Preparation method of high corrosion resistance sintered neodymium iron boron

A high corrosion resistance, NdFeB technology, applied in the direction of magnetic materials, magnetic objects, inorganic materials, etc., can solve the problems of demanding working environment, short corrosion resistance time, easy oxidation of neodymium, etc. Corrosion, corrosion resistance improvement, coercivity improvement effect

Inactive Publication Date: 2007-02-14
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the anti-corrosion problem of magnets has not been fundamentally solved. Various protection methods have different defects. For example, the coating of organic coatings on the surface of magnets has requirements for the working environment, and the corrosion resistance time is not long; during aqueous electroplating, neodymium is easily oxidized and Hydrogen exists in the coating to cause hydrogen embrittlement, etc.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] 1) The NdFeB alloy is prepared by the quick-setting sheet casting process, the nominal composition of which is Nd 30.1 Fe 67.64 B 0.95 (Dy 1 Nb 0.4 ) (wt%).

[0027] 2) The neodymium iron boron alloy is roughly broken through a jaw crusher, and the middle crusher is broken.

[0028] 3) The crushed NdFeB alloy is respectively made into powders with an average particle diameter of 2 μm by jet milling under the protection of nitrogen.

[0029] 4) Prepare the degreasing solution, the activation solution and the electroless copper plating solution with a pH of 11. The formula is as follows:

[0030] Degreasing liquid formula: NaOH 20g / L, NaCO 3 45g / L, Na 3 PO 4 60g / L, Na 3 SiO 3 0.1g / L, OP emulsifier 1;

[0031] Activating solution formula: HCl 1g / L, HNO 3 10g / L, sodium lauryl sulfate 0.1g / L and urea 3g / L;

[0032] Chemical copper plating solution formula: CuSO 4 ·5H 2 O 20g / L, KNaC 4 H 4 O·4H 2 O 40g / L, NaOH 10g / L, polyethylene glycol 2.5g / L, formaldehyde 6g / L, thiourea 0.01 mg...

Embodiment 2

[0038] 1) The NdFeB alloy is prepared by the rapid-setting sheet casting process, the nominal composition of which is Nd 30.5 Fe 66.04 B 0.96 (Dy 1 Al 0.1 Co 1 Nb 0.4 ) (wt%).

[0039] 2) Directly crush the NdFeB alloy by hydrogen explosion method, saturate and absorb hydrogen at room temperature, and then dehydrogenate at 550°C for 8 hours to produce hydrogen explosion powder.

[0040] 3) The crushed hydrogen explosive powders are respectively made into powders with an average particle diameter of 3.3 μm by airflow milling under the protection of nitrogen.

[0041] 4) Prepare degreasing solution, activation solution and electroless copper plating solution with a pH of 11.5. The formula is as follows:

[0042] Degreasing liquid formula: NaOH 25g / L, NaCO 3 40g / L, Na 3 PO 4 65g / L, Na 3 SiO 3 1g / L, OP emulsifier 0.1;

[0043] Activating solution formula: HCl 3g / L, HNO 3 8g / L, sodium lauryl sulfate 1g / L and urea 3g / L;

[0044] Chemical copper plating solution formula: CuSO 4 ·5H 2 O 2...

Embodiment 3

[0051] 1) Using ingot casting process to make NdFeB alloy ingot, its nominal composition is Nd 30.5 Fe 68.5 B 1 (wt%).

[0052] 2) The neodymium iron boron alloy is roughly broken through a jaw crusher, and the middle crusher is broken.

[0053] 3) The crushed NdFeB alloy is respectively passed through a ball mill grinding material under the protection of nitrogen, and ball milled to an average particle diameter of 3.5 μm powder.

[0054] 4) Prepare degreasing solution, activation solution and electroless copper plating solution with pH 12, the formula is as follows:

[0055] Degreasing liquid formula: NaOH 25g / L, NaCO 3 40g / L, Na 3 PO 4 65g / L, Na 3 SiO 3 10g / L, OP emulsifier 1g / L;

[0056] Activating solution formula: HCl 2g / L, HNO 3 9g / L, sodium lauryl sulfate 1.5g / L and urea 4g / L;

[0057] Chemical copper plating solution formula: CuSO 4 ·5H 2 O 30g / L, KNaC 4 H 4 O·4H 2 O 55g / L, NaOH 15g / L, polyethylene glycol 3g / L, formaldehyde 8.5g / L, thiourea 0.2mg / L.

[0058] 5) Degrease th...

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Abstract

This invention discloses a preparation method for anti-corrosion sintered NdFeB including: 1, preparing the NdFeB alloy by casting or rapid hardening rejection band strip technology then applying ball grinding or gas flow grinding to process powder after hydrogen explosion or mechanical crushing, 2, confecting oil eliminator, activated solution and chemical plating solution, 3, eliminating oil from the magnetic powder with oil eliminator then dunk rinsing with activated solution, 4, adding the powder into a plating solution for chemical-plating copper then drying it with vacuum drier, 5, pressing the dried powder to molded-blanks, 6, preparing the molded-blanks to sintered magnet in a high vacuum sintering oven.

Description

Technical field [0001] The invention relates to a preparation method of sintered neodymium iron boron with high corrosion resistance. Background technique [0002] Nd-Fe-B permanent magnet material is the third-generation new functional material developed in the early 1980s. It has the following characteristics: (1) High magnetic properties; (2) The price is at the middle to low level; (3) The mechanical properties are good; (4) The Curie point is low, the temperature stability is poor, and the corrosion resistance is also poor. Due to its excellent magnetic properties and good cost performance, Nd-Fe-B has been widely used in microwave communication technology, audio-visual technology, instrumentation technology, electrical engineering, computers, magnetic separation technology, magnetic medical equipment and other fields. An important material basis for contemporary new technologies. [0003] The NdFeB alloy is produced by ingot casting or quick-setting spin strip, hydrogen exp...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F1/08H01F1/057
Inventor 严密崔熙贵于濂清罗伟吴进明
Owner ZHEJIANG UNIV
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