Patents by Inventor William McCallum

William McCallum has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5690889
    Abstract: A method of making a rare earth compound, such as a earth-transition metal permanent magnet compound, without the need for producing rare earth metal as a process step, comprises carbothermically reacting a rare earth oxide to form a rare earth carbide and heating the rare earth carbide, a compound-forming reactant (e.g. a transition metal and optional boron), and a carbide-forming element (e.g. a refractory metal) that forms a carbide that is more thermodynamically favorable than the rare earth carbide whereby the rare earth compound (e.g. Nd.sub.2 Fe.sub.14 B or LaNi.sub.5) and a carbide of the carbide-forming element are formed.
    Type: Grant
    Filed: February 15, 1996
    Date of Patent: November 25, 1997
    Assignee: Iowa State University Research Foundation, Inc.
    Inventors: R. William McCallum, Timothy W. Ellis, Kevin W. Dennis, Robert J. Hofer, Daniel J. Branagan
  • Patent number: 5486240
    Abstract: A method of making a permanent magnet wherein 1) a melt is formed having a base alloy composition comprising RE, Fe and/or Co, and B (where RE is one or more rare earth elements) and 2) TR (where TR is a transition metal selected from at least one of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, and Al) and at least one of C and N are provided in the base alloy composition melt in substantially stoichiometric amounts to form a thermodynamically stable compound (e.g. TR carbide, nitride or carbonitride). The melt is rapidly solidified in a manner to form particulates having a substantially amorphous (metallic glass) structure and a dispersion of primary TRC, TRN and/or TRC/N precipitates. The amorphous particulates are heated above the crystallization temperature of the base alloy composition to nucleate and grow a hard magnetic phase to an optimum grain size and to form secondary TRC, TRN and/or TRC/N precipitates dispersed at grain boundaries.
    Type: Grant
    Filed: April 25, 1994
    Date of Patent: January 23, 1996
    Assignee: Iowa State University Research Foundation, Inc.
    Inventors: R. William McCallum, Daniel J. Branagan
  • Patent number: 5470401
    Abstract: An isotropic permanent magnet is made by mixing a thermally responsive, low viscosity binder and atomized rare earth-transition metal (e.g., iron) alloy powder having a carbon-bearing (e.g., graphite) layer thereon that facilitates wetting and bonding of the powder particles by the binder. Prior to mixing with the binder, the atomized alloy powder may be sized or classified to provide a particular particle size fraction having a grain size within a given relatively narrow range. A selected particle size fraction is mixed with the binder and the mixture is molded to a desired complex magnet shape. A molded isotropic permanent magnet is thereby formed. A sintered isotropic permanent magnet can be formed by removing the binder from the molded mixture and thereafter sintering to full density.
    Type: Grant
    Filed: July 26, 1993
    Date of Patent: November 28, 1995
    Assignee: Iowa State University Research Foundation, Inc.
    Inventors: R. William McCallum, Kevin W. Dennis, Barbara K. Lograsso, Iver E. Anderson
  • Patent number: 5433978
    Abstract: A method of making quasicrystalline alloy particulates wherein an alloy is superheated and the melt is atomized to form generally spherical alloy particulates free of mechanical fracture and exhibiting a predominantly quasicrystalline in the atomized condition structure. The particulates can be plasma sprayed to form a coating or consolidated to form an article of manufacture.
    Type: Grant
    Filed: September 27, 1993
    Date of Patent: July 18, 1995
    Assignee: Iowa State University Research Foundation, Inc.
    Inventors: Jeffrey E. Shield, Alan I. Goldman, Iver E. Anderson, Timothy W. Ellis, R. William McCallum, Daniel J. Sordelet
  • Patent number: 5242508
    Abstract: A method for making an isotropic permanent magnet comprises atomizing a melt of a rare earth-transition metal alloy (e.g., an Nd--Fe--B alloy enriched in Nd and B) under conditions to produce protectively coated, rapidly solidified, generally spherical alloy particles wherein a majority of the particles are produced/size classified within a given size fraction (e.g., 5 to 40 microns diameter) exhibiting optimum as-atomized magnetic properties and subjecting the particles to concurrent elevated temperature and elevated isotropic pressure for a time effective to yield a densified, magnetically isotropic magnet compact having enhanced magnetic properties and mechanical properties.
    Type: Grant
    Filed: April 15, 1992
    Date of Patent: September 7, 1993
    Assignee: Iowa State University Research Foundation, Inc.
    Inventors: R. William McCallum, Kevin W. Dennis, Barbara K. Lograsso, Iver E. Anderson
  • Patent number: 5240513
    Abstract: An isotropic permanent magnet is made by mixing a thermally responsive, low viscosity binder and atomized rare earth-transition metal (e.g., iron) alloy powder having a carbon-bearing (e.g., graphite) layer thereon that facilitates wetting and bonding of the powder particles by the binder. Prior to mixing with the binder, the atomized alloy powder may be sized or classified to provide a particular particle size fraction having a grain size within a given relatively narrow range. A selected particle size fraction is mixed with the binder and the mixture is molded to a desired complex magnet shape. A molded isotropic permanent magnet is thereby formed. A sintered isotropic permanent magnet can be formed by removing the binder from the molded mixture and thereafter sintering to full density.
    Type: Grant
    Filed: October 9, 1990
    Date of Patent: August 31, 1993
    Assignee: Iowa State University Research Foundation, Inc.
    Inventors: R. William McCallum, Kevin W. Dennis, Barbara K. Lograsso, Iver E. Anderson
  • Patent number: 4637967
    Abstract: The present invention provides an electrode which uses a disordered active material preferably formed by rapid solidification. The active material does not need a binder to be used as an electrode, and thus, is considered self-supporting. The material also is substantially non-porous or impermeable to an electrolyte and when used as an electrode exhibits an increase in cell capacity with improved resistance to corrosion. An electrode of the present invention provides greatly improved cycle life and energy density without a significant decrease in cell capacity. Methods of making the electrode by rapidly solidifying a disordered material are also included. A method of assembling an electrochemical cell using a self-supporting electrode includes the step of producing a disordered active material and aligning the material in a predetermined position in a cell casing.
    Type: Grant
    Filed: August 29, 1985
    Date of Patent: January 20, 1987
    Assignee: Energy Conversion Devices, Inc.
    Inventors: John E. Keem, Richard C. Bergeron, Russell C. Custer, R. William McCallum