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A method for simultaneously improving the oxidation and corrosion resistance of ndfeb powders and magnets

An anti-oxidation and magnet technology, applied in the direction of magnets, magnetic objects, magnetic materials, etc., can solve the problems of less powder, easy to cause pollution, high cost of raw material preparation, etc., to reduce energy loss, lower heat preservation temperature, and good protection effect Effect

Active Publication Date: 2021-12-24
BEIJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The method in the invention 201410135609.X has many deficiencies. One is that the pretreatment process of the powder is complicated, not only oil removal but also activation are required
Second, the composition of the electroless plating solution is complex and expensive, and the cost of raw material preparation is high
Third, the amount of powder that can be processed by electroless Ni plating is relatively small, which is not suitable for mass production
Fourth, the subsequent treatment process of the used solution is easy to cause pollution
Although there are many coatings on the surface of the magnet, the operation process of Invention 201611157661.0 is too complicated, a variety of organic solvents are used, and the process is very cumbersome
Besides that, the method in Invention 201611157661.0 is not suitable for mass production

Method used

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  • A method for simultaneously improving the oxidation and corrosion resistance of ndfeb powders and magnets
  • A method for simultaneously improving the oxidation and corrosion resistance of ndfeb powders and magnets
  • A method for simultaneously improving the oxidation and corrosion resistance of ndfeb powders and magnets

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] 1) Take about 50g of NdFeB magnetic powder, mix it with Zn particles with a mass of 100g and a diameter of about 3mm, and put it into a heat treatment furnace;

[0029] 2) Set the speed of the heat treatment furnace to 4r / min, and the vacuum in the furnace is greater than 10 -3 When Pa is filled with Ar until the pressure is 60kPa;

[0030] 3) Turn on the heat treatment furnace for heating, the heating temperature is 350°C, and the holding time is 6h;

[0031] 4) Take out the powder after the heat treatment, use a sieve to separate the NdFeB powder from the Zn particles, and collect the obtained powder;

[0032] 5) Use VSM to test the performance of the powder before and after coating:

[0033] Table 1 Powder magnetic properties before and after Zn coating

[0034] Powder type Coercivity / Oe Remanence / emu·g -1

Powder before coating 10125 93.54 coated powder 9843 93.05

[0035] After coating the powder, the coercive force is reduc...

Embodiment 2

[0042] 1) Take about 10 pieces of NdFeB magnets, the total mass of which is about 30g, and uniformly mix with Cu particles with a mass of about 60g and a diameter of about 3mm, and place them in a heat treatment furnace;

[0043] 2) Set the speed of the heat treatment furnace to 4r / min, and the vacuum in the furnace is greater than 10 -3 Pa filled with Ar until the air pressure is 70kPa;

[0044] 3) Turn on the heat treatment furnace for heating, the heating temperature is 600°C, and the holding time is 3h;

[0045] 4) Take out the magnet after the heat treatment, and mix the magnet with 60g of Al quick-setting sheets with a length and width of 10mm and a thickness of about 0.5mm, and put them back into the heat treatment furnace after mixing evenly;

[0046] 5) The speed of the heat treatment furnace remains unchanged, and the vacuum degree in the furnace is greater than 10 -3 When Pa is filled with Ar until the air pressure is 65kPa;

[0047] 6) Turn on the heat treatment...

Embodiment 3

[0057] 1) Take 10 sintered NdFeB magnets with a total weight of about 30g.

[0058] 2) Take an AlZn alloy quick-setting sheet with a mass of 90 g, a length of about 6 mm, and a thickness of about 0.5 mm, and mix the magnet and the quick-setting sheet evenly into a heat treatment furnace;

[0059] 3) Set the speed of the heat treatment furnace to 5r / min, and the vacuum in the furnace is greater than 10- 3 When Pa is filled with Ar until the air pressure is 80kPa;

[0060] 4) Turn on the heat treatment furnace for heating, the heating temperature is 200°C, and the holding time is 5h;

[0061] 5) After the heat treatment, the magnet is taken out, and the magnet is separated from the quick-setting sheet.

[0062] 6) Use the BH permanent magnet measurement system to test the magnetic properties of the processed magnet;

[0063] Table 5 Energy table of magnets before and after coating AlZn alloy

[0064] Magnet type Coercivity / kOe Remanence / kG Magnet before wr...

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Abstract

The invention discloses a method capable of simultaneously improving the oxidation and corrosion resistance of NdFeB powder and a magnet, which belongs to the technical field of magnetic materials. The present invention protects the NdFeB powder and the magnet by heating the NdFeB powder or the magnet together with the coating layer metal to form an Al, Zn, Ni, Cu or alloy coating layer on the surface, so that the magnetic powder has better oxidation resistance, and the subsequent treatment The process can be realized in air, and the magnet can be applied in the device without electroplating.

Description

technical field [0001] The invention relates to a method for forming Al, Zn, Ni, Cu or alloy coatings thereof on the surface of NdFeB powder or a magnet to enhance its oxidation resistance and corrosion resistance, and belongs to the technical field of magnetic materials. Background technique [0002] NdFeB magnetic material is a kind of rare earth permanent magnet material. It has the characteristics of high coercive force and high magnetic energy product. It is called hard magnetic material because it can maintain a constant magnetism once it is magnetized. NdFeB permanent magnet is currently the most cost-effective commercial magnetic material, which has the advantages of high magnetic energy product, small size and light weight. NdFeB magnets are indispensable and important materials in high-tech fields such as aerospace, information engineering, new energy vehicles, and high-speed trains. Therefore, the preparation and forming of NdFeB materials has become a research a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01F41/02H01F1/057H01F7/02
CPCH01F41/026H01F1/0572H01F7/021
Inventor 岳明高京园刘卫强奚望吴迪张东涛路清梅张红国吴琼李玉卿
Owner BEIJING UNIV OF TECH
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