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A method of improving the corrosion resistance of phosphating film of sintered NdFeB permanent magnet

A technology of neodymium iron boron and phosphating film, which is applied in the direction of metal material coating process, etc., can solve the problems of coarse crystallization of phosphating film, poor continuity of phosphating film, and lag in film formation in the anode area, and achieve low production cost and high production efficiency. High efficiency and the effect of reducing pollution emissions

Active Publication Date: 2019-12-20
EARTH PANDA ADVANCE MAGNETIC MATERIAL
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  • Abstract
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Problems solved by technology

However, after the phosphating treatment of the magnet, the corrosion resistance of the phosphating film on the surface is poor. As far as ordinary low-temperature phosphating is concerned, after the phosphating treatment, the magnet is sampled for a damp heat test (implementation standard GJB150.9A-2009) for 3 hours It will rust if it is not reached, and even after some magnets are phosphating, rust spots will appear after drying
The reasons are as follows: First, the preparation of sintered NdFeB permanent magnet materials belongs to powder metallurgy, and because of the complexity of the magnet itself, the surface of the magnet is loose and porous, so the phosphating film formed on the surface has poor continuity and porosity. High, so the corrosion resistance is poor
Secondly, because the sintered NdFeB permanent magnet material is composed of the main phase Nd 2 Fe 14 B. Multi-phase powder alloy composed of Nd-rich phase and B-rich phase. When the magnet is placed in the phosphating solution for phosphating, because the Nd-rich phase is more active, it will become the micro-anode area in the process of phosphating reaction and be preferentially fast Corrosion leads to lagging and slow film formation in the anode area, resulting in a thinner film, and at the same time, a phosphating film is rapidly formed in the micro-cathode area. The phosphating film has coarse crystals and high porosity, which makes the phosphating film on the entire magnet surface extremely poor. Uniform, porous, even incomplete, so the corrosion resistance is poor

Method used

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  • A method of improving the corrosion resistance of phosphating film of sintered NdFeB permanent magnet
  • A method of improving the corrosion resistance of phosphating film of sintered NdFeB permanent magnet
  • A method of improving the corrosion resistance of phosphating film of sintered NdFeB permanent magnet

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Embodiment 1

[0028] (1) Take a number of sintered NdFeB magnets with a specification of 25×12×4 and use corundum abrasives to chamfer on a spiral vibration finishing machine. After chamfering, the R angle of the product is controlled at 0.5mm;

[0029] (2) Wash the chamfered product with clean water, put it into a degreasing solution at a temperature of 40°C, turn on the ultrasonic wave, take it out after 15 minutes of degreasing, and then clean it with hot water at 50°C;

[0030] (3) The product washed with hot water is washed countercurrently by two channels of tap water for 10 seconds; then it is pickled in nitric acid with a concentration of 3g / L for 40 seconds;

[0031] (4) Wash the product after pickling by two channels of running water countercurrently for 10 seconds; then put it into an ultrasonic cleaning machine filled with flowing water and clean it for 40 seconds;

[0032] (5) After the product washed by ultrasonic water is cleaned by two deionized water, it is immediately put ...

Embodiment 2

[0041] (1) Take a number of sintered NdFeB magnets with a specification of φ10.5×2 and chamfer them on a horizontal drum finishing machine with corundum abrasives. After chamfering, the R angle of the product is controlled at 0.2mm;

[0042] (2) Wash the chamfered product with clean water and put it into a degreasing solution at a temperature of 50°C, turn on the ultrasonic wave, take it out after 30 minutes of degreasing, and then clean it with hot water at 60°C;

[0043] (3) Wash the product after hot water washing by two countercurrent tap water for 20s; then put it into nitric acid with a concentration of 4.5g / L for pickling for 70s;

[0044] (3) Wash the product after pickling by two channels of running water countercurrently for 20s; then put it into an ultrasonic cleaning machine filled with running water and clean it for 110s;

[0045] (4) After the product washed by ultrasonic water is cleaned by two deionized water, it is immediately put into the surface conditioning...

Embodiment 3

[0057] (1) Take a number of sintered NdFeB magnets with a specification of φ36-φ24×10.5 and use corundum abrasives to chamfer on a spiral vibration finishing machine. After chamfering, the R angle of the product is controlled at 0.8mm;

[0058] (2) Wash the chamfered product with clean water and put it into a degreasing solution at a temperature of 50°C, turn on the ultrasonic wave, take it out after 30 minutes of degreasing, and then clean it with hot water at 60°C;

[0059] (3) The product washed with hot water is washed countercurrently by two channels of tap water for 10 seconds; then it is pickled in nitric acid with a concentration of 5 g / L for 80 seconds;

[0060] (4) Wash the product after pickling by two channels of running water countercurrently for 15 seconds; then put it into an ultrasonic cleaning machine filled with running water and clean it for 100 seconds;

[0061] (5) After the product washed by ultrasonic water is washed with deionized water twice, it is imm...

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Abstract

The invention discloses a method for improving corrosion resistance of a sintered neodymium iron boron permanent magnet phosphating film. The method comprises the steps that a machined and formed neodymium iron boron magnet is subjected to chamfering processing and is subjected to oil removing, acid pickling and water washing processing in sequence; in the stirring situation, the magnet is placed into surface conditioning liquid at the temperature of 20-30 DEG C for surface conditioning for 1-3 minutes, and the surface conditioning liquid is composed of a titanium salt surface conditioning agent, nanometer Fe powder particles and deionized water; and finally, the magnet is placed into a phosphating solution at the temperature of 20-40 DEG C for phosphating treatment for 10-20 minutes, and circulating filtration is performed. After the magnet is subjected to jointed surface conditioning by the titanium salt solution mixed with the nanometer Fe powder particles, the surface of the magnet is uniformly provided with a plurality of activated points and film forming factors, therefore the magnet can obtain the more uniform, more fine and more complete phosphating film in the phosphating reaction process, and thus corrosion resistance of the magnet is greatly improved.

Description

technical field [0001] The invention belongs to the field of sintered NdFeB permanent magnet materials, and in particular relates to a method for improving the corrosion resistance of a phosphating film of a sintered NdFeB permanent magnet. Background technique [0002] Since the advent of NdFeB permanent magnet materials in the 1980s, they have been widely used in many fields such as electronics, electrical appliances, instruments, medical equipment, motors, sensors, automobiles, and wind power due to their excellent magnetic properties. However, due to the particularity of the sintered NdFeB magnet due to its material composition and preparation process, the magnet has disadvantages such as easy oxidation, poor corrosion resistance, and strong self-powdering ability. [0003] In order to protect the magnet from the erosion of the external environment and maintain the stability of the magnet performance, the magnet needs to be treated with surface protection after processin...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C23C22/80C23C22/36
CPCC23C22/362C23C22/80
Inventor 王守春章毅汪扬黄秀莲陈静武衣晓飞熊永飞
Owner EARTH PANDA ADVANCE MAGNETIC MATERIAL
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