A soft-magnetic powder coated with a silicon-based coating, wherein the silicon-based coating comprises at least one fluorine containing composition of formula (I), Si.sub.1-0.75c MCO.sub.2-0.5c F.sub.d (I), wherein c is in the range of 0.01 to 0.5, d is in the range of 0.04 to 2, and M is B or Al.

The present invention relates into a device and method for controlling distribution of superparamagnetic nanoparticles (NPs) in a microfluidic chamber. By applying a strong magnetic field, localization of the NPs to inter-pillar spaces between soft magnetic coated micropillars is demonstrated, even with a modest fluid flow across the inter-pillar space. Flow splitting techniques are also provided to force particles to reliably interact with the NPs, specifically by using a Brevais lattice with a primative vector of 1°-15° with respect to flow direction. The pillars may have non-circular cross-sectional shape and be arranged to direct NP clouds more effectively. An array of the pillars has multiple axes for rotating NP cloud distributions in multiple orientations, allowing for a rotating magnetic field to move the NP cloud for mixing a fluid that is otherwise stationary.

The present invention relates into a device and method for controlling distribution of superparamagnetic nanoparticles (NPs) in a microfluidic chamber. By applying a strong magnetic field, localization of the NPs to inter-pillar spaces between soft magnetic coated micropillars is demonstrated, even with a modest fluid flow across the inter-pillar space. Flow splitting techniques are also provided to force particles to reliably interact with the NPs, specifically by using a Brevais lattice with a primative vector of 1°-15° with respect to flow direction. The pillars may have non-circular cross-sectional shape and be arranged to direct NP clouds more effectively. An array of the pillars has multiple axes for rotating NP cloud distributions in multiple orientations, allowing for a rotating magnetic field to move the NP cloud for mixing a fluid that is otherwise stationary.

A compact is provided. When the compact is used for a magnetic core, a magnetic path cross section has a cross-sectional perimeter of more than 20 mm, and at least part of a surface of the compact is covered with an iron-based oxide film having an average thickness of 0.5 μm or more and 10.0 μm or less. Letting the proportion of the surface area of the compact to the volume of the compact be surface area/volume, the content of Fe.sub.3O.sub.4 present in the iron-based oxide film with respect to 100% by volume of the compact satisfies any one of (1) to (3): (1) less than 0.085% by volume when the (surface area/volume) is 0.40 mm.sup.−1 or less, (2) 0.12% or less by volume when the (surface area/volume) is more than 0.40 mm.sup.−1 and 0.60 mm.sup.−1 or less, and (3) 0.15% or less by volume when the (surface area/volume) is more than 0.60 mm.sup.−1.

A compact is provided. When the compact is used for a magnetic core, a magnetic path cross section has a cross-sectional perimeter of more than 20 mm, and at least part of a surface of the compact is covered with an iron-based oxide film having an average thickness of 0.5 μm or more and 10.0 μm or less. Letting the proportion of the surface area of the compact to the volume of the compact be surface area/volume, the content of Fe.sub.3O.sub.4 present in the iron-based oxide film with respect to 100% by volume of the compact satisfies any one of (1) to (3): (1) less than 0.085% by volume when the (surface area/volume) is 0.40 mm.sup.−1 or less, (2) 0.12% or less by volume when the (surface area/volume) is more than 0.40 mm.sup.−1 and 0.60 mm.sup.−1 or less, and (3) 0.15% or less by volume when the (surface area/volume) is more than 0.60 mm.sup.−1.

A method of producing an atomized powder includes: an atomizing step of forming magnetic alloy particles from a molten metal by an atomizing method, to obtain a slurry in which the magnetic alloy particles are dispersed in an aqueous dispersion medium; a slurry concentration step of causing magnetic separation means to separate the magnetic alloy particles from the slurry to form a concentrated slurry having the magnetic alloy particles of more than 80% by mass, the magnetic separation means using a rotary drum including a magnetic circuit part fixedly disposed at a position where at least a part of the magnetic circuit part is immersed in the slurry and an outer sleeve capable of rotating outside the magnetic circuit part; and a drying step of causing drying means using an air flow dryer to dry the concentrated slurry to form a magnetic alloy powder.

Soft magnetic alloy powder includes plurality of soft magnetic alloy particles of soft magnetic alloy represented by composition formula (Fe.sub.(1−(α+β))X1.sub.αX2.sub.β).sub.(1−(a+b+c++e+f+g))M.sub.aB.sub.bP.sub.cSi.sub.dC.sub.eS.sub.fTi.sub.g, wherein X1 represents Co and/or Ni; X2 represents at least one selected from group consisting of Al, Mn, Ag, Zn, Sn, As, Sb, Cu, Cr, Bi, N, O, and rare earth elements; M represents at least one selected from group consisting of Nb, Hf, Zr, Ta, Mo, W, and V; 0.020≤a≤0.14, 0.020<b≤0.20, 0<c≤0.15, 0≤d≤0.060, 0≤e≤0.040, 0≤f≤0.010, 0≤g≤0.0010, α≥0, β≥0, and 0≤α+β≤0.50 are satisfied, wherein at least one of f and g is more than 0; and wherein soft magnetic alloy has a nano-heterostructure with initial fine crystals present in an amorphous substance; and surface of each of the soft magnetic alloy particles is covered with a coating portion including a compound of at least one element selected from group consisting of P, Si, Bi, and Zn.

Soft magnetic alloy powder includes plurality of soft magnetic alloy particles of soft magnetic alloy represented by composition formula (Fe.sub.(1−(α+β))X1.sub.αX2.sub.β).sub.(1−(a+b+c++e+f+g))M.sub.aB.sub.bP.sub.cSi.sub.dC.sub.eS.sub.fTi.sub.g, wherein X1 represents Co and/or Ni; X2 represents at least one selected from group consisting of Al, Mn, Ag, Zn, Sn, As, Sb, Cu, Cr, Bi, N, O, and rare earth elements; M represents at least one selected from group consisting of Nb, Hf, Zr, Ta, Mo, W, and V; 0.020≤a≤0.14, 0.020<b≤0.20, 0<c≤0.15, 0≤d≤0.060, 0≤e≤0.040, 0≤f≤0.010, 0≤g≤0.0010, α≥0, β≥0, and 0≤α+β≤0.50 are satisfied, wherein at least one of f and g is more than 0; and wherein soft magnetic alloy has a nano-heterostructure with initial fine crystals present in an amorphous substance; and surface of each of the soft magnetic alloy particles is covered with a coating portion including a compound of at least one element selected from group consisting of P, Si, Bi, and Zn.

A metal magnetic particle provided with an oxide layer on a surface of an alloy particle containing Fe and Si, wherein the oxide layer has a first oxide layer, a second oxide layer, and a third oxide layer from the alloy particle side. Also, in line analysis of element content by using a scanning transmission electron microscope-energy dispersive X-ray spectroscopy, the first oxide layer is a layer where Si content takes a local maximum value, the second oxide layer is a layer where Fe content takes a local maximum value, and the third oxide layer is a layer where Si content takes a local maximum value.

The object of the present invention is to provide a fluidizing particle capable of improving a fluidity of a magnetic particle for a magnetic core and capable of improving a permeability of the magnetic core. The fluidizing particle includes a particle body having a magnetic property and a coating layer including a silicon compound covering the particle body, wherein a particle size of the fluidizing particle is 10 to 40 nm, and a circularity of the fluidizing particle is 0.55 or more.