US3109817A - Method of making ferrite cores - Google Patents

Method of making ferrite cores Download PDF

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Publication number
US3109817A
US3109817A US660892A US66089257A US3109817A US 3109817 A US3109817 A US 3109817A US 660892 A US660892 A US 660892A US 66089257 A US66089257 A US 66089257A US 3109817 A US3109817 A US 3109817A
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US
United States
Prior art keywords
briquette
furnace
nitrogen
air
mixture
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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
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US660892A
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English (en)
Inventor
Paul M Miller
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NCR Voyix Corp
National Cash Register Co
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NCR Corp
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Publication date
Application filed by NCR Corp filed Critical NCR Corp
Priority to US660892A priority Critical patent/US3109817A/en
Priority to GB8218/58A priority patent/GB833845A/en
Priority to BE567621D priority patent/BE567621A/xx
Priority to FR1209150D priority patent/FR1209150A/fr
Application granted granted Critical
Publication of US3109817A publication Critical patent/US3109817A/en
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    • 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
    • C04B35/2608—Compositions containing one or more ferrites of the group comprising manganese, zinc, nickel, copper or cobalt and one or more ferrites of the group comprising rare earth metals, alkali metals, alkaline earth metals or lead
    • C04B35/2625—Compositions containing one or more ferrites of the group comprising manganese, zinc, nickel, copper or cobalt and one or more ferrites of the group comprising rare earth metals, alkali metals, alkaline earth metals or lead containing magnesium

Definitions

  • This invention relates to magnetic-ferrite material and to a method of making it, said material having substantially square hysteresis loop magnetic characteristics, low coercivity, high remanence, and high resistance to change in polarity when repeatedly disturbed by low-level driving currents which individually are less than that required to change the polarity completely.
  • the ferrite material made by the novel method, from molded and sintered powdered metal oxides, is particular- 1y suitable for making magnetic core storage devices, of toroid shape, for electronic calculating machines, which storage devices can be driven by high-speed switching transistors.
  • the ferrite material further, is stable in the driving current requirements and output characteristics over a wide temperature range, such range being approximately between 50 degrees Fahrenheit and 125 degrees Fahrenheit.
  • the method is unique in that, in sintering, the heating and the cooling are carried on in a single step without removal from the furnace, the temperature being gradually elevated in an air atmosphere to the sintering temperature and held there for a number of hours preferably while nitrogen is added to the air, such nitrogen addition increasing the coercivity of the end product, to dilute or replace the air.
  • the ferrite material is allowed to cool in the furnace in the presence of nitrogen.
  • the preferred form of the invention will be described with reference to the making of a transistor-driven toroidshaped magnetic-ferrite core.
  • the desired mixture of metallic oxides taken from the ranges shown in box 20 of the drawing, are pulverized to pass through a screen which will screen out particles over 180 microns in diameter.
  • a small amount of binder is added, so that the mixture can be press-molded into a briquette of the desired shape.
  • the briquette is placed in a controlled-gas furnace for sintering, the briquette being heated in air until a temperature of 2,350 degrees Fahrenheit -100 degrees is reached, at which time the air is either diluted or replaced with nitrogen while the temperature is maintained at 2,350 degrees Fahrenheit i100 degrees for from three to ten hours, after which pure nitrogen is introduced to displace the air, if any is present, and the furnace is allowed to cool in the presence of nitrogen.
  • Example I A mixture of the following ingredients in powdered form is made:
  • This mixture is calcined in air at approximately 1,800 degrees Fahrenheit for approximately ten hours; during which the MgCO is converted to MgO and the MnCO is 'ice converted to MnO.
  • the calcined mixture which has begun to become ferritic, is pulverized and screened, so that the maximum particle size is about 180 microns in diam eter.
  • To this pulverized mixture is added 1 percent, by weight, of polyvinyl alcohol, added as a 4 percent aqueous solution, said polyvinyl alcohol being so selected that thesolution has a viscosity of 4 to 6 centipoises as determined by the Hoeppler falling ball-method.
  • the resultant tacky mass is granulated and thoroughly dried.
  • Example II Using the green" briquette of Example I, the sintering temperature is maintained for two hours in air, followed by alternating the air with nitrogen every fifteen minutes for four additional hours at sintering temperature, followed by cooling in pure nitrogen.
  • Example Ill using the green briquette of Example I, a mixture of two parts of nitrogen to one part of air is used for the six-hour sintering period, followed by cooling in nitrogen.
  • Example IV using the green briquet-te of Example I, a gas mixture of equal parts of air and nitrogen is used during the six-hour sintering period.
  • the foregoing examples provide cores that have high output currents when switched by relatively low input currents.
  • the sintering time may be varied, good results being obtained in the range of from three to ten hours, and the mixture of metallic oxides may be varied within the ranges set forth in box 20 of the drawing.
  • novel features of the method are, first, the use of all or part nitrogen in the sintering temperature period, followed by cooling in nitrogen; and, second, that the heating, the sintering, and the cooling are done in a single continuous operation without removal of the treated material from the furnace.
  • Qther materials than polyvinyl alcohol may be used as binders in proper solutions, among which are slightly hydrolyzed starches, emulsified poly-glycols, methyl-cellulose, and other similar organic materials.
  • the method of making magnetic-ferrite material including the steps of molding a briquette of a mixture of pulverized magnesium oxide, manganese oxide, iron oxide, and zinc oxide within the ranges shown in the drawing; heating the briquette in a furnace, first in air to 2,350 degrees Fahrenheit i100 degrees; controlling the furnace to maintain said temperature for from three to ten hours and during this time introducing a selected amount of nitrogen into the furnace to replace an equivalent amount or" air according to increased coercivity desired in said magnetic-ferrite material; and cooling the sintered briquette in the furnace in nitrogen.
  • the method of making a magnetic-ferrite core including the steps of molding a toroid-shaped briquctte from pulverized magnesium oxide, manganese oxide, iron oxide, and zinc oxide in desired amounts within the ranges shown in the drawing; heating the briquette in a controlled-gas furnace up to 2,350 degrees Fahrenheit 1-100 degrees in air; maintaining the temperature of the briquette, While still in the furnace, at 2,350 degrees Fahrenheit 1-100 degrees for a period of from three to ten hours; introducing into the furnace at selected amount of nitrogen during the three-to ten-hour period according to increased coercivity desired in said magnetic-ferrite core; and finally cooling the briquette in the furnace in nitrogen.
  • a binder a 4 percent aqueous solution of polyvinyl alcohol, said solution having a viscosity of 4 to 6 oentipoises as measured by the Hoeppler falling ball method, and the amount of polyvinyl alcohol amounting to about 1 percent, by Weight, of the mixture; placing the briquette in a controlled-gas furnace and raising the temperature to a sintering temperature of 2,350 degrees Fahrenheit :100 degrees in air; maintaining the sintering temperature for six hours, the air being displaced by nitrogen during the last four of the six hours; and cooling the "briquette in nitrogen without removal from the furnace.
  • a binder a 4 percent aqueous solution of polyvinyl alcohol, said solution having a viscosity of 4 to 6 centipoise as measured by the Hoeppler falling ball method, and the amount of polyvinyl alcohol amounting to about 1 percent, by Weight, of the mixture; placing the briquette in a controlled-gas furnace and raising the temperature to a sintering temperature of 2,350 degrees Fahrenheit :100
  • a binder a 4 percent aqueous solution of polyvinyl alcohol, said solution having a viscosity of 4 to 6 centipoises as measured by the Hoepp-ler falling ball method, and the amount of polyvinyl alcohol amounting to about 1 percent, by weight, of the mixture; placing the briquette in a controlled-gas furnace and raising the temperature to a sintering temperature of 2,350 degrees Fahrenheit degrees in air; maintaining the sintering temperature for six hours in an atmosphere or two parts of nitrogen to one part of air; and cooling the briquette in nitnogen without removal from the furnace.
  • the method of making a magnetioferrite toroid core including the steps of pressing into a toroid briquette 0.0 055 gram of a pulverized mixture of Molar percent MgO 14.25 M 40.82 Fe O 41.23 ZnO 3.70
  • a binder a 4 percent aqueous solution of polyvinyl alcohol, said solution having a viscosity of 4 to 6 centipoises as measured by the Hoeppler falling ball method, and the amount of polyvinyl alcohol amounting to about 1 percent, by Weight, of the mixture; placing the briquette in a controlled-gas furnace and raising the temperature to a sintering temperature of 2,350 degrees Fahrenheit i100 degrees in air; maintaining the sintering ternperature for six hours in an atmosphere of one part of nitrogen to one part of air; and cooling the briquette in nitrogen without removal from the furnace.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Ceramic Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Magnetic Ceramics (AREA)
US660892A 1957-05-22 1957-05-22 Method of making ferrite cores Expired - Lifetime US3109817A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US660892A US3109817A (en) 1957-05-22 1957-05-22 Method of making ferrite cores
GB8218/58A GB833845A (en) 1957-05-22 1958-03-14 Method of making bi-stable state magnetic-ferrite cores
BE567621D BE567621A (en)) 1957-05-22 1958-05-13
FR1209150D FR1209150A (fr) 1957-05-22 1958-05-20 Procédé d'obtention d'un matériau en ferrite magnétique

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US660892A US3109817A (en) 1957-05-22 1957-05-22 Method of making ferrite cores

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US3109817A true US3109817A (en) 1963-11-05

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US660892A Expired - Lifetime US3109817A (en) 1957-05-22 1957-05-22 Method of making ferrite cores

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US (1) US3109817A (en))
BE (1) BE567621A (en))
FR (1) FR1209150A (en))
GB (1) GB833845A (en))

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3953562A (en) * 1974-07-15 1976-04-27 International Business Machines Corporation Process for the elimination of dimensional changes in ceramic green sheets

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT158857B (de) * 1932-12-01 1940-06-10 Schering Kahlbaum Ag Verfahren zur Herstellung von Dihydrofollikelhormon.
US2640813A (en) * 1948-06-26 1953-06-02 Aladdin Ind Inc Reaction product of a mixed ferrite and lead titanate
GB730703A (en) * 1952-07-31 1955-05-25 Centre Nat Rech Scient Magnetic materials and methods of manufacturing such materials
US2754172A (en) * 1950-12-08 1956-07-10 Method of manufacturing ferromagnetic material and bodies
US2762778A (en) * 1951-12-21 1956-09-11 Hartford Nat Bank & Trust Co Method of making magneticallyanisotropic permanent magnets
US2842500A (en) * 1954-10-18 1958-07-08 Ibm Method of making ferrite structures

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT158857B (de) * 1932-12-01 1940-06-10 Schering Kahlbaum Ag Verfahren zur Herstellung von Dihydrofollikelhormon.
US2640813A (en) * 1948-06-26 1953-06-02 Aladdin Ind Inc Reaction product of a mixed ferrite and lead titanate
US2754172A (en) * 1950-12-08 1956-07-10 Method of manufacturing ferromagnetic material and bodies
US2762778A (en) * 1951-12-21 1956-09-11 Hartford Nat Bank & Trust Co Method of making magneticallyanisotropic permanent magnets
GB730703A (en) * 1952-07-31 1955-05-25 Centre Nat Rech Scient Magnetic materials and methods of manufacturing such materials
US2842500A (en) * 1954-10-18 1958-07-08 Ibm Method of making ferrite structures

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3953562A (en) * 1974-07-15 1976-04-27 International Business Machines Corporation Process for the elimination of dimensional changes in ceramic green sheets

Also Published As

Publication number Publication date
FR1209150A (fr) 1960-02-29
BE567621A (en)) 1958-05-31
GB833845A (en) 1960-05-04

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