阅读说明：本技术 一种疏水型导热粘结磁性复合材料及其制备方法 (Hydrophobic heat-conducting bonded magnetic composite material and preparation method thereof ) 是由 邵萌 段晓峰 于 2020-06-29 设计创作，主要内容包括：本发明涉及一种疏水型导热粘结磁性复合材料及其制备方法。该疏水型导热粘结磁性复合材料包括如下重量份组分：Sm-Co-Fe-Zr纳米复相永磁材料40～50份、粘结树脂20～30份、导热填料10～20份、助剂5～10份；所述粘结树脂由环氧树脂和三元氯醋树脂,按1:(0.2～0.4)的重量配比混合而成；所述导热填料为氮化铝和二硼化钛混合物。制备时,按配比将各组分通过混合、球磨、螺旋挤压、热压成型过程制备得到。本发明所述的疏水型导热粘结磁性复合材料具有疏水性好、导热率高、磁力性质强的特点。(The invention relates to a hydrophobic heat-conducting bonded magnetic composite material and a preparation method thereof. The hydrophobic heat-conducting bonded magnetic composite material comprises the following components in parts by weight: 40-50 parts of Sm-Co-Fe-Zr nano complex phase permanent magnetic material, 20-30 parts of bonding resin, 10-20 parts of heat conducting filler and 5-10 parts of auxiliary agent; the adhesive resin is prepared by mixing epoxy resin and ternary vinyl chloride-vinyl acetate copolymer resin according to the weight ratio of 1 (0.2-0.4); the heat conducting filler is a mixture of aluminum nitride and titanium diboride. When in preparation, the components are prepared according to the proportion through the processes of mixing, ball milling, screw extrusion and hot press molding. The hydrophobic heat-conducting bonded magnetic composite material has the characteristics of good hydrophobicity, high heat conductivity and strong magnetic property.)

1. The hydrophobic heat-conducting bonding magnetic composite material is characterized by comprising the following components in parts by weight: 40-50 parts of Sm-Co-Fe-Zr nano complex phase permanent magnetic material, 20-30 parts of bonding resin, 10-20 parts of heat conducting filler and 5-10 parts of auxiliary agent; the adhesive resin is prepared by mixing epoxy resin and ternary vinyl chloride-vinyl acetate copolymer resin according to the weight ratio of 1 (0.2-0.4).

2. The composite material of claim 1, wherein the heat conductive filler is formed by mixing aluminum nitride and titanium diboride according to a weight ratio of 1 (0.1-0.3).

3. The composite material of claim 1, wherein the adjuvants comprise a coupling agent, a hydrophobic reinforcing agent, and a curing agent; the coupling agent is a silane coupling agent; the hydrophobic reinforcing agent is zinc oxide; the curing agent is 2-ethyl-4-methylimidazole.

4. The composite material according to claim 1, wherein the auxiliary agent comprises (2-6%) by mass of the coupling agent, the hydrophobic reinforcing agent and the curing agent: (1-3%): (0.5% -3%).

5. The composite material of claim 1, wherein the particle size of the nano composite permanent magnetic material is 0.1-10 μm.

6. The magnetic composite material of claim 2, wherein the aluminum nitride has a particle size of 50 to 100 μm and the titanium diboride has a particle size of 0.1 to 5 μm.

7. A method of preparing a composite material as claimed in any one of claims 1 to 6, comprising the steps of:

(1) weighing the nano multiphase permanent magnet material according to the formula, drying in vacuum, placing in an ethanol solution for ultrasonic dispersion for 20-30 min, adding a silane coupling agent, continuing ultrasonic dispersion for 10-20 min, standing for 60-80 min, and drying in vacuum; the concentration of the ethanol solution is 75-95% by mass percent;

(2) adding the bonding resin and the hydrophobic reinforcing agent into the nano complex phase permanent magnetic material dried in the step 1, uniformly stirring, adding the curing agent, uniformly mixing, placing into a ball mill, and carrying out ball milling for 60-80 min at the rotating speed of 100-120 r/min;

(3) placing the mixture subjected to ball milling in the step 2 into a double-screw extruder for extrusion granulation, wherein the extrusion temperature of the double-screw extruder is 180-200 ℃, and the extrusion rotating speed is 250-350 r/min, so as to obtain a blending sample;

(4) and (3) placing the blending sample obtained in the step (3) in a flat vulcanizing machine for compression molding, carrying out hot pressing for 10-20 min, exhausting and maintaining pressure for 5-10 min, cooling and then demolding to obtain the composite material.

8. The preparation method of the composite material according to claim 7, wherein the vacuum drying condition in the step 1 is drying for 6-8 hours at a temperature of 70-80 ℃.

9. The method for preparing a composite material according to claim 7, wherein the processing conditions of the twin-screw extruder in the step 3 are as follows: the first zone was 190 deg.C, the second zone was 210 deg.C, the third zone was 230 deg.C, the fourth zone was 200 deg.C and the fifth zone was 190 deg.C.

Technical Field

The invention belongs to the technical field of magnetic materials and composite materials, and particularly relates to a hydrophobic heat-conducting bonded magnetic composite material and a preparation method thereof.

Background

Bonded magnets have found wide applications in the field of electric machines due to their advantages of high cost performance, large freedom of shape, and high dimensional accuracy. However, since most of the permanent magnet materials in the bonded magnet are made of alloy, the bonded magnet is extremely active in chemical property and is easily oxidized and corroded in humid air or other corrosive environments. Therefore, methods such as electroplating or electrophoretic deposition are often used to improve the corrosion resistance of the magnet. Because the bonded magnet is prepared by mixing magnetic powder and high polymer resin and adopting a mould pressing or injection molding method, the bonded magnet has the defects of poor heat conductivity, low density, large porosity and the like. Especially when the magnet is irregular in shape, it is not easy to obtain a uniform and dense coating on the surface of the magnet by electroplating or electrophoretic deposition due to the presence of relatively significant tip discharge and edge effects. In the electroplating or electrophoretic deposition process, the plating solution is easy to permeate into the magnet through the pores, and if the pretreatment and the post-treatment of the magnet are improper, the corrosion of the magnet is accelerated to influence the performance of the magnet.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides a hydrophobic heat-conducting bonded magnetic composite material and a preparation method thereof. The composite material prepared by adopting the high-quality magnetic material nano complex phase permanent magnetic material and the bonding resin and the coupling agent with good hydrophobic property, the hydrophobic reinforcing agent, the curing agent and the heat conducting filler has the characteristics of good hydrophobic property, high heat conductivity and strong magnetic property.

In order to achieve the purpose, the invention adopts the technical scheme that:

on the one hand, the hydrophobic heat-conducting bonded magnetic composite material comprises the following components in parts by weight: 40-50 parts of Sm-Co-Fe-Zr nano complex phase permanent magnetic material, 20-30 parts of bonding resin, 10-20 parts of heat conducting filler and 5-10 parts of auxiliary agent.

Furthermore, the adhesive resin is prepared by mixing epoxy resin and ternary vinyl chloride-vinyl acetate copolymer resin according to the weight ratio of 1 (0.2-0.4).

Furthermore, the heat conducting filler is formed by mixing aluminum nitride and titanium diboride according to the weight ratio of 1 (0.1-0.3).

Further, the auxiliary agent comprises a coupling agent, a hydrophobic reinforcing agent and a curing agent.

The coupling agent used in the present invention is a silane coupling agent.

The hydrophobicity enhancing agent used in the present invention is zinc oxide.

The curing agent used in the present invention is 2-ethyl-4-methylimidazole.

Further, the auxiliary agent comprises the following components in percentage by mass (2-6%): (1-3%): (0.5% -3%).

Furthermore, the particle size of the nano complex phase permanent magnetic material is 0.1-10 μm.

Further, the particle size of the aluminum nitride is 50 to 100 μm, and the particle size of the titanium diboride is 0.1 to 5 μm.

On the other hand, the preparation method of the hydrophobic heat-conducting bonded magnetic composite material comprises the following steps:

(1) weighing the nano multiphase permanent magnet material according to the formula, drying in vacuum, placing in an ethanol solution for ultrasonic dispersion for 20-30 min, adding a silane coupling agent, continuing ultrasonic dispersion for 10-20 min, standing for 60-80 min, and drying in vacuum; the concentration of the ethanol solution is 75-95% by mass percent;

(2) uniformly stirring the nano complex phase permanent magnetic material, the bonding resin and the hydrophobic reinforcing agent which are dried in the step 1, adding a curing agent, uniformly mixing, placing in a ball mill, and carrying out ball milling for 60-80 min at the rotating speed of 100-120 r/min;

(3) placing the mixture subjected to ball milling in the step 2 into a double-screw extruder for extrusion granulation, wherein the extrusion temperature of the double-screw extruder is 180-200 ℃, and the extrusion rotating speed is 250-350 r/min, so as to obtain a blending sample;

(4) and (3) placing the blending sample obtained in the step (3) in a flat vulcanizing machine for compression molding, carrying out hot pressing for 10-20 min, exhausting and maintaining pressure for 5-10 min, cooling and then demolding to obtain the composite material.

Further, the vacuum drying condition in the step 1 is specifically drying for 6-8 hours at the temperature of 70-80 ℃;

further, the processing conditions of the twin-screw extruder in the step 4 are specifically as follows: the first zone was 190 deg.C, the second zone was 210 deg.C, the third zone was 230 deg.C, the fourth zone was 200 deg.C and the fifth zone was 190 deg.C.

The invention has the beneficial effects that:

(1) according to the invention, the bonding resin with strong hydrophobic property, the hydrophobic coupling agent wraps the nano complex-phase magnet material, and the ZnO particles are added into the epoxy resin, so that a micro rough structure is constructed in the resin to form micro papillae, a lotus effect appears on the surface of the composite material to a certain extent, and the hydrophobic property of the composite material is improved in a combination of the above modes.

(2) The invention increases the bonding capacity of the nano complex phase permanent magnetic material and the resin binder by the physical mode of coating the coupling agent on the nano complex phase permanent magnetic material; secondly, the compression resistance and the heat resistance of the bonding resin are further enhanced by adding a cross-linking product generated by the curing action of the curing agent and the bonding resin.

(3) The invention adopts Sm-Co-Fe-Zr nano complex phase permanent magnetic material with high magnetic performance, bonding resin with strong hydrophobic performance, coupling agent and curing agent are added, and insulating heat-conducting fillers of aluminum nitride and titanium diboride are added, so that the prepared bonded magnetic composite material improves the defects of single-component bonding materials, has good hydrophobic performance, high heat conductivity and strong magnetic force property, the relative magnetic conductivity reaches 6.2, and the specific saturation magnetization intensity is 192.3 (A.m)²) Perkg, coercive force 3.52 × 10⁴A/m。

Detailed Description

The present invention is further described in the following examples, which should not be construed as limiting the scope of the invention, but rather as providing the following examples which are set forth to illustrate and not limit the scope of the invention.