Nanometer Zn crystal boundary modified sintered NdFeB magnet with high corrosion resistance and preparation method thereof

A technology of grain boundary modification and high corrosion resistance, applied in the direction of magnetic objects, magnetic materials, inorganic materials, etc., can solve problems such as poor corrosion resistance, and achieve the effects of high magnetic performance, easy operation, and good corrosion resistance.

Inactive Publication Date: 2009-12-30
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

With the gradual improvement of magnetic properties, the disadvantages of poor corrosion resistance of si

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0018] The preparation method of the high corrosion resistance sintered NdFeB magnet modified by nano-Zn grain boundary includes the following steps:

[0019] 1) The main phase alloy is made into ingots or quick-setting thin ribbons by casting process or rapid-setting stripping process, and the grain boundary phase alloys are made into fast-quenched belts by rapid quenching process; then coarse crushing is carried out by mechanical crushing or hydrogen explosion crushing respectively. , After coarse crushing, ball milling or jet milling is used to obtain the main phase alloy powder with an average particle diameter of 2-10μm and the grain boundary phase alloy powder with 1-8μm;

[0020] 2) Add 1%-20% by weight of nano-Zn powder and 1%-10% of antioxidant to the grain boundary phase alloy powder, and mix uniformly to obtain nano-Zn modified grain boundary phase alloy powder;

[0021] 3) Add 1-20% by weight of nano-Zn modified grain boundary phase alloy powder to the main phase alloy...

Example Embodiment

[0025] Example 1:

[0026] 1) Prepare the main phase alloy and the grain boundary phase alloy separately. The main phase alloy is prepared by the rapid-setting strip spinning process, the surface linear speed of the copper roller is 1.6m / s, and the composition is Nd 12.2 Dy 0.2 Fe bal Al 0.4 Zr 0.1 B 5.8 (at%), the grain boundary phase alloy is prepared by rapid quenching process, the rapid quenching speed is 23m / s, and the composition is Nd 20 Dy 2 Fe bal Ga 0.5 Nb 0.5 B 6.5 (at%);

[0027] 2) Separate powdering of the main phase alloy and the grain boundary phase alloy. Coarse crushing by jaw crusher, medium crushing by medium crusher, and jet mill under the protection of nitrogen to produce powders with average particle diameters of 3.6μm and 2.8μm respectively;

[0028] 3) Add 5% by weight of nano-Zn powder with an average particle diameter of 20nm and an antioxidant with a weight ratio of 4% to the grain boundary phase alloy powder, and mix them evenly in the mixer;

[0029] ...

Example Embodiment

[0037] Example 2:

[0038] 1) Prepare the main phase alloy and the grain boundary phase alloy separately. The main phase alloy is prepared by casting process and the composition is Nd 13.8 Fe bal B 5.95 (at%), the grain boundary phase alloy is prepared by the rapid quenching process, the rapid quenching speed is 16m / s, and the composition is Nd 17 Dy 3 Tb 0.5 Fe bal Ga 0.1 Cu 0.4 B 6.2 (at%);

[0039] 2) Separate powdering of the main phase alloy and the grain boundary phase alloy. Roughly crushed by hydrogen explosion method, and then made into powder with average particle diameter of 4.2μm and 3.5μm by jet mill under the protection of nitrogen;

[0040] 3) Add 20% by weight of nano-Zn powder with an average particle diameter of 40nm and 2% by weight of antioxidant to the grain boundary phase alloy powder, and mix them evenly in the mixer;

[0041] 4) Add nano-Zn modified grain boundary phase alloy powder to the main phase alloy powder, the weight percentage is 10%, and 2% by wei...

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Abstract

The invention discloses a preparation method of nanometer Zn crystal boundary modified sintered NdFeB magnet with high corrosion resistance, comprising the following steps: 1) main-phase alloy and crystal boundary phase alloy are respectively prepared, wherein, the main-phase alloy adopts casting technology or rapid hardening melt-spun technology to prepare a cast ingot or a rapid hardening thin strip, and the crystal boundary phase alloy adopts rapid quenching technology to prepare a rapid quenching strip; 2) the prepared main-phase alloy and crystal boundary phase alloy are respectively prepared into powder; 3) nanometer Zn powder is mixed with the crystal boundary phase alloy powder to evenly disperse the mixture on the crystal boundary phase alloy powder surface; 4) after nanometer Zn modified crystal phase alloy powder is evenly mixed with the main-phase alloy powder, orientation compression in a magnetic field is prepared into a green body; 5) the green body is sintered in a high vacuum sintering furnace and tempered to prepare the final magnet. The sintered NdFeB magnet prepared by the method of the invention has high performance, favourable corrosion resistance, simple technology and simple operation, and is favourable for batch production on large scale.

Description

technical field [0001] The invention relates to a preparation method of a highly corrosion-resistant sintered NdFeB magnet modified by nano-Zn grain boundaries. Background technique [0002] Sintered NdFeB magnets are a new generation of rare earth permanent magnet materials launched in the early 1980s. They have excellent comprehensive magnetic properties, high cost performance and easy processing. They have been widely used in computers, motors, wind turbines, Electric vehicles, instrumentation, high-fidelity speakers, nuclear magnetic resonance imagers and aerospace navigators and other fields. Because of its high magnetic energy product, it is especially suitable for various replacement products that require miniaturization, light weight, and integration. [0003] Sintered NdFeB magnets are based on Nd 2 Fe 14 The B compound is the matrix, and its magnetic properties are derived from Nd 2 Fe 14 Intrinsic magnetic parameters of B compounds, such as H A 、J s , T c ...

Claims

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Application Information

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IPC IPC(8): H01F1/057H01F1/08B22F9/04B22F3/16
Inventor 严密崔熙贵马天宇罗伟
Owner ZHEJIANG UNIV
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