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Raw material alloy for R-T-B system sintered magnet, R-T-B system sintered magnet and production method thereof

A technology for sintered magnets and sintered bodies, which is used in the manufacture of inductors/transformers/magnets, magnetic materials, magnetic objects, etc. Effect of improving residual magnetic flux density and coercive force

Active Publication Date: 2009-12-16
TDK CORPARATION
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The crystalline structure of the R-T-B type sintered magnet obtained by molding and sintering the pulverized powder whose particle size distribution fluctuates in a magnetic field also becomes uneven, resulting in a problem that the magnetic properties, especially the coercive force, decrease, and the coercive force decreases. increased volatility

Method used

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  • Raw material alloy for R-T-B system sintered magnet, R-T-B system sintered magnet and production method thereof
  • Raw material alloy for R-T-B system sintered magnet, R-T-B system sintered magnet and production method thereof
  • Raw material alloy for R-T-B system sintered magnet, R-T-B system sintered magnet and production method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0057] Prepare high-purity Fe raw materials. The raw material alloy is produced by the strip continuous casting method, and the raw material alloy has a composition of 26.5wt%Nd-5.9wt%Dy-0.25wt%Al-0.5wt%Co-0.07wt%Cu-1wt%B-the balance is Fe. At this time, P (phosphorus) and S (sulfur) are appropriately added to produce raw material alloys with different amounts of P and S.

[0058] Next, hydrogen is absorbed in the raw alloy at room temperature, and then dehydrogenation is performed at 600° C. for 1 hour in an argon atmosphere to perform a hydrogen pulverization treatment. In the alloy subjected to the hydrogen pulverization treatment, 0.05 to 0.1% by weight of lubricants that contribute to improving pulverization and orientation during molding are mixed. The mixing of the lubricant can be carried out for about 5 to 30 minutes using a Nauta-mixer or the like, for example. Then, it is finely pulverized under certain conditions to obtain finely pulverized powder with an average parti...

Embodiment 2

[0066] The alloy composition is set to 28.6wt%Nd-0.2wt%Dy-0.05wt%Al-0.2wt%Co-0.03wt%Cu-1wt%B-0.08wt%Zr-the balance is Fe; (Recovery after pulverization) In each step of sintering (putting into the sintering furnace), the atmosphere of each step is controlled to a level where the oxygen concentration is less than 100 ppm; and the sintering temperature is set to 1070°C. In addition, In the same manner as in Example 1, a sintered body was produced. In this step, the particle size of the finely pulverized powder was measured in the same manner as in Example 1. In addition, the obtained sintered body was measured in the same manner as in Example 1. The result is Figure 5 Shown. In addition, Figure 6 Shows the relationship between the content of P and S in the raw alloy and D50, Figure 7 It shows the relationship between the content of P and S in the sintered body and the coercivity (iHc), and Figure 8 It shows the relationship between the content of P and S in the sintered body and...

Embodiment 3

[0070] The alloy composition is set to 27.2wt%Nd-4.9wt%Pr-0.2wt%Dy-0.25wt%Al-4.0wt%Co-0.3wt%Cu-1.3wt%B-0.25wt%Zr-the balance is Fe ; Further, in each process from the pulverization process (recovery after the pulverization process) to sintering (input into the sintering furnace), the atmosphere of each process is controlled to a level where the oxygen concentration is less than 100 ppm; and the sintering temperature is set Except that the temperature was 1020°C, a sintered body was produced in the same manner as in Example 1. The obtained sintered body was measured in the same manner as in Example 1. The result is Picture 9 Shown. In addition, Picture 10 Shows the relationship between the content of P and S in the raw alloy and D50, Picture 11 It shows the relationship between the content of P and S in the sintered body and the coercivity (iHc), and Picture 12 It shows the relationship between the content of P and S in the sintered body and the residual magnetic flux density (...

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Abstract

The purpose of the present invention is to make the crystal structure of the raw material alloy produced by the strip continuous casting method more uniform, thereby making the pulverized powder obtained from the raw material alloy finer and narrowing the range of particle size distribution, thereby obtaining high coercive force R-T-B type sintered magnets. The raw material alloy for the R-T-B type sintered magnet has crystal grains composed of R2T14B compound, and the content of P and / or S is 100-950 ppm. The preferred composition of the raw material alloy is: R: 25-35wt%, B: 0.5-4wt%, one or two of Al and Cu: 0.02-0.6wt%, Co: 5wt% or less, and the balance is basically Up is Fe. Wherein, R is one, two or more elements selected from rare earth elements, T is one, two or more elements selected from transition metal elements containing Fe, or Fe and Co element.

Description

Technical field [0001] The present invention relates to a raw material alloy for manufacturing R-T-B sintered magnets, R-T-B sintered magnets and a manufacturing method thereof. Here, R is one, two or more elements selected from rare earth elements, and T is one, two or more elements selected from transition metal elements containing Fe, or Fe and Co element. Background technique [0002] The basic manufacturing process of R-T-B sintered magnets includes the production of raw alloys, the pulverization of the obtained raw alloys, the molding, sintering and aging of the pulverized alloy powder in a magnetic field. In order to improve the magnetic properties of R-T-B based sintered magnets, various manufacturing processes have been tried. For example, in order to reduce the oxygen content in the sintered body, in the manufacturing process, the oxygen content in the atmosphere is reduced; multiple (typically two) raw material alloys are used. Among them, as described below, the subje...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01F1/053H01F1/057C22C38/00H01F41/02C22C33/00
Inventor 榎户靖石坂力西泽刚一
Owner TDK CORPARATION
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