Process for producing alloy slab for rare-earth sintered magnet, alloy slab for rare-earth sintered magnet and rare-earth sintered magnet

A technology of sintered magnets and a manufacturing method, which is applied in the directions of magnetic materials, magnetic objects, inorganic materials, etc., can solve the problem of not being able to obtain alloy castings and the like

Active Publication Date: 2007-04-04
SANTOKU CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, even if such a cooling roll is used, it is not possible to obtain dendrites including R-rich domains and a 2-14-1 phase, the ratio of the dendrites is 80% by volume or more, and the space between the dendrites Alloy cast sheet with uniform alloy structure

Method used

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  • Process for producing alloy slab for rare-earth sintered magnet, alloy slab for rare-earth sintered magnet and rare-earth sintered magnet
  • Process for producing alloy slab for rare-earth sintered magnet, alloy slab for rare-earth sintered magnet and rare-earth sintered magnet
  • Process for producing alloy slab for rare-earth sintered magnet, alloy slab for rare-earth sintered magnet and rare-earth sintered magnet

Examples

Experimental program
Comparison scheme
Effect test

reference example 1

[0156] An alloy of 31.5% by mass of neodymium, 1.04% by mass of boron, and the balance of iron is mixed with neodymium metal, boron-iron alloy and iron, and melted in a high-frequency melting furnace in an argon atmosphere. In the state where the alloy is completely melted, after standing still for a while, the oxide of neodymium will float as slag, and then remove the slag.

[0157] Next, the obtained alloy solution having a temperature of 1500° C. was supplied to a single roll by the strip casting method, and cooled at a peripheral speed shown in Table 1 to produce an alloy cast sheet having a thickness of 0.2 mm. At this time, a tundish made of refractory ceramics was used. On the other hand, for iron rollers, Ra adjusted to 1 μm was used.

[0158] The average crystal grain size, the average interval r of R-rich regions, and the total volume ratio of chilled grains and fine structures of the obtained alloy slabs were measured. The results are shown in Table 1.

[0159] Nex...

reference example 2 and 3

[0161] Except that the thickness of the alloy cast pieces was 0.3 mm and 0.4 mm, alloy cast pieces and sintered magnets were produced in the same manner as in Reference Example 1, and various measurements were performed. The results are shown in Table 1. In addition, the alloy microstructure photos of the alloy cast sheet obtained in Reference Example 3 were detached from the cooling roll and perpendicular to the moving direction (C section with respect to the direction of roll rotation) through an optical microscope and a polarizing microscope, respectively. Figure 13 shows.

[0162] Refer to Comparative Examples 1 and 2

[0163] After melting the alloy, do not stand still, remove the slag, and preheat the tundish, and use a copper roll with Ra of 7 μm, except that the thickness of the alloy cast piece is made 0.2 mm, 0.7 mm, the same as Reference Example 1 Operation, production of alloy castings, sintered magnets, and various measurements. The results are shown in Table 1...

Embodiment 1

[0170] An alloy of 31.5% by mass of neodymium, 1.0% by mass of boron and the balance of iron is mixed with neodymium metal, boron-iron alloy and iron, and melted in a high-frequency melting furnace in an argon atmosphere.

[0171] Next, the obtained alloy solution at a temperature of 1500° C. was supplied to a single roll through a tundish for strip casting, cooled and solidified at a peripheral speed of 0.8 m / sec, and an alloy cast sheet with a thickness of 0.3 to 0.4 mm was produced. The cooling roll used is that, on the surface of the cooling roll, the solidification nucleation generation part having the protruding part of the cross-sectional shape shown in FIG. A cooling roll made of copper having a surface pattern shown in FIG. 4 . The solidification nucleation generation part is formed at the top of the peak of the cross section, and the linear solidification nucleation suppression part containing the argon atmosphere is formed at the valley part. The interval at the to...

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Abstract

A process for producing an alloy slab for rare-earth sintered magnet, in which homogenization of R-rich region and 2-14-1 phase dendrite spacings, sizes, orientations, shapes, etc. can be attained with the generation of chill crystal suppressed, which alloy slab facilitates pulverization into uniform particle size in the step of pulverization for production of rare-earth sintered magnet and enables control of contraction ratio of an alloy powder compact after the pulverization; an alloy slab for rare-earth sintered magnet produced by the process; and a rare-earth sintered magnet excelling in magnetic properties. There is provided a process comprising the step of preparing a melt of alloy composed of R such as a rare earth metal element, B and Fe together with the balance of M and the step of feeding the alloy melt to cooling rolls with surfaces having multiple linear solidification nucleus generation inhibiting parts capable of inhibiting the generation of dendrite, etc. and solidification nucleus generating parts capable of generation of dendrite wherein the line width of solidification nucleus generation inhibiting parts has a region of > 100 mum, thereby effecting cooling solidification.

Description

technical field [0001] The present invention relates to a method for producing an alloy ingot for a rare earth sintered magnet, a specific alloy ingot for a rare earth sintered magnet obtained by the method, and a rare earth sintered magnet using the alloy ingot. Background technique [0002] As electronic devices are being miniaturized and lightened, magnets used in them are required to have higher magnetic properties. where the high flux density of R 2 Fe 14 The development of B-type rare earth sintered magnets is actively underway. Usually, R 2 Fe 14 Class B rare earth sintered magnets can be obtained by melting, casting, and pulverizing raw materials to obtain magnet raw material alloys, and forming, sintering, and aging treatment of the magnet raw material alloys in a magnetic field. [0003] in the manufacture of R 2 Fe 14 In the case of B-type rare earth sintered magnets, the raw material alloy used as the raw material of the magnet usually contains R 2 Fe 14...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22D11/06B22D11/106B22F3/00B22F9/04C22C33/02C22C38/00H01F1/053H01F1/08
Inventor 新谷和雅村上亮山本和彦
Owner SANTOKU CORP
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