Abstract: A process for manufacturing a magnetic material, comprising: coating a nanoparticle dispersion containing alloy nanoparticles capable of forming a ferromagnetic ordered alloy phase, and a fusion inhibitor on a support to form a coated film of a nanoparticle magnetic layer, and heat-treating the coated film to ferromagnetize the alloy nanoparticles. Further, a magnetic material comprising a support and a nanoparticle magnetic layer of a nanoparticle dispersion coated thereon, wherein the nanoparticle dispersion comprises alloy nanoparticles capable of forming a ferromagnetic ordered alloy phase and a fusion inhibitor, is provided.

Abstract: Ferromagnetic nanoparticles which are produced by reducing, in the presence of a polymer, two or more metals having different reduction potentials twice or more, using two or more reducing agents having different reduction potentials, a material coated with a dispersion of ferromagnetic nanoparticles in which the ferromagnetic nanoparticles are dispersed, and a magnetic recording medium which has a magnetic layer consisting of the material. The ferromagnetic nanoparticles having a holding power Hc of 95.5 kA/m or more, the material coated with the dispersion of ferromagnetic nanoparticles having excellent industrial coatability, and the magnetic recording medium using the dispersion are provided.

Abstract: A method of producing a nanoparticle, the method comprising: a reducing step of adding an reverse micelle solution (II) obtained by mixing a water-insoluble organic solvent containing a surfactant with an aqueous metal salt solution to an reverse micelle solution (I) obtained by mixing a water-insoluble organic solvent containing a surfactant with an aqueous reducing agent solution, to carry out a reducing reaction; and a maturing step of raising the temperature of the reduced mixture to mature the reduced mixture is provided. A method of producing a plural type alloy nanoparticle, the method comprising producing a nanoparticle made of a plural type alloy through a reducing step of mixing one or more reverse micelle solutions (I) containing a metal salt with an reverse micelle solution (II) containing a reducing agent to carry out reducing treatment and a maturing step of carrying out maturing treatment is also provided.

Abstract: The present invention relates to a method of producing a magnetic particle including forming a layer containing an alloy particle that can form a CuAu-type or Cu3Au-type hard magnetic ordered alloy phase on a support, oxidizing the layer, and annealing the layer in a non-oxidizing atmosphere. The invention also relates to a method of producing a magnetic particle including producing an alloy particle that can form a hard magnetic ordered alloy phase, oxidizing the alloy particle, and annealing the particle in a non-oxidizing atmosphere, and a magnetic particle produced by the foregoing production method. Further, the invention relates to a magnetic recording medium comprising a magnetic layer containing a magnetic particle and a method of producing a magnetic recording medium including forming a layer containing an alloy that can form the foregoing hard magnetic ordered alloy phase, oxidizing the layer, and annealing the layer in a non-oxidizing atmosphere.

Abstract: The present invention is a magnetic particle coated material comprising: a first support having a magnetic layer formed on one surface thereof; and a second support having a magnetic layer formed on one surface thereof, wherein the first support and the second support are attached to each other so that the other surfaces thereof on which the magnetic layers are not formed face each other, and the magnetic layers comprise magnetic particles having a CuAu type or Cu3Au type ferromagnetic ordered alloy phase.

Abstract: The invention provides methods for producing nanoparticles having a CuAu type or Cu3Au type magnetically hard ordered alloy phase. One method includes a step of reducing, in liquid phase, a base metal and then reducing, in liquid phase, a noble metal. Another method includes a step of reducing, in liquid phase, at first a base metal and a part of a noble metal, and then reducing, in liquid phase, a remainder of the noble metal in liquid phase.

Abstract: The present invention provides a magnetic particle-coated material having a layer including a CuAu type or Cu3Au type ferromagnetic ordered alloy phase on an organic support. Further, the present invention provides a method of manufacturing a magnetic particle-coated material that sequentially includes a step of manufacturing alloy particles capable of forming a ferromagnetic ordered alloy phase, a step of coating an organic support with the alloy particles to form a coating film, and a step of annealing the coating film in a reducing atmosphere to make the alloy particles into magnetic particles, and further includes a step of oxidizing the alloy particles, the oxidizing step being performed between the alloy particle manufacturing step and the annealing step.

Abstract: A method of producing a magnetic recording medium including the steps of preparing alloy particles capable of forming a CuAu type or Cu3Au type ferromagnetic order alloy phase, forming an alloy particle layer on a support using the alloy particles, oxidizing the alloy particles, and annealing the alloy particle layer in a magnetic field under a reducing atmosphere. Also disclosed is a magnetic recording medium produced by the method, that is, a magnetic recording medium including a magnetic layer which contains magnetic particles in a CuAu type or Cu3Au type ferromagnetic order alloy phase and which has a squareness ratio of 0.75 or higher.

Abstract: In a method of producing magnetic particles which includes the steps of preparing alloy particles capable of forming a CuAu or Cu3Au hard magnetic ordered alloy phase and of forming magnetic particles for forming CuAu or Cu3Au magnetic particles, a plurality of solutions L1 and L2 for preparing the alloy particles are passed in a thin-plate laminar flow and diffused in the direction perpendicular to the flow direction at the contact interface of the solutions L1 and L2 in a mixing channel by using a microreactor, whereby a uniform mixing reaction is conducted in a short time.

Abstract: A magnetic recording medium including: a support; and a magnetic layer provided on the support, the magnetic layer containing a magnetic particle of a CuAu type or Cu3Au type ferromagnetic ordered alloy phase, wherein a content of boron in the magnetic particle is 0 to 0.9 at %, and a content of fluorine in the magnetic particle is 0.09 to 0.3 at %. Also provided is a method for producing a magnetic recording medium including: forming an alloy particle capable of forming a CuAu type or Cu3Au type ferromagnetic ordered alloy phase by a reduction method in which a reducing agent containing a boron atom is used; forming a layer including the alloy particle on a support; heat-treating the alloy particle at a temperature below a transformation temperature of the alloy particle; and annealing the alloy particle at a temperature which is not lower than the transformation temperature of the alloy particle.

Abstract: Disclosed is a method for extracting magnetically hard alloy nanoparticles, which comprises preparing a magnetic alloy nanoparticle dispersion by heating an organometallic compound containing a metal constituting a magnetically hard ordered alloy with a polyol compound having a boiling point of 150 to 350° C. and extracting magnetically hard alloy nanoparticles from the dispersion into a hydrophobic organic solvent in the presence of a hydrophobic surface modifying agent. The method can provide magnetically hard alloy nanoparticles showing almost no particle aggregation and markedly reduced load for drying.

Abstract: A method of producing a nanoparticle, the method comprising: a reducing step of adding an reverse micelle solution (II) obtained by mixing a water-insoluble organic solvent containing a surfactant with an aqueous metal salt solution to an reverse micelle solution (I) obtained by mixing a water-insoluble organic solvent containing a surfactant with an aqueous reducing agent solution, to carry out a reducing reaction; and a maturing step of raising the temperature of the reduced mixture to mature the reduced mixture is provided. A method of producing a plural type alloy nanoparticle, the method comprising producing a nanoparticle made of a plural type alloy through a reducing step of mixing one or more reverse micelle solutions (I) containing a metal salt with an reverse micelle solution (II) containing a reducing agent to carry out reducing treatment and a maturing step of carrying out maturing treatment is also provided.

Abstract: A method of producing a magnetic recording medium including the steps of preparing alloy particles capable of forming a CuAu type or Cu3Au type ferromagnetic order alloy phase, forming an alloy particle layer on a support using the alloy particles, oxidizing the alloy particles, and annealing the alloy particle layer in a magnetic field under a reducing atmosphere. Also disclosed is a magnetic recording medium produced by the method, that is, a magnetic recording medium including a magnetic layer which contains magnetic particles in a CuAu type or Cu3Au type ferromagnetic order alloy phase and which has a squareness ratio of 0.75 or higher.

Abstract: The present invention is a magnetic particle coated material comprising: a first support having a magnetic layer formed on one surface thereof; and a second support having a magnetic layer formed on one surface thereof, wherein the first support and the second support are attached to each other so that the other surfaces thereof on which the magnetic layers are not formed face each other, and the magnetic layers comprise magnetic particles having a CuAu type or Cu3Au type ferromagnetic ordered alloy phase.

Abstract: When a reaction liquid is passed through a gas-liquid separation pipe having a larger volume per unit length than the volume per unit length of a pipe, a headspace part into which gas can be released is formed above the gas-liquid separation pipe, and the byproduct gas generated by the reaction changes into bubbles, moves upward in the reaction liquid, and is continuously released from a gas-liquid interface into the headspace part. While the gas is removed in the gas-liquid separation pipe, the pressure of the headspace part is controlled so as to be constant by a pressure adjustment device.

Abstract: The producing unit for continuously producing metal microparticles formed of a multicomponent alloy accompanied by the generation of a byproduct gas through an early reaction of the formation of the metal particles comprises a first mixing unit for continuously supplying and mixing a plurality of solutions for conducting the early reaction, a second mixing unit for continuously supplying another solution to the reaction liquid containing the metal microparticles formed in the early reaction and for mixing the two solutions, to introduce dissimilar metal atoms into the crystal lattices of the metal microparticles, and a gas-liquid separation unit that is installed in a midway of the pipe which is made so as to have enough length to finish the early reaction, and which continuously passes the reaction liquid to the second mixing unit from the first mixing unit, and that continuously removes the byproduct gas generated with the proceeding of the early reaction.

Abstract: Magnetic particles including a ferromagnetic ordered alloy phase, wherein the surface of the magnetic particles is in contact with an organic substance. The invention also provides a method of producing magnetic particles having a ferromagnetic ordered alloy phase, including preparing alloy particles capable of forming the ferromagnetic ordered alloy phase, subjecting the alloy particles to an oxidation treatment, and then annealing the alloy particles in a solvent. A magnetic recording medium including a magnetic layer which contains the magnetic particles described above is also provided.

Abstract: The invention provides a method of producing a nanoparticle coated material, comprising a support and a nanoparticle layer formed on the support, wherein the nanoparticle layer contains nanoparticles comprising a CuAu type or Cu3Au type hard magnetic ordered alloy, and wherein the method satisfies at least one of the following conditions (i) and (ii): (i) the method comprises the steps of forming a shielding layer on the support before forming the nanoparticle layer; and (ii) a step of forming the nanoparticle layer comprises: the steps of applying a coating liquid containing nanoparticles capable of forming a CuAu type or Cu3Au type hard magnetic ordered alloy phase on the support to form a coating film; and irradiating laser light on the coating film.

Abstract: The present invention provides a magnetic recording medium sequentially having a magnetic layer, a protective layer and a lubricant layer, on a substrate, and the magnetic layer contains magnetic particles having ferromagnetic ordered alloys having a CuAu or Cu3Au crystal structure in a metal oxide matrix. The protective layer preferably contains at least one of carbon and silicon, and the lubricant layer preferably contains fluorine. The invention provides a magnetic recording medium having a high film strength with a magnetic layer having a high adhesion to the substrate, and exhibiting good electromagnetic conversion characteristics.

Abstract: Disclosed are alloy nano-particles having a fluctuation coefficient of particle size of 20% or less and a fluctuation coefficient of composition of 20% or less. The alloy nano-particles have a low transformation point and hardly aggregate and which can form a flat magnetic film having high coercive force.