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Method for producing ferrite sintered compact

A manufacturing method and ferrite technology, which is applied in the manufacture of inductors/transformers/magnets, electrical components, circuits, etc., can solve problems such as cracks in formed bodies, failure to form, and poor dehydration, and achieve high magnetic properties and reduce forming bad effect

Inactive Publication Date: 2008-11-26
TDK CORPARATION
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

That is, it has been confirmed that the average particle diameter is in the range of 0.04 to 0.06 μm. If the particles are too fine, the dehydration property will be deteriorated when molding in a wet magnetic field, and molding will not be possible, or cracks and cracks will occur on the molded body.
In addition, when using a ball mill or an attritor for fine pulverization, although the average particle size can be controlled in the above-mentioned range of 0.04 to 0.06 μm, particles with a particle size of less than 0.04 μm will actually be generated, and dehydration during wet molding Bad becomes noticeable

Method used

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  • Method for producing ferrite sintered compact
  • Method for producing ferrite sintered compact
  • Method for producing ferrite sintered compact

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0061] Hereinafter, the present invention will be described based on specific examples.

[0062] First, as a raw material powder, prepare Fe 2 O 3 Powder (primary particle size: 0.3μm), SrCO 3 Powder (primary particle size: 2μm) and BaCO 3 Powder (primary particle size: 0.05 μm). After these raw material powders were weighed, they were mixed and pulverized with a wet mill for 2 hours.

[0063] Next, pre-fire. Burn-in using a tubular furnace to the N 2 It was carried out under the condition of keeping in air atmosphere for 1 hour. In addition, the heating and holding temperature was set to 1300° C., and the rate of temperature rise until reaching the heating and holding temperature and the rate of temperature drop from the heating and holding temperature were set to 5° C. / min.

[0064] Next, coarse pulverization was performed by a vibratory ball mill, and the coarse pulverization by a vibratory ball mill was performed for 10 minutes with respect to 200 g of calcined bodi...

Embodiment 2

[0082] except as figure 2 Sintered bodies (sample Nos. 15 to 20) were produced under the same conditions as sample No. 8 except that the oxygen concentration during heat treatment was set as shown. In addition, the oxygen concentration during heat treatment is changed by mixing atmospheric gas and nitrogen gas.

[0083] For the obtained sintered body, the coercive force (HcJ), the remanence magnetic flux density (Br) and the squareness ratio (Hk / HcJ) were measured under the same conditions as in Example 1, and the X-ray diffractometer was used to identify each sintered body. phase state. The results are shown in figure 2 . For comparison, the magnetic properties and molar ratio of the W phase of sample No. 2 (oxygen concentration at the time of heat treatment: 20% by volume) heat-treated in the air are also shown in figure 2 .

[0084] like figure 2 As shown, as the oxygen concentration decreases, the ratio of the W phase increases, and higher magnetic properties can...

Embodiment 3

[0086] A sintered body was produced under the same conditions as in Example 1 except that the compounding ratio of the raw material powders was changed. The composition of the obtained sintered body was as follows.

[0087] Composition X:

[0088] In the above composition formula (1), Sr:Ba=0.60:0.40, a=1.6 and a+b=14.1

[0089] Composition Y:

[0090] In the above composition formula (1), Sr:Ba=0.70:0.30, a=2.0 and a+b=18.4

[0091] Composition Z:

[0092] In the above composition formula (1), Sr:Ba=1.00:0, a=1.7 and a+b=16.4

[0093] For the obtained sintered body, the coercive force (HcJ), residual magnetic flux density (Br) and squareness ratio (Hk / HcJ) were measured under the same conditions as in Example 1, and the phase of each sintered body was identified by an X-ray diffraction device. state. The results are shown in image 3 .

[0094] like image 3 As shown, it was confirmed that when the composition was changed within the range recommended by the present i...

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Abstract

There is provided a process for producing W-type ferrite having high magnetic properties by reducing compacting defects during wet compacting. The process comprising: a calcining step of obtaining a calcined body from a raw material compound; a first milling step of milling the calcined body to a predetermined size; a heat treatment step of holding fine powder obtained from the first milling step for a predetermined time in a predetermined temperature range in an atmosphere having an oxygen concentration of 10% by volume or less; a second milling step of milling the fine powder which has undergone the heat treatment step to a predetermined size; a step of wet compacting the fine powder which has undergone the second milling step in a magnetic field; and a sintering step of sintering the compacted body obtained by the wet compacting. Specifically, there is a provided a process for producing a ferrite sintered body having a main composition of the following formula (1): AFe 2+ a Fe 3+ b O 27 (1) wherein 1.5<=a<=2.1, 14<=a+b<=18.5, and A is at least one element selected from Sr, Ba and Pb.

Description

technical field [0001] The present invention relates to a method for producing a ferrite sintered body, and more particularly to a method for producing a W-shaped ferrite sintered body capable of obtaining high magnetic properties. Background technique [0002] W-type ferrite magnets that have the possibility of exhibiting magnetic properties exceeding those of M-type ferrite magnets are attracting attention. For example, it has been disclosed in Patent Document 1: In order to make the composition formula SrO·2(FeO)·n(Fe 2 o 3 ) of n is 7.2 ~ 7.7, in the mixed SrCO 3 and Fe 2 o 3 Add C (carbon) to the raw material powder, add CaO and SiO respectively after calcining 2 and C (carbon), crushed to an average particle size of 0.06 μm or less, formed in a magnetic field, and sintered in a non-oxidizing atmosphere, thereby providing W-type ferrite easily and inexpensively. [0003] Document 1 discloses that when the average particle size of finely pulverized powder before mo...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B35/26H01F1/11H01F41/02
CPCC04B2235/3418C04B2235/5445C04B2235/5409C04B35/6261C04B2235/605C04B35/2683C04B35/62675H01F41/0273H01F1/11C04B2235/3215C04B35/6268C04B2235/3217C04B2235/3208C04B2235/422C04B2235/3213C04B35/62625C04B35/6265C04B2235/83C04B2235/3241C04B2235/3272C04B35/26
Inventor 皆地良彦长冈淳一村濑琢伊藤升仓泽俊佑梅田秀信
Owner TDK CORPARATION
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