Abstract: There is provided a magnetic core having both high strength and high resistivity, a coil component produced with such a magnetic core, and a magnetic core manufacturing method capable of easily manufacturing a magnetic core with high strength and high resistivity. The present invention provides a method for manufacturing a magnetic core having a structure including dispersed Fe-based soft magnetic alloy particles, the method including: a first step including mixing a first Fe-based soft magnetic alloy powder containing Al and Cr, a second Fe-based soft magnetic alloy powder containing Cr and Si, and a binder; a second step including pressing the mixture obtained after the first step; and a third step including heat-treating the compact obtained after the second step, wherein the heat treatment forms an oxide layer on the surface of Fe-based soft magnetic alloy particles and bonds the Fe-based soft magnetic alloy particles together through the oxide layer.

Abstract: An object of the invention is to provide a method that is for manufacturing a powder magnetic core through simple compression molding and capable of manufacturing a complicatedly shaped powder magnetic core with reliable high strength and insulating properties. The invention is directed to a method for manufacturing a powder magnetic core with a metallic soft magnetic material powder, the method including: a first step including mixing a soft magnetic material powder and a binder; a second step including compression molding the mixture obtained after the first step; a third step including performing at least one of grinding and cutting on the compact obtained after the second step; and a fourth step including heat-treating the compact after the third step, wherein in the fourth step, the compact is heat-treated so that an oxide layer containing an element constituting the soft magnetic material powder is formed on the surface of the soft magnetic material powder.

Abstract: A magnetic core includes alloy phases 20 each made of Fe-based soft magnetic alloy grains including M1 (wherein M1 represents both elements of Al and Cr), Si, and R (wherein R represents at least one element selected from the group consisting of Y, Zr, Nb, La, Hf and Ta), and has a structure in which the alloy phases 20 are connected to each other through a grain boundary phase 30. In the grain boundary phase 30, an oxide region is produced. The oxide region includes Fe, M1, Si and R and further includes Al in a larger proportion by mass than the alloy phases 20.

Abstract: A magnetic core has a structure in which alloy phases 20 each including Fe, Al, Cr and Si are dispersed and any adjacent two of the alloy phases 20 are connected to each other through a grain boundary phase 30. In this grain boundary phase 30, an oxide region is produced which includes Fe, Al, Cr and Si, and includes Al in a larger proportion by mass than the alloy phases 20. This magnetic core includes Al in a proportion of 3 to 10% both inclusive by mass, Cr in a proportion of 3 to 10% both inclusive by mass, and Si in a proportion more than 1% and 4% or less by mass provided that the sum of the quantities of Fe, Al, Cr and Si is regarded as being 100% by mass; and includes Fe and inevitable impurities as the balance of the core.

Abstract: A magnetic core has a structure in which Fe-based soft magnetic alloy particles are connected via a grain boundary. The Fe-based soft magnetic alloy particles contain Al, Cr and Si. An oxide layer containing at least Fe, Al, Cr and Si is formed at the grain boundary that connects the neighboring Fe-based soft magnetic alloy particles. The oxide layer contains an amount of Al larger than that in Fe-based soft magnetic alloy particles, and includes a first region in which the ratio of Al is higher than the ratio of each of Fe, Cr and Si to the sum of Fe, Cr, Al and Si, and a second region in which the ratio of Fe is higher than the ratio of each of Al, Cr and Si to the sum of Fe, Cr, Al and Si. The first region is on the Fe-based soft magnetic alloy particle side.

Abstract: A primary ultrafine-crystalline alloy having a composition represented by the general formula: Fe100-x-y-zAxByXz, wherein A is Cu and/or Au, X is at least one element selected from the group consisting of Si, S, C, P, Al, Ge, Ga and Be, and x, y and z are numbers (by atomic %) meeting the conditions of 0<x?5, 10?y?22, 0?z?10, and x+y+z?25, and a structure in which 5-30% by volume of primary ultrafine crystal grains having an average particle size of 30 nm or less are dispersed in an amorphous matrix; its differential scanning calorimetry (DSC) curve having a first exothermic peak and a second exothermic peak lower than the first exothermic peak between a crystallization initiation temperature TX1 and a compound precipitation temperature TX3; and a ratio of the heat quantity of the second exothermic peak to the total heat quantity of the first and second exothermic peaks being 3% or less.

Abstract: A method for manufacturing a powder magnetic core using a soft magnetic material powder, wherein the method has: a first step of mixing the soft magnetic material powder with a binder, a second step of subjecting a mixture obtained through the first step to pressure forming, and a third step of subjecting a formed body obtained through the second step to heat treatment. The soft magnetic material powder is an Fe—Cr—Al based alloy powder comprising Fe, Cr and Al. An oxide layer is formed on a surface of the soft magnetic material powder by the heat treatment. The oxide layer has a higher ratio by mass of Al to the sum of Fe, Cr and Al than an alloy phase inside the powder.

Abstract: A primary ultrafine-crystalline alloy having a composition represented by the general formula: Fe100-x-y-zAxByXz, wherein A is Cu and/or Au, X is at least one element selected from the group consisting of Si, S, C, P, Al, Ge, Ga and Be, and x, y and z are numbers (by atomic %) meeting the conditions of 0<x?5, 10?y?22, 0?z?10, and x+y+z?25, and a structure in which 5-30% by volume of primary ultrafine crystal grains having an average particle size of 30 nm or less are dispersed in an amorphous matrix; its differential scanning calorimetry (DSC) curve having a first exothermic peak and a second exothermic peak lower than the first exothermic peak between a crystallization initiation temperature TX1 and a compound precipitation temperature TX3; and a ratio of the heat quantity of the second exothermic peak to the total heat quantity of the first and second exothermic peaks being 3% or less.

Abstract: A process for producing an immobilized enzyme composition comprises simultaneously reacting a non-proteolytic enzyme and a water soluble-multifunctional reagent with a non-hardened granular gelatin in an aqueous medium wherein the reacting is carried out in the presence of a water-soluble protein polymer compound in an amount of from 0.01 to 2 parts by weight relative to one part of the non-proteolytic enzyme. The non-proteolytic enzyme forms a uniform film on the surface of the granular gelatin and the bond between the non-proteolytic enzyme and the granular gelatin is strengthened by the water soluble protein polymer.