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Magnetic core comprising a bond magnet including magnetic powder whose particle's surface is coated with oxidation-resistant metal

A bonded magnet, anti-oxidation technology, applied in the direction of inductors with magnetic cores, magnetic cores/yokes, transformers/inductor cores, etc., can solve problems such as the quality of difficult magnetic cores

Inactive Publication Date: 2006-06-21
TOKIN CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, the need has become high level, and for choke coils and transformers, it is difficult to determine whether the core is good or bad by measuring the core temperature

Method used

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  • Magnetic core comprising a bond magnet including magnetic powder whose particle's surface is coated with oxidation-resistant metal
  • Magnetic core comprising a bond magnet including magnetic powder whose particle's surface is coated with oxidation-resistant metal
  • Magnetic core comprising a bond magnet including magnetic powder whose particle's surface is coated with oxidation-resistant metal

Examples

Experimental program
Comparison scheme
Effect test

no. 1 example

[0100] Now, the measurement of the magnetic flux change in the case of heat treatment and a comparative example are described. In a constant temperature chamber, a ferrite core of the Sm2Co17 series has a magnetic gap in which a bonded magnet is inserted, wherein the bonded magnet is composed of aggregated magnetic particles. Sm2Co17 magnetic powder, each magnetic particle has a surface covering various types of metals.

[0101] To make bonded magnets, Sm2Co17 magnetic powder (average particle size of 2.3μm) is mixed with 5vol% of each metal of zinc, aluminum, bismuth, gallium, indium, magnesium, lead, dysprosium, and tin, and then placed in an argon environment For 2 hours of heat treatment. Each heat treatment temperature for each metal is shown in Table 1.

[0102] Element

Heat treatment temperature (℃)

Zn

Al

Bi

Ga

In

Mg

Pb

Sb

Sn

475

725

325

100

225

700

375

700

300

[0103] Thereafter, each magneti...

no. 2 example

[0107] Now, measure and compare the characteristics of Sm-Fe-N bonded magnets, where different amounts of Zn cover the surface of each particle in the magnetic powder, measure the magnetic flux of the magnet before and after heat treatment and calculate its change. In addition, it is shown that the comparison of DC superposition characteristics and core loss characteristics is completed with each of those magnets placed in the magnetic gap of the magnetic circuit of the Mn-Zn series ferrite core.

[0108] The manufacture of the bonded magnet is completed as follows. The metal coating is completed by mixing Sm-Fe-N (average particle size of approximately 3 μm) magnetic powder with 3 vol% Zn, and performing a heat treatment in an Ar environment at a temperature of 425° C. for 2 hours. Thereafter, each magnetic powder was mixed with 12-nylon resin in an amount equivalent to 40 vol% of the total volume as a binder resin, and subjected to heat stirring and hot pressing without a magnet...

no. 3 example

[0128] Now, the figure shows a measurement and comparative example of the DC superimposition characteristic and core loss characteristic of the Mn-Zn series ferrite core with the magnetic gap inserted in the Sm-Co bonded magnet, in which the bonded magnet contains the surface There are various types of metal-coated magnetic particles aggregated to form magnetic powder.

[0129] To make bonded magnets, Sm-Co magnetic powder (average particle size of 3μm) is mixed with 5 vol% of each metal of zinc, aluminum, bismuth, gallium, indium, magnesium, lead, dysprosium, and tin, and then in argon Heat treatment for 2 hours. Each heat treatment temperature for each metal is shown in the above-mentioned Table 1 described in the above-mentioned first embodiment.

[0130] Thereafter, each magnetic powder was mixed with an epoxy resin in an amount equivalent to 40 vol% of the total amount as a binder resin, and thereafter formed with a die without a magnetic field. The ferrite core used in the e...

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Abstract

An inductance component of the present invention includes a magnetic core and an inductor connected to the magnetic core, the inductance component is processed by reflow soldering, the magnetic core has at least one magnetic gap in its magnetic circuit, the magnetic core including a magnetic bias magnet placed in the magnetic gap to provide magnetic bias from opposite ends of the magnetic gap to the magnetic core, characterized in that the magnetic bias magnet comprises a bonded magnet comprising a rare earth A magnetic powder and a binder resin, the rare earth magnetic powder having an intrinsic coercive force of 5 kOe or more, a Curie temperature of 300° C. or higher which is higher than the temperature in the reflow soldering process, and The average particle diameter is 2.5-50 μm, and the rare earth magnetic powder is composed of aggregated magnetic particles coated with a metal layer containing an anti-oxidation metal.

Description

[0001] This application is a divisional application with application number 01145653.1. The filing date of the parent case is November 28, 2001, the earlier application is JP00-361289, and the priority date is November 28, 2000. Technical field [0002] The present invention relates to magnetic cores (hereinafter referred to as "cores") used in inductance elements such as chokes and converters used in switching power supplies, and more particularly to magnetic cores containing permanent magnets for magnetic bias. Background technique [0003] In chokes and transformers used in switching power supplies, for example, a voltage is usually applied with an AC component superimposed on a DC component. Therefore, it is necessary for the magnetic cores used in those chokes and transformers to have good magnetic permeability and magnetic characteristics, so that the magnetic cores are not magnetically saturated due to the superimposed DC component. This magnetic characteristic is called "D...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F17/04H01F27/25C09K15/00H01F1/053H01F3/00H01F3/10H01F3/14H01F27/24H01F29/14
CPCH01F3/10H01F3/14H01F17/04H01F29/146H01F2003/103H01F27/25
Inventor 藤原照彦石井政义保志晴辉矶谷桂太松本初男伊藤透安保多美子
Owner TOKIN CORP