Nd-Fe-B magnet inorganic sealing hole adhesion and cathode electrophoresis composite surface protection technique

A cathodic electrophoresis and composite surface technology, which is applied in the direction of magnetic objects, circuits, magnetic materials, etc., can solve the problems of large difference in surface electrophoretic activity, complex process, and increased conductivity of the solution, and achieve good appearance and insulation performance, sealing holes The effect of simple process and excellent corrosion resistance

Inactive Publication Date: 2007-08-15
WUHAN RES INST OF MATERIALS PROTECTION
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the special features of NdFeB magnets, such as high resistance, high porosity, large difference in surface electrophoretic activity, accumulation of magnets in the bath solution, lead to accumulation of impurity ions, and increased conductivity of the solution limit the electrophoresis during the coating process. The increase of voltage makes the thickness of the coating film low (≤20um) and it is difficult to ensure uniformity, and it is easy to cause defects such as fish eyes and bubbles in the coating film
Japanese patent Jp005428 / 2000 introduces the method of sealing the surface coating of the magnet with the inorganic sealing agent of alkali metal silicate. It first protects the electroplating layer on the magnet, and then performs sealing treatment on the porous electroplating layer. It only seals The pores of the protective electroplating layer on the surface of the magnet are blocked, but the pores of the magnet itself have not been effectively blocked, and no additives to improve corrosion resistance are added to the sealing agent, so the effect of blocking the pores of the NdFeB magnet is not effective. Not obvious
Japanese patent JP2002088402 introduces a method of sealing magnets by mixing vegetable media and metal powder, but the process is relatively complicated and the practicability is poor

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] Immerse 1Kg of ф25×15 bonded NdFeB material into the potassium silicate inorganic material with a modulus of 3.3, put it in a vacuum kettle, and evacuate it to above 750mmHg for 10 to 15 minutes. Take out the test piece and rinse it with water. After curing in an oven at 100°C-140°C for 2h-4h, after phosphating and washing with water, cathodic electrophoresis coating is carried out: the initial voltage of cathodic electrophoresis is 80-90V, the deposition voltage is 140-160V, the electrophoresis temperature is 28-30°C, and the electrophoresis The time is 150-180s, after washing with water and then curing, that is, first bake at 80°C for 20-30 minutes, and then bake at 170°C for 30 minutes to complete the curing. That is to say, the bonded NdFeB magnet product that has undergone inorganic sealing treatment and composite protection of cathodic electrophoretic coating film is obtained. The corrosion resistance test of this NdFeB magnetic ring protective coating is carried ...

Embodiment 2

[0046] Immerse 1Kg of ф25×15 bonded NdFeB material into the potassium silicate inorganic material with a modulus of 4.8, put it into a vacuum kettle, and evacuate it to above 750mmHg for 10-15min, then take out the test piece and rinse it with water. After curing in an oven at 100°C-140°C for 2h-4h, after phosphating and washing with water, cathodic electrophoresis coating is carried out: the initial voltage of cathodic electrophoresis is 80-90V, the deposition voltage is 140-160V, the electrophoresis temperature is 28-30°C, and the electrophoresis The time is 150-180s, after washing with water and then curing, that is, first bake at 80°C for 20-30 minutes, and then bake at 170°C for 30 minutes to complete the curing. That is to say, the bonded NdFeB magnet product that has undergone inorganic sealing treatment and composite protection of cathodic electrophoretic coating film is obtained. The corrosion resistance test of this NdFeB magnetic ring protective coating is carried o...

Embodiment 3

[0051] Immerse 1Kg of ф25×15 bonded NdFeB material into potassium silicate inorganic sealing agent with a modulus of 4.8, add 1% hexamethylenetetramine and 0.6% octahydroxyquinoline to the sealing agent, put In the vacuum kettle, vacuumize to 750mmHg or more for 10-15min, take out the test piece and rinse it with water, cure it in an oven at 100°C-140°C for 2h-4h, phosphate, wash with water, and then apply cathodic electrophoretic coating: The initial voltage of cathodic electrophoresis is 80-90V, the deposition voltage is 140-160V, the electrophoresis temperature is 28-30°C, and the electrophoresis time is 150-180s. After washing with water, it is cured, that is, it is baked at 80°C for 20-30 minutes, and then baked at 170°C. 30min to complete curing. That is to say, a bonded NdFeB magnet product with inorganic sealing treatment and cathodic electrophoresis composite protection containing corrosion inhibitor additives can be obtained. The corrosion resistance test of this Nd...

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PUM

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Abstract

The invention relates to a method for adhering neodymium iron boron inorganic hole and cathode electrophoresis composite surface protection, wherein the invention uses inorganic hole agent of potassium metasilicate, liquid glass or lithium silicate whose modules are 3.3-5.4, 3.3 and 4.5, added with inhibitor additive as 0.5-2% hexamethylene tetramine, 0.2-1% bioquin and 0.5-3% sodium molybdatem, under vacuum condition to seal the holes of neodymium iron boron magnet, then processes composite surface protection of electrophoresis coat. The invention has simple operation and semi-automatic operation, to obtain uniform thickness and better insulation property.

Description

technical field [0001] The invention discloses an inorganic sealing and cathodic electrophoresis composite surface protection technology for bonding NdFeB magnets, which belongs to the technical field of surface protection for porous magnets, and in particular relates to a surface protection method and process for bonding NdFeB magnets. Background technique [0002] As the third-generation rare earth permanent magnet material, NdFeB has excellent magnetic properties and high cost performance, so it has achieved rapid development in scientific research, production and application in recent years. Widely used in high-tech fields such as electronic appliances, machinery and medical equipment, automobiles, and aviation. With the continuous improvement of its performance, new application growth points continue to emerge, especially the development of knowledge economy represented by the information industry. Functional materials such as permanent magnets continue to bring new use...

Claims

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Application Information

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IPC IPC(8): B22F3/24H01F41/02H01F1/057
Inventor 邱大健肖祥定倪晓雪赵定义谢鸽平
Owner WUHAN RES INST OF MATERIALS PROTECTION
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