A dust core including soft magnetic particles having pure iron or an iron alloy and a grain boundary layer present between adjacent soft magnetic particles. The grain boundary layer has a main phase and a barrier phase. The main phase having a spinel-type ferrite of a metal element. The metal element serves as a divalent cation. The barrier phase having one or more of Cu, Sn, or Co. The dust core can be obtained by using a powder for magnetic cores including soft magnetic particles coated with a film in which a first ferrite and a second ferrite coexist. The barrier phase blocks the Fe diffusion from the soft magnetic particles and suppresses the deterioration of the main phase having the second ferrite responsible for the insulating property.

When an inductor component is adopted as an inductor for a DC-DC converter, high efficiency is achieved at a light load, and a large current is also handled. An inductor component includes a body containing metal magnetic powder containing an iron element, and an inductor provided in the body and having both ends exposed from the body. In a DC superposition characteristic curve of the inductor, a first steady region and a second steady region exist as a steady region, and a transition region exists between the first steady region and the second steady region.

An inductor includes an air-core coil assembled with a T-shaped core and a composite magnetic material and resin mixture embedding the T-shaped core and the air-core coil. The air-core coil has: a coil member having a coil axis and first and second sides opposite to each other; and first and second leads that are integrally connected to the coil member. The first and second leads respectively have: first and second bent members at the first side; first and second ends at the second side; and first and second bottom extensions respectively connected between the first and second bent members and the first and second ends. The first and second bent members extend in a first direction parallel to the coil axis, the first and second ends extend in a second direction parallel to the coil axis, and the first and second bottom extensions extend perpendicular to the coil axis.

A coil component includes a magnetic body portion that includes metallic particles and a resin material, a coil conductor that is embedded in the magnetic body portion, and a first outer electrode and a second outer electrode each of which is electrically connected to the coil conductor. At least a portion of an outer layer of the magnetic body portion forms an electrically conductive layer that includes a second metallic material having a specific resistance lower than a specific resistance of a first metallic material forming the metallic particles. The electrically conductive layer includes a first electrically conductive layer that is electrically connected to the first outer electrode and a second electrically conductive layer that is electrically connected to the second outer electrode. The first electrically conductive layer and the second electrically conductive layer are electrically isolated from each other.

A method for producing a coated magnetic powder in which particle surfaces of a soft magnetic powder are coated with a silicone resin includes a preparation step of preparing a silicone emulsion by mixing a silicone resin with water containing a surfactant and dispersing the silicone resin in the water, an application step of applying the silicone emulsion onto particle surfaces of a soft magnetic powder, and a drying step of drying the soft magnetic powder after the silicone emulsion is applied.

A manufacturing method of a coil component comprising the steps of: preparing a coil assembly body in which a coil is attached on a magnetic core and a mold body which is formed with a cavity portion in the inside thereof and which includes at least one opening portion, putting a viscous admixture including magnetic powders and thermosetting resin and the coil assembly body in the cavity portion, pushing the put-in viscous admixture in the mold body, and thermally-curing the pushed-in viscous admixture and forming a magnetic exterior body which covers the coil assembly body.

A coil device includes a coil portion, an element body, and a terminal electrode. The coil portion is formed by a wire wound in a coil shape. The element body contains the coil portion where a part of an outer circumference of a lead-out part of the coil portion is exposed as an exposed portion from a bottom surface of the element body and where the rest of the outer circumference of the lead-out part of the coil portion is embedded as an embedded portion in the element body. The terminal electrode is formed on the bottom surface of the element body and connected with the exposed portion. An embedded length of the outer circumference of the lead-out part in the embedded portion is larger than a substantially half of a full length of the outer circumference of the lead-out part.

A reactor includes: a reactor main body including a core formed of a powder magnetic core, a resin member covering the circumference of the core, and a coil wound around the outer circumference of the resin member; a casing which includes a bottom surface and a side wall standing upright therefrom, and which houses therein the reactor main body; and a filler molding portion formed of a cured filler, and fastening the reactor main body to the casing. The resin member is provided with a bottom opening provided in an end surface that faces the bottom surface of the casing and exposing the core, and a back-side opening provided in an end surface orthogonal to the winding direction of the coil and facing the side wall, and exposing the core. The back-side opening is provided with exposing portions which is not covered with the filler molding portion and is exposed.

A coil component is capable of suppressing occurrence of peeling at an interface between a coil conductor and resin in a magnetic portion due to heating during mounting. The coil component includes an element body that includes a coil conductor formed by winding a conductive wire coated with an insulating film, and a magnetic portion that contains metal magnetic particles and resin, and external electrodes that are electrically connected to exposed surfaces of extended portions of the coil conductor exposed on a surface of the element body, and are arranged on the surface of the element body. The metal magnetic particles are arranged in recesses formed in a surface of the conductive wire in the extended portions of the coil conductor.

A coil device 1 comprises a coil 10, a T-shaped core 20 including a columnar portion 21 around which the coil 10 is disposed and a flange 22 formed at a first end 21a of the columnar portion 21 in an axial direction thereof, and an exterior body 30 covering the coil 10 and the columnar portion 21 and made of an exterior material including magnetic particles and a resin. The core 20 is provided with a recess 40 including at least one of a first recess 41 or a second recess 42. The first recess 41 extends between the first end 21a and a second end 21b of the columnar portion 21 in the axial direction. The second recess 42 extends from an inner side towards an outer side of the flange 22.