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A kind of preparation method of large size high density bonded permanent magnet

A bonded permanent magnet, high-density technology, applied in the direction of magnetic objects, inductance/transformer/magnet manufacturing, magnetic materials, etc., can solve the problems of difficult to achieve density, uneven density distribution, heavy workload, etc., to improve loose packing Density and fluidity, good density uniformity, and the effect of improving service life

Active Publication Date: 2017-02-08
HUNAN AEROSPACE MAGNET & MAGNETO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The bonded magnets pressed by this method are all Φ10×10mm cylinders and small-sized samples. When pressing large-sized samples, it is difficult for the final product to reach 6.3-6.4 g / cm due to the reduced effective efficiency of pressure transmission. 3 The main reason is that the density of the pre-pressed intermediate is high, the crushing is difficult and the workload is heavy, and multiple crushing will seriously affect the intrinsic coercive force Hcj of the magnet
The second is that in conventional production, the method of increasing the molding pressure is usually used, but the effect is limited for bonded permanent magnets with larger sizes. This is because when the size is larger, the effective transmission rate of the pressing pressure is small and the pressure distribution is not good. Uniform, and the friction is large, it is easy to cause uneven density distribution and product cracking
For bonded permanent magnets, the conventional products are miniature, the product size is very small, the density requirement is not high, and the mechanical strength of the miniature bonded magnet is limited, and it is easy to crack when isostatic pressing; at the same time, the product size is small and the packaging is relatively small. Difficult, low productivity

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] (1) Ingredients mix:

[0025] Mix 194g of bisphenol A epoxy resin (500 epoxy equivalent), 6g of dicyandiamide curing agent and 1500g of acetone, then add 9790g of quick-quenched NdFeB magnetic powder MQP-B2 powder, mix evenly, dry, and finally add 10g of zinc stearate lubricant is fully mixed to obtain 10kg of composite powder, and the bulk density of this composite powder is 2.4g / cm 3 , fluidity is 36s / 50g;

[0026] (2) Compression molding:

[0027] Put the composite powder obtained in step (1) into the forming mold and apply 6T / cm 2 , 8T / cm 2 、10T / cm 2 The pressure is pressed and formed into a bonded permanent magnet intermediate by means of floating two-way pressing, and the cross-sectional area of ​​the permanent magnet in the pressing direction is 20cm 2 , with a height of 14mm;

[0028] (3) Cold isostatic pressing:

[0029] Vacuum-encapsulate the bonded permanent magnet intermediate obtained in step (2), and perform cold isostatic pressing with a cold isost...

Embodiment 2

[0037] Vacuum ball mill the quick-quenched NdFeB magnetic powder MQP-B2 through a 120-mesh sieve and a 250-mesh sieve, select 10kg of 120-250-mesh magnetic powder, soak it in 2kg of silane coupling agent KH550 with a mass concentration of 5% acetone solution for 5 hours, and ultrasonic 40kHz Disperse for 2.5 hours, sonicate once every 30 minutes, each time for 15 minutes, and dry at 80°C for 2 hours.

[0038] (1) Ingredients mix:

[0039]Mix 250g of bisphenol A epoxy resin (epoxy equivalent of 300), 6g of dicyandiamide curing agent and 1500g of acetone, then add 9719g of processed NdFeB magnetic powder MQP-B2, mix evenly, dry, and finally Add 25g of zinc stearate lubricant and mix well to obtain 10kg of composite powder. The bulk density of the composite powder is 3.2g / cm 3 , fluidity is 25s / 50g;

[0040] (2) Compression molding:

[0041] Put the composite powder obtained in step (1) into the forming mold and apply 6 T / cm 2 , 8T / cm 2 、10T / cm 2 The pressure is pressed and...

Embodiment 3

[0051] The domestic NdFeB magnetic powder XQP-15-10 is vacuum ball-milled through 160-mesh sieve and 250-mesh sieve, and 10kg of 160-250-mesh magnetic powder is selected and soaked in 2kg of silane coupling agent KH550 mass concentration of 10% acetone solution for 5 hours, ultrasonic Disperse at 40kHz for 5.5h, sonicate once every 30min, 15min each time, and dry at 80°C for 2h.

[0052] (1) Ingredients mix:

[0053] Mix 275g of bisphenol A epoxy resin (epoxy equivalent of 200), 8g of organic anhydride curing agent and 1800g of acetone, then add 9707g of domestic NdFeB magnetic powder XQP-15-10 after treatment, mix evenly, dry, and finally Add 10g of magnesium stearate lubricant and mix well to obtain 10kg of composite powder. The bulk density of the composite powder is 3.6g / cm 3 , fluidity is 23s / 50g;

[0054] (2) Compression molding:

[0055] Put the composite powder obtained in step (1) into the forming mold and apply 10T / cm 2 The pressure is pressed and formed into a b...

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Abstract

The invention discloses a method for manufacturing a large-sized high-density bonded permanent magnet. The method comprises the following steps: burdening and mixing: uniformly mixing thermosetting resin, a curing agent, acetone, permanent magnet powder and a lubricating agent to obtain composite powder; (2) press molding: molding the composite powder into an intermediate of the bonded permanent magnet by pressing; (3) cold isostatic pressing: packing the bonded permanent magnet intermediate in vacuum for performing cold isostatic pressing treatment to obtain a bonded permanent magnet green body; (4) curing: curing the bonded permanent magnet green body to obtain the large-sized high-density bonded permanent magnet. Moreover, before burdening and mixing, the permanent magnet powder can be subjected to ball-milling and sieving in vacuum, and be subjected to surface treatment by using a silane coupling agent. Compared with the conventional method, the method has the advantages that under the same mold pressing pressure (6-10T / cm<2>), the density of the bonded permanent magnet can be increased by 1-3 percent, higher density uniformity is achieved, and the magnetic performance of the permanent magnet is effectively enhanced. The method is particularly suitable for manufacturing a large-sized bonded permanent magnet having a high density requirement.

Description

technical field [0001] The invention relates to a method for preparing a bonded permanent magnet, in particular to a method for preparing a large-size and high-density bonded permanent magnet. Background technique [0002] Bonded permanent magnets have developed rapidly in recent years due to their low cost, high dimensional accuracy, large degree of freedom in shape, and simple preparation process. They have been widely used in industry, agriculture, and national defense, and have become important basic functional materials in the information age. At present, most bonded permanent magnets are small in size and miniaturized. There is little research and production of large-size, high-density bonded permanent magnets formed by compression molding. [0003] Density is one of the key factors affecting the magnetic properties of bonded components. Increasing density can not only improve the magnetic properties of bonded components, but also improve the corrosion resistance of b...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01F41/02H01F1/053B22F9/04B22F3/02
Inventor 李彬谭春林胡盛青向芳周朝晖
Owner HUNAN AEROSPACE MAGNET & MAGNETO