US3694361A - Lithium titanium bismuth cobalt ferrites - Google Patents

Lithium titanium bismuth cobalt ferrites Download PDF

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Publication number
US3694361A
US3694361A US178057A US3694361DA US3694361A US 3694361 A US3694361 A US 3694361A US 178057 A US178057 A US 178057A US 3694361D A US3694361D A US 3694361DA US 3694361 A US3694361 A US 3694361A
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United States
Prior art keywords
ferrites
cobalt
ferrite
lithium titanium
microwave
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Expired - Lifetime
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US178057A
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English (en)
Inventor
Jan Smit
Paul David Baba
Giltan Michael Argentina
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Ampex Corp
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Ampex 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
    • C04B35/2608—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
    • C04B35/2616—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 lithium
    • 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
    • C04B35/2691—Other ferrites containing alkaline metals

Definitions

  • Microwave ferrites with high power handling capability, narrow resonance linewidths, good temperature performance, low losses, low costs, and rectangular hysteresis loops are made from a lithium-titanium-bismuth ferrite containing a small amount of cobalt.
  • small amounts of zinc or manganese can be present in the ferrites.
  • garnets are ordinarily employed at microwave frequencies. However, garnets are expensive and have poor temperature performance. Although it has been suggested that ferrites might be used, the losses have been high, the densities have been low or the coercive forces have been too high.
  • the power handling capability of such ferrites is greatly enhanced by the addition of a small amount of cobalt.
  • Oxides of the constituent metal ions are generally employed when possible.
  • the anhydrous carbonate of the metal ion is used.
  • the raw materials are weighed out in stoichiometric proportions and are wet mixed for one hour or more in a ball mill.
  • the resulting slurry is then dried at around 100 C. and the dried raw material mixture is then forced through a standard 20 mesh screen for ease of handling.
  • the screened oxide mixture is then loaded into refractory boats.
  • the boats are placed in a box type furnace, and
  • Patented Sept. 26, 1972 heated to a predetermined temperature.
  • the exact temperature can vary from 700 C. to 900 C.
  • the object of this step is twofold: the primary object is to provide sufiicient energy to react the oxide mixture to a 70% ferrite 30% oxide mixture by a solid state reaction.
  • the secondary objective is the simple thermal decomposition of any carbonates used.
  • the reacted mixture is generally characterized by a relatively large predominant particle size. Before the mixture can be shaped and sintered into a single phase ferrite body the particle size must be reduced. Ball milling is employed in essentially the same manner as outlined above. The ferrite-oxide slurry is then dried at around C. to a fine powder.
  • a typical binder is polyvinyl alcohol.
  • the addition of the binder can be carried out in the second ball milling step, or in an additional step employing any sort of method facilitating uniform distribution of the substance used as a binder.
  • the binder impregnated powder is then shaped in tool steel dies with enough pressure to facilitate uniform compaction.
  • the pressed shapes are then sintered at temperatures ranging from 950 C. to 1150 C. in atmospheres of oxygen or air.
  • novel ferrites of the present invention have the following composition:
  • Example 1 illustrates a composition which does not contain cobalt while Example 2 shows the same composition with the addition of cobalt showing the beneficial effect of the cobalt addition:
  • EXAMPLE 1 A ferrite was prepared by the above procedure. The reaction step was performed at 800 C. The sintering step was performed at 1025 C. in an air atmosphere.
  • Dielectric loss tangent 0.0005
  • magnetic loss tangent 0.0007
  • resonance linewidth 210 oersteds
  • spinwave linewidth 6.2 oersteds
  • peak power handling capability 7.0 kilowatts.
  • Example 2 wherein cobalt was employed has a factor of greater peak power handling capability than does Example 1 which has no cobalt.
  • Example 2 has a slightly larger magnetic loss tangent than does Example -1; otherwise, the usefulness of Example 2 as a microwave material has not been impaired by the addition of cobalt.
  • a lithium-titanium-bismuth cobalt ferrite having the following compositions:

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Ceramic Engineering (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Magnetic Ceramics (AREA)
  • Soft Magnetic Materials (AREA)
  • Compounds Of Iron (AREA)
US178057A 1971-09-07 1971-09-07 Lithium titanium bismuth cobalt ferrites Expired - Lifetime US3694361A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US17805771A 1971-09-07 1971-09-07

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US3694361A true US3694361A (en) 1972-09-26

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US178057A Expired - Lifetime US3694361A (en) 1971-09-07 1971-09-07 Lithium titanium bismuth cobalt ferrites

Country Status (7)

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US (1) US3694361A (enrdf_load_stackoverflow)
JP (1) JPS4836699A (enrdf_load_stackoverflow)
BE (1) BE788442A (enrdf_load_stackoverflow)
DE (1) DE2243975B2 (enrdf_load_stackoverflow)
FR (1) FR2152601A1 (enrdf_load_stackoverflow)
GB (1) GB1355779A (enrdf_load_stackoverflow)
NL (1) NL7211331A (enrdf_load_stackoverflow)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4277356A (en) * 1976-12-14 1981-07-07 Thomson-Csf Soft lithium-titanium-zinc ferrite
CN102010012A (zh) * 2010-12-14 2011-04-13 中国科学院新疆理化技术研究所 两步固相反应制备铁酸铋材料的方法

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CS167056B1 (enrdf_load_stackoverflow) * 1973-11-19 1976-04-29
JPS5741801B2 (enrdf_load_stackoverflow) * 1973-11-27 1982-09-04
JPS5215062A (en) * 1975-07-25 1977-02-04 Tsubakimoto Kogyo Kk Transfer apparatus of member having center hole

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4277356A (en) * 1976-12-14 1981-07-07 Thomson-Csf Soft lithium-titanium-zinc ferrite
CN102010012A (zh) * 2010-12-14 2011-04-13 中国科学院新疆理化技术研究所 两步固相反应制备铁酸铋材料的方法
CN102010012B (zh) * 2010-12-14 2012-07-25 中国科学院新疆理化技术研究所 两步固相反应制备铁酸铋材料的方法

Also Published As

Publication number Publication date
FR2152601A1 (enrdf_load_stackoverflow) 1973-04-27
DE2243975B2 (de) 1974-02-07
NL7211331A (enrdf_load_stackoverflow) 1973-03-09
BE788442A (fr) 1973-01-02
GB1355779A (en) 1974-06-05
JPS4836699A (enrdf_load_stackoverflow) 1973-05-30
DE2243975A1 (de) 1973-03-22

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