US2960470A - Method of manufacturing permanent magnets - Google Patents
Method of manufacturing permanent magnets Download PDFInfo
- Publication number
- US2960470A US2960470A US554605A US55460555A US2960470A US 2960470 A US2960470 A US 2960470A US 554605 A US554605 A US 554605A US 55460555 A US55460555 A US 55460555A US 2960470 A US2960470 A US 2960470A
- Authority
- US
- United States
- Prior art keywords
- conglomerate
- produce
- magnetic field
- anisotropic
- permanent
- 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
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
- C04B35/26—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on ferrites
- C04B35/2683—Other ferrites containing alkaline earth metals or lead
-
- 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
- Permanent magnets which substantially consist of simple crystals or mixed crystals having a constitution according to the formula M Ca O.6Fe O where M is one or more of the metals Ba, Sr or Pb and O.6x- -l, are known (see for example French patent specification No. 1,048,792 or U.S. Patent 2,672,777, and Philips Technical Review, volume 13, No. 7, January 1952, pages 194-208). It is also known (see French patent specification 1,080,514, or U.S. Patent 2,762,778) to manufacture crystal oriented or anisotropic permanent magnets which consist of such materials.
- the constituent essential to the magnetic properties of the material is MFe O or MO.6Fe O M being barium, strontium or lead, or mixed crystals of two or more of those compounds. Calcium may be substituted for one of said metals in an amount up to 0.4 as an atomic fraction of those metals.
- the formula of the essential constitutent may be written (to include calcium) as M Ca 0.6Fe O or x being greater than 0.6 and less than 1.
- Other, and nonessential constituents may and often are present.
- an excess of one of the oxides, preferably the bivalent metal oxide is employed in the starting mixture and this excess may remain as unreacted or partially reacted material in the final composition, for as noted in U.S. Patent 2,762,777, these materials may be prepared by mixing the oxides in a relatively wide range of proportions representing a significant departure from the ratio appearing in the constitutent essential to the magnetic properties of the material.
- this material can be made anisotropic by orienting the crystals while they are in a mobile state. Preferably this is accomplished by suspending the material, in finely-divided form, in a liquid arranged between the poles of magnet. The material is preferably compressed during orientation and then sintered at a temperature of about 1100 to 1450 C. to form a coherent body.
- This method has already led to the manufacture of permanent magnets having a (BH) -value exceeding 2 10 gauss-oersted. The mechanical properties also of the magnets thus produced are generally satisfactory. However, the method concerned does not give complete satisfaction when magnets of more or less complicated shape have to be manufactured. It should be borne in mind that the dies which must be used for carrying out said method must obviously also frequently break down owing to wear when comparatively large quantities of water are drawn off.
- the invention solves the problem of manufacturing anisotropic permanent magnets of the kind described and having a comparatively complicated structure, by the use of a method which comprises features both of the wet and of the dry moulding method.
- a method which comprises features both of the wet and of the dry moulding method.
- the permanent magnet powder is suspended in an indifferent liquid, for example water, and the liquid is removed from the suspension, for example by filtering, while the suspension is arranged between the poles of a magnet.
- an indifferent liquid for example water
- the liquid is removed from the suspension, for example by filtering, while the suspension is arranged between the poles of a magnet.
- a conglomerate is obtained which has a magnetic directive effect: it is magnetically anisotropic.
- the conglomerate is granulated, for example by means of a sieve, through which the solid substance is pressed.
- Suitable substances are particularly solid organic substances which are liquefied under a slight pressure (of less than 500 kg./cm.
- Camphor or chemically related substances have proved very suitable for the purpose concerned; thus, camphor is liquefied at a pressure of from to kg./cm.
- the camphor or similar substance are added in the form of an alcoholic solution, for example a solution of 2% by weight, which is sprayed over the granulate required to be molded.
- camphor or a similar substance use may, for example, be made of paraflin.
- Example I Finely powdered barium carbonate, BaCO and ferric oxide, Fe O are thoroughly mixed at a ratio of 1.1:6 mol. The mixture is compressed to form blocks and these blocks are fired for approximately 15 minutes at 1280 C. After cooling, the blocks are pulverised and the obtained powder is worked up into a suspension after the addition of a small amount of water and 1% by weight of calcium carbonate, CaCO From this suspension the water is removed by filtering in a magnetic field, after which the filter cake is dried by exposure to air. The airdried substance is subsequently pressed through a sieve having meshes of approximately 2 x 2 mms. The grains produced are compressed in a magnetic field and finally fired for approximately 5 minutes at approximately 1250" C.
- the properties of the permanent magnet produced by this method were as follows:
- a permanent anisotropic magnet the steps of suspending in a chemically inert liquid crystals of a material having a composition in which M is at least one of the metals selected from the group consisting of barium, strontium and lead, and x is at least equal to 0.6 and not greater than 1, filtering the liquid under the action of a magnetic field to thereby produce a magnetically anisotropic conglomerate, granulating the conglomerate, adding to the granulated conglomerate an organic binder adapted to increase cohesion between grains without increasing friction therebetween during molding, molding the conglomerate under the action of a magnetic field to produce a magnetically anisotropic body, and sintering said body at a temperature of about 1100 to 1400 C. to produce a highly-coherent permanent magnet body having a (BI-l) value exceeding approximately 1.5 x10 gauss-oersted.
- a permanent anisotropic magnet In the manufacture of a permanent anisotropic magnet, the steps of suspending in a chemically inert liquid crystals of a material having a composition in which M is at least one of the metals selected from the group consisting of barium, strontium and lead, and x is at least equal to 0.6 and not greater than 1, filtering the liquid under the action of a magnetic field to thereby produce a magnetically anisotropic conglomerate, granulating the conglomerate, adding to the granulated conglomerate an organic binder adapted to be liquefied at a pressure of less than about 500 lag/cm.
- a permanent anisotropic magnet the steps of suspending in a chemically inert liquid crystals of a material having a composition in which M is at least one of the metals selected from the group consisting of barium, strontium and lead, and x is at least equal to 0.6 and not greater than 1, filtering the liquid under the action of a magnetic field to thereby produce a magnetically anisotropic conglomerate, granulating the conglomerate, adding camphor to the granulated conglomerate, molding the conglomerate under the action of a magnetic field to produce a magnetically anisotropic body, and sintering said body at a temperature of about ll00 to 1400 C. to produce a highly-coherent permanent magnet body having a (BI-U value exceeding ap proximately 1.5 10 gauss-oersted.
- a permanent anisotropic magnet the steps of suspending in a chemically inert liquid crystals of a material having a composition in which M is at least one of the metals selected from the group consisting of barium, strontium and lead, and x is at least equal to 0.6 and not greater than 1, filtering the liquid under the action of a magnetic field to thereby produce a magnetically anisotropic conglomerate, granulating the conglomerate, adding an alcoholic solution of camphor to the granulated conglomerate, molding the conglomerate under the action of a magnetic field to produce a mag netically anisotropic body, and sintering said body at a temperature of about 1100 to 1400 C. to produce a highly-coherent permanent magnet body having a (EH) value exceeding approximately 1.5 10 gaussoersted.
- a permanent anisotropic magnet the steps of suspending in a chemically inert liquid crystals of a material having a composition in which M is at least one of the metals selected from the group consisting of barium, strontium and lead, and x is at least equal to 0.6 and not greater than 1, filtering the liquid under the action of a magnetic field to thereby produce a magnetically anisotropic conglomerate, granulating the conglomerate, spraying the granulated conglomerate with an alcoholic camphor solution, molding the conglomerate under the action of magnetic field to produce a magnetically anisotropic body, and sintering said body at a temperature of about 1100 to 1400 C. to produce a highly-coherent permanent magnet body having a (BH) value exceeding approximately 1.5 10 gauss oersted.
- M is at least one of the metals selected from the group consisting of barium, strontium and lead
- x is at least equal to 0.6 and not greater than 1
- a permanent anisotropic mag- M Ca 0.61 6 0 in which M is at least one of the metals selected firom the group consisting of barium, strontium and lead, and x is at least equal to 0.6 and not greater than 1, filtering the liquid under the action of a magnetic field to thereby produce a magnetically anisotropic conglomerate, granulating the conglomerate, adding paraflin to the granulated conglomerate, molding the conglomerate under the action of a magnetic field to produce a magnetically anisotropic body, and sintering said body at a temperature of about 1100 to 1400 C. to produce a highly-coherent permanent magnet body having a (BH),,,,,, value exceeding approximately 1.5 X gauss-oersted.
- BH highly-coherent permanent magnet body having a
- a permanent anisotropic magnet the steps of suspending in a chemically inert liquid crystals of a material having a composition in which x is at least equal to 0.6 and not greater than 1, filtering the liquid under the action of -a magnetic field to thereby produce a magnetically anisotropic conglomerate, granulating the conglomerate, spraying the granulated conglomerate with an alcoholic camphor solution, molding the conglomerate under the action of a magnetic field to produce a magnetically anisotropic body, and sintering said body at a temperature of about 1100 to 1400 C. to produce a highly-coherent permanent magnet body having a (BH) value exceeding approximately 1.5 x10 gaussoersted.
- BH highly-coherent permanent magnet body having a (BH) value exceeding approximately 1.5 x10 gaussoersted.
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Ceramic Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Hard Magnetic Materials (AREA)
- Magnetic Ceramics (AREA)
- Manufacturing Cores, Coils, And Magnets (AREA)
- Magnetic Treatment Devices (AREA)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NL783237X | 1954-12-21 |
Publications (1)
Publication Number | Publication Date |
---|---|
US2960470A true US2960470A (en) | 1960-11-15 |
Family
ID=19832209
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US554605A Expired - Lifetime US2960470A (en) | 1954-12-21 | 1955-12-21 | Method of manufacturing permanent magnets |
Country Status (8)
Country | Link |
---|---|
US (1) | US2960470A (fr) |
BE (1) | BE543773A (fr) |
CH (1) | CH347585A (fr) |
DE (1) | DE1028708B (fr) |
FR (1) | FR1144257A (fr) |
GB (1) | GB783237A (fr) |
LU (1) | LU34051A1 (fr) |
NL (2) | NL86918C (fr) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3113927A (en) * | 1960-10-18 | 1963-12-10 | Westinghouse Electric Corp | Ferrite magnets |
US3136033A (en) * | 1961-07-17 | 1964-06-09 | Allen Bradley Co | Method and apparatus for producing permanent magnets |
US4117058A (en) * | 1976-12-03 | 1978-09-26 | General Motors Corporation | Method of making boron containing strontium ferrite |
Citations (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
BE521244A (fr) * | 1952-07-07 | |||
BE516598A (fr) * | ||||
US2535025A (en) * | 1949-10-06 | 1950-12-26 | Steatite Res Corp | Process of treating ferrites |
US2565861A (en) * | 1947-09-26 | 1951-08-28 | Rca Corp | Magnetic materials |
FR1080514A (fr) * | 1951-12-21 | 1954-12-09 | Philips Nv | Aimant permanent et son procédé de fabrication |
US2705701A (en) * | 1952-11-28 | 1955-04-05 | Henry L Crowley & Company Inc | Method for preparing magnetic compositions |
US2714580A (en) * | 1951-09-19 | 1955-08-02 | Mallory & Co Inc P R | Magnetic materials and methods of making the same |
US2723238A (en) * | 1952-08-19 | 1955-11-08 | Rca Corp | Manganese zinc ferrospinel compositions, including copper oxide |
US2762777A (en) * | 1950-09-19 | 1956-09-11 | Hartford Nat Bank & Trust Co | Permanent magnet and method of making the same |
US2849312A (en) * | 1954-02-01 | 1958-08-26 | Milton J Peterman | Method of aligning magnetic particles in a non-magnetic matrix |
US2854412A (en) * | 1954-12-23 | 1958-09-30 | Philips Corp | Method of making a permanent magnet |
-
0
- LU LU34051D patent/LU34051A1/xx unknown
- BE BE543773D patent/BE543773A/xx unknown
- NL NL193422D patent/NL193422A/xx unknown
- NL NL86918D patent/NL86918C/xx active
-
1955
- 1955-12-16 GB GB36158/55A patent/GB783237A/en not_active Expired
- 1955-12-19 DE DEN11616A patent/DE1028708B/de active Pending
- 1955-12-19 FR FR1144257D patent/FR1144257A/fr not_active Expired
- 1955-12-19 CH CH347585D patent/CH347585A/de unknown
- 1955-12-21 US US554605A patent/US2960470A/en not_active Expired - Lifetime
Patent Citations (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
BE516598A (fr) * | ||||
US2565861A (en) * | 1947-09-26 | 1951-08-28 | Rca Corp | Magnetic materials |
US2535025A (en) * | 1949-10-06 | 1950-12-26 | Steatite Res Corp | Process of treating ferrites |
US2762777A (en) * | 1950-09-19 | 1956-09-11 | Hartford Nat Bank & Trust Co | Permanent magnet and method of making the same |
US2714580A (en) * | 1951-09-19 | 1955-08-02 | Mallory & Co Inc P R | Magnetic materials and methods of making the same |
FR1080514A (fr) * | 1951-12-21 | 1954-12-09 | Philips Nv | Aimant permanent et son procédé de fabrication |
BE521244A (fr) * | 1952-07-07 | |||
US2723238A (en) * | 1952-08-19 | 1955-11-08 | Rca Corp | Manganese zinc ferrospinel compositions, including copper oxide |
US2705701A (en) * | 1952-11-28 | 1955-04-05 | Henry L Crowley & Company Inc | Method for preparing magnetic compositions |
US2849312A (en) * | 1954-02-01 | 1958-08-26 | Milton J Peterman | Method of aligning magnetic particles in a non-magnetic matrix |
US2854412A (en) * | 1954-12-23 | 1958-09-30 | Philips Corp | Method of making a permanent magnet |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3113927A (en) * | 1960-10-18 | 1963-12-10 | Westinghouse Electric Corp | Ferrite magnets |
US3136033A (en) * | 1961-07-17 | 1964-06-09 | Allen Bradley Co | Method and apparatus for producing permanent magnets |
US4117058A (en) * | 1976-12-03 | 1978-09-26 | General Motors Corporation | Method of making boron containing strontium ferrite |
Also Published As
Publication number | Publication date |
---|---|
NL86918C (fr) | |
NL193422A (fr) | |
DE1028708B (de) | 1958-04-24 |
CH347585A (de) | 1960-07-15 |
FR1144257A (fr) | 1957-10-11 |
BE543773A (fr) | |
GB783237A (en) | 1957-09-18 |
LU34051A1 (fr) |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US2762777A (en) | Permanent magnet and method of making the same | |
US2837483A (en) | Method of making a permanent magnet | |
GB747724A (en) | Improvements in or relating to non-metallic permanent magnets | |
US3113927A (en) | Ferrite magnets | |
US2900344A (en) | Making anisotropic permanent magnets | |
US3085291A (en) | Device for manufacturing magnetically anisotropic bodies | |
US2960470A (en) | Method of manufacturing permanent magnets | |
US2955085A (en) | Ferrites of decreased initial permeability at high frequencies | |
US2854412A (en) | Method of making a permanent magnet | |
US2946752A (en) | Ferromagnetic material | |
US2989473A (en) | Ferrite with constricted magnetic hysteresis loop | |
US2946753A (en) | Ferromagnetic material | |
US2977312A (en) | Ferromagnetic material | |
US2828264A (en) | Manufacture process of permanent magnets from sintered mixtures of oxides | |
GB747737A (en) | Improvements in or relating to methods of manufacturing non-metallic permanent magnets | |
US3438900A (en) | Ferrimagnetic material suitable for use at frequencies of at least 50 mc./sec. with improved properties | |
US3046227A (en) | Ferromagnetic material | |
US2935411A (en) | High dielectric constant ceramics | |
US2960471A (en) | Ferromagnetic materials and methods of preparing the same | |
US3630912A (en) | Lithium titanium bismuth ferrites | |
US3036008A (en) | Permanent magnet ferrite | |
US3337461A (en) | Two-phase ferrite magnet composition and method for preparing same | |
US3461072A (en) | Ferrimagnetic material for use at frequencies higher than 50 mc./sec. having reduced loss factor and higher quality factor | |
US3804767A (en) | Method of manufacturing ceramic magnets containing strontium or barium ferrite | |
US2989476A (en) | Ferrite with constricted magnetic hysteresis loop |