Class 252/62.51C - Chromium or chromium compound containing

Subclass of Class 252 - Compositions
No. of patents: 39
Last issue date: 02/10/2004

Number	Title	Issue Date
6689287	Ferroelectric and ferromagnetic material having improved impedance matching The subject invention includes a composite material comprising a ferroelectric material and a ferromagnetic material having a loss factor (tan δ) for the composite material which includes a dielectric loss factor of the ferroelectric material and a magne...	02/10/2004
6284150	Bonded magnet, magnet roll, a ferrite powder used therefor and method for producing same A ferrite powder for bonded magnets having a substantially magnetoplumbite-type crystal structure and an average diameter of 0.9-2 μm, the ferrite powder having a basic composition represented by the following general formula: (A1-x Rx	09/04/2001
6254781	Method for recycling ferrofluid constituents used in a materials separation process Ferrofluid coated particles resulting from a ferrofluid materials separation process are washed with a solvent which is the same material as the liquid carrier employed in the ferrofluid. The result is a "dirty" solvent which is a very weak ferrofluid. Th...	07/03/2001
6080233	Cobalt-containing iron oxide pigments, process for producing the same and magnetic recording medium containing the same Disclosure describes a cobalt-containing iron oxide pigments comprising: a cobalt-containing iron oxide core, the average concentration of cobalt distributed evenly in an innermost 50% by weight of the cobalt-containing iron oxide core being from 0.1 to 1.0% b...	06/27/2000
6059988	Magnetite particles and process for production thereof Magnetite particles continuously contain a total amount of 0.2 to 1.2 wt. %, based on magnetite, of a silicon component and an aluminum component expressed as silicon and aluminum, in a region ranging from the center to the surface of the particle, a tota...	05/09/2000
5985168	Magnetorheological fluid A magnetorheological (MR) fluid including magnetically soft particles suspended in a carrier solvent is disclosed. The MR fluid also includes additive particles of smaller size than the magnetically soft particles and a bridging polymer. The additive part...	11/16/1999
5935866	Preparation of sub 100 A magnetic particles and magnetic molecular switches Inorganic oxides of substantially uniform particle size distribution are prepared by contacting aqueous solutions of an inorganic salt and an inorganic base across a porous membrane wherein the membrane contains a plurality of pores which allows for preci...	08/10/1999
5900146	Polymer beads and method for preparation thereof The present invention relates to a process for producing polymer beads incorporating solid particles and to the novel polymer beads per se. The invention provides a process for producing polymer beads incorporating solid particulate material, which proces...	05/04/1999
5856008	Article comprising magnetoresistive material An article that uses a magnetoresistive material comprising one or more CrO2 grains having an insulating material, advantageously Cr2 O3, along at least a portion of the grain boundary or boundaries, the magnetoresistive a...	01/05/1999
5607781	Oxide film with preferred crystal orientation, method of manufacturing the same, and magneto-optical recording medium An oxide film having, for example, a spinel structure is deposited on a substrate, and ions of an inert gas such as He, Ar, Ne, Kr, or Xe, oxygen gas ions, or metal ion of a film constituting element are radiated onto the film during deposition, thereby t...	03/04/1997
5569409	Finely divided acicular magnetic modified chromium dioxide A finely divided acicular CrO2 modified with iron, tellurium and/or antimony and having a high coercive force possesses improved heat stability of the residual induction and a relatively narrow distribution of the particle size and of the coerc...	10/29/1996
5552073	Ferromagnetic fine particles of &3xb5; iron carbide and method for producing the same Ferromagnetic granular ultrafine particles consisting essentially of &3xb5;' iron carbide represented by the composition formula: &3xb5;'-Fe2.2 C having an average particle size of about 0.01 to 0.2 μm, and ferromagnetic acicular ultrafine particle...	09/03/1996
5378383	Process for preparing modified chromium dioxide A magnetic recording medium comprising a nonmagnetic substrate and at least one magnetic layer applied thereon and containing an acicular chromium dioxide uniformly distributed in a polymeric binder and additives and having a coercive force of at least 60...	01/03/1995
5176842	Method of manufacturing a resin bound magnet A method of manufacturing a resin bound magnet comprising, mixing and kneading a powdered magnetic material and a rubber modified epoxy resin obtained from the addition polymerization of an epoxy resin and a butadiene or nitrile rubber and thereafter mold...	01/05/1993
5164173	Preparation of stabilized acicular ferromagnetic chromium dioxide Stabilized acicular ferromagnetic chromium dioxide is prepared by a method in which the chromium dioxide surface formed as a result of a reductive treatment is treated with adsorbed monobasic or polybasic hydroxycarboxylic acids....	11/17/1992
5064549	Preparation of stabilized chromium dioxide with sodium tetracarbonylferrate Stabilized acicular ferromagnetic chromium dioxide is prepared by reductive treatment of the chromium dioxide with Na2 [Fe(CO)4 ], and this material is present in magnetic recording media....	11/12/1991
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
5009877	Stabilization of acicular ferromagnetic chromium dioxide Acicular ferromagnetic chromium dioxide is stabilized by treatment with an alkali metal hydroxide in an aqueous alkaline suspension at elevated temperatures....	04/23/1991
4781851	Preparation of ferromagnetic chromium dioxide Ferromagnetic chromium dioxide is improved by subjecting chromium dioxide materials prepared by a known method to an additional heat treatment....	11/01/1988
4769165	Process for synthesis of ferromagnetic chromium dioxide Acetic acid is substituted for a portion of the chromic oxide employed in the hydrothermal reaction of chromium trioxide and chromic oxide to form ferromagnetic chromium dioxide....	09/06/1988
4769293	Magnetic recording medium and production thereof A magnetic recording medium comprising a non-magnetic substrate and a magnetic layer formed thereon which contains chromium oxide ferromagnetic powder comprising chromium oxide of the formula: wherein x is not smaller than 1.74 and not larger than 1.91, which ...	09/06/1988
4747974	Mixed Cr₂ O₃ paste for CrO₂ synthesis Chromic acid and inexpensive, coarse grained Cr2 O3 are dissolved in water prior to adding more costly fine grained Cr2 O3 to produce chrome pastes which are more economical than pastes prepared by prior art tec...	05/31/1988
4698220	Partitioned reduction process for ferromagnetic chromium dioxide A new process for synthesis of ferromagnetic chromium dioxide is provided wherein a chromium trioxide solution is mixed with reducing agent that only partially reacts with chromium trioxide during formation of paste below about 100° C. and completes reac...	10/06/1987
4670177	Preparation of ferromagnetic chromium dioxide Ferromagnetic chromium dioxide is prepared by converting oxides of trivalent and hexavalent chromium under superatmospheric pressure and at elevated temperatures in the presence of water and with the addition of an antimony compound as a modifier and, if ...	06/02/1987
4524008	Controlled initiation chromium dioxide synthesis Modified chromium dioxide crystals with narrower particle size and more uniform coercivity are produced by adding the modifying agent in an aqueous CrO3 solution. Antimony, tellurium and iron oxides may be dissolved in a saturated CrO3	06/18/1985
4428852	Continuous synthesis of chromium dioxide Ferromagnetic chromium dioxide is produced in a continuous operation by feeding a preheated paste of hydrated chromium oxides and additives into a twin screw reactor, reacting at elevated temperature and pressure for a short time while venting oxygen and ...	01/31/1984
4374118	Process for stabilizing ferromagnetic chromium dioxide This invention relates to a process for stabilizing ferromagnetic chromium dioxide in respect of water and oxidizable organic compounds which it may contact in magnetic tapes. The process is applicable to a starting CrO2 having good magnetic pr...	02/15/1983
4340494	Process for the manufacture of ferromagnetic chromium dioxide A process for the manufacture of ferromagnetic chromium dioxide modified with foreign elements, by reacting oxides of trivalent and hexavalent chromium under superatmospheric pressure at an elevated temperature in the presence of water and of antimony(III...	07/20/1982
4311770	Novel ferromagnetic chromium dioxide and rhodium dioxide material and its preparation Process for making a novel ferromagnetic chromium dioxide and rhodium dioxide material in the form of a solid solution Cr1-x Rhx O2 where x is a number between 0 and 0.5. It essentially comprises oxidation, under suitable condi...	01/19/1982
4244932	Stabilized ferromagnetic chromium dioxide and process for obtaining same A ferromagnetic chromium dioxide stabilized by coating the particles thereof with a stabilizing substance is disclosed, wherein the stabilizing substance consists essentially of an equimolecular mixture of Fe2 O3 and MnO or of a mixt...	01/13/1981
4169802	Stabilized ferromagnetic chromium dioxide and process for its preparation The present invention concerns a stabilized ferromagnetic chromium dioxide and a process for obtaining the same. More particularly, the present invention relates to ferromagnetic chromium dioxide stabilized by means of the coating of its particles with a ...	10/02/1979
4126714	Process for treating chromium dioxide Ferromagnetic chromium dioxode is normally produced using other chromium compounds as starting materials. In most reactions a Cr(VI) compound, such as chromium trioxide is used in some stage of the procedure. Following the conversion reaction there are in...	11/21/1978
4092439	Process for obtaining chromium dioxide CrO₂ Chromium dioxide CrO2 is prepared by oxidizing hydrated trivalent chromium oxide Cr2 O3, xH2 O, where x is at least 1, at a temperature of at least 350° C and under pressures of at least 2 kilobars. The reactio...	05/30/1978
4068038	Stabilized chromium dioxide compositions Composition comprising a highly ferromagnetic CrO2 having deposited on the surface thereof an insoluble or sparingly soluble compound, thereby rendering the composition essentially non-reactive to water or oxidizable organic substances. Compoun...	01/10/1978
4018690	Process for preparing sulfur-containing ferromagnetic chromium oxide Modified ferromagnetic chromium oxide having an intrinsic coercive force above 150 Oersteds, a Curie temperature lower than that of unmodified chromium dioxide, and a specific magnetization in the range of 50-110 emu/gm., is prepared by heating material c...	04/19/1977
3979310	Process for preparing ferromagnetic chromium dioxide Ferromagnetic chromium dioxide is prepared by thermally decomposing, at a temperature of 250°-500°C, and a pressure of at least 80 atmospheres, a mixture of hydrated trivalent chromium chromate of the formula Cr2 (CrO4)3.nH.su...	09/07/1976
3956151	Method for producing a ferromagnetic chromium oxide A method for producing, under a low pressure such as an ambient atmospheric pressure, a ferromagnetic chromium oxide having a sufficiently high saturation magnetization and, if necessary, sufficiently high coercive force as well. The main feature of this ...	05/11/1976
3956152	Magnetic recording media A magnetic recording medium or composition which comprises a ferromagnetic chromium dioxide product containing a proper quantity of tungsten alone or admixed with a member selected from the group consisting of copper and zinc, which has an excellent ferro...	05/11/1976
3954641	Process for the preparation of sulfur modified ferromagnetic chromium oxide The present invention provides a ferromagnetic chromium oxide powder having an additive of sulfur incorporated therewith, which powder has a lower curie temperature than that of pure chromium dioxide powder and a high saturation magnetization. Said powder...	05/04/1976

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Class 252/62.51C - Chromium or chromium compound containing