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| Number | Title | Issue Date |
| 5120604 | Acicular magnetic iron oxide particles and magnetic recording media using such particles Disclosed herein are acicular magnetic iron oxide particles coated with double coating layers consisting of a Co compound layer as a lower layer and a spinel-type ferrite layer containing Mn-Zn, Ni-Zn or Mn-Ni-Zn as an upper layer, a process for producing... | 06/09/1992 |
| 5104582 | Electrically conductive fluids The invention refers to an electrically conducting, preferably magnetic fluid, which contains magnetic particles, dispersed in a carrier fluid by means of a dispersant. The fluid is characterized therein that it also contains an electrolyte, which is held... | 04/14/1992 |
| 5094767 | Highly viscous magnetic fluids having nonmagnetic particles Highly viscous magnetic fluids essentially consist of superparamagnetic solid particles coated with a surfactant and colloidally dispersed in a carrier liquid.... | 03/10/1992 |
| 5093100 | Plate-like magnetite particles, plate-like maghemite particles and processes of producing the same Disclosed herein are poreless, non-sintered plate-like magnetite particles having an average particle diameter of more than 0.5 μm and not more than 2.0 μm, and a BET specific surface area of not more than 6.0 m2 /g, and poreless, non-sintere... | 03/03/1992 |
| 5089159 | Magnetic substance having sharp permeability transition temperature, process for making, and apparatus A magnetic mateial which includes an impurity metal of relatively large atomic diameter such as zinc, titanium, zirconium, yttrium, or cadmium introduced uniformly therein in amount sufficient to distort its crystaline structure to alter its anisotrophy s... | 02/18/1992 |
| 5082582 | Nucleating device for thermal energy storage compositions A nucleating agent for NaOH/H2 O solutions comprises a metal bar, magnetic tape adhered to a surface area of the bar and particulate magnetite on the surface of the tape. The magnetic field created by the tape holds the bar, tape and magnetite ... | 01/21/1992 |
| 5078984 | Process for producing microcrystalline barium ferrite platelets A process for producing microcrystalline barium ferrite platelets which comprises: forming an aqueous alkaline dispersion containing coprecipitates of hydroxides of barium ions, iron (III) ions, and optionally ions of a substituent element; heating the di... | 01/07/1992 |
| 5059337 | Soft magnetic materials comprising 9 to 15 atomic percent carbon atoms The present invention provides a novel soft magnetic material superior in corrosion resistance which contains (a) a ferromagnetic metal and (b) a carbide of a ferromagnetic metal and/or a silicide of a ferromagnetic metal with at least one of (c) an amorp... | 10/22/1991 |
| 5055214 | Magnetic material for microwave and millimeter wave frequencies A magnetic material for microwave and millimeter wave frequencies consists essentially of a composition represented by the general formula: (Y1-x Gdx)w (Fe1-y-z Aly Mnz)8-w O12 | 10/08/1991 |
| 5049307 | Process for the production of a ferromagnetic composition, ferromagnetic liquid crystal obtained by this process and apparatus using said liquid crystal A composition comprising a lyotropic ferromagnetic liquid crystal. The lyotropic ferromagnetic liquid crystal contains 1 to 90% by weight of a surfactant, 1 to 90% by weight of a co-surfactant, 1 to 97% by weight of oil and 1 to 97% by weight of a polar l... | 09/17/1991 |
| 5043070 | Magnetic solvent extraction Particles of a magnetic material coated with a hydrophobic surfactant are dispersed in an organic solvent extractant to produce a magnetic solvent extractant which can be used in solvent extraction processes. Phase separation of an organic phase, carrying... | 08/27/1991 |
| 5041307 | Process for producing magnetic iron oxide particles for magnetic recording A process for producing magnetic ion oxide particles for magnetic rcording which comprises heat-treating a magnetic iron oxide particles of magnetite, berthollide or maghemite as a starting materials, in the presence of a zinc component or both a zinc com... | 08/20/1991 |
| 5039553 | Mixed batchwise and continuous process for the production of cobalt modified magnetic iron oxide powder for use in high density recording A process for the continuous production of cobalt-modified magnetic iron oxide. This process comprises carrying out a batchwise preliminary cobalt treatment by adding a magnetic iron oxide powder to an alkaline solution followed by the addition of a cobal... | 08/13/1991 |
| 5039559 | Method of making magnetically attractable particles Magnetically attractable particles comprise a core of magnetic material encapsulated in a metal oxide coating. They may be made by emulsifying an aqueous solution or dispersion of the magnetic material or precursor, and an aqueous solution or sol of a coa... | 08/13/1991 |
| 5030371 | Process for preparing acicular ferromagnetic material consisting essentially of iron-containing chromium dioxide An acicular, ferromagnetic material which has a high coercive force and essentially consists of iron-containing chromium dioxide is prepared by thermal decomposition of hydrated chromium(III) chromate under superatmospheric pressure.... | 07/09/1991 |
| 5028483 | Magnetic recording medium comprising acicular dendrite free iron oxide magnetic pigment particles A magnetic recording medium comprising a nonmagnetizable substrate and a magnetizable layer coated onto the substrate. The magnetizable layer comprises about 83 to 89 percent by weight of acicular, substantialy dendrite-free, iron oxide magnetic pigment p... | 07/02/1991 |
| 5013365 | Iron oxide black pigments, processes for their preparation and their use A process is disclosed for preparing iron oxide black pigments obtained by the nitrobenzene reduction process, wherein the iron oxide black is heated to 400°-800° C. in a slightly oxidizing atmosphere with optional milling. The pigments are useful for c... | 05/07/1991 |
| 5002609 | Iron oxide black pigment granules, processes for their preparation and their use A process is disclosed for preparing dispersant-free iron oxide pigment granules by spraying or atomizing an iron oxide black pigment suspension and heating the resulting granules at a temperature of 400°-800° C. The granules are useful for coloring bui... | 03/26/1991 |
| 4995999 | Method of producing magnetic carbon black Magnetic carbon black, a process for preparing the same, and a method of modifying magnetic carbon black are provided. The magnetic carbon black is prepared by process A in which when a hydrocarbon is supplied into a high temperature combustion gas stream... | 02/26/1991 |
| 4975267 | Stable K2 FE22 O34 potassium ferrite phase and method of manufacture Stable K2 Fe22 O34 in the form of lamellar platelets useful as a dehydrogenation catalyst and a method of manufacturing the same, including the steps of mixing iron oxide and a potassium compound, such as potassium carbona... | 12/04/1990 |
| 4975214 | Magnetic iron oxide containing silicon element and process for producing same Magnetic iron oxide containing silicon element is produced in the form of generally octahedral particles having a sharp particle size distribution through a reaction of an aqueous solution of a ferrous salt having a controlled Fe(II)/Fe(III) ratio and con... | 12/04/1990 |
| 4969962 | Magnetic alloys for magnetic head Novel magnetic alloys for magnetic heads are provided and are broadly of the formula, Fe-O-N. In a more specific embodiment, the alloys are of the compositional formula, Fev Nw Ox My, wherein M represents a memb... | 11/13/1990 |
| 4963343 | Stable k2 fe22 o34 potassium ferrite phase Stable K2 Fe22 O34 in the form of lamellar platelets useful as a dehydrogenation catalyst and a method of manufacturing the same, including the steps of mixing iron oxide and a potassium compound, such as potassium carbona... | 10/16/1990 |
| 4957812 | Composite magnetic powder, method for producing the same and recording medium containing the same Disclosed is a composite magnetic powder comprising two crystal phases of a hexagonal ferrite portion and a spinel structure ferrite portion, which are different in thermal characteristic and in crystal structure and which are in a crystallographically ep... | 09/18/1990 |
| 4952331 | Composite magnetic compacts and their forming methods Composite magnetic compacts having good conductivity and excellent mechanical and magnetic properties and their forming methods. The composite magnetic compacts are basically made by forming mixtures consisting essentially of 1 to 50 percent by weight of ... | 08/28/1990 |
| 4946623 | Process for the production of a ferromagnetic composition, ferromagnetic liquid crystal obtained by this process and apparatus using said liquid crystal There is provided a process for the production of a composition and, in particular, of a ferromagnetic liquid crystal. The process comprises (1) forming a micro-emulsion by dispersing an aqueous solution containing ferrous cations and ferric cations in an... | 08/07/1990 |
| 4935325 | Toner and image forming method using magnetic material with specific tap density and linseed oil absorption A magnetic toner suitably used for developing a digital latent image is provided. The magnetic toner comprises a binder resin and a specific magnetic material comprising spherical magnetic particles which have a tap density of 1.2-2.5 g/cm3 and... | 06/19/1990 |
| 4929376 | Quaternary ammonium salt of an alkoxysilane as a dispersant for magnetic pigment There is disclosed the use of a quaternary ammonium salt of an alkoxysilane as a dispersant for magnetic pigment particles in the preparation of magnetic recording media. The dispersant of the present invention can bind to the pigment particles and may be... | 05/29/1990 |
| 4913890 | Preparation of acicular -Fe2 O3 Finely divided acicular and pore-free -Fe2 O3 is prepared from an iron(III) salt in the presence of one or more organic substances which form complexes with iron(III) ions, in alkaline supension at from 80° to 250° C., and i... | 04/03/1990 |
| 4912070 | Continuously porous absorbent material possessing far infrared electromagnetic field A continuously porous adsorbent material substantially comprising zeolite type clay powder particles, magnetized magnetite particles and ettringite crystals bonding the clay particles and the magnetic particles, wherein the adsorbent material possesses co... | 03/27/1990 |
| 4904530 | Magnetic material, magnetic recording medium, and method of manufacturing a magnetic material The invention relates to a magnetic material for use in the magnetic recording and playback of information, which material consists of ferrite particles having the composition A1-y Zny Fe2 O4, wherein A is one o... | 02/27/1990 |
| 4900465 | Process for preparing magnetic carbon black Magnetic carbon black, a process for preparing the same, and a method of modifying magnetic carbon black are provided. The magnetic carbon black is prepared by process A in which when a hydrocarbon is supplied into a high temperature combustion gas stream... | 02/13/1990 |
| 4894305 | Carrier and developer compositions generated from fly ash particles Carrier particles with an average diameter of greater than 44 microns are generated from fly ash, and subsequently admixed with toner compositions enabling developer compositions useful for incorporation into xerographic imaging apparatuses. The aforement... | 01/16/1990 |
| 4892672 | Process for controlling ferrous iron content in manganese zinc ferrite Process of calcining the ball milling manganese zinc MnZn, ferrite material for achieving a ferrite having a ferrous iron content appropriate for optimum magnetic properties. A first initial ball milling step is very carefully controlled as a small amount... | 01/09/1990 |
| 4876022 | Method for preparing ferromagnetic iron oxide particles A method for preparing ferromagnetic iron oxide particles comprising the steps of depositing Co-ferrite fine particles onto the surface of acicular iron oxyhydroxide particles and then calcining said acicular iron oxyhydroxide having said C0-ferrite fine ... | 10/24/1989 |
| 4867910 | Electrically conductive ferrofluid composition A ferrofluid composition consists of organic solvent or solvents to be used as liquid carriers, a charge-transfer complex or complexes for imparting electrical conductivity to the composition, fine particles of ferromagnetic material and additives for sta... | 09/19/1989 |
| 4863795 | Magnetic recording medium A magnetic recording medium comprises a base film and a magnetic film having magnetic particles, formed on the base film. The magnetic film has a coercive force ranging from 750 Oe to 980 Oe and a residual magnetic flux density of 1,250 Gauss or over. In ... | 09/05/1989 |
| 4857417 | Cobalt-containing iron oxide magnetic particles and method for the preparation of the same Cobalt-containing iron oxide magnetic particles having a high coercive force and a small surface electrical resistance which are useful as a recording element for a magnetic recording medium, and a method for the preparation of the same comprising reducin... | 08/15/1989 |
| 4851292 | Plate-like barium ferrite particles suitable for use in magnetic recording and process for producing the same Disclosed herein are plate-like barium ferrite particles with a solid solution of zinc on the surface thereof, which have an average particle diameter of not less than 0.03 μm and less than 0.1 μm, a BET specific surface are of 55 to 80 m2 /g... | 07/25/1989 |
| 4851258 | Method for preparing magnetic particles for magnetic-recording media Magnetic particles of modified γ-ferric oxide particles for magnetic recording media which have excellent electrical conductivity, saturation magnetization, and print-through, and have a higher coercivity, are prepared by modifying γ-ferric oxide partic... | 07/25/1989 |
