阅读说明：本技术 一种铁基合金磁粉芯的防锈处理方法 (Rust-proof treatment method for iron-based alloy magnetic powder core ) 是由 徐涛涛 张博玮 冯松松 张鑫 朱玉飞 邹中秋 仝西川 马剑 于 2021-07-19 设计创作，主要内容包括：本发明公开了一种铁基合金磁粉芯的防锈处理方法,属于磁性材料技术领域。本发明将绝缘后的铁基合金粉放入防锈液中浸泡,防锈液可在绝缘后的磁粉表面成膜；起到防锈、改善磁粉表面绝缘质量从而防止损耗恶化,以及提高磁粉成形性从而提升粉芯机械强度的效果；接着压制成生坯,将生坯再放入防锈液中进行二次浸泡,可以有效修复生坯表面可能因压制而损坏的防锈膜层和绝缘包覆层,起到防锈和防止损耗显著恶化的效果。用本发明方法可以解决现有喷漆防锈工艺成本高、环境污染大,常规防锈液浸泡工艺不能长期和全面防锈,以及硅烷偶联剂防锈工艺损害粉芯磁性能的问题,有效防止铁基合金磁粉芯因环境湿度大、放置时间较长等因素引起的表面锈蚀。(The invention discloses an antirust treatment method for an iron-based alloy magnetic powder core, and belongs to the technical field of magnetic materials. According to the invention, the insulated iron-based alloy powder is soaked in the antirust liquid, and the antirust liquid can form a film on the surface of the insulated magnetic powder; the effects of rust prevention, improvement of the surface insulation quality of the magnetic powder so as to prevent loss deterioration, and improvement of the formability of the magnetic powder so as to improve the mechanical strength of the powder core are achieved; and then pressing into a green body, and putting the green body into antirust liquid for secondary soaking, so that an antirust film layer and an insulating coating layer which are possibly damaged by pressing on the surface of the green body can be effectively repaired, and the effects of rust prevention and remarkable deterioration prevention of loss are achieved. The method can solve the problems that the existing spray painting antirust process has high cost and large environmental pollution, the conventional antirust liquid soaking process can not realize long-term and comprehensive antirust, and the silane coupling agent antirust process damages the magnetic performance of the powder core, and effectively prevents the surface of the iron-based alloy magnetic powder core from being rusted due to factors such as large environmental humidity, long standing time and the like.)

1. An antirust treatment method of an iron-based alloy magnetic powder core is characterized by comprising the following operation steps:

(1) soaking the insulated iron-based alloy powder in an antirust liquid for 20-80 min; drying at the temperature of 60-160 ℃ for 60-80 min to obtain antirust iron-based alloy powder;

the antirust liquid is a mixed solution of acrylic emulsion, epoxy acrylate resin and dodecyl alcohol ester;

(2) adding a release agent into the antirust iron-based alloy powder, uniformly mixing, pressing into a green body, wherein the addition amount of the release agent is 1-10 per mill of the mass of the antirust iron-based alloy powder, and the forming pressure is 1600-2500 MPa;

(3) placing the green body into an antirust liquid for secondary soaking, wherein the soaking time is 60-180 min; drying the surface of the green body at 60-80 ℃; and then low-temperature baking is carried out, wherein the low-temperature baking condition is as follows: the temperature is 130-300 ℃, and the time is 30-100 min; obtaining a soaked green body;

the antirust liquid is the same as the antirust liquid in the step (1);

(4) annealing the soaked green body in nitrogen, wherein the annealing temperature is 700-900 ℃, the heat preservation time is 40-120 min, and naturally cooling to obtain the iron-based alloy magnetic powder core;

the relative magnetic permeability of the iron-based alloy magnetic powder core is 58-73, and the loss of 50kHz/100mT is 267.3-501.2 mW/cm³The breaking strength is 479 to 643N.

2. The rust-proofing treatment method for an iron-based alloy magnetic powder core according to claim 1, characterized in that: in the step (1), the iron-based alloy powder is one of gas atomized iron-silicon-aluminum alloy powder, ball-milled crushed iron-silicon-aluminum alloy powder and gas atomized iron-silicon-aluminum alloy powder.

3. The rust-proofing treatment method for an iron-based alloy magnetic powder core according to claim 1, characterized in that: in the step (1), the antirust liquid is prepared by uniformly mixing acrylic emulsion, epoxy acrylate resin and dodecyl alcohol ester according to the volume ratio of 1:1: 3-18.

Technical Field

The invention belongs to the technical field of magnetic materials, and particularly relates to an anti-rust method for an iron-based alloy magnetic powder core.

Background

The common iron-based alloy magnetic powder core comprises an iron-silicon powder core, an iron-silicon-aluminum powder core, an iron-nickel powder core and a pure iron powder core, and is widely applied to power electronic equipment such as an active filter, an inverter, an uninterruptible power supply and the like. At present, most of magnetic powder cores are prepared by powder metallurgy processes such as insulation coating, press forming, annealing heat treatment and the like, and have the advantages of easy processing and excellent magnetic property.

However, since most of the soft magnetic powder cores are made of iron, the soft magnetic powder cores are easily rusted under the condition of air humidity or long-term storage, and the anti-rusting capability of the soft magnetic powder cores is poor. In order to prevent the iron-based alloy magnetic powder core from being rusted, a method of painting or soaking in anti-rust oil is usually adopted in actual production to isolate the magnetic core from air so as to prevent the iron-based alloy magnetic powder core from being rusted. However, the environment is easily polluted by spray painting, and the outer surface skin of the paint layer is easy to drop after long-time use; and because the air in the tiny air gaps inside the magnetic core is difficult to be completely discharged, the rust preventive oil is difficult to completely enter the air gaps inside the powder core, and the purposes of comprehensive rust prevention and long-term rust prevention are difficult to achieve. In addition, there are also researchers who perform rust prevention treatment on the magnetic powder core using a silane coupling agent, but this method requires acid washing or alkali washing of the magnetic core during rust prevention, and both the acid and alkali react with the magnetic powder to passivate the surface thereof, thereby causing deterioration of the magnetic performance of the magnetic powder core. Therefore, a process method which does not affect the magnetic performance of the powder core and can realize long-term and comprehensive rust prevention is developed, and the method has important significance for optimizing the comprehensive physical properties of the iron-based alloy magnetic powder core.

Disclosure of Invention

The invention provides an antirust treatment method for an iron-based alloy magnetic powder core, aiming at solving the problems that the existing paint spraying antirust process is high in cost and large in environmental pollution, an antirust liquid soaking process cannot realize long-term and comprehensive antirust, and a silane coupling agent antirust process damages the magnetic performance of the powder core, and the like, and realizing the purposes of enhancing the antirust capacity of the magnetic powder core and improving the mechanical strength of the magnetic powder core under the condition of not influencing the magnetic performance of the iron-based alloy magnetic powder core.

The rust-proof treatment operation steps of the iron-based alloy magnetic powder core are as follows:

(1) soaking the insulated iron-based alloy powder in an antirust liquid for 20-80 min; drying at the temperature of 60-160 ℃ for 60-80 min to obtain antirust iron-based alloy powder;

the antirust liquid is a mixed solution of acrylic emulsion, epoxy acrylate resin and dodecyl alcohol ester;

(2) adding a release agent into the antirust iron-based alloy powder, uniformly mixing, pressing into a green body, wherein the addition amount of the release agent is 1-10 per mill of the mass of the antirust iron-based alloy powder, and the forming pressure is 1600-2500 MPa;

(3) placing the green body into an antirust liquid for secondary soaking, wherein the soaking time is 60-180 min; drying the surface of the green body at 60-80 ℃; and then low-temperature baking is carried out, wherein the low-temperature baking condition is as follows: the temperature is 130-300 ℃, and the time is 30-100 min; obtaining a soaked green body;

the antirust liquid is the same as the antirust liquid in the step (1);

(4) annealing the soaked green body in nitrogen, wherein the annealing temperature is 700-900 ℃, the heat preservation time is 40-120 min, and naturally cooling to obtain the iron-based alloy magnetic powder core;

the relative magnetic permeability of the iron-based alloy magnetic powder core is 58-73, and the loss of 50kHz/100mT is 267.3-501.2 mW/cm³The breaking strength is 479 to 643N.

The further concrete technical scheme is as follows:

in the step (1), the iron-based alloy powder is one of gas atomized iron-silicon-aluminum alloy powder, ball-milled crushed iron-silicon-aluminum alloy powder and gas atomized iron-silicon-aluminum alloy powder.

The antirust liquid is prepared by uniformly mixing acrylic emulsion, epoxy acrylate resin and dodecyl alcohol ester according to the volume ratio of 1:1: 3-18.

The beneficial technical effects of the invention are embodied in the following aspects:

1. according to the invention, the insulated iron-based alloy powder is soaked in the antirust liquid, the antirust liquid can form a film on the surface of the insulated magnetic powder, so that the unevenness of insulation coating can be compensated, and the formed antirust liquid film has the functions of hydrophobicity and adhesion, so that the antirust liquid film can play a role in rust prevention, the eddy current path of the magnetic powder is blocked, the loss is prevented from being obviously deteriorated, and the formability of the magnetic powder is improved, thereby improving the mechanical strength of the powder core.

2. The invention puts the pressed and formed green body into the antirust liquid for secondary soaking, and can effectively repair the antirust film layer and the insulating coating layer which are possibly damaged by pressing on the surface of the green body, thereby having the effects of rust prevention and remarkable deterioration prevention of loss.

3. Taking a ball-milling crushed sendust magnetic powder core with the relative permeability grade of 60 (+/-8%) as an example, the No. 1 sample is a sample which is not subjected to rust prevention treatment, and the No. 2 sample is a sample prepared by the process. Their magnetic properties and tensile strength versus strength are shown in table 1. Therefore, the permeability and the loss of the sample treated by the rust-proof process are not changed greatly, but the breaking strength is obviously enhanced. Figure 1 is a photograph of the appearance of two samples after 360 hours of double 85 testing. Therefore, after the antirust process disclosed by the invention is adopted for treatment, the surface of a sample is not rusted, and a good antirust effect is achieved.

Drawings

FIG. 1 is a photograph showing the appearance of a ball-milled crushed sendust core after being subjected to (a) no rust prevention treatment and (b) the rust prevention process of the present invention after 360 hours of a double 85 test.

Detailed Description

The present invention will be described with reference to specific examples.

Example 1

The rust-proof treatment operation steps of the iron-based alloy magnetic powder core are as follows:

(1) 500g of insulated gas atomized iron-silicon-aluminum alloy powder is put into 5kg of antirust liquid for soaking for 20 min; and (3) drying at the temperature of 60 ℃ for 60min to obtain the antirust iron-based alloy powder.

The antirust liquid is prepared by uniformly mixing acrylic emulsion, epoxy acrylate resin and dodecyl alcohol ester according to the volume ratio of 1:1: 3.

(2) 500g of antirust iron-based alloy powder and 0.5g of release agent are uniformly mixed and pressed into a green body, and the forming pressure is 1600 MPa.

(3) And (3) putting the green body into antirust liquid for secondary soaking, wherein the soaking time is 60 min. Drying the surface of the green body at 60 ℃, and then baking at low temperature of 130 ℃ for 30min to obtain a soaked green body.

The antirust liquid is the same as that in the step (1).

(4) And annealing the soaked green body at 700 ℃ for 40min to obtain the gas atomized Fe-Si-Al soft magnetic powder core.

The relative permeability of the gas atomized sendust soft magnetic powder core of the embodiment 1 is 62, the loss of 50kHz/100mT is 267.3mW/cm³And the breaking strength is 479N.

Example 2

The rust-proof treatment operation steps of the iron-based alloy magnetic powder core are as follows:

(1) and (3) taking 500g of insulated ball-milling crushed iron-silicon-aluminum alloy powder, putting the insulated ball-milling crushed iron-silicon-aluminum alloy powder into 5kg of antirust liquid for soaking for 60min, and drying at the temperature of 120 ℃ for 70 min to obtain the antirust ball-milling crushed iron-silicon-aluminum alloy powder.

The antirust liquid is prepared by uniformly mixing acrylic emulsion, epoxy acrylate resin and dodecyl alcohol ester according to the volume ratio of 1:1: 10.

(2) 500g of antirust ball-milling crushed iron-silicon-aluminum alloy powder and 2.5g of release agent are uniformly mixed and pressed into a green body, and the forming pressure is 1900 MPa.

(3) And (3) putting the green body into an antirust liquid for secondary soaking, wherein the soaking time is 120 min. Drying the surface of the green body at 70 ℃, and then baking at low temperature of 200 ℃ for 60min to obtain a soaked green body.

The antirust liquid is the same as that in the step (1).

(4) And annealing the soaked green body at 800 ℃ for 80min to obtain the ball-milled broken Fe-Si-Al soft magnetic powder core.

The relative magnetic permeability of the ball-milled broken sendust soft magnetic powder core of the embodiment 2 is 58, and the loss of 50kHz/100mT is 329.3mW/cm³The breaking strength was 643N.

Referring to fig. 1, fig. 1 (a) is a photograph showing the appearance of a ball-milled crushed sendust core without rust prevention after 360 hours of a double 85 test, which shows that rust spots exist on the surface of the ball-milled crushed sendust core. Fig. 1 (b) is an appearance photograph of a sample after 360 hours of a double 85 test of the ball-milled crushed sendust magnetic powder core treated by the rust prevention process of the present invention, which shows that the surface of the ball-milled crushed sendust magnetic powder core treated by the rust prevention process of the present invention has no rust stains.

Example 3

The rust-proof treatment operation steps of the iron-based alloy magnetic powder core are as follows:

(1) 500g of insulated gas atomized ferrosilicon powder is taken and put into 5kg of antirust liquid for soaking for 80 min; and (4) drying at 160 ℃ for 80min to obtain the rust-proof gas atomized iron-silicon alloy powder.

The antirust liquid is prepared by uniformly mixing acrylic emulsion, epoxy acrylate resin and dodecyl alcohol ester according to the volume ratio of 1:1: 18.

(2) 500g of rust-proof gas atomized iron-silicon alloy powder and 5g of release agent are uniformly mixed and pressed into a green body, and the forming pressure is 2500 MPa.

(3) And (4) putting the green body into an antirust liquid for secondary soaking, wherein the soaking time is 180 min. Drying the surface of the green body at 80 ℃, and then baking at low temperature of 300 ℃ for 100min to obtain the soaked green body.

The antirust liquid is the same as that in the step (1).

(4) And annealing the soaked green body at the annealing temperature of 900 ℃ for 120min to obtain the gas atomized iron-silicon soft magnetic powder core.

The relative permeability of the gas atomized iron-silicon soft magnetic powder core of the embodiment 3 is 73, and the loss of 50kHz/100mT is 501.2mW/cm³The breaking strength was 598N.

The above description is only exemplary of the present invention, and is not intended to limit the present invention, and any modifications and equivalents of the method according to the present invention may still fall within the scope of the present invention.