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Production method for rare earth alloy magnetic powder forming body and rare-earth magnet

A technology of rare earth alloys and manufacturing methods, which is applied in the manufacture of rare earth magnets and the manufacture of rare earth alloy magnetic powder compacts. It can solve the problems of poor corrosion resistance test results, poor HAST tests, and increased frictional resistance, so as to prevent oxidation. , the degree of orientation increases, the effect of improving the degree of orientation

Active Publication Date: 2014-02-26
FUJIAN CHANGJIANG GOLDEN DRAGON RARE EARTH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This super-dry state is easy to generate static electricity, which will cause strong electrostatic repulsion between powders, resulting in poor formability, and at the same time reduce the degree of orientation, Br, (BH)max
This is because if there is no oxygen and moisture on the surface of the powder, there will be a strong bond like a metal bond, the friction resistance between the powders will increase, and the degree of orientation will decrease.
[0008] In addition, if the inert gas is passed into the atmosphere of the completely sealed molding machine, and the molding is performed at low oxygen content and low humidity, problems such as abnormal grain growth (AGG) and coercive force reduction are prone to occur.
What's more, because the oxygen content in the sintered body is extremely low, it will also cause the problem of poor HAST test
This is because there is almost no oxidized component in ultra-low oxygen content and ultra-low humidity, and the unoxidized metal Nd component will increase sharply, which will easily cause abnormal grain growth (AGG), which will easily cause coercive Reduced force, poor test results for corrosion resistance (HAST)

Method used

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  • Production method for rare earth alloy magnetic powder forming body and rare-earth magnet
  • Production method for rare earth alloy magnetic powder forming body and rare-earth magnet
  • Production method for rare earth alloy magnetic powder forming body and rare-earth magnet

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Experimental program
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Effect test

Embodiment 1

[0035] The present invention takes NdFeB series rare earth alloy magnetic powder as an example to illustrate the magnetic field forming process of rare earth alloy magnetic powder.

[0036] Its production process mainly includes the following processes: raw material preparation→smelting→casting→hydrogen crushing→fine pulverization→forming in a magnetic field→sintering→heat treatment→magnetic performance evaluation→evaluation of oxygen content in the sintered body.

[0037] In raw material preparation process: prepare the Co of the Nd of purity 99.5%, industrial use Fe-B, industrial pure Fe, purity 99.9%, the weight ratio of each composition meets as shown in table 1:

[0038] The weight proportion of each composition of table 1

[0039]

[0040] In order to complete the above preparation composition, a total of 500Kg of raw materials were weighed and prepared.

[0041] In the smelting process: the prepared raw materials are put into a crucible made of alumina, and a high-f...

Embodiment 2

[0058] The difference between embodiment 2 and embodiment 1 is listed as follows:

[0059] 1) Add methyl octanoate used as an organic additive to the pulverized powder in an amount of 0.01% of the weight of the rare earth alloy magnetic powder, and fully mix with a V-shaped mixer.

[0060] 2) Forming process in a magnetic field: Divide the powder into 10 equal parts, and use a right-angle orientation magnetic field forming machine for each part, in a 1.8T orientation magnetic field, at 0.8 ton / cm 2 Under the molding pressure of , a cube with a side length of 25mm was formed, and after forming, it was demagnetized in a magnetic field of 0.2T.

[0061] Argon atmosphere is used for molding, and the oxygen content in the argon atmosphere is fixed below 1000ppm. Humidifiers and cooling equipment are installed in the molding machine. The temperature range of the atmosphere is 10°C to 55°C, and the relative humidity range is 5% to 45%. forming in an atmosphere.

[0062] Table 3 is ...

Embodiment 3

[0066] The difference between embodiment 3 and embodiment 1 is listed as follows:

[0067] 1) Add methyl octanoate to the pulverized powder in an amount of 1.5% of the weight of the rare earth alloy magnetic powder, and then fully mix with a V-shaped mixer.

[0068] 2) Forming process in a magnetic field: Divide the powder into 10 equal parts, and use a right-angle orientation magnetic field forming machine for each part, in a 1.8T orientation magnetic field, at 0.3 ton / cm 2 Under the molding pressure of , a cube with a side length of 25mm was formed, and after forming, it was demagnetized in a magnetic field of 0.2T.

[0069] Argon atmosphere is used for molding, and the oxygen content in the argon atmosphere is fixed below 1000ppm. Humidifiers and cooling equipment are installed in the molding machine. The temperature range of the atmosphere is 10°C to 55°C, and the relative humidity range is 5% to 45%. forming in an atmosphere.

[0070] Table 4 is a comparative table of m...

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Abstract

The invention discloses a production method for a rear earth alloy magnetic powder forming body and a rare-earth magnet. The production method for the rear earth alloy magnetic powder forming body comprises pressing organic additive added rear earth alloy magnetic powder through a one section forming method under the atmosphere with the temperature of 25 to 50 DEG C and the relative humidity of 10 to 40 % in inert gas atmosphere enclosed space. The production method for the rear earth alloy magnetic powder forming body has the advantages of restraining poor forming (fracture, unfilled corner and crack) of a low oxygen content magnet after sintering and rising the degree of orientation, Br and (BH) max due to specific setting of the temperature and the humidity of the inert gas atmosphere in a completely enclosed environment.

Description

technical field [0001] The present invention relates to a magnet manufacturing method, in particular to a manufacturing method of a rare earth alloy magnetic powder compact and a manufacturing method of a rare earth magnet. Background technique [0002] Rare earth magnets are based on intermetallic compounds R 2 T 14 B-based magnets, in which R is a rare earth element, T is iron, or a transition metal element that replaces iron and a part of iron, B is boron, which has extremely high magnetic properties, and is known as the king of magnetism. The maximum magnetic energy product (BH)max is more than 10 times higher than the maximum magnetic energy product of ferrite magnets (Ferrite). In addition, the machining performance of rare earth magnets is excellent, and the working temperature can reach up to 200 degrees Celsius. Moreover, its texture is hard and its performance is stable. It has a good cost performance and is widely used. [0003] There are two kinds of productio...

Claims

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Application Information

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IPC IPC(8): B22F3/02B22F9/08C22C1/04H01F1/057H01F41/02
Inventor 永田浩吴冲浒
Owner FUJIAN CHANGJIANG GOLDEN DRAGON RARE EARTH CO LTD
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