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Method for preparing corrosion-resistant sintered neodymium iron boron (NdFeB) magnet

A NdFeB, corrosion-resistant technology, applied in the direction of magnetic objects, inductance/transformer/magnet manufacturing, magnetic materials, etc., can solve the problem of corrosion resistance of high-performance sintered NdFeB magnets, low comprehensive performance of rare earth permanent magnets, etc. problems, to achieve the effects of reduced weight loss, satisfactory corrosion resistance, and strong electrochemical corrosion resistance

Inactive Publication Date: 2011-01-26
WUXI NANLIGONG TECH DEV +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the comprehensive properties of the rare earth permanent magnets corresponding to the material formulations and production methods involved in these two patents are relatively low, and the problems related to the corrosion resistance of high-performance sintered NdFeB magnets are not solved.

Method used

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  • Method for preparing corrosion-resistant sintered neodymium iron boron (NdFeB) magnet

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preparation example Construction

[0018] In conjunction with the accompanying drawings, a method for preparing a corrosion-resistant sintered NdFeB magnet of the present invention comprises the following steps:

[0019] Step 1, select the main alloy, the main alloy is the NdFeB alloy ingot made by casting process or the NdFeB quick-setting sheet made by the quick-setting sheet process, and the atomic ratio of its composition is close to Nd:Fe:B=2 : 14:1, the specific composition is adjusted according to the performance requirements; for the alloy ingot, the composition is homogenized at 1050-1150°C for 10-20h.

[0020] Step 2, preparation auxiliary alloy, the atomic percentage of auxiliary alloy is R1 100-x-y-z co x m y R2 z , where 25≤x≤60, 0≤y≤10, 0≤z≤10, R1 is one of Nd or Pr or a mixture of both, R2 is one of Dy, Tb or a mixture of both, M is one or a mixture of two or more of Al, Ga, Cu, Ti, Nb, Zr, and Hf.

[0021] Step 3. Under the protection of inert gas, the auxiliary alloy is melted in an interm...

Embodiment 1

[0029] A method for preparing a corrosion-resistant sintered NdFeB magnet, comprising the following steps:

[0030] Step 1. Select the main alloy as an alloy ingot. The atomic percentage composition of the main alloy is Nd: 11.0%, Dy: 1.0%, Tb: 0.5%, Nb: 0.1%, Al: 0.2%, Cu: 0.1%, Ga: 0.1 %, Fe: 81.0%, B: 6.0%, the main alloy ingot was homogenized at 1100°C for 20h.

[0031] Step 2, preparing auxiliary alloy, the atomic percentage composition of auxiliary alloy is Nd: 40.0%, Co: 60.0%.

[0032] In step 3, the auxiliary alloy is smelted by an induction melting method to obtain an auxiliary alloy ingot.

[0033] Step 4, the main and auxiliary alloys are respectively hydrogen crushed to make powder. Dehydrogenate the crushed main alloy at 550°C for 3h.

[0034] Step 5, mixing the main and auxiliary alloys after the hydrogen crushing treatment, the weight of the auxiliary alloy powder accounts for 5% of the total weight of the two, and simultaneously adds a lubricant accounting ...

Embodiment 2

[0040] A method for preparing a corrosion-resistant sintered NdFeB magnet, comprising the following steps:

[0041] Step 1. Select the main alloy as quick-setting flakes, and the atomic percentage composition of the main alloy is Nd: 7.2%, Pr: 0.5%, Dy: 2.2%, Tb: 0.9%, Co: 1.5%, Nb: 0.3%, Al: 0.3 %, Fe: 80.8%, B: 6.3%.

[0042] Step 2, preparing auxiliary alloy, the atomic percentage composition of auxiliary alloy is Nd: 30%, Pr: 25%, Dy: 1%, Co: 40%, Cu: 2%, Ga: 2%.

[0043] In step 3, the auxiliary alloy is smelted by an induction melting method to obtain an auxiliary alloy ingot.

[0044] Step 4, the main and auxiliary alloys are hydrogen crushed to make powder respectively, and the crushed main alloy is dehydrogenated at 500° C. for 4 hours.

[0045] Step 5, mixing the main and auxiliary alloys after the hydrogen crushing treatment, the weight of the auxiliary alloy powder accounts for 7% of the total weight of the two, and simultaneously adds 0.1% of the lubricant by we...

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Abstract

The invention discloses a method for preparing a corrosion-resistant sintered neodymium iron boron (NdFeB) magnet. In the method, an intergranular phase optimized design is used as a starting point on the basis of preparation technology of a double-alloy method, the high-cobalt content rare earth cobalt-based alloy which does not contain iron and boron is selected as an auxiliary alloy, and the melting point of the auxiliary alloy is ensured to be lower than 1,050 DEG C through component control so as to meet the liquid-phase sintering effect. By measuring the weightlessness condition of the material placed in an environment of the temperature of 120 DEG C, two atmosphere and 100 percent of humidity for 96 hours, results show that the weightlessness of the prepared sintered NdFeB magnet is only less than 1 / 3 of that of the sintered NdFeB magnet prepared by a single-alloy method and a conventional double-alloy method, and the sintered NdFeB magnet has excellent corrosion resistance. The method for preparing the corrosion-resistant sintered NdFeB magnet can be widely applied in the field of production of high-performance sintered NdFeB magnets.

Description

technical field [0001] The invention relates to a preparation method of a sintered NdFeB magnet, in particular to a preparation method of a corrosion-resistant sintered NdFeB magnet. Background technique [0002] Sintered NdFeB magnets prepared by powder metallurgy have excellent magnetic properties and have been widely used in many fields such as electronics, automobiles, computers, electric power, machinery, energy, environmental protection, national defense, and medical equipment. The sintered NdFeB permanent magnet material is mainly composed of the main phase (close to Nd 2 Fe 14 Phase B) and rare earth-rich phase (Note: There is also a boron-rich phase, which can be ignored when the atomic percentage of boron in sintered NdFeB is less than 6.5%). The rare earth-rich phase is generally distributed at the grain boundary, constituting the grain boundary phase. The rare earth-rich phase is mainly composed of rare earth-iron intermetallic compounds, and its atomic percen...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F1/057H01F41/02C22C1/03B22F1/00
Inventor 徐锋陈栋陈光卢国文朱海南杜宇雷李永胜杨森
Owner WUXI NANLIGONG TECH DEV
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