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
  • C04B35/2608—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 a ferromagnetic ceramic material with a high saturation-flux density and method of making the same.
• An object of this invention is to provide a method of making a ceramic magnetic material with a high saturation-flux density.
• Another object of the invention is to provide a ceramic magnetic material with a high saturation-flux density.
• Another object of the invention is to provide a ceramic magnetic material with a relatively high Curie point and a high saturation-flux density, and process of making the same.
• Another object of the invention is to provide a ceramic magnetic material with a relatively low temperature coefficient, a relatively high Curie point and a high saturation-flux density and a process of making the same.
• ferrite compounds have been developed and described in the technical literature, i. e., ferromagnetic oxides of the general formula MFe2O4, where M represents a bivalent metal, as, for instance, manganese, copper or magnesium.
• M represents a bivalent metal, as, for instance, manganese, copper or magnesium.
• M represents a bivalent metal, as, for instance, manganese, copper or magnesium.
• ferromagnetic oxides of the general formula MFe2O4 where M represents a bivalent metal, as, for instance, manganese, copper or magnesium.
• M represents a bivalent metal, as, for instance, manganese, copper or magnesium.
• M represents a bivalent metal, as, for instance, manganese, copper or magnesium.
• ferrite compounds which forms crystals of the same shape as the magnetite, F6304, has a different magnetic permeability, ohmic resistance, Curie point and magnetic losses.
• these compounds or suitable mixtures of them cover a range ofin
• a high initial permeability is desirable but according to the present invention it has been found that by sacrificing a certain amount of the high initial permeability property, other very valuable properties are obtained. It might be expected that higher Curie points could be obtained from compositions having a medium or low initial permeability but the particular composition employed in the present invention is very unusual in that it has a high saturation-flux density which exceeds that of the high permeability bodies.
• the ferrite compounds of this invention have an initial permeability between 200 and 350, small magnetic losses over the frequency range of 60 cs. to about 10 mos, a Curie point of 250 C. or
• a peculiarity of these materials is the fact that they show a high saturation flux-density of at least 3750 up to more than 000 exceeding the saturation fiux-density of the high permeability bodies.
• the high saturation bodies are fired at fairlyhigh temperatures between Seger cones 7 and 10 and cooled in air, i. e. without applying a protective atmosphere.
• the various components or compounds adapted to form the components of the final product during firing are combined in the proper proportions.
• the manganese oxide component of the final product is preferably added in the form of manganese dioxide and when lithium oxide is employed as a component it is added in the form of the carbonate, etc. During firing these compounds are reduced to the required oxides.
• the "mol ratio refers to the final product
• the composition refers to the mix before firing.
• the powders are preferably ground to a very fine particle size, for example, less than 0.010 m. m.
• the final pulverized mixed powder is wet with an aqueous binder which may be just ordinary water or may contain emulsified waxes or other plasticizers or binding agents.
• Enough of the aqueous binder is added to make the mix coherent when placed under pressure and the mix is thereafter molded.
• Any molding device such as a steel die or a ceramic extruding machine may be employed. After molding the articles are fired at Seger cones 7-10 and cooled. No special precautions are required during cooling.
• Example 1 The mix is ballmilled and moistened and plasticized by an addition of 4% of a wax-water emulsion.
• the wax-water emulsion contains 50% of wax.
• the mix is then molded by pressing and fired at about Seger-cone 9. 1 After firing the molded article is cooled in air at room temperature.
• the physical properties of this material are shown in the following table:
• Example 3 A mix is made up of the following components: Mol ratio: .09 MgO:.4 MnO:.34 ZnO:.l7 NiO: about 1 F6203.
• a ferromagnetic ceramic material consisting mainly of iron oxide compounds of the magnetitetype, suitable for the use at frequencies between 60 cs. and about 10 mos. composed of the bivalent metal oxides MgO MnO, ZnO and MO and F6203 in the mol ratio of .05-.15 MgO:.2-.4 MnO:.3-.4 ZnO:.l5-.4 Nioiabout 1.0 FezOs, the total mol ratio of said bivalent metal oxides to F6203 being approximately 1:1 said material having a Curie point of at least 250 C., an initial permeability between 200 and 350, a saturation-flux density of at least 3750 and a temperature coemcient of a of 25 to 35% (measured on a toroid) between room temperature and C.
• a process of making a ferromagnetic ceramic material having small magnetic losses over a frequency range of 60 cycles to 10 megacycles and a high saturation-flux density comprising the steps of grinding and mixing together cornponents adapted to yield after firing the bivalent metal oxides MgO, MnO, ZnO and MO and F6203 in the mol ratio of .05-.15 NIgOLZ-fl MnO:.3-.4 ZnO:.15-.4 NiO:about 1.0 F8203, the total mol ratio of said bivalent metal oxides to F8203 being approximately 1:1 moistening the powdered mix with an aqueous binding composition, molding the resulting plastic mix to the desired shape, firing the molded article at Seger cones 7-10 to produce a ferromagnetic molded product having a Curie point of at least 250 (3., an initial perineability of 200-350, a saturation flux density of at least 3750 and a temperature coefficient of U. of 25-35% (measured on a toroid) between
• a process of making a ferromagnetic ceramic material having small magnetic losses over a frequency range of 60 cycles to 10 megacycles and a high saturation-flux density comprising the steps of grinding and mixing the metallic oxides MgO, Win02, ZnO, 'rliO, and FezOa in the mol ratio of .O -.5 MgO:.2-.4 manganese oxide calculated as lvIn :.3-.4 ZnO:.15-.4 NiO:about 1.0 FezOa, the mol ratio of the iron to the total amount of the other said metals being approximately 2:1 moistening the powdered mix with water, molding the resulting plastic mix to the desired shape, firing the molded article Seger cones 7-10 and permitting it to cool in air to produce a ferromagnetic molded product having a Curie point of at least 250 (3., an initial permeability of #0 of 200-350, a saturation flux density of at least 3750 and a temperature coefficient of p. of 25-35%
• a process of making a ferromagnetic ceramic material having small magnetic losses over a frequency range of 50 cycles to 10 megacycles and a high saturation-flux density comprising the steps of grinding and mixing the metallic oxides MgO, M1102, ZnO, Ni(), and FezOs, the mol ratio of the iron to the total amount of the other said metals being approximatel 2:1 nioistening the powdered mix with water, adding a wax as a plasticizer, molding the resultant plastic mix to the desired shape, firing the molded article at Seger cones 7-10 and permitting it to cool in air to produce a ferromagnetic molded product having a Curie point of at least 250 0., an initial permeability of t of 200-350, a saturation flux density of at least 3750 and a temperature coefficient of n of 25-35% (measured on a toroid) between room temperature and 125 C.

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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)
• Soft Magnetic Materials (AREA)
• Magnetic Ceramics (AREA)

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Cited By (9)

Citations (2)

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• 1949
  • 1949-05-26 US US95581A patent/US2565058A/en not_active Expired - Lifetime
• 1950
  • 1950-05-10 GB GB11667/50A patent/GB668700A/en not_active Expired
  • 1950-05-18 DE DEST1079A patent/DE907995C/de not_active Expired
  • 1950-05-24 FR FR1018561D patent/FR1018561A/fr not_active Expired
  • 1950-05-25 CH CH288263D patent/CH288263A/de unknown
  • 1950-05-26 NL NL78165D patent/NL78165C/xx active

Patent Citations (2)

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