Sintered magnet and fabrication method thereof

A technology of bonded magnets and magnetic powder, applied in the manufacture of permanent magnets, magnetic objects, inductors/transformers/magnets, etc. The effect of low cost and preparation cost

Inactive Publication Date: 2019-11-12
NEO PERFORMANCE MATERIALS (SINGAPORE) PTE LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The main purpose of the present invention is to provide a bonded magnet and its preparation method to solve the problem of poor corrosion resistance of the coating existing in the existing magnet coating preparation process

Method used

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  • Sintered magnet and fabrication method thereof
  • Sintered magnet and fabrication method thereof
  • Sintered magnet and fabrication method thereof

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Experimental program
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preparation example Construction

[0035] As described in the background art, the existing magnet coating preparation process has the problem of poor corrosion resistance of the coating. In order to solve the above technical problems, the present application provides a method for preparing a bonded magnet. The preparation method includes: using magnetic powder and an adhesive as raw materials to perform compression molding to obtain a green body; preheating the green body; The heat-treated green body is heated and vacuumized so that the adhesive forms a coating on the surface of the green body to obtain a bonded magnet, wherein the temperature of the heating process is higher than the melting point of the adhesive.

[0036] Through the preheating process, the adhesive in the green body is in a fluid state, and then using the flow and curing characteristics of the adhesive during the magnet curing process, under vacuum conditions, a part of the adhesive is evenly covered on the surface of the magnet to form a mag...

Embodiment 1

[0051] The raw material of mixed magnetic powder is: the content of FeNdB magnetic powder 94.68% (percentage by weight), particle size is less than 90 orders; Binding agent is epoxy resin adhesive (accounting for the weight percent of mixed magnetic powder, it comprises 5% epoxy Resin, 0.11% dicyandiamide curing agent and 0.01% curing accelerator DMP30); zinc stearate is a lubricant, and the content is 0.2% (percentage by weight).

[0052] Compress the above raw materials on a press to obtain a blank, wherein the molding pressure is 7t / cm 2 , The formed body is a cylinder with a diameter of 9.5mm and a height of 6.3mm.

[0053] Put the above blank in a vacuum oven at 180°C, heat for 5 minutes, start the vacuum pump, and carry out vacuum treatment to obtain the required bonded magnet. The vacuum degree of the vacuum treatment process is 1×10 -2 Pa, the processing time is 25min. For coating application, see Figure 4a .

[0054] Performance Testing:

[0055] The anti-corros...

Embodiment 2

[0057] The difference of embodiment 1 is:

[0058] The vacuum degree of the vacuum treatment process is 3.5×10 3 ~4×10 3 Pa, the processing time is 10min. For coating application, see Figure 5a .

[0059] The test method of anti-corrosion performance is with embodiment 1, and test result sees Figure 5b .

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Abstract

The invention provides a sintered magnet and a fabrication method thereof. The fabrication method comprises the steps of performing pressing and formation on magnetic powder and an adhesive agent which are used raw materials to obtain a blank; pre-heating the blank; and performing heating and vacuum pumping on the blank after pre-heating so that the adhesive forms a coating layer on a surface of the blank to obtain the sintered magnet, wherein the temperature of the heating process is higher than a melting point of the adhesive agent. The coating layer fabricated by the method, the magnet andthe adhesive agent are integrated, and no interface between the magnet coating layer and the magnet exists. Compared with an existing coating layer, the coating layer fabricated by the method is difficult to generate coating layer stripping, and thus, the corrosion resistance of the coating layer can be better. Moreover, according to the fabrication method, the coating layer formation process andthe magnet curing process are simultaneously performed, the material for forming the coating layer is also a part of the adhesive layer, and thus, the process cost and the material cost of the coatinglayer fabrication process can be substantially reduced.

Description

technical field [0001] The invention relates to the field of magnet preparation, in particular to a bonded magnet and a preparation method thereof. Background technique [0002] Press-molded bonded NdFeB magnets usually require a magnet coating on the magnet surface to achieve corrosion resistance. Common magnet coating processes include electrophoretic coating, powder coating, electroplating coating and physical / chemical deposition coating. Common coating materials include epoxy resin, fluorine-containing polymer resin, polyester resin, polyamide resin, polyacrylic resin, and organic resins such as parylene and carbon, metal coatings such as nickel, chromium, and aluminum, and Ceramic coatings such as silica and alumina. [0003] The coatings currently applied to press-bonded NdFeB magnets have the following deficiencies: [0004] Regardless of the above-mentioned coating process and coating material, since the coating is applied on the outer surface of the magnet after ...

Claims

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Application Information

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IPC IPC(8): H01F41/02H01F1/055H01F1/057H01F1/059
CPCH01F1/0558H01F1/0578H01F1/059H01F41/026
Inventor韩智三赵巍
OwnerNEO PERFORMANCE MATERIALS (SINGAPORE) PTE LTD