US3090107A - Method of making a permanent magnet - Google Patents

Method of making a permanent magnet Download PDF

Info

Publication number
US3090107A
US3090107A US750725A US75072558A US3090107A US 3090107 A US3090107 A US 3090107A US 750725 A US750725 A US 750725A US 75072558 A US75072558 A US 75072558A US 3090107 A US3090107 A US 3090107A
Authority
US
United States
Prior art keywords
container
magnetic
binder
particles
permanent magnet
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US750725A
Inventor
Henry T Minden
Berenbaum Leonard
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
GTE Sylvania Inc
Original Assignee
Sylvania Electric Products Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sylvania Electric Products Inc filed Critical Sylvania Electric Products Inc
Priority to US750725A priority Critical patent/US3090107A/en
Application granted granted Critical
Publication of US3090107A publication Critical patent/US3090107A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
    • H01F1/06—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys in the form of particles, e.g. powder
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49002—Electrical device making
    • Y10T29/4902—Electromagnet, transformer or inductor
    • Y10T29/49075—Electromagnet, transformer or inductor including permanent magnet or core
    • Y10T29/49076—From comminuted material

Definitions

  • 'Ihis invention relates to improved permanent magnets. 'Ihere are various applications which require the use of v a permanent magnet having a very high coercive force.
  • the coercive force of a magnet is a measure of its ability to retain its magnetic strength under the inuence of an opposing magnetic field.
  • a plurality of magnets having a general toroidal or washer shape are stacked in such manner that the resultant magnetic field is axial and adjacent faces of adjacent magnets have opposite magnetic poles.
  • the magnets so shaped and so arranged must possess a high coercive force.
  • Another object of this invention is to provide a method for making magnets having-a higher coercive force than conventional magnetic materials arid which will not be subject to corrosion, deterioration or cracking.
  • Still another object is to produce apparatus for making improved permanent magnets of the type herein dcscribed.
  • a mixture of manganese bismuthide particles and a binder is placed in a non-magnetic container.
  • This container is then placed in an apparatus where the binder 1s tirst subjected to a sutiicient amount of heat to melt the binder material.
  • a magnetic iield is applied to magnetically orient the particles of manganese bismuthide therein in the direction of the magnetic lines of force.
  • the mixture is then cooled to solidify the binder while maintaining the pressure and the magnetic field.
  • the container housing the magnet thus produced is then hermetically sealed to protect the magnetic substance from the atmosphere.
  • a magnet is thus produced which has a very high coercive force and magnetic strength and which is not deleteriously affected by atmospheric conditions.
  • a brass or other non-magnetic metallic container toroidal in shape which is lined with thin aluminum foil 11.
  • a mixture 12 of manganese bismuthide and bismuth (bismanol) is then placed in the container and a at cover 14 is placed over the container.
  • the loaded container is United States Patent Oice 3,090,107 Patented May 2l, 1963 next placed on the top annular surface 15 of a lower die member 16 which has a central portion 18 extending into the center region of the toroidal container 10. This portion supports the inner sides of the container 10, when the mixture within the container is subjected to pressure as will later appear.
  • An upper die member 20 is next placed over the container cover 14 in alignment with the lower die member 16.
  • the upper die member is provided with outer and inner annular grooves 24 and 26 respectively for receiving any molten overliow squeezed from the when heat and pressure are applied thereto in accordance with the method to be described.
  • the central bore of the upper die member terminates at one end in a conical shape 28 td facilitate more even distribution of lines through the upper die member 20.
  • Lower and upper co1- lar members 30 and 32 are disposed about the lower and upper die members 16 and 20 respectively, and support the external surface of container 10 when pressure is applied thereto.
  • thermocouple 36 Surrounding the upper and lower die members in the region of the container 10 is an electric heater 34 ⁇ having wires 35 for heating the mixture in the container 10.
  • a thermocouple 36 is located in the lower die member 16, which, in conjunction with an automatic controller (not shown) maintains the mixture at the proper temperature.
  • Cooling coils 38 which carry circulating cold water are provided about the lower portion of the lower die member for cooling the mixture at the proper time.
  • the cooling coils 38 are located some distance below the level of the container 10, so that the mixture can be cooled from the bottom of the container 10 rather than from its sides.
  • the upper and lower die member assembly just described is supported on the top face 39 of a lower pole piece 40, which is part of a large electromagnet comprising a lower pole piece 40, an upper pole piece 42, a yoke portion 44, and current carrying coils 46 disposed about both thc upper and lower pole pieces.
  • the upper yoke member 42 is slidably held by the yoke 44 to allow vertical movement thereof so that the face of the upper pole piece 42 can be brought into direct contact with the top of the upper die member 20. Provision is also made to apply pressure vertically from a press, not shown, through a bar 48, the upper pole piece 42, upper die member 20 and the container cover 14, to compress the contents 12 in the container -10 thereby densifying the same.
  • the process is conducted in the following manner.
  • the bismanol powder 12, which is composed of particles of manganese bismuthide and bismuth is loaded into the non-magnetic toroidal container 10. This is done under the protection of nitrogen to prevent reaction with the atmosphere.
  • the cover 14 is then placed on the container 10.
  • the loaded container is placed on the top surface 15 of the lower die member 16 which has disposed about it the lower collar 30, heater 34 and cooling coils 38.
  • the upper die member 20 is then placed over the container cover 14, the upper collar 32 is placed in position and the upper pole piece 42 is lowered into contact with the top of the upper die member 20.
  • the heater 34 is then turned on and the temperature is automatically regulated by a controller in cooperation with the thermocouple 36.
  • the mixture is heated to 300 C., a temperature above which bismuth melts of magneticfFlf-Li 3 (271 C.) butbelow the Curie temperature of manganese bismuthide (360 C.), which is the temperature above which the latter material will lose its permanent magnetism.
  • the manganese bismuthide particles While maintaining a temperature of 300 C., the manganese bismuthide particles become dispersed in the liquid bismuth medium and are magnetically oriented and then permanently retained in this position by freezing the liquid bismuth, as will now appear.
  • the magnetizing coils 46 are energized to create a strong magnetic ield to thus magnetically' orient the manganese bismuthide particles with respect to the direction of the applied magnetic iield so that upon removal of the tield, a strong permanent magnet will have been produced in the direction of the axis of the toroid.
  • the mixture is held at a temperature of ap- .proximately 300 C.
  • the mag- 'petic field should be maintained for a sutcient time gvhile the bismuth is molten. This time varies fromsevmi minutes for very thin magnets to several hours for very thick ones.
  • a pressure is applied through the. bar 48 to increase the density of the contents of the containerlO.
  • the magnitude of the pressure is a variable depending upon the thickness of the magnet.
  • the heater 34 is turned off and the container is cooled by passingvcold water through the cooling coils 38. Cool air may also be blown over the apparatus to speed up the cooling process.
  • the magnet After the magnet is cooled, it is removed from the apparatus and sealed to protect the manganese bismuthide from the deleterious eteets of the atmosphere.
  • the sealing may be carried out by low temperature soldering or 4 react with the latter. Plastics and other compositions can also be used.
  • a modification of our process can be carried out by forming the magnet in the desired shape without the use of a container and subsequently sealing the magnet off from the deleterious effects of the atmosphere by the use of a protective coating.
  • the method of making a permanent magnet comprising, charging a toroidal container of non-magnetic material lined with aluminum foil and having a toroidal cover with a powder containing particles of manganese bismuthide and bismuth, heating said powder to a temperature suicient to form a dispersion of manganese bisany other suitable method so long as the method does j.: not result in4 melting of the bismuth or in otherwise decreasing the strength of the magnet.
  • the Girie temperature of manganese bismuthide would be suitable if they do not muthide particles in molten bismuth but below the Curie -temperature of said manganese bismuthide, applying a magnetic field to said dispersion to magnetically orient said .particles of manganese bismuthide with respect to said applied magnetic ⁇ ield, applying pressure between said toroidal cover and the bottom of said container to densify said solution, and direetionally'cooling said solution to solidify said bismuth while maintaining said manganese bismuthide particles so oriented, and hermetically sealing the cover on said container of non-magnetic material lined with aluminum foil, to protect the magnet so produced from the atmosphere.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Hard Magnetic Materials (AREA)

Description

May 21, 1963 H. T. MINDEN Erm METHOD oF MAKING A PERMANENT MAGNET Filed July 24, 1958 lNvENToRs F0/YARD BEREA/EAI/M B/ENRY AIM/06W ATTORNEYJ METHOD F MAKING A PERMANENT MAGNET Henry T. Minden, Roslyn Heights, and Leonard Berenbaum, Flushing, N.Y., assignors, by m'esne assignments,
to Sylvania Electric Products Inc., Wilmington, Del., a
corporation of Delaware Filed July 24, 1958, Ser. No. 750,725 2 Claims. (CL 29155.6)
'Ihis invention relates to improved permanent magnets. 'Ihere are various applications which require the use of v a permanent magnet having a very high coercive force.
(The coercive force of a magnet is a measure of its ability to retain its magnetic strength under the inuence of an opposing magnetic field.) For example, in certain traveling wave tube applications, a plurality of magnets having a general toroidal or washer shape are stacked in such manner that the resultant magnetic field is axial and adjacent faces of adjacent magnets have opposite magnetic poles. In order to produce the desired field strength, the magnets so shaped and so arranged must possess a high coercive force.
Conventional materials from which permanent magnets are made, such as Aluico V, lack the high degree of coercive force desired in the application described. Permanent magnets made of bismanol, however, do have the required high degree of coercive force, but corrode rapidly and suffer a permanent reduction in magnetic strength when exposed to a humid atmosphere not uncommonly encountered. Eventually the corrosion progresses to a point where cracking and pulverization of the magnet occurs, rendering it useless as a magnet.
Accordingly it is an object of our invention to produce an improved permanent magnet having a very high degree of coercive force so that it will retain its magnetic strength under the influence of demagnetizing fields.
Another object of this invention is to provide a method for making magnets having-a higher coercive force than conventional magnetic materials arid which will not be subject to corrosion, deterioration or cracking.
Still another object is to produce apparatus for making improved permanent magnets of the type herein dcscribed. In accordance with the principles of our invention, a mixture of manganese bismuthide particles and a binder is placed in a non-magnetic container. This container is then placed in an apparatus where the binder 1s tirst subjected to a sutiicient amount of heat to melt the binder material. While the binder is in a liquid state, pressure is applied to the mixture and simultaneously a magnetic iield is applied to magnetically orient the particles of manganese bismuthide therein in the direction of the magnetic lines of force. The mixture is then cooled to solidify the binder while maintaining the pressure and the magnetic field. The container housing the magnet thus produced is then hermetically sealed to protect the magnetic substance from the atmosphere. A magnet is thus produced which has a very high coercive force and magnetic strength and which is not deleteriously affected by atmospheric conditions.
Our invention will now be described in detail with reference to the accompanying drawing which shows partly in cross section one embodiment of an apparatus employed to carry out the method of making the improved magnets.
Referring now to the drawing, there is shown a brass or other non-magnetic metallic container toroidal in shape, which is lined with thin aluminum foil 11. A mixture 12 of manganese bismuthide and bismuth (bismanol) is then placed in the container and a at cover 14 is placed over the container. The loaded container is United States Patent Oice 3,090,107 Patented May 2l, 1963 next placed on the top annular surface 15 of a lower die member 16 which has a central portion 18 extending into the center region of the toroidal container 10. This portion supports the inner sides of the container 10, when the mixture within the container is subjected to pressure as will later appear.
An upper die member 20 is next placed over the container cover 14 in alignment with the lower die member 16. The upper die member is provided with outer and inner annular grooves 24 and 26 respectively for receiving any molten overliow squeezed from the when heat and pressure are applied thereto in accordance with the method to be described. By providing annular grooves to collect the overow, it is easier to break 'the container freefrom the upper die member when the container 10 process is complete. The central bore of the upper die member terminates at one end in a conical shape 28 td facilitate more even distribution of lines through the upper die member 20. Lower and upper co1- lar members 30 and 32 are disposed about the lower and upper die members 16 and 20 respectively, and support the external surface of container 10 when pressure is applied thereto. v
Surrounding the upper and lower die members in the region of the container 10 is an electric heater 34`having wires 35 for heating the mixture in the container 10. A thermocouple 36 is located in the lower die member 16, which, in conjunction with an automatic controller (not shown) maintains the mixture at the proper temperature. Cooling coils 38 which carry circulating cold water are provided about the lower portion of the lower die member for cooling the mixture at the proper time. The cooling coils 38 are located some distance below the level of the container 10, so that the mixture can be cooled from the bottom of the container 10 rather than from its sides. Such directional cooling and the use of the aluminum foil 1,1 to eliminate sticking of the mixture to the inner wall of the container, prevent cracking of the magnet during the cooling process.
The upper and lower die member assembly just described is supported on the top face 39 of a lower pole piece 40, which is part of a large electromagnet comprising a lower pole piece 40, an upper pole piece 42, a yoke portion 44, and current carrying coils 46 disposed about both thc upper and lower pole pieces. The upper yoke member 42 is slidably held by the yoke 44 to allow vertical movement thereof so that the face of the upper pole piece 42 can be brought into direct contact with the top of the upper die member 20. Provision is also made to apply pressure vertically from a press, not shown, through a bar 48, the upper pole piece 42, upper die member 20 and the container cover 14, to compress the contents 12 in the container -10 thereby densifying the same.
The process is conducted in the following manner. The bismanol powder 12, which is composed of particles of manganese bismuthide and bismuth is loaded into the non-magnetic toroidal container 10. This is done under the protection of nitrogen to prevent reaction with the atmosphere. The cover 14 is then placed on the container 10. The loaded container is placed on the top surface 15 of the lower die member 16 which has disposed about it the lower collar 30, heater 34 and cooling coils 38. The upper die member 20 is then placed over the container cover 14, the upper collar 32 is placed in position and the upper pole piece 42 is lowered into contact with the top of the upper die member 20.
The heater 34 is then turned on and the temperature is automatically regulated by a controller in cooperation with the thermocouple 36. The mixture is heated to 300 C., a temperature above which bismuth melts of magneticfFlf-Li 3 (271 C.) butbelow the Curie temperature of manganese bismuthide (360 C.), which is the temperature above which the latter material will lose its permanent magnetism.
While maintaining a temperature of 300 C., the manganese bismuthide particles become dispersed in the liquid bismuth medium and are magnetically oriented and then permanently retained in this position by freezing the liquid bismuth, as will now appear.
When the melting point of bismuth is reached, the magnetizing coils 46 are energized to create a strong magnetic ield to thus magnetically' orient the manganese bismuthide particles with respect to the direction of the applied magnetic iield so that upon removal of the tield, a strong permanent magnet will have been produced in the direction of the axis of the toroid. While the magneticiield is applied, the mixture is held at a temperature of ap- .proximately 300 C. In order to insure the proper orientation of all the manganese bismuthide particles, the mag- 'petic field should be maintained for a sutcient time gvhile the bismuth is molten. This time varies fromsevmi minutes for very thin magnets to several hours for very thick ones.
While the bismuth is molten, a pressure is applied through the. bar 48 to increase the density of the contents of the containerlO. The magnitude of the pressure is a variable depending upon the thickness of the magnet. After sulhcient healing time has elapsed, the heater 34 is turned off and the container is cooled by passingvcold water through the cooling coils 38. Cool air may also be blown over the apparatus to speed up the cooling process. To achieve maximum magnetic strength, it is important to maintain the magnetic iield while the molten bismuth is above its melting point to insure that the man ganese bismuthide particles are frozen in their properly oriented positions.
After the magnet is cooled, it is removed from the apparatus and sealed to protect the manganese bismuthide from the deleterious eteets of the atmosphere. The sealing may be carried out by low temperature soldering or 4 react with the latter. Plastics and other compositions can also be used.
A modification of our process can be carried out by forming the magnet in the desired shape without the use of a container and subsequently sealing the magnet off from the deleterious effects of the atmosphere by the use of a protective coating.
What is claimed is:
1. The method of making a permanent magnet comprising, charging a toroidal container of non-magnetic material lined with aluminum foil and having a toroidal cover with a powder containing particles of manganese bismuthide and bismuth, heating said powder to a temperature suicient to form a dispersion of manganese bisany other suitable method so long as the method does j.: not result in4 melting of the bismuth or in otherwise decreasing the strength of the magnet.
By this method a permanent magnet is produced, which has a high magnetic strength and also a much higher coercive force than conventional magnets. While our process has been described using bismuth as a binder to maintain the manganese bismuthide particles magnetically oriented in their proper positions, it should be understood than other substances can also be used. For example, other non-magnetic metals having a melting point somewhat below 360 C., the Girie temperature of manganese bismuthide, would be suitable if they do not muthide particles in molten bismuth but below the Curie -temperature of said manganese bismuthide, applying a magnetic field to said dispersion to magnetically orient said .particles of manganese bismuthide with respect to said applied magnetic `ield, applying pressure between said toroidal cover and the bottom of said container to densify said solution, and direetionally'cooling said solution to solidify said bismuth while maintaining said manganese bismuthide particles so oriented, and hermetically sealing the cover on said container of non-magnetic material lined with aluminum foil, to protect the magnet so produced from the atmosphere. l Y
2. The method of making a permanent magnet cornprising dispersing particles of a ferromagnetic material in a liquid binder held in a non-magnetic container having a cover, said binder being held at a temperature suiicient to maintain said binder in a liquid state but below the Oirie temperature of saidA ferromagnetic material, subjecting said ferromagnetic material to the inuence of a magnetic field to magnetically orient said ferromagnetic particles with respect to the direction of said applied magnetic field, densifying said dispersion, directionally cooling and freezing said binder while maintaining said ferromagnetic particles so oriented to permanently tix said particles in said oriented direction, and sealing the cover on said container of non-magnetic material to protect lits contents from the atmosphere.
References Cited in the tile of this patent UNITED STATES PATENTS 2,576,679 Guilland Nov. 27, 1951 2,589,766 Bradley Mar. 18, 1952, 2,698,9-17 Van Urk et al. Ian. 4, 1955 2,751,525 Hekelaar .Tune 19, 1956 2,825,670 Adams et al Mar. 4, 1958 2,849,312 Peterman Ang. 26, 1958 2,862,287 Koch et al. Dec. 2, 1958 2,865,085 Cornish Dec. 23, 1958 2,892,M8 Weber et al. June 30, 1959

Claims (1)

  1. 2. THE METHOD OF MAKING A PERMANENT MAGNET COMPRISING DISPERSING PARTICLES OF A FERROMAGNETIC MATERIAL IN A LIQUID BINDER HOLD IN A NON-MAGNETIC CONTAINER HAVING A COVER, SAID BINDER BEING HELD AT A TEMPERATURE SUFFICIENT TO MAINTAIN SAID BINDER IN A LIQUID STATE BUT BELOW THE CURIE TEMPERATURE OF SAID FERROMAGNETIC MATERIAL, SUBJECTING SAID FERROMAGNETIC MATERIAL TO THE INFLUENCE OF A MAGNETIC FIELD TO MAGNETICALLY ORIENT SAID FERROMAGNETIC PARTICLES WITH RESPECT TO THE DIRECTIN OF SAID APPLIED MAGNETIC FIELD, DENSIFYING SAID DISPERSION, DIRECTIONALLY COOLING AND FREEZING SAID BINDER WHILE MAINTAINING SAID FERROMAGNETIC PARTICLES SO ORIENTED TO PERMANENTLY FIX SAID
US750725A 1958-07-24 1958-07-24 Method of making a permanent magnet Expired - Lifetime US3090107A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US750725A US3090107A (en) 1958-07-24 1958-07-24 Method of making a permanent magnet

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US750725A US3090107A (en) 1958-07-24 1958-07-24 Method of making a permanent magnet

Publications (1)

Publication Number Publication Date
US3090107A true US3090107A (en) 1963-05-21

Family

ID=25018935

Family Applications (1)

Application Number Title Priority Date Filing Date
US750725A Expired - Lifetime US3090107A (en) 1958-07-24 1958-07-24 Method of making a permanent magnet

Country Status (1)

Country Link
US (1) US3090107A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3341940A (en) * 1962-03-29 1967-09-19 Philips Corp Method of making a permanent magnet

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2576679A (en) * 1939-08-02 1951-11-27 Electro Chimie Metal Permanent magnet and method of manufacture thereof
US2589766A (en) * 1945-05-04 1952-03-18 Bradley Evelyn Magnetic oil seal construction
US2698917A (en) * 1951-04-23 1955-01-04 Hartford Nat Bank & Trust Co Magnetic circuit comprising a ferromagnetic part having high permeability and a substantially flat, thin permanent magnet
US2751525A (en) * 1953-07-24 1956-06-19 Hartford Nat Bank & Trust Co Permanent magnet
US2825670A (en) * 1952-08-21 1958-03-04 Adams Edmond Permanent magnet and process for making same
US2849312A (en) * 1954-02-01 1958-08-26 Milton J Peterman Method of aligning magnetic particles in a non-magnetic matrix
US2862287A (en) * 1952-12-17 1958-12-02 Philips Corp Method of making cast alnico magnets
US2865085A (en) * 1954-07-30 1958-12-23 Westinghouse Electric Corp Preparation of magnetic materials and magnetic members
US2892248A (en) * 1953-09-09 1959-06-30 Philips Corp Method of manufacturing sintered permanent magnets

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2576679A (en) * 1939-08-02 1951-11-27 Electro Chimie Metal Permanent magnet and method of manufacture thereof
US2589766A (en) * 1945-05-04 1952-03-18 Bradley Evelyn Magnetic oil seal construction
US2698917A (en) * 1951-04-23 1955-01-04 Hartford Nat Bank & Trust Co Magnetic circuit comprising a ferromagnetic part having high permeability and a substantially flat, thin permanent magnet
US2825670A (en) * 1952-08-21 1958-03-04 Adams Edmond Permanent magnet and process for making same
US2862287A (en) * 1952-12-17 1958-12-02 Philips Corp Method of making cast alnico magnets
US2751525A (en) * 1953-07-24 1956-06-19 Hartford Nat Bank & Trust Co Permanent magnet
US2892248A (en) * 1953-09-09 1959-06-30 Philips Corp Method of manufacturing sintered permanent magnets
US2849312A (en) * 1954-02-01 1958-08-26 Milton J Peterman Method of aligning magnetic particles in a non-magnetic matrix
US2865085A (en) * 1954-07-30 1958-12-23 Westinghouse Electric Corp Preparation of magnetic materials and magnetic members

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3341940A (en) * 1962-03-29 1967-09-19 Philips Corp Method of making a permanent magnet

Similar Documents

Publication Publication Date Title
US2903329A (en) Device for molding anisotropic permanent magnets
US2762778A (en) Method of making magneticallyanisotropic permanent magnets
US3564705A (en) Method for providing oriented pole pieces in a dynamoelectric machine
US2825670A (en) Permanent magnet and process for making same
US3977918A (en) Method of making magnets
Gubbens et al. Magnetic and electric properties of R2Fe17 compounds studied by means of the Mössbauer effect
US4063970A (en) Method of making permanent magnets
US3085291A (en) Device for manufacturing magnetically anisotropic bodies
US2827437A (en) Method of making a permanent magnet
US4881984A (en) Consolidation of magnet alloy powders by extrusion and product therefrom
US3090107A (en) Method of making a permanent magnet
US4113521A (en) Process for producing magnetic particles by vacuum evaporation of iron with collection on a magnetized surface
JPS5660001A (en) Magnetic recording medium
JPS60161490A (en) Apparatus for producing magnetic fluid
US3196532A (en) Method of forming a superconductive body
US2893830A (en) Ferromagnetic material of the formula bafe3o5f and its preparation
US2828264A (en) Manufacture process of permanent magnets from sintered mixtures of oxides
Gould Permanent magnets
US3809145A (en) Process for the production of permanent magnets
US3266954A (en) Process for making mnal permanent magnet having tetragonal phase
US4915891A (en) Method for producing a noncircular permanent magnet
US3253193A (en) Superconducting means for concentrating magnetic flux
US3956031A (en) Magnetic materials and the formation thereof
US2381363A (en) Manufacture of ferromagnetic material
US3738876A (en) Permanent magnet material powders having superior magnetic characteristics and method