US3671436A - Method of manufacturing a sintered oxidic ferromagnetic body - Google Patents

Method of manufacturing a sintered oxidic ferromagnetic body Download PDF

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Publication number
US3671436A
US3671436A US18676A US3671436DA US3671436A US 3671436 A US3671436 A US 3671436A US 18676 A US18676 A US 18676A US 3671436D A US3671436D A US 3671436DA US 3671436 A US3671436 A US 3671436A
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Prior art keywords
sintered
crystals
percent
manufacturing
alkaline earth
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Expired - Lifetime
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US18676A
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English (en)
Inventor
Hans Peter Peloschek
David Jacob Perduijn
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US Philips Corp
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US Philips Corp
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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
    • C04B35/265—Compositions containing one or more ferrites of the group comprising manganese or zinc and one or more ferrites of the group comprising nickel, copper or cobalt
    • 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
    • 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
    • H01F1/0302—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity characterised by unspecified or heterogeneous hardness or specially adapted for magnetic hardness transitions
    • H01F1/0311—Compounds
    • H01F1/0313—Oxidic compounds

Definitions

  • Sintered oxidic ferromagnetic material which consists if fiii of large interlocking crystals (diameter more than 50 microns) 5 d 56 62 58 has a high resistance to detrition.
  • a method of obtaining such l e o m a crystal structure comprises the addition of from 0.01 to 0.1 percent by weight of an alkaline earth metaborate to the start- [56] References cued ing mixture of the metal oxides to be sintered, e.g. NiO, ZnO
  • the invention relates to a method of manufacturing a sintered, oxidic, ferromagnetic body consisting of interlocking crystals having an average grain size of more than 50 microns.
  • a ferrite is to be understood to mean herein a soft-magnetic solid consisting of cubic crystals having a chemical composition according to the formula (MO. Fe O (ZnO. v Fe O wherein M is a bivalent metal, for example, Ni (nickel) or Mn (manganese), while 0.8 1.50.8 v 1.50 2 1.
  • the properties of the magnetic head which is manufactured from such a material will more and more deteriorate as a result of this pull out of crystals out of the operative face as a result of the scouring effect of the record carrier, particularly when the pull out is in the proximity of the operative gap.
  • German Pat. specification No. 1,094,995 a sintered oxidic ferromagnetic body has been proposed consisting of interlocking ferrite crystals which are as large as possible as a core for a magnetic head which must have a large mechanical resistance to detrition. In such a crystal structure the possibility that a crystal is torn out is much smaller since the large interlocking crystals hold" each other. It is proposed in particular in this said German patent specification to use a ferrite monocrystal as a core for a magnetic head. The method of manufacturing ferrite monocrystals, however, is expensive also as a result of the low production output. Moreover, it is difficult to obtain stress-free monocrystals (stress freedom is an imperative requirement in this connection).
  • the method according to the invention enables in a simple and cheap manner the manufacture of a sintered oxidic ferromagnetic body which fulfils the above-mentioned requirements. It is characterized in that from 0.01 to 0.10 percent by weight (preferably from 0.0l to 0.05 percent by weight) of an alkaline earth metaborate is added to the starting mixture of the materials to be sintered during manufacturing according to the normal manufacturing method.
  • This normal method involves that a pre-compressed body consisting of a finely divided mixture of the starting substances (oxides, or compounds convertible into oxides at the temperature of the sintered process) is sintered in a gas atmosphere.
  • calcium metaborate is preferably added to the starting mixture.
  • the invention also relates to a sintered oxidic ferromagnetic body, manufactured by using the method according to the invention.
  • composition of the starting material is preferably chosen to be so that the relative quantities of the metal oxides constructing the ferrite in the sintered oxidic ferromagnetic body manufactured by using the method according to the invention expressed in mol. percent lie between the following limits:
  • a ferrite body having this composition and manufactured in the manner described is excellently suitable owing to its excellent detn'tion properties to serve as a core for a magnetic head, especially when high tape speeds are required.
  • the method according to the invention can advantageously be applied.
  • the method according to the invention can successfully be used in manufacturing all those sintered ceramic bodies which are used in places where they are exposed to agressive mechanical forces.
  • Such sintered ceramic bodies, manufactured while using the method according to the invention are characterized in that they contain from 0.01 to 0.1 percent by weight of alkaline earth borate.
  • EXAMPLE 0.05 percent by weight of calcium metaborate is added to a finely divided mixture consisting of 12.5 percent by weight of NiO, 23.0 percent by weight of ZnO and 64.5 percent by weight of Fe O This mixture is prefired for 1 hour at a temperature of 850 C. in an oxygen-containing atmosphere. The prefired product is then ground and compressed, preferably isostatically. The compressed product is then fired for 20 hours at a temperature of l,200 C. in pure oxygen followed by cooling to room temperature. The ferrite body obtained in this manner is found to consist of interlocked crystals having an average grain size of more than 50 microns, as is shown in the copy of the microphotograph.
  • the quantity of alkaline earth metaborate to be added to the starting mixture lies between the said limits.
  • undesirable agglomerations of pores are formed.
  • the said quantity of alkaline earth metaborate is added to the starting mixture.
  • a sintered oxidic ferromagnetic body consisting of interlocking crystals having an average grain size of more than 50 microns, in which a mixture of 5-35 mol% Ni0, about 15-45 mol% ZnO, and about 48 to 50 mol percent Fe 0 is formed which is compacted into bodies which are sintered at a temperature of about l,200 C. and cooled, the step of adding to said mixture about 0.01 to 0.10 percent of an alkaline earth metaborate.

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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)
  • Power Engineering (AREA)
  • Soft Magnetic Materials (AREA)
  • Magnetic Ceramics (AREA)
US18676A 1969-03-20 1970-03-11 Method of manufacturing a sintered oxidic ferromagnetic body Expired - Lifetime US3671436A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL6904352A NL6904352A (en(2012)) 1969-03-20 1969-03-20

Publications (1)

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US3671436A true US3671436A (en) 1972-06-20

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US (1) US3671436A (en(2012))
BE (1) BE747579A (en(2012))
CA (1) CA928059A (en(2012))
FR (1) FR2039710A5 (en(2012))
GB (1) GB1292735A (en(2012))
NL (1) NL6904352A (en(2012))

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3837910A (en) * 1970-10-07 1974-09-24 Philips Corp Method of manufacturing a polycrystalline ferrite body
US6628190B2 (en) * 1999-12-16 2003-09-30 Tdk Corporation Powder for magnetic ferrite, magnetic ferrite, multilayer ferrite components and production method thereof

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114180951B (zh) * 2021-12-24 2023-02-28 安徽龙磁科技股份有限公司 一种含硬硼钙石的铁氧体浆料及其制备方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB820855A (en) * 1956-02-14 1959-09-30 Standard Telephones Cables Ltd Ferromagnetic ceramic materials with rectangular hysteresis cycle
DE1094995B (de) * 1960-01-26 1960-12-15 Grundig Max Magnetkopf
US3117934A (en) * 1961-04-17 1964-01-14 Bell Telephone Labor Inc Garnet growth from barium oxide-boron oxide flux
US3472780A (en) * 1962-07-25 1969-10-14 Philips Corp Low porosity nickel zinc ferrite

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB820855A (en) * 1956-02-14 1959-09-30 Standard Telephones Cables Ltd Ferromagnetic ceramic materials with rectangular hysteresis cycle
DE1094995B (de) * 1960-01-26 1960-12-15 Grundig Max Magnetkopf
US3117934A (en) * 1961-04-17 1964-01-14 Bell Telephone Labor Inc Garnet growth from barium oxide-boron oxide flux
US3472780A (en) * 1962-07-25 1969-10-14 Philips Corp Low porosity nickel zinc ferrite

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3837910A (en) * 1970-10-07 1974-09-24 Philips Corp Method of manufacturing a polycrystalline ferrite body
US6628190B2 (en) * 1999-12-16 2003-09-30 Tdk Corporation Powder for magnetic ferrite, magnetic ferrite, multilayer ferrite components and production method thereof

Also Published As

Publication number Publication date
DE2010761B2 (de) 1977-04-21
GB1292735A (en) 1972-10-11
FR2039710A5 (en(2012)) 1971-01-15
BE747579A (fr) 1970-09-18
CA928059A (en) 1973-06-12
DE2010761A1 (de) 1970-10-01
NL6904352A (en(2012)) 1970-09-22

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