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History of Rare-Earth Magnets

Year Energy Product Summary
1966 18 MGOe  Dr. Karl J. Strnat discovers the high energy product of the Samarium-Cobalt (SmCo5) compound.
1972 30 MGOe  Dr. Karl J. Strnat and Dr. Alden Ray develop a higher energy product Samarium-Cobalt (Sm2Co17) compound.
1983 35 MGOe  General Motors, Sumitomo Special Metals and the Chinese Academy of Sciences develop a high energy product Neodymium-Iron-Boron (Nd2Fe14B) compound.

Patents and Intellectual Property

There many U.S. and international patents that are related to the development and manufacture of rare-earth magnetic products.  Many patents related to Neodymium-Iron-Boron magnets are currently valid and enforced by their owners.  Of particular importance are the patents held by Sumitomo Special Metals Co., Ltd., and Magnequench, Inc.  These patents are based on the original intellectual property of General Motors, Sumitomo Special Metals and The Chinese Academy of Sciences that independently discovered the new permanent magnet material composed of neodymium, iron and boron.

Sumitomo and Magnequench have a cross-license agreement that covers the sale of Nd-Fe-B magnetic products in the United States.  Only magnets produced under license to these companies are legally entitled for sale in the United States.

Many of the basic Rare-Earth-Iron-Boron patents will be expiring in the year 2003.  The following table shows the expiration dates for the major composition patents:

Company Patent Composition   Japan  USA Europe
SUMITOMO  Basic RE-Fe-B Composition 2003 2003 2003
 RE-Fe, Co-B Composition 2008 2003 2007
 Nd, Dy-Fe, Co-B Composition    2003 2010 2003
 RE-Fe-B Compound 2003  2014  N/A
 RE-Fe, Co-B Compound 2003 2014 N/A
 MAGNEQUENCH   Basic RE-Fe-B Composition 2003 2006 2004
 Including Co 2004 2012 N/A

Source: Sumitomo Special Metals Co., Ltd.

There are hundreds of patents related to the development and production of rare-earth magnets and related products.  The following is a partial listing of some of the more notable U.S. patents.  Each listing provides a link to the U.S. Patent and Trademark Office Internet Site:

3982971 Sep., 1976 Yamanaka et al. Rare earth-containing permanent magnets
4063970 Dec., 1977 Steingroever Method of making permanent magnets
4065330 Dec., 1977 Masumoto et al. Wear-resistant high-permeability alloy
4222770 Sep., 1980 Osumi et al. Alloy for occlusion of hydrogen
4402770 Sep., 1983 Koon. Hard magnetic alloys of a transition metal and lanthanide
4409043 Oct., 1983 Koon. Amorphous transition metal-lanthanide alloys
4496395 Jan., 1985 Croat High coercivity rare earth-iron magnets
4533408 Aug., 1985 Koon. Preparation of hard magnetic alloys of a transition metal and lanthanide
4597938 Jul., 1986 Matsuura et al. Process for producing permanent magnet materials
4601875 Jul., 1986 Yamamoto et al. Process for producing magnetic materials 
4663066 May., 1987 Fruchart et al. Magnetic rare earth/iron/boron and rare earth/cobalt/boron hydrides, the process for their manufacture of the corresponding pulverulent dehydrogenated products
4664724 May., 1987 Mizoguchi et al. Permanent magnetic alloy and method of manufacturing the same
4684406 Aug., 1987 Matsuura et al. Permanent magnet materials
4684448 Aug., 1987 Itoh et al. Process of producing neodymium-iron alloy
4689073 Aug., 1987 Nate et al. Method for production of rare-earth element/cobalt type magnetic powder for resin magnet
4734131 Mar., 1988 Arai et al. Permanent-magnetic material
4747874 May., 1988 Ghandehari. Rare earth-iron-boron permanent magnets with enhanced coercivity
4747924 May., 1988 Itoh et al. Apparatus for producing neodymium-iron alloy
4765848 Aug., 1988 Mohri et al. Permanent magnent and method for producing same
4767450 Aug., 1988 Ishigaki et al. Process for producing the rare earth alloy powders
4767455 Aug., 1988 Jourdan Process for the preparation of pure alloys based on rare earths and transition metals by metallothermy
4770702 Sep., 1988 Ishigaki et al. Process for producing the rare earth alloy powders
4770723 Sep., 1988 Sagawa et al. Magnetic materials and permanent magnets
4792367 Dec., 1988 Lee. Iron-rare earth-boron permanent
4792368 Dec., 1988 Sagawa et al. Magnetic materials and permanent magnets
4801340 Jan., 1989 Inoue et al. Method for manufacturing permanent magnets
4802931 Feb., 1989 Croat High energy product rare earth-iron magnet alloys
4814139 Mar., 1989 Tokunaga et al. Permanent magnet having good thermal stability and method for manufacturing same
4836868 Jun., 1989 Yajima et al. Permanent magnet and method of producing same
4837109 Jun., 1989 Tokunaga et al. Method of producing neodymium-iron-boron permanent magnet
4842656 Jun., 1989 Maines et al. Anisotropic neodymium-iron-boron powder with high coercivity
4844754 Jul., 1989 Lee. Iron-rare earth-boron permanent magnets by hot working
4851058 Jul., 1989 Croat High energy product rare earth-iron magnet alloys
4859254 Aug., 1989 Mizoguchi et al. Permanent magnet
4865660 Sep., 1989 Nate et al. Rare-earth element/cobalt type magnet powder for resin magnets
4867785 Sep., 1989 Keem et al. Method of forming alloy particulates having controlled submicron crystallite size distributions
4875946 Oct., 1989 Heh et al. Process for producing rare earth-cobalt permanent magnet
4898625 Feb., 1990 Otsuka et al. Method for producing a rare earth metal-iron-boron permanent magnet by use of a rapidly-quenched alloy powder
4902360 Feb., 1990 Ma et al. Permanent magnet alloy for elevated temperature applications
4921551 May., 1990 Vernia et al. Permanent magnet manufacture from very low coercivity crystalline rare earth-transition metal-boron alloy
4921553 May., 1990 Tokunga et al. Magnetically anisotropic bond magnet, magnetic powder for the magnet and manufacturing method of the powder
4935074 Jun., 1990 DeMooij et al. Magnetic material comprising iron, boron and a rare earth metal 
4935075 Jun., 1990 Mizoguchi et al. Permanent magnet 
4952239 Aug., 1990 Tokunaga et al. Magnetically anisotropic bond magnet, magnetic powder for the magnet and manufacturing method of the powder
4968347 Nov., 1990 Ramesh et al. High energy product permanent magnet having improved intrinsic coercivity and method of making same
4975129 Dec., 1990 Fujimura et al. Permanent magnet
4975130 Dec., 1990 Matsuura et al. Permanent magnet materials
4975213 Dec., 1990 Sakai et al. Resin-bonded rare earth-iron-boron magnet
4981532 Jan., 1991 Takeshita et al. Rare earth-iron-boron magnet powder and process of producing same
4983232 Jan., 1991 Endoh et al. Anisotropic magnetic powder and magnet thereof and method of producing same
4994109 Feb., 1991 Willman et al. Method for producing permanent magnet alloy particles for use in producing bonded permanent magnets
5022939 Jun., 1991 Yajima et al. Permanent magnet
5026438 Jun., 1991 Young et al. Method of making self-aligning anisotropic powder for magnets
5037492 Aug., 1991 Brewer et al. Alloying low-level additives into hot-worked Nd-Fe-B magnets
5041171 Aug., 1991 Buschow et al. Hard magnetic material
5041172 Aug., 1991 Tokunaga et al. Permanent magnet having good thermal stability and method for manufacturing same
5049203 Sep., 1991 Mukai et al. Method of making rare earth magnets
5049208 Sep., 1991 Yajima et al. Permanent magnets
5056585 Oct., 1991 Croat High energy product rare earth-iron magnet alloys
5071493 Dec., 1991 Mizoguchi et al. Rare earth-iron-boron-based permanent magnet
5093076 Mar., 1992 Young et al. Hot pressed magnets in open air presses
5096512 Mar., 1992 Sagawa et al. Magnetic materials and permanent magnets
5100485 Mar., 1992 Yamashita et al. Method for manufacturing permanent magnets
5114502 May., 1992 Bogatin. Magnetic materials and process for producing the same
5135584 Aug., 1992 Fujiwara. Permanent magnet powders
5162064 Nov., 1992 Kim et al. Permanent magnet having improved corrosion resistance and method for producing the same
5164023 Nov., 1992 Tabaru et al. Rare earth permanent magnet, method of heat treatment of same, and magnet body
5167915 Dec., 1992 Yamashita et al. Process for producing a rare earth-iron-boron magnet
5172751 Dec., 1992 Croat. High energy product rare earth-iron magnet alloys
5174362 Dec., 1992 Croat. High-energy product rare earth-iron magnet alloys
5178692 Jan., 1993 Panchanathan Anisotropic neodymium-iron-boron powder with high coercivity and method for forming same
5186761 Feb., 1993 Kobayashi et al. Magnetic alloy and method of production
5194098 Mar., 1993 Sagawa et al. Magnetic materials
5209789 May., 1993 Yoneyama et al. Permanent magnet material and method for making
5213631 May., 1993 Akioka et al. Rare earth-iron system permanent magnet and process for producing the same
5223047 Jun., 1993 Endoh et al. Permanent magnet with good thermal stability
5228930 Jul., 1993 Nakayama et al. Rare earth permanent magnet power, method for producing same and bonded magnet
5230751 Jul., 1993 Endoh et al. Permanent magnet with good thermal stability
5250206 Oct., 1993 Nakayama et al. Rare earth element-Fe-B or rare earth element-Fe-Co-B permanent magnet powder excellent in magnetic anisotropy and corrosion resistivity and bonded magnet manufactured therefrom
5281250 Jan., 1994 Hamamura et al. Powder material for rare earth-iron-boron based permanent magnets
5309977 May., 1994 Yoneyama et al. Permanent magnet material and method for making
5338520 Aug., 1994 Leveque et al. Recovery of neodymium/didymium values from bastnaesite ores
5403408 Apr., 1995 Krause et al. Non-uniaxial permanent magnet material 
5411608 May., 1995 Hazelton et al. Performance light rare earth, iron, and boron magnetic alloys
5449417 Sep., 1995 Shimizu et al. R-Fe-B magnet alloy, isotropic bonded magnet and method of producing same 
5460662 Oct., 1995 Kobayashi et al. Permanent magnet and method of production
5514224 May., 1996 Panchanathan High remanence hot pressed magnets
5545266 Aug., 1996 Hirosawa et al. Rare earth magnets and alloy powder for rare earth magnets and their manufacturing methods
5549766 Aug., 1996 Tsutai et al. Magnetic material
5567891 Oct., 1996 Bogatin et al. Rare earth element-metal-hydrogen-boron permanent magnet
5591276 Jan., 1997 Yoshizawa et al. Magnetic alloy with ultrafine crystal grains and method of producing same
5591535 Jan., 1997 Hisano et al. Ferromagnetic metal powder
5597425 Jan., 1997 Akioka et al. Rare earth cast alloy permanent magnets and methods of preparation
5626690 May., 1997 Matsuki et al. Low boron amorphous alloy having excellent soft magnetic characteristics
5634987 Jun., 1997 Zhang et al. Magnetic materials and method of making them
5643491 Jul., 1997 Honkura et al. Rare earth magnetic powder, its fabrication method, and resin bonded magnet
5645651 Jul., 1997 Fujimura et al. Magnetic materials and permanent magnets
5647886 Jul., 1997 Kitazawa et al. Magnetic powder, permanent magnet produced therefrom and process for producing them
5656100 Aug., 1997 Yamamoto et al. Alloy ingot for permanent magnet, anisotropic powders for permanent magnet, method for producing same and permanent magnet 
5665177 Sep., 1997 Fukuno et al. Method for preparing permanent magnet material, chill roll, permanent magnet material, and permanent magnet material powder 
5674327 Oct., 1997 Yamamoto et al. Alloy ingot for permanent magnet, anisotropic powders for permanent magnet, method for producing same and permanent magnet
5690752 Nov., 1997 Yamamoto et al. Permanent magnet containing rare earth metal, boron and iron 
6019859 Feb., 2000 Kanekiyo et al. Iron-based permanent magnets and their fabrication as well as iron-based permanent magnet alloy powders for permanent bonded magnets and iron-based bonded magnets
6120620 Sep., 2000 Benz et al. Praseodymium-rich iron-boron-rare earth composition, permanent magnet produced therefrom, and method of making
6143193 Nov., 2000 Akioka et al. Rare earth bonded magnet, rare earth magnetic composition, and method for manufacturing rare earth bonded magnet
6168673 Jan., 2001 Kanekiyo et al. Sheet magnet having microcrystalline structure and method of manufacturing the same, and method of manufacturing isotropic permanent magnet powder
6261387 Jul., 2001 Panchanathan Rare-earth iron-boron magnet containing cerium and lanthanum 

 
 

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