US2232352A - Production of magnetic material - Google Patents

Production of magnetic material Download PDF

Info

Publication number
US2232352A
US2232352A US13900037A US2232352A US 2232352 A US2232352 A US 2232352A US 13900037 A US13900037 A US 13900037A US 2232352 A US2232352 A US 2232352A
Authority
US
Grant status
Grant
Patent type
Prior art keywords
magnetic
material
solution
particles
phosphate
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
Inventor
Verweij Evert Johannes Willem
Boer Jan Hendrik De
Spoor Theodorus Anthenius
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.)
RCA Corp
Original Assignee
RCA Corp
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
Grant date

Links

Images

Classifications

    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01FMAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/12Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
    • H01F1/14Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
    • H01F1/20Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of particles, e.g. powder
    • H01F1/22Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of particles, e.g. powder pressed, sintered, or bound together
    • H01F1/24Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of particles, e.g. powder pressed, sintered, or bound together the particles being insulated

Description

Patented Feb. 18, 1941 UNITED STATES PATENT OFFICE am-saessm s is:

assignments, to Radio Corporation of America, New York, N. Y.. a corporation of Delaware No Drawing.

Application April 26, IQS'L'SQI'III No. 139,000. Iii Germany April 29, 1938 SCIaims.

It is common to produce magnetic cores for intermediate and high frequency purposes from finely powdered magnetic material, such as iron or ferromagnetic alloys, by compressing the particles by means of a bindingagent to form a solid material. For the purpose of avoiding conductive relative contact between the'said particles, various methods have been proposed according to' thereto, a film of a phosphoric acid metal compound is mounted on the magnetic particles without these particles assisting genetically in the tack of the surface since the rate and the uniiormity of the chemical attack per particle canonly be controlled with difiiculty. The fact that in accordance with the invention no gas development as a result of chemical reaction arises is also conducive to uniformity.

The invention is consequently particularly adapted for use with magnetic particles the di-- mensions of which are in the order of magnitude to a few a, the thickness of the insulating films to be obtained notexceeding 20 ma. 0

Since in accordance with the invention the magnetic particles have been provided with a thin insulating film, the magnetic powder thus obtained can be given any shape by compression. I

In order to increase the mechanical strength of the magnet core a binding agent may be used with advantage in a manner known per se after the insulating film is mounted. For this purpose, use may be made, for example, of a synthetic resin which may be capable of being hardened.

In the use of a resin capable of being hardened.

even distribution of the magnetic particles in the final product may be assisted by grinding the material after mixture ,with the resin, by next giving it at ordinary temperatures the desired shape and by then heating it to cause it to harden.

Example I I 1 kg. of magnetic powder is introduced into 1 litre of a 2 normal solution of aqua-ammonia containing 60 milliequivalents of zinc ion and 60 milliequivalents of phosphate ion. The excess of aqua-ammonia is then removed by boiling while shaking continuously so that all the zinc phosphate present in the solution is precipitated on the surface of the particles. After being filtered and dried, the powder is squeezed into the desired shape at a pressure of about 5000 kgJcm.

zinc ion and 45 milliequlvalents of phosphate ion per 100 cm. The paste thus obtained is kneaded while evaporating the excess of aqua-ammonia and water, which may be efi'ected while heating.

to a low extent or in vacuo at ordinary temperatures. The material is then completely dried and ground to form a powder which is mixed with an alcohol solution containing 60 grams of a hardening phenoli'ormaldehyde condensation product. Alter volatilisation of the solvent the powderlng operation is renewed and the powder is then squeezed at 150 C. into the desired shape, it being possible to apply a squeezing pressure of 1500 k8./cm.

In order to avoid the presence of other electrolytes which would affect the properties of the core, the ammoniacal zinc phosphate solution may be obtained by newly precipitated zinc hydroxidebeing dissolved in a concentrated solution of aqua-ammonia, by a dilute phosphoric 1 kg. of magnetic powder is intimately mixed with about 100 cm. of a weakly-acid ferric phosphate solution containing 30 mllliequivalents of ferri-lon and milliequivalents of phosphate 7 tained is reduced to the form of a powder and mixed with an acetone solution containing grams of the commercial resin known under the registered trade mark "plastopal H. Alter volatilisation of the solvent, the material is squeezed into the desired shape at ordinary temperatures, it being possible to apply a pressure of 5000 kg./cm.

1 kg. of magnetic powder is intimately mixed with about 100 cm. of a 2 normal solution of aqua-ammonia containing 30 milliequivalents of cupri-ion and 45 milliequivalents or phosphate ion per 100 cm. and the mixture is evaporated to dryness and powdered, while-kneading, in the manner described in the second example. The powder is agitated in a solution containing grams of a hardening phenolformaldehyde condensation product and is then evaporated to dryness while shaking. The material thus obtained is reduced to the form of a powder and then squeezed at ordinary temperatures at a pressure of about 5000 lrg./cm. The cores thus obtained are hardened in a furnace by heating for three hours at 130 C.

The quantities, indicated in the examples described, of the substances used are chosen to accord with the specific weight of the iron and an average size of the particles 01 3 a as possessed by certain known commercial powdered iron by means of which the invention yields particularly favourable results.

What we claim is:

1. A process of providing particles of ferromagnetic-metallic material with a coating of insulation material substantially entirely by precipitation of phosphoric acid metal compound from a dispersion which has substantially no chemical reaction with the magnetic material itself whereby the original size of the magnetic particles is substantially unafiected during the process, which consists in intimately mixing comminuted ferro-magnetic-metallic material with a compound comprising weakly-acid ferric phosphate solution containing substantially equal molecular amounts of ferri-ion and phosphateion to form a paste, drying the mixture while subjecting it to a kneading action and thereafter comminuting the resulting material.

2. The process described in the next preceding claim characterized by that each kilogram of ferro-magnetic-metallic material is mixed with approximately cubic centimeters of weaklyacid ferric phosphate solution containing 30 milliequivalents of ferri-ion and 30 milliequivalents of phosphate ion.

3. The steps in a process of providing particles of Ierro-magnetic-metallic material with a coating of insulation material which consist in intimately mixing comminuted ferro-magnetic-metallic material with a compound comprising weakly-acid ferric phosphate solution containing substantially equal molecular amounts of ferri-ion and phosphate-ion, and drying the mixture while subjecting it to substantially continuous agitation.

EVERT JOHANNES WILLEM VERWEIJ. JAN HENDRIK DE BOER. THEODORUS ANTHONIUS SPOOR.

US2232352A 1936-04-29 1937-04-26 Production of magnetic material Expired - Lifetime US2232352A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE2232352X 1936-04-29

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US2306198A US2306198A (en) 1937-04-26 1939-11-10 Production of magnetic material

Publications (1)

Publication Number Publication Date
US2232352A true US2232352A (en) 1941-02-18

Family

ID=7991472

Family Applications (1)

Application Number Title Priority Date Filing Date
US2232352A Expired - Lifetime US2232352A (en) 1936-04-29 1937-04-26 Production of magnetic material

Country Status (1)

Country Link
US (1) US2232352A (en)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2601212A (en) * 1948-11-09 1952-06-17 Gen Aniline & Film Corp Heat resistant magnetic cores and method of making
US2762776A (en) * 1953-10-05 1956-09-11 Rca Corp Ferrospinel bodies and methods of making same
US2791561A (en) * 1950-04-27 1957-05-07 Gen Aniline & Film Corp Magnetic powders and method of making the same
US3054751A (en) * 1958-12-30 1962-09-18 Ibm Magnetic lithographic inks
US3178319A (en) * 1958-06-05 1965-04-13 Geraldine D Henricks Phosphate coating compositions and methods of making and using the same
US3330693A (en) * 1962-10-29 1967-07-11 Pateco Method of making a magnetic record member with encapsulated ferromagnetic particles in a binder and resulting product
US4668283A (en) * 1984-06-25 1987-05-26 Mitsui Toatsu Chemicals, Incorporated Magnetic powder and production process thereof
US5063011A (en) * 1989-06-12 1991-11-05 Hoeganaes Corporation Doubly-coated iron particles
US5198137A (en) * 1989-06-12 1993-03-30 Hoeganaes Corporation Thermoplastic coated magnetic powder compositions and methods of making same
US5306524A (en) * 1989-06-12 1994-04-26 Hoeganaes Corporation Thermoplastic coated magnetic powder compositions and methods of making same
US5536985A (en) * 1994-05-09 1996-07-16 General Motors Corporation Composite armature assembly
US6348265B1 (en) * 1996-02-23 2002-02-19 Höganäs Ab Phosphate coated iron powder and method for the manufacturing thereof

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2601212A (en) * 1948-11-09 1952-06-17 Gen Aniline & Film Corp Heat resistant magnetic cores and method of making
US2791561A (en) * 1950-04-27 1957-05-07 Gen Aniline & Film Corp Magnetic powders and method of making the same
US2762776A (en) * 1953-10-05 1956-09-11 Rca Corp Ferrospinel bodies and methods of making same
US3178319A (en) * 1958-06-05 1965-04-13 Geraldine D Henricks Phosphate coating compositions and methods of making and using the same
US3054751A (en) * 1958-12-30 1962-09-18 Ibm Magnetic lithographic inks
US3330693A (en) * 1962-10-29 1967-07-11 Pateco Method of making a magnetic record member with encapsulated ferromagnetic particles in a binder and resulting product
US4668283A (en) * 1984-06-25 1987-05-26 Mitsui Toatsu Chemicals, Incorporated Magnetic powder and production process thereof
US5063011A (en) * 1989-06-12 1991-11-05 Hoeganaes Corporation Doubly-coated iron particles
US5198137A (en) * 1989-06-12 1993-03-30 Hoeganaes Corporation Thermoplastic coated magnetic powder compositions and methods of making same
US5306524A (en) * 1989-06-12 1994-04-26 Hoeganaes Corporation Thermoplastic coated magnetic powder compositions and methods of making same
US5543174A (en) * 1989-06-12 1996-08-06 Hoeganaes Corporation Thermoplastic coated magnetic powder compositions and methods of making same
US5536985A (en) * 1994-05-09 1996-07-16 General Motors Corporation Composite armature assembly
US6348265B1 (en) * 1996-02-23 2002-02-19 Höganäs Ab Phosphate coated iron powder and method for the manufacturing thereof

Similar Documents

Publication Publication Date Title
US3488711A (en) Process for impregnating red phosphorus
US3632785A (en) Method of forming shell molds
US3491491A (en) Aluminous slurries containing ferric ammonium citrate
US3969547A (en) Process of preparing polymer-coated powder particles
US4810524A (en) Inorganic powders with improved dispersibility
Carter et al. Molecular recognition of caffeine by shell molecular imprinted core–shell polymer particles in aqueous media
US5362472A (en) Method of manufacturing aqueous ceramic suspensions and the use of said suspensions
US2451590A (en) Process of forming a luminescent screen
US5063011A (en) Doubly-coated iron particles
US2783208A (en) Powdered iron magnetic core materials
US4772322A (en) Production of flat products from particulate material
US4165232A (en) Manufacture of ferromagnetic metal particles essentially consisting of iron
US2640813A (en) Reaction product of a mixed ferrite and lead titanate
US6348265B1 (en) Phosphate coated iron powder and method for the manufacturing thereof
US4456713A (en) Composition for injection molding
US3725521A (en) Method of making steel powder particles of select electrical resistivity
US3933961A (en) Tabletting spherical dental amalgam alloy
US3846460A (en) Method of manufacturing copper oxalate
US2415036A (en) Resistance material
US2526059A (en) Fixed electrical resistor
US2744040A (en) Process of preparing iron powder for magnetic cores
JPH10106875A (en) Manufacturing method of rare-earth magnet
US2967789A (en) Process of coating granules with phenol-aldehyde resin
US4832891A (en) Method of making an epoxy bonded rare earth-iron magnet
US2857270A (en) Method for the production of metal powder for powder metallurgical purposes