Crucible Materials Corporation

Edward J Dulis

William Stasko

Floyd E Camp

Andrew S Kim

Carl J Dorsch

Kalatur S Narasimhan

Carol J Willman

Kalathur S Narasimhan

Thomas Lizzi

Francis S Snyder

George A Strichman

A permanent magnet of the neodymium-iron-boron type having improved corrosion resistance imparted by a combination of oxygen, carbon and nitrogen. Oxygen is provided in an amount equal to or greater than 0.6 weight percent in combination with carbon of 0.05-0.15 weight percent and nitrogen 0.15 weight percent maximum. Preferably, oxygen is within the range of 0.6-1.2% with carbon of 0.05-0.1% and nitrogen 0.02-0.15 weight percent or more preferably 0.04-0.08 weight percent. The magnet may be heated in an argon atmosphere and thereafter quenched in an atmosphere of either argon or nitrogen to further improve the corrosion resistance of the magnet.

Permanent magnet having improved corrosion resistance and method for

A method for producing permanent magnet alloy particles suitable for use in producing bonded permanent magnets. A melt or molten mass of a permanent magnet alloy having at least one rare earth element, at least one transition element, preferably iron, and boron is produced. The melt is inert gas atomized to form spherical particles within the size range of 1 to 1000 microns. The particles are heat treated in a nonoxidizing atmosphere for a time at temperature to significantly increase the intrinsic coercivity of the particles without sintering the particles to substantially full density. Thereafter, the particles are separated to produce a discrete particle mass. The particles during heat treatment may be maintained in motion to prevent sintering thereof.

Method for producing permanent magnet alloy particles for use in

A powder metallurgy produced high speed tool steel article comprising a mixture of prealloyed high speed tool steel particles coated with a hard, wear resistant material, such as a carbide or nitride, mixed with prealloyed high speed tool steel uncoated particles; the particles are compacted to essentially full density and the hard, wear resistant material is at the boundaries of the coated particles and contained in a continuous matrix of the high speed tool steel. The article is produced by hot compacting a particle charge to essentially full density of a mixture of the coated and uncoated particles.

Powder metallurgy high speed tool steel article and method of manufacture

A permanent magnet alloy that when used in the production of a permanent magnet results in a magnet that is highly resistant to disintegration when exposed to a combination of humidity and heat. Consequently, the alloy consists essentially of, in weight percent, 30 to 36 of at least one rare earth element, 60 to 66 iron, 6,000 to 35,000 ppm oxygen and balance boron.

Oxygen containing permanent magnet alloy

A method for making rare earth-permanent magnets wherein a molten mass of a rare earth magnet alloy is produced such as by induction melting and while in a protective atmosphere is introduced in the form of a stream into a chamber having a protective atmosphere and a bottom portion containing a cooling medium, such as a cryogenic liquid which may be liquid argon. After cooling and solidification, the alloy is collected from the chamber and comminuted to produce particles. The particles are formed into a magnet body. Alternately, the stream may be atomized, as by striking the same with a jet of inert gas, to produce discrete droplets, which droplets are directed to the cooling medium at the chamber bottom for cooling, solidification and collection.

Method for making rare-earth element containing permanent magnets

A method for producing iron-silicon alloy articles having an improved combination of hot workability and electrical properties; the method comprises taking a molten alloy mass of an iron-silicon alloy from which the article is to be made and gas atomizing it to form alloy particles which are quickly cooled to solidification temperature. These alloy particles are then hot isostatically pressed to form a substantially fully dense article. The fully dense article is then hot rolled to sheet form suitable for example for use as laminates in the manufacture of transformer cores.

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Pittsburgh, PA, United States of America

Edward J Dulis