Ferrite magnet

A ferrite magnet, ferrite technology, applied in the direction of magnetic objects, magnetic materials, iron compounds, etc., can solve the problems of high coercivity, high residual magnetic flux density, etc.

Active Publication Date: 2019-01-04
TDK CORPARATION
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] For example, Japanese Patent No. 4591684 (Patent Document 1) proposes a La-Co ferrite sintered magnet, which has a higher level than the existing M-type Sr ferrite or M-type Ba ferrite sintered magnet. The residual magnetic flux density and high coercive force

Method used

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Examples

Experimental program
Comparison scheme
Effect test

experiment example 1

[0126] [Experimental example 1] (Manufacture of ferrite sintered magnet)

[0127] First, iron oxide (Fe 2 o 3 ), strontium carbonate (SrCO 3 ), cobalt oxide (Co 3 o 4 ) and lanthanum hydroxide (La(OH) 3 ), and these raw materials were weighed so that the composition after calcination became the following composition formula.

[0128] Composition formula:

[0129] A 1-x R x (Fe 12-y Me y ) z

[0130] In the formula, A=Sr, R=La, Me=Co. In addition, x=0.80, y=0.35, and z=1.10.

[0131] Next, the weighed raw materials were mixed with a wet mill for 1 hour and pulverized to obtain a slurry (blending step). After drying the slurry, firing was carried out in air at a rate of temperature rise and fall of 15° C. / min and held at 1310° C. for 2 hours (calcination step).

[0132] The obtained calcined powder was coarsely pulverized for 10 minutes with a small rod vibrating mill. Iron oxide, strontium carbonate, cobalt oxide, and lanthanum hydroxide were added to this coars...

experiment example 2

[0142] [Experimental example 2] (Manufacture of ferrite sintered magnet)

[0143] In Experimental Example 2, except that the composition of the sintered body after firing was the composition formula in Table 2, and the content of Si was SiO2 relative to the sintered body after firing. 2 SiO is added to the coarsely ground material in conversion to 0.05% by mass 2 , and the sintered ferrite magnet was produced in the same manner as in Experimental Example 1 except that the sintering temperature was set to 1290°C.

[0144] In this Experimental Example 2, various ferrite sintered magnets of samples 2-1 to 2-8 were manufactured so as to greatly change the atomic ratio of La (x=0.51 to 0.91) in particular. Using the ferrite sintered magnets obtained in Experimental Example 2, their ratios of Br(G), HcJ(Oe), M phase, orthoferrite phase, and hematite phase were determined in the same manner as in Experimental Example 1. The obtained results are shown in Table 2.

[0145] [Table 2]...

experiment example 3

[0148] [Experimental Example 3] (Manufacture of Ferrite Sintered Magnet)

[0149] In Experimental Example 3, except that the composition of the fired sintered body was the composition formula in Table 3, and the content of Si was SiO 2 SiO is added to the coarsely ground material in conversion to 0.05% by mass 2 Except for this, the same procedure as in Experimental Example 1 was performed to produce a sintered ferrite magnet.

[0150] In this Experimental Example 3, various ferrite sintered magnets of samples 3-1 to 3-7 were manufactured so as to significantly change the atomic ratio of Co (y=0.20 to 0.61). Using the ferrite sintered magnets obtained in Experimental Example 3, their Br(G), HcJ(Oe), M phase, orthoferrite phase, hematite phase, and spinel were obtained in the same manner as in Experimental Example 1. Ratio of stone phase. Table 3 shows the obtained results.

[0151] [table 3]

[0152]

[0153] According to Table 3, when the ratio (y) of Co is 0.30 or mo...

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Abstract

The invention provides a ferrite magnet, which has a ferrite phase having a magnetoplumbite structure, and an orthoferrite phase, and which is characterized in that the composition ratios of the totalof each metal element A, R, Fe and Me is represented by expression (1) A1-xRx(Fe12-yMey)z, (in expression (1), A is at least one element selected from Sr, Ba, Ca and Pb; R is at least one element selected from the rare-earth elements (including Y) and Bi, and includes at least La, and Me is Co, or Co and Zn) and in that the content (m) of the orthoferrite phase is 0<m<28.0 in mol%. The inventionmakes it possible to achieve a ferrite magnet with increased Br.

Description

technical field [0001] The present invention relates to a ferrite magnet, and in particular to improvement of the residual magnetic flux density (Br) of the ferrite magnet. Background technique [0002] Hexagonal M-type (magnetoplumbite-type) Sr ferrite and Ba ferrite are known as materials for permanent magnets made of oxides. Ferrite magnets made of these ferrites are supplied as permanent magnets in the form of sintered magnets or bonded magnets. In recent years, along with miniaturization and high performance of electronic components, permanent magnets made of ferrite magnets are also required to be small and have high magnetic properties. [0003] As indicators of the magnetic properties of permanent magnets, remanence (Br) and coercive force (HcJ) are generally used, and permanent magnets with high values ​​of these indicators are evaluated as having high magnetic properties. Conventionally, from the viewpoint of improving Br and HcJ of permanent magnets, studies hav...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F1/11C01G49/00C04B35/26
CPCH01F1/11C01P2002/52C01P2006/42C01G49/0054C01G51/68C04B35/2633C04B2235/3213C04B2235/3215C04B2235/3208C04B2235/3296C04B2235/3224C04B2235/3225C04B2235/3298C04B2235/3227C04B2235/3275C04B2235/3284C04B2235/3418C04B2235/604C04B2235/605C04B35/6264C04B2235/5436C04B2235/5445C04B2235/5409C04B35/62615C04B35/62675C04B2235/6562C04B2235/6565C04B2235/606C04B35/26C04B2235/3274C04B2235/767C04B2235/83C04B35/62645H01F1/0315H01F1/10
Inventor 长冈淳一田口仁
Owner TDK CORPARATION
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