reactive grain boundary phase normally present in non-stoichiometric alloys.

Permanent magnets and method of making

A hydrogen storage material for releasably storing hydrogen having a microstructure containing an alloy phase of the general formula R.sub.2 Fe.sub.17, wherein R is cerium and lanthanum and, optionally, at least one other rare earth element, and wherein a microstructure also contains from about 2 to 35% by weight, based on the total weight of all phases, of a eutectic of the formula R'/R'Fe.sub.2, wherein R' is lanthanum-starved R; the alloy phase of the general formula R.sub.2 Fe.sub.17 being present in an amount of not less than 40% by weight of the material, and the material contains less than 60% by weight of cerium based on the total amount of cerium, lanthanum and, if present, at least one other rare earth element. A method for producing such material by heat treating in an inert atmosphere so as to homogenize same and to increase the proportion of alloy phase in the material is also described.

Hydrogen storage material

Growing community of inventors

Birmingham, United Kingdom

Ivor Rex Harris