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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 of sintered magnets and sintered bodies, which is applied in the manufacture of inductors/transformers/magnets, magnetic materials, magnetic objects, etc., can solve problems such as increased coercive force fluctuations, decreased coercive force of magnetic properties, and uneven crystal structure, etc., to achieve high Effects of Remanence Flux Density and Coercive Force Improvement

Active Publication Date: 2006-08-02
TDK CORPARATION
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  • 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
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Effect test

Embodiment 1

[0057]Prepare high-purity Fe raw materials. The strip continuous casting method is used to produce the raw alloy, which has a composition of 26.5wt% Nd-5.9wt% Dy-0.25wt% Al-0.5wt% Co-0.07% 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, the raw material alloy was allowed to absorb hydrogen at room temperature, and then dehydrogenated in an argon atmosphere at 600° C. for 1 hour to perform a hydrogen pulverization treatment. In the alloy subjected to the hydrogen pulverization treatment, 0.05 to 0.1 wt % of a lubricant that contributes to improvement of pulverization and orientation during molding is mixed. The mixing of the lubricant can be performed for about 5 to 30 minutes using a Nauta mixer or the like, for example. Then, finely pulverize under certain conditions to obtain finely pulverized powder with an average particle size of 4-5 μm. In ...

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 crushing treatment) In each process of sintering (putting into a sintering furnace), the atmosphere of each process is controlled at a level where the oxygen concentration is lower than 100ppm; and the sintering temperature is set to 1070°C. In addition, A sintered body was produced in the same manner as in Example 1. 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 shown in Figure 5. In addition, Figure 6 shows the relationship between the content of P and S in the raw material alloy and D50, Figure 7 shows the relationship between the content of P and S in the sintered body and the coercivity (iHc), and Figure 8 shows the relationship between P and S in the sintered ...

Embodiment 3

[0070] Set the alloy composition as 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 and then in each process from crushing (recovery after crushing) to sintering (putting into the sintering furnace), the atmosphere of each process is controlled at a level where the oxygen concentration is lower than 100ppm; and the sintering temperature is set A sintered body was produced in the same manner as in Example 1 except that the temperature was 1020°C. The obtained sintered body was measured in the same manner as in Example 1. The result is shown in FIG. 9 . In addition, Figure 10 shows the relationship between the content of P and S in the raw material alloy and D50, Figure 11 shows the relationship between the content of P and S in the sintered body and the coercive force (iHc), and Figure 12 shows the relationship between P and S in the sintered body The relationship between S content and remanence flux density (Br). In additi...

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Abstract

The invention aims at leading crystalline structure of raw material alloy which is manufactured through adopting a strip stock continuous metal cast process to be more even, therefore comminuted powder which is got through the raw material alloy is micronized and the scope of particle size distribution is dwindled, thereby obtaining R-T-B type sintered magnetic body with high coercive force. The raw material alloy for the R-T-B type sintered magnetic body has crystal grains which are constituted by R2T14B compound, and the content of P and / or S is 100-950ppm. The optimum composition of the raw material alloy comprise R 25-35wt%, B 0.5-4wt%, one or both of Al and Cu 0.02-0.6wt%, Co 5wt% or below, and the others are Fe basically, wherein R is one, two or more elements which is / are chosen from rare-earth element, T contains Fe or is one, two or more elements which is / are chosen from transition metal elements of Fe and Co.

Description

technical field [0001] The 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 material alloys, the pulverization of the obtained raw material alloys, the molding of pulverized alloy powders in a magnetic field, sintering and aging treatment. In order to improve the magnetic properties of R-T-B type sintered magnets, various attempts have been made in each manufacturing process. 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, and ...

Claims

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Application Information

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Patent Type & Authority Applications(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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