Method for improving corrosion resistance of phosphate coating on surface of neodymium-iron-boron permanent magnet

A surface phosphating, permanent magnet technology, applied in the direction of metal material coating process, can solve the problem of low corrosion resistance of phosphating film, and achieve the effect of improving corrosion resistance, simple process and good combination

Inactive Publication Date: 2013-03-13
SHENYANG POLYTECHNIC UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the corrosion resistance of phosphating film is not high at present, and it is usually only used as the bottom layer of protection, which limits its application

Method used

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  • Method for improving corrosion resistance of phosphate coating on surface of neodymium-iron-boron permanent magnet
  • Method for improving corrosion resistance of phosphate coating on surface of neodymium-iron-boron permanent magnet

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] The substrate is sintered NdFeB permanent magnet (source of sample: Antai Technology Co., Ltd., main composition: 63.95% Fe, 29% Nd, 1.1% B and a small amount of other elements), sample size: 5 cm × 1cm × 0.25cm .

[0039] (1) Alkaline washing and degreasing process conditions: sodium phosphate 60 g / L, sodium carbonate 40 g / L, sodium hydroxide 5g / L, OP-10 emulsifier 0.5g / L, sodium lauryl sulfate 0.1 g / L L, temperature 70°C, processing time: 1min;

[0040] (2) Pickling is carried out after alkaline washing and cleaning, nitric acid 40 mL / L, hexamethylenetetramine 2.0 g / L, sodium lauryl sulfate 0.5 g / L, temperature is 25°C, and treatment time is 15s ;

[0041] (3) The composition and process of phosphating solution are: potassium dihydrogen phosphate 50 g / L, phosphoric acid 5 mL / L, zinc nitrate 1 g / L, sodium nitrate 0.5 g / L, ammonium molybdate 0.5 g / L, dodecyl Sodium sulfate 0.1 g / L, sulfosalicylic acid 0.1 g / L, pH = 1.5, phosphating temperature 25°C, phosphating time ...

Embodiment 2

[0045] The substrate is sintered NdFeB permanent magnet (source of sample: Antai Technology Co., Ltd., main composition: 63.95% Fe, 29% Nd, 1.1% B and a small amount of other elements), sample size: 5 cm × 1cm × 0.25cm .

[0046] (1) Alkaline washing and degreasing process conditions: sodium phosphate 80 g / L, sodium carbonate 60 g / L, sodium hydroxide 10 g / L, OP-10 emulsifier 1.0 g / L, sodium lauryl sulfate 0.5 g / L L, temperature 60°C, processing time: 2min;

[0047] (2) Pickling is carried out after alkaline washing and cleaning, nitric acid 60 mL / L, hexamethylenetetramine 1.0 g / L, sodium lauryl sulfate 0.1 g / L, temperature 15°C, treatment time 25s ;

[0048] (3) The composition and process of phosphating solution are: potassium dihydrogen phosphate 90g / L, phosphoric acid 15mL / L, zinc nitrate 3g / L, sodium nitrate 2.0 g / L, ammonium molybdate 2.5g / L, lauryl sulfate Sodium 0.35 g / L, sulfosalicylic acid 0.5 g / L, pH = 2.5, phosphating temperature 55°C, phosphating time 20 minutes...

Embodiment 3

[0052] The substrate is sintered NdFeB permanent magnet (source of sample: Antai Technology Co., Ltd., main composition: 63.95% Fe, 29% Nd, 1.1% B and a small amount of other elements), sample size: 5 cm × 1cm × 0.25cm .

[0053] (1) Alkaline washing and degreasing process conditions: sodium phosphate 70 g / L, sodium carbonate 50 g / L, sodium hydroxide 7g / L, OP-10 emulsifier 0.8g / L, sodium lauryl sulfate 0.3 g / L L, temperature 65°C, processing time: 1.5min;

[0054] (2) Pickling is carried out after alkaline washing and cleaning, nitric acid 50 mL / L, hexamethylenetetramine 1.5 g / L, sodium lauryl sulfate 0.3 g / L, temperature is 20°C, and treatment time is 20s ;

[0055] (3) The composition and process of phosphating solution are: potassium dihydrogen phosphate 70g / L, phosphoric acid 10mL / L, zinc nitrate 2g / L, sodium nitrate 1.0 g / L, ammonium molybdate 1.5g / L, lauryl sulfate Sodium 0.2 g / L, sulfosalicylic acid 0.3 g / L, pH = 2.0, phosphating temperature 35°C, phosphating time 40...

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Abstract

The invention belongs to the neodymium-iron-boron material surface electroplating field and mainly relates to a method for improving the corrosion resistance of a phosphate coating on the surface of a neodymium-iron-boron permanent magnet, wherein basic oil removal and rust removal through acid washing are performed before phosphorization and drying is performed after phosphorization; a desired surface for phosphorization is obtained by means of controllable acid washing solution; the conventional process of performing surface adjustment after acid washing is omitted; the problem of low corrosion resistance of the existing neodymium-iron-boron phosphate coating and the problem that the conventional process still needs chromic acid passivating treatment after phosphorization in order to improve the corrosion resistance of the phosphate coating are solved; and the obtained film is even and compact in surface and thereby protects the neodymium-iron-boron substrate. The preparation method is simple in process flow, convenient to operate and friendly to the environment.

Description

technical field [0001] The invention relates to the field of surface electroplating of NdFeB materials, in particular to a method for improving the corrosion resistance of a phosphating film on the surface of a permanent magnet made of NdFeB materials. Background technique [0002] NdFeB permanent magnet materials have rapidly entered the industrialized society due to their excellent magnetic properties, price ratio and abundant resource reserves. However, the surface of NdFeB material is porous, loose and rough, and is easily oxidized and rusted, resulting in poor corrosion resistance, which severely limits its application range. [0003] Many people at home and abroad have done a lot of research in order to improve the corrosion resistance of NdFeB magnets, such as alloying treatment and surface treatment, but although the addition of alloying elements can improve the corrosion resistance of magnets to a certain extent, the effect is very Limited, and sometimes at the ex...

Claims

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Application Information

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IPC IPC(8): C23C22/42
Inventor 孙硕苏博张有平王勇刘磊娄桂艳迟松江
Owner SHENYANG POLYTECHNIC UNIV
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