Abstract: A magnetic metal particle aggregate includes a plurality of magnetic metal particles including at least one magnetic metal selected from a first group consisting of Fe, Co, and Ni. The plurality of magnetic metal particles are partly bound with each other, and an average particle diameter of the plurality of magnetic metal particles is 10 nm or more and 50 nm or less. The magnetic metal particle aggregate has an average particle diameter of 15 nm or more and 200 nm or less.

Abstract: A magnetic material is disclosed, which includes magnetic particles containing at least one magnetic metal selected from the group including Fe, Co and Ni, and at least one non-magnetic metal selected from Mg, Al, Si, Ca, Zr, Ti, Hf, Zn, Mn, rare earth elements, Ba and Sr; a first coating layer of a first oxide that covers at least a portion of the magnetic particles; oxide particles of a second oxide that is present between the magnetic particles and constitutes an eutectic reaction system with the first oxide; and an oxide phase that is present between the magnetic particles and has an eutectic structure of the first oxide and the second oxide.

Abstract: A radio wave absorber according to an embodiment includes a plurality of metal particles including at least one kind of magnetic metal element selected from a first group of Fe, Co, and Ni. Each of the plurality of metal particles has a linear expansion coefficient of 1×10?6/K or more and 10×10?6/K or less. The radio wave absorber also includes a binding layer binding the metal particles and having higher resistance than the metal particle, wherein a volume filling ratio of the metal particles in the radio wave absorber is 10% or more and 50% or less.

Abstract: Provided is a magnetic material which includes a plurality of magnetic metal particles having a rate of change in the lattice constant of ±1% or less with respect to the lattice constant obtained after a heat treatment at 1000° C., a plurality of insulating coating layers insulating and covering at least a portion of the magnetic metal particles, and an insulating resin disposed around the magnetic metal particles and the insulating coating layers. The insulating coating layers are in contact with one another.

Abstract: Provided is a method for producing a magnetic material, the method including preparing a mixed phase material including a first magnetic metal phase formed from a magnetic metal and a second phase containing any one of oxygen (O), nitrogen (N) or carbon (C) and a non-magnetic metal, conducting a first heat treatment to the mixed phase material at a temperature of from 50° C. to 800° C., forming nanoparticle aggregates including a plurality of magnetic metal nanoparticles formed from the first magnetic metal phase and the second phase, and conducting a second heat treatment to the nanoparticle aggregates at a temperature of from 50° C. to 800° C. The nanoparticle aggregates are formed by decreasing an average particle size and a particle size distribution variation of the first magnetic metal phase after the first heat treatment.

Abstract: Provided is a magnetic material including a plurality of flat particles containing a magnetic metal, and a matrix phase disposed around the flat particles and having higher electrical resistance than the flat particles. In a cross-section of the magnetic material, the aspect ratio of the flat particles is 10 or higher. If the major axis of one of the flat particles is designated as L and the length of a straight line connecting two endpoints of the flat particle is designated as W, the proportion of the area surrounded by the outer peripheries of parts in which flat particles satisfying the relationship: W?0.95×L are continuously laminated, is 10% or more of the cross-section.

Abstract: Provided is a method for producing a magnetic material. The method includes preparing magnetic metal particles containing at least one magnetic metal selected from a first group consisting of Fe, Co and Ni, and at least one non-magnetic metal selected from a second group consisting of Mg, Al, Si, Ca, Zr, Ti, Hf, Zn, Mn, Ba, Sr, Cr, Mo, Ag, Ga, Sc, V, Y, Nb, Pb, Cu, In, Sn and rare earth elements, pulverizing and reaggregating the magnetic metal particles, and thereby forming composite particles containing a magnetic metal phase and an interstitial phase, and heat-treating the composite particles at a temperature of from 50° C. to 800° C. The particle size distribution of the magnetic metal particles in the preparing magnetic metal particles has two or more peaks.

Abstract: A radiowave absorber of an embodiment includes: core-shell particles each including: a core portion that contains at least one magnetic metal element selected from a first group including Fe, Co, and Ni, and at least one metal element selected from a second group including Mg, Al, Si, Ca, Zr, Ti, Hf, Zn, Mn, rare-earth elements, Ba, and Sr; and a shell layer that coats at least part of the core portion, and includes an oxide layer containing at least one metal element selected from the second group and contained in the core portion; and a binding layer that binds the core-shell particles, and has a higher resistance than the resistance of the core-shell particles. The volume filling rate of the core-shell particles in the radiowave absorber is not lower than 10% and not higher than 55%.

Abstract: A radio wave absorber according to an embodiment includes a plurality of metal particles including at least one kind of magnetic metal element selected from a first group of Fe, Co, and Ni. Each of the plurality of metal particles has a linear expansion coefficient of 1×10?6/K or more and 10×10?6/K or less. The radio wave absorber also includes a binding layer binding the metal particles and having higher resistance than the metal particle, wherein a volume filling ratio of the metal particles in the radio wave absorber is 10% or more and 50% or less.

Abstract: An exhaust gas recirculation (EGR) device includes an EGR passage, a cooling medium circuit, an EGR cooler, and an intercooler. A part of exhaust gas flowing through an exhaust passage of an internal combustion engine is recirculated as EGR gas into an intake passage of the engine through the EGR passage. A cooling medium flows through the cooling medium circuit. The EGR cooler performs a heat exchange between EGR gas flowing through the EGR passage and the cooling medium flowing through the cooling medium circuit so as to cool EGR gas. The intercooler is disposed at the intake passage on a downstream side of a merging part between the intake passage and the EGR passage in a flow direction of intake air, and performs a heat exchange between intake air including EGR gas and flowing through the intake passage, and the cooling medium flowing through the cooling medium circuit so as to cool intake air.

Abstract: A magnetic metal particle aggregate includes a plurality of magnetic metal particles including at least one magnetic metal selected from a first group consisting of Fe, Co, and Ni. The plurality of magnetic metal particles are partly bound with each other, and an average particle diameter of the plurality of magnetic metal particles is 10 nm or more and 50 nm or less. The magnetic metal particle aggregate has an average particle diameter of 15 nm or more and 200 nm or less.

Abstract: A magnetic material of an embodiment includes a plurality of magnetic metal particles, a plurality of columnar oxide particles, and a matrix phase. Each of the plurality of the magnetic metal particles includes at least one element selected from a first group consisting of Fe, Co, and Ni. Each of the plurality of the columnar oxide particles includes at least one oxide selected from a second group consisting of Al2O3, SiO2, and TiO2 and is in contact with the magnetic metal particle. The matrix phase has a higher electrical resistance than each of the plurality of the magnetic metal particles. The matrix phase surrounds the plurality of magnetic metal particles and the plurality of columnar oxide particles. In the magnetic material, 5 nm?l?L and 0.002?L/R?0.4 hold, where R represents a particle size of the magnetic metal particle, L represents a length of the columnar oxide particle, and l represents a breadth of the columnar oxide particle.

Abstract: A core-shell magnetic material having an excellent characteristic in a high-frequency band, in particular a GHz-band and a high environment resistance is provided. The core-shell magnetic material includes: a magnetic member in which plural core-shell magnetic particles are bound by a binder made of a first resin; and a coating layer that is made of a second resin different from the first resin, a surface of the magnetic member being covered with the coating layer. The core-shell magnetic material is characterized in that the core-shell magnetic particle includes a magnetic metallic particle and a covering layer that covers at least part of a surface of the magnetic metallic particle, the magnetic metallic particle contains at least one magnetic metal selected from a group consisting of Fe, Co, and Ni, and the covering layer is made of an oxide, a nitride, or a carbide that contains at least one magnetic metal.

Abstract: A magnetic material of an embodiment includes: first magnetic particles that contain at least one magnetic metal selected from the group including Fe, Co, and Ni, are 1 ?m or greater in particle size, and are 5 to 50 ?m in average particle size; second magnetic particles that contain at least one magnetic metal selected from the group including Fe, Co, and Ni, are smaller than 1 ?m in particle size, and are 5 to 50 nm in average particle size; and an intermediate phase that exists between the first magnetic particles and the second magnetic particles.

Abstract: A magnetic material of an embodiment includes a plurality of magnetic metal particles and a matrix phase. Each of the plurality of magnetic metal particles includes a magnetic metal and a first compound included in the magnetic metal. The magnetic metal includes at least one element selected from Fe, Co, and Ni. The first compound is an oxide, a nitride, or a carbide including at least one element selected from Fe, Al, Si, B, Mg, Ca, Zr, Ti, Hf, Zn, Mn, Nb, Ta, Mo, Cr, Cu, W, a rare-earth element, Ba, and Sr. The matrix phase fills a space between the plurality of magnetic metal particles and has higher electric resistance than the plurality of magnetic metal particles.

Abstract: A magnetic material is disclosed, which includes magnetic particles containing at least one magnetic metal selected from the group including Fe, Co and Ni, and at least one non-magnetic metal selected from Mg, Al, Si, Ca, Zr, Ti, Hf, Zn, Mn, rare earth elements, Ba and Sr; a first coating layer of a first oxide that covers at least a portion of the magnetic particles; oxide particles of a second oxide that is present between the magnetic particles and constitutes an eutectic reaction system with the first oxide; and an oxide phase that is present between the magnetic particles and has an eutectic structure of the first oxide and the second oxide.

Abstract: A magnetic material is disclosed, which includes magnetic particles containing at least one magnetic metal selected from the group including Fe, Co and Ni, and at least one non-magnetic metal selected from Mg, Al, Si, Ca, Zr, Ti, Hf, Zn, Mn, rare earth elements, Ba and Sr; a first coating layer of a first oxide that covers at least a portion of the magnetic particles; oxide particles of a second oxide that is present between the magnetic particles and constitutes an eutectic reaction system with the first oxide; and an oxide phase that is present between the magnetic particles and has an eutectic structure of the first oxide and the second oxide.

Abstract: A radiowave absorber of an embodiment includes: core-shell particles each including: a core portion that contains at least one magnetic metal element selected from a first group including Fe, Co, and Ni, and at least one metal element selected from a second group including Mg, Al, Si, Ca, Zr, Ti, Hf, Zn, Mn, rare-earth elements, Ba, and Sr; and a shell layer that coats at least part of the core portion, and includes an oxide layer containing at least one metal element selected from the second group and contained in the core portion; and a binding layer that binds the core-shell particles, and has a higher resistance than the resistance of the core-shell particles. The volume filling rate of the core-shell particles in the radiowave absorber is not lower than 10% and not higher than 55%.

Abstract: A magnetic material of an embodiment includes: first magnetic particles that contain at least one magnetic metal selected from the group including Fe, Co, and Ni, are 1 ?m or greater in particle size, and are 5 to 50 ?m in average particle size; second magnetic particles that contain at least one magnetic metal selected from the group including Fe, Co, and Ni, are smaller than 1 ?m in particle size, and are 5 to 50 nm in average particle size; and an intermediate phase that exists between the first magnetic particles and the second magnetic particles.

Abstract: A magnetic material is disclosed, which includes magnetic particles containing at least one magnetic metal selected from the group including Fe, Co and Ni, and at least one non-magnetic metal selected from Mg, Al, Si, Ca, Zr, Ti, Hf, Zn, Mn, rare earth elements, Ba and Sr; a first coating layer of a first oxide that covers at least a portion of the magnetic particles; oxide particles of a second oxide that is present between the magnetic particles and constitutes an eutectic reaction system with the first oxide; and an oxide phase that is present between the magnetic particles and has an eutectic structure of the first oxide and the second oxide.