A magnetic powder contains a magnetic metal particle comprising iron (Fe) and an insulating coating layer disposed on a surface of the magnetic metal particle and comprising tin (Sn), phosphorous (P) and oxygen (O), and a coil component contains such a magnetic powder.

A coil component includes a body having a molded portion and a cover portion disposed on one surface of the molded portion, and including magnetic metal powder; a winding coil disposed between one surface of the molded portion and the cover portion and embedded in the body, and including a coating layer surrounding a surface of each of a plurality of turns; and a first protective film disposed between the one surface of the molded portion and the cover portion and between at least a portion of the surface of the winding coil and the cover portion.

A coil component includes a base body containing metal magnetic particles and a binder binding together the metal magnetic particles and having a first surface extending along a coil axis and a second surface opposing the first surface, a first external electrode provided on the base body, a second external electrode provided on the base body, and a coil conductor electrically connected to the first and second external electrodes and extending around the coil axis. In one embodiment, the coil conductor has a winding portion, the winding portion has first conductor portions and one or more second conductor portions smaller in number than the first conductor portions, and the first and second conductor portions alternate with and are connected to each other, and a distance between the first conductor portions and the first surface is less than a distance between the second conductor portions and the second surface.

A forming method of a composite magnetic sheet. The forming method comprises a preparing step, a forming step and a heat-treating step. In the preparing step, magnetic slurry is prepared by mixing at least a soft magnetic powder having a flat shape, a first resin having a solid component and a second resin having a solid component, weight loss of the solid component of the first resin being 4.0% or less at 220° C., weight loss of the solid component of the second resin being 5.0% or more at 220° C. In the forming step, the magnetic slurry is formed into an intermediate body having a sheet-like shape. In the heat-treating step, the intermediate body is heat-treated at a heat-treatment temperature between 220° C. and 400° C. (both inclusive).

The present invention provides a magnetic multilayer pigment flake and a magnetic coating composition that are relatively safe for human health and the environment. The pigment flake includes one or more magnetic layers of a magnetic alloy and one or more dielectric layers of a dielectric material. The magnetic alloy is an iron-chromium alloy or an iron-chromium-aluminum alloy, having a substantially nickel-free composition. The coating composition includes a plurality of the pigment flakes disposed in a binder medium.

A dust core includes large particles having an average particle size of 8-15 μm, medium particles having an average particle size of 1-5 μm, and small particles having an average particle size of 300-900 nm when a cross section thereof is observed. An area ratio occupied by the large particles is 50% to 90%, an area ratio occupied by the medium particles is 0% to 30%, and an area ratio occupied by the small particles is 5% to 30%, when a total area ratio occupied by the large particles, the medium particles and the small particles is 100% in the cross section. Vickers hardness (Hv) of the large particles, the medium particles and the small particles is 150-600 respectively. The small particles are alloy powder containing Fe and at least Si or N. The dust core may be included in an inductor element.

A multilayer coil component includes an element body including a plurality of metal magnetic particles, and a plurality of coil conductors. The plurality of coil conductors is disposed in the element body. The plurality of coil conductors is separated from each other in a predetermined direction and electrically connected to each other. The plurality of coil conductors includes one pair of side surfaces opposing each other in the predetermined direction. Surface roughness of the one pair of side surfaces is less than 40% of an average particle size of the plurality of metal magnetic particles.

A ferromagnetic-polymer composite material comprises a polymer and a plurality of ferromagnetic film platelets disposed in the polymer. Each ferromagnetic film platelet comprises first and second insulator layers and a ferromagnetic layer disposed between the first and second insulator layers. The ferromagnetic layer can be magnetically anisotropic in which a hard axis of magnetization is aligned parallel to a plane that passes through and parallel to an interface between the first insulator layer and the ferromagnetic layer. The easy and/or hard axes of magnetization in the ferromagnetic film platelets can be aligned. An inductor can have a core formed of the ferromagnetic-polymer composite material.

A soft magnetic composite comprising an iron or iron alloy ferromagnetic material coated with an oxide material. An interface between the ferromagnetic material and the layer of oxide contains antiphase domain boundaries. Two processes for producing a soft magnetic composite are also provided. One process includes depositing an oxide layer onto an iron or iron alloy ferromagnetic material by molecular beam epitaxy at a partial oxygen pressure of from 1×10.sup.−5 Torr to 1×10.sup.−7 Torr to form a coated composite. The other process includes milling an iron or iron alloy ferromagnetic material powder and an oxide powder by high-energy milling to form a mixture; compacting the mixture and curing in an inert gas atmosphere at a temperature from 500° C. to 1200° C. to form a soft magnetic composite.

A soft magnetic composite comprising an iron or iron alloy ferromagnetic material coated with an oxide material. An interface between the ferromagnetic material and the layer of oxide contains antiphase domain boundaries. Two processes for producing a soft magnetic composite are also provided. One process includes depositing an oxide layer onto an iron or iron alloy ferromagnetic material by molecular beam epitaxy at a partial oxygen pressure of from 1×10.sup.−5 Torr to 1×10.sup.−7 Torr to form a coated composite. The other process includes milling an iron or iron alloy ferromagnetic material powder and an oxide powder by high-energy milling to form a mixture; compacting the mixture and curing in an inert gas atmosphere at a temperature from 500° C. to 1200° C. to form a soft magnetic composite.