阅读说明：本技术 软磁复合材料及其制备方法和应用 (Soft magnetic composite material and preparation method and application thereof ) 是由 吕先松 郭峰 刘斌斌 汪贤 于 2021-06-02 设计创作，主要内容包括：本发明提供一种软磁复合材料及其制备方法和应用,软磁复合材料包括如下重量份数的原料混合制备而成：90～110份的软磁粉末、2～5份的粘接剂以及0.1～3份的辅助添加剂,其中,粘接剂由树脂和固化剂组成,辅助添加剂选自端羧基丁腈橡胶、聚硫橡胶、聚氨酯、650低分子聚酰胺树脂、651低分子聚酰胺树脂和双酚A型不饱和聚酯树脂中的至少一种。通过优化其原料的组成及比例,在软磁粉末和粘接剂中添加辅助添加剂,辅料添加剂的加入可以枝接在粘接剂的树脂或者固化剂分子链上,增加了树脂和固化剂反应的空间位阻,进而降低了反应活性,可以有效地提高软磁复合材料的稳定性,明显改善长时间室温存储下软磁复合材料的磁导率的衰减问题。(The invention provides a soft magnetic composite material and a preparation method and application thereof, wherein the soft magnetic composite material is prepared by mixing the following raw materials in parts by weight: the adhesive comprises 90-110 parts of soft magnetic powder, 2-5 parts of an adhesive and 0.1-3 parts of an auxiliary additive, wherein the adhesive comprises resin and a curing agent, and the auxiliary additive is selected from at least one of carboxyl-terminated nitrile rubber, polysulfide rubber, polyurethane, 650 low-molecular polyamide resin, 651 low-molecular polyamide resin and bisphenol A type unsaturated polyester resin. By optimizing the composition and proportion of the raw materials, the auxiliary additive is added into the soft magnetic powder and the adhesive, and the auxiliary additive can be grafted on a resin or curing agent molecular chain of the adhesive, so that the steric hindrance of the reaction of the resin and the curing agent is increased, the reaction activity is further reduced, the stability of the soft magnetic composite material can be effectively improved, and the problem of attenuation of the magnetic conductivity of the soft magnetic composite material under long-time room-temperature storage is obviously solved.)

1. The soft magnetic composite material is characterized by being prepared by mixing the following raw materials in parts by weight:

90-110 parts of soft magnetic powder,

2 to 5 parts of a binder, and

0.1-3 parts of auxiliary additive;

wherein the adhesive comprises resin and a curing agent,

the auxiliary additive is selected from at least one of carboxyl-terminated nitrile rubber, polysulfide rubber, polyurethane, 650 low-molecular polyamide resin, 651 low-molecular polyamide resin and bisphenol A type unsaturated polyester resin.

2. The soft magnetic composite material according to claim 1, wherein the mass ratio of the resin to the curing agent in the binder is (90-110) to (4-20).

3. The soft magnetic composite material according to claim 1, wherein the soft magnetic powder is at least one selected from carbonyl iron powder, iron silicon chromium powder, iron silicon aluminum powder, iron nickel powder, and iron silicon powder; and/or

The curing agent is at least one selected from aromatic amine type curing agents, anhydride type curing agents and imidazole type curing agents.

4. A soft magnetic composite material according to any of claims 1 to 3, wherein the resin is a thermosetting resin.

5. A soft magnetic composite material according to claim 4, wherein the thermosetting resin is at least one selected from the group consisting of epoxy resin, novolac epoxy resin and cyanate ester.

6. A preparation method of a soft magnetic composite material is characterized by comprising the following steps:

mixing the raw materials of the soft magnetic composite material according to any one of claims 1 to 5, and drying.

7. The method for preparing a soft magnetic composite material according to claim 6, wherein the resin and the curing agent of the binder and the auxiliary additive are mixed in a solvent, and then the soft magnetic powder is added, mixed and dried.

8. A process for preparing a soft magnetic composite material as claimed in claim 6 or 7, wherein in the drying process, the drying temperature is 40 ℃ to 80 ℃ and the drying time is 0.5 hour to 1.5 hours.

9. Use of the soft magnetic composite material according to any of claims 1 to 5 for the preparation of electronic products.

10. An electronic product comprising the soft magnetic composite material according to any one of claims 1 to 5.

Technical Field

The invention relates to the technical field of metal material powder metallurgy manufacturing, in particular to a soft magnetic composite material and a preparation method and application thereof.

Background

Soft magnetic materials are a class of materials that are both easily magnetized and demagnetized, and have very low coercivity. Generally, the main characteristics and requirements of such materials are: high saturation magnetic flux density, low coercive force, high magnetic permeability, low (power) loss and good stability. Soft magnetic materials have been developed for nearly a hundred years to date. The development and the application of the method drive the development of a plurality of related technical fields, particularly the power electronic technology and the like, and make outstanding contribution to the progress of the society. In the development history of soft magnetic materials, the most representative materials are silicon steel, ferrite, permalloy, amorphous and nanocrystalline and the like. At present, in the aspects of communication equipment, electric power, industrial automation equipment, computers and peripherals thereof, electronic instruments and meters and the like, the soft magnetic material is the most widely used magnetic material.

The soft magnetic composite material is mainly formed by mixing and pressing metal magnetic powder and an insulating medium by using a powder metallurgy process, and an insulating layer is arranged between adjacent magnetic powder particles. The soft magnetic composite material has the characteristics of 3D isotropic magnetic property, high saturation magnetic flux density, wide working frequency range, lower loss and the like, and can be prepared into various complicated shapes such as C-shaped, E-shaped, I-shaped, U-shaped, annular and the like due to the fact that the powder metallurgy process is adopted for compression molding, and as electronic devices gradually develop towards miniaturization and high frequency, the application of the soft magnetic composite material is wider.

In the soft magnetic material, the metal soft magnetic composite material (also called soft magnetic powder core) combines the advantages of soft magnetic alloy and ferrite material, thereby not only maintaining higher soft magnetic performance, but also having higher resistivity. At the end of the 19 th century, metallic soft magnetic materials began to find application in industry. Motors and transformers were made using mild steel at the time. By the beginning of the 20 th century, low-carbon steel is replaced by silicon steel sheets, loss of the silicon steel sheets is reduced, and efficiency of the transformer is improved. Until now, the amount of silicon steel sheets has been the first place in soft magnetic alloys for the power industry.

In the 20 th century, radio technology began to rise, high permeability magnetic materials developed rapidly, and permalloy and other soft magnetic alloys appeared. In the 40-60 th century, scientific technology developed rapidly, and integrated circuits, radars, television broadcasts and the like put forward higher requirements on soft magnetic materials, and soft magnetic alloy thin strip materials were produced. In the 70 s, with the rapid development of computer, telecommunication, and automatic control industries, soft magnetic alloys for magnetic heads were developed. In addition to the conventional crystalline soft magnetic alloy, research and development of amorphous soft magnetic alloy and nanocrystalline soft magnetic alloy have been promoted. The common metal soft magnetic composite materials include electrician pure iron, silicon steel, iron-aluminum alloy, iron-silicon-aluminum alloy, iron-nickel alloy and the like.

Generally, compared with metal soft magnetic alloy, the soft magnetic composite material has isotropic magnetic energy due to the specific three-dimensional network structure, and simultaneously has higher resistivity and three-dimensional forming technology. The soft magnetic composite material has the advantages of high saturation magnetic induction intensity and high reliability. Thus. The soft magnetic composite material provides a combination of high magnetic flux and low loss for electronic products, and develops towards high precision, high sensitivity, multiple functions, large capacity and miniaturization with the electronic products. Soft magnetic composites with high power, low loss and high reliability can be used to fabricate high performance electromagnetic components for use in specific environments.

The integrated inductor is one of the important applications of the soft magnetic composite material. The adhesive applied to the soft magnetic composite material of the integrally formed inductor mostly adopts epoxy resin adhesive, and the epoxy resin adhesive can generate partial cross-linking reaction in the long-term storage process at room temperature, so that the problems of magnetic permeability and strength attenuation of the soft magnetic composite material in the storage process are caused; in order to solve the problem of magnetic permeability attenuation of the soft magnetic composite material in the storage process, the traditional method usually adopts refrigeration treatment, but the production cost of the soft magnetic composite material is greatly increased; or when designing the raw material formula of the soft magnetic composite material, the designed magnetic permeability value is often higher than the target value, so that a certain space is provided for the attenuation of the magnetic permeability of the soft magnetic composite material, but the electromagnetic property of the soft magnetic composite material is sacrificed by the method.

Disclosure of Invention

Based on the above, there is a need for a soft magnetic composite material, and a preparation method and an application thereof, which can enhance the anti-attenuation performance of the permeability of the soft magnetic composite material.

The invention provides a soft magnetic composite material which is prepared by mixing the following raw materials in parts by weight:

90-110 parts of soft magnetic powder,

2 to 5 parts of a binder, and

0.1-3 parts of auxiliary additive;

wherein the adhesive comprises resin and a curing agent,

the auxiliary additive is selected from at least one of carboxyl-terminated nitrile rubber, polysulfide rubber, polyurethane, 650 low-molecular polyamide resin, 651 low-molecular polyamide resin and bisphenol A type unsaturated polyester resin.

In one embodiment, the mass ratio of the resin to the curing agent in the adhesive is (90-110) to (4-20).

In one embodiment, the soft magnetic powder is selected from at least one of carbonyl iron powder, iron silicon chromium powder, iron silicon aluminum powder, iron nickel powder, and iron silicon powder; and/or

The curing agent is at least one selected from aromatic amine type curing agents, anhydride type curing agents and imidazole type curing agents.

In one embodiment, the resin is a thermosetting resin.

In one embodiment, the thermosetting resin is selected from at least one of an epoxy resin, a novolac epoxy resin, and a cyanate ester.

The invention further provides a preparation method of the soft magnetic composite material, which comprises the following steps:

the raw materials of the soft magnetic composite material are mixed and then dried.

In one embodiment, the resin and the curing agent of the adhesive and the auxiliary additive are mixed in a solvent, and then the soft magnetic powder is added and mixed, and dried.

In one embodiment, in the drying process, the drying temperature is 40 ℃ to 80 ℃, and the drying time is 0.5 hour to 1.5 hours.

Furthermore, the invention also provides the use of a soft magnetic composite material as described in which for the preparation of electronic products.

The invention also provides an electronic product comprising the soft magnetic composite material.

According to the soft magnetic composite material, the composition and the proportion of the raw materials are optimized, the auxiliary additive is added into the soft magnetic powder and the adhesive, and the auxiliary additive can be grafted on a resin or curing agent molecular chain of the adhesive, so that the steric hindrance of the reaction of the resin and the curing agent is increased, the reaction activity is further reduced, the stability of the soft magnetic composite material can be effectively improved, the problem of attenuation of the magnetic conductivity of the soft magnetic composite material during long-time room-temperature storage is obviously solved, and the anti-attenuation performance of the magnetic conductivity of the soft magnetic composite material is improved. Furthermore, the soft magnetic composite material also improves the problem of attenuation of the magnetic conductivity of the soft magnetic composite material under long-time room temperature storage, and improves the attenuation resistance of the magnetic conductivity of the soft magnetic composite material.

Detailed Description

In order that the invention may be more fully understood, reference will now be made to the following description. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the invention, "a plurality" means at least two, e.g., two, three, etc., unless explicitly specified otherwise. In the description of the present invention, "a plurality" means at least one, e.g., one, two, etc., unless specifically limited otherwise.

The words "preferably," "more preferably," and the like in this disclosure mean embodiments of the invention that may, in some instances, provide certain benefits. However, other embodiments may be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, nor is it intended to exclude other embodiments from the scope of the invention.

When a range of values is disclosed herein, the range is considered to be continuous and includes both the minimum and maximum values of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values of the range is included. Further, when multiple range-describing features or characteristics are provided, the ranges may be combined. In other words, unless otherwise indicated, all ranges disclosed herein are to be understood to encompass any and all subranges subsumed therein.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The invention provides a soft magnetic composite material which is prepared by mixing the following raw materials in parts by weight:

90-110 parts of soft magnetic powder,

2 to 5 parts of a binder, and

0.1-3 parts of auxiliary additive;

wherein the adhesive comprises resin and a curing agent.

Preferably, the soft magnetic composite material is prepared by mixing the following raw materials in parts by weight:

95-105 parts of soft magnetic powder,

2-4 parts of adhesive and

0.5-3 parts of auxiliary additive.

It is understood that the resin reacts with the curing agent to form a network-like steric polymer, and the soft magnetic powder is encapsulated in the network-like steric polymer.

In a specific example, the auxiliary additive is selected from at least one of carboxyl-terminated nitrile rubber, polysulfide rubber, polyurethane, 650 low-molecular polyamide resin, 651 low-molecular polyamide resin, and bisphenol a type unsaturated polyester resin, and preferably, the auxiliary additive is selected from at least one of polysulfide rubber and carboxyl-terminated nitrile rubber.

According to the soft magnetic composite material, the composition and the proportion of the raw materials are optimized, the auxiliary additive is added into the soft magnetic powder and the adhesive, and the auxiliary additive can be grafted on a resin or curing agent molecular chain of the adhesive, so that the steric hindrance of the reaction of the resin and the curing agent is increased, the reaction activity is further reduced, the stability of the soft magnetic composite material can be effectively improved, the problem of attenuation of the magnetic conductivity of the soft magnetic composite material during long-time room-temperature storage is obviously solved, and the anti-attenuation performance of the magnetic conductivity of the soft magnetic composite material is improved.

In a specific example, the mass ratio of the resin to the curing agent in the adhesive is (90-110) to (4-20).

Furthermore, the mass ratio of the resin to the curing agent in the adhesive can be, but is not limited to (95-102): 5-18.

In a specific example, the soft magnetic powder is selected from at least one of carbonyl iron powder, iron silicon chromium powder, iron silicon aluminum powder, iron nickel powder, and iron silicon powder.

In one particular example, the resin is a thermosetting resin.

In a specific example, the thermosetting resin is selected from at least one of an epoxy resin, a novolac epoxy resin, and a cyanate ester, and preferably the thermosetting resin is selected from at least one of a cyanate ester and an epoxy resin.

In a specific example, the curing agent is selected from at least one of an aromatic amine type curing agent, an acid anhydride type curing agent, and an imidazole type curing agent, and preferably the curing agent is an aromatic amine type curing agent, specifically at least one selected from 4,4' -diaminodiphenyl sulfone and m-phenylenediamine.

The soft magnetic composite material is prepared by mixing the following raw materials in parts by weight:

in a specific example, the solvent is an organic solvent, and preferably, the solvent may be, but is not limited to, acetone.

Furthermore, the invention also provides a preparation method of the soft magnetic composite material, which comprises the following steps of firstly preparing materials according to the raw materials of the soft magnetic composite material; then the raw materials are mixed, stirred uniformly, granulated and dried to obtain the soft magnetic composite material.

Specifically, the resin of the adhesive, the curing agent and the auxiliary additive are mixed in a solvent, and then the soft magnetic powder is added and mixed, and dried.

In a specific example, in the drying process, the drying temperature is 40 ℃ to 80 ℃, and the drying time is 0.5 hour to 1.5 hours.

It is understood that the drying temperature may be, but is not limited to, 40 deg.C, 42 deg.C, 44 deg.C, 46 deg.C, 48 deg.C, 50 deg.C, 52 deg.C, 56 deg.C, 58 deg.C, 60 deg.C, 62 deg.C, 64 deg.C, 66 deg.C, 68 deg.C, 70 deg.C, 72 deg.C, 74 deg.C, 76 deg.C, 78 deg.C or 80 deg.C.

Further, the drying time may be, but is not limited to, 0.5 hour, 0.7 hour, 0.9 hour, 1.1 hour, 1.3 hours, or 1.5 hours.

It is to be understood that the drying may be, but is not limited to, baking.

According to the soft magnetic composite material, the composition and the proportion of the raw materials are optimized, the auxiliary additive is added into the soft magnetic powder and the adhesive, and the auxiliary additive can be grafted on a resin or curing agent molecular chain of the adhesive, so that the steric hindrance of the reaction of the resin and the curing agent is increased, the reaction activity is further reduced, the stability of the soft magnetic composite material can be effectively improved, and the magnetic conductivity of the soft magnetic composite material under long-time room-temperature storage is obviously improved. Furthermore, the soft magnetic composite material also improves the problem of attenuation of the magnetic conductivity of the soft magnetic composite material under long-time room temperature storage, and improves the attenuation resistance of the magnetic conductivity of the soft magnetic composite material.

The invention also provides the application of the soft magnetic composite material in preparing electronic products.

An electronic product comprises the soft magnetic composite material.

In some of these embodiments, the electronic product may be, but is not limited to, an integrally formed inductor, relay, or transformer.

In the following examples, all the starting materials are commercially available unless otherwise specified. Specifically, in the following examples and comparative examples, iron-silicon-chromium powder (500 mesh) and iron-nickel powder (500 mesh) were purchased from Antai science and technology, RZEL-1(D50 ═ 5um) carbonyl iron powder was purchased from Jiangsu Tianyi ultra-fine metal powder, Inc., carboxyl-terminated nitrile rubber was purchased from Shanghai Shih International trade, cyanate ester was purchased from Shandong Manghai chemical science and technology, 4,4' -diaminodiphenyl sulfone was purchased from Complex high-New Material, polysulfide rubber was purchased from Simplex chemical research institute, epoxy resin E51 was purchased from south Asia resin Mills, and m-phenylene diamine was purchased from Complex high-New Material, Inc.

Example 1

The embodiment provides a soft magnetic composite material, which comprises, by weight, 100 parts of 500-mesh iron-silicon-chromium powder, 3 parts of an adhesive, 0.5 part of an auxiliary additive carboxyl-terminated nitrile rubber, and 15 parts of acetone, wherein the adhesive comprises a resin and a curing agent in a mass ratio of 100:6, the resin is cyanate ester, and the curing agent is 4,4' -diaminodiphenyl sulfone.

The preparation method of the soft magnetic composite material comprises the following steps: dissolving cyanate ester, 4' -diaminodiphenyl sulfone and the auxiliary additive carboxyl-terminated butadiene-acrylonitrile rubber in the adhesive in acetone, uniformly mixing, pouring into iron-silicon-chromium powder, uniformly stirring, granulating, and baking at 60 ℃ for 1 hour to prepare the soft magnetic composite material of the embodiment.

Example 2

The embodiment provides a soft magnetic composite material, which comprises, by weight, 100 parts of 500-mesh iron-nickel powder, 2.5 parts of an adhesive, 2 parts of an auxiliary additive carboxyl-terminated butadiene-acrylonitrile rubber, and 15 parts of acetone, wherein the adhesive comprises a resin and a curing agent in a mass ratio of 100:6, the resin is cyanate ester, and the curing agent is 4,4' -diaminodiphenyl sulfone.

The preparation method of the soft magnetic composite material comprises the following steps: dissolving cyanate ester, 4' -diaminodiphenyl sulfone and the auxiliary additive carboxyl-terminated butadiene-acrylonitrile rubber in the adhesive in acetone, uniformly mixing, pouring the mixture into FeNi powder, uniformly stirring, granulating, and baking at 60 ℃ for 1 hour to prepare the soft magnetic composite material of the embodiment.

Example 3

The embodiment provides a soft magnetic composite material, which comprises, by weight, 100 parts of carbonyl iron powder RZEL-1(D50 ═ 5um), 3.5 parts of an adhesive, 1 part of an auxiliary additive polysulfide rubber, and 15 parts of acetone, wherein the adhesive consists of a resin and a curing agent in a mass ratio of 100:6, the resin is cyanate ester, and the curing agent is 4,4' -diaminodiphenyl sulfone.

The preparation method of the soft magnetic composite material comprises the following steps: dissolving cyanate ester, 4' -diaminodiphenyl sulfone and the auxiliary additive polysulfide rubber in the adhesive in acetone, uniformly mixing, pouring into carbonyl iron powder, uniformly stirring, granulating, and baking at 60 ℃ for 1 hour to prepare the soft magnetic composite material of the embodiment.

Example 4

The embodiment provides a soft magnetic composite material, which comprises, by weight, 100 parts of 500-mesh iron-silicon-chromium powder, 3.5 parts of an adhesive, 3 parts of an auxiliary additive carboxyl-terminated nitrile rubber and 12 parts of acetone, wherein the adhesive comprises a resin and a curing agent in a mass ratio of 100:15, the resin is epoxy resin E51, and the curing agent is m-phenylenediamine.

The preparation method of the soft magnetic composite material comprises the following steps: dissolving epoxy resin E51, m-phenylenediamine and auxiliary additive carboxyl-terminated butadiene-acrylonitrile rubber in the adhesive in acetone, uniformly mixing, pouring into 500-mesh iron-silicon-chromium powder, uniformly stirring, granulating, and baking at 60 ℃ for 1 hour to prepare the soft magnetic composite material of the embodiment.

Comparative example 1

This comparative example differs from example 1 in that no auxiliary additive is added to the carboxyl-terminated nitrile rubber.

The comparative example provides a soft magnetic composite material, which comprises, by weight, 100 parts of 500-mesh iron-silicon-chromium powder, 3 parts of an adhesive and 15 parts of acetone, wherein the adhesive comprises a resin and a curing agent in a mass ratio of 100:6, the resin is cyanate ester, and the curing agent is 4,4' -diaminodiphenyl sulfone.

The preparation method of the soft magnetic composite material comprises the following steps: dissolving cyanate ester and 4,4' -diaminodiphenyl sulfone in the adhesive in acetone, uniformly mixing, pouring into iron-silicon-chromium powder, uniformly stirring, granulating, and baking at 60 ℃ for 1 hour to obtain the soft magnetic composite material of the comparative example.

Comparative example 2

This comparative example differs from example 2 in that no auxiliary additive is added to the carboxyl-terminated nitrile rubber.

The comparative example provides a soft magnetic composite material, which comprises, by weight, 100 parts of 500-mesh iron-nickel powder, 2.5 parts of an adhesive and 15 parts of acetone, wherein the adhesive comprises a resin and a curing agent in a mass ratio of 100:6, the resin is cyanate ester, and the curing agent is 4,4' -diaminodiphenyl sulfone.

The preparation method of the soft magnetic composite material comprises the following steps: dissolving cyanate ester and 4,4' -diaminodiphenyl sulfone in the adhesive in acetone, uniformly mixing, pouring into iron-nickel powder, uniformly stirring, granulating, and baking at 60 ℃ for 1 hour to obtain the soft magnetic composite material of the comparative example.

Comparative example 3

This comparative example differs from example 3 in that no auxiliary additive polysulfide rubber is added.

The comparative example provides a soft magnetic composite material, which comprises 100 parts by weight of carbonyl iron powder RZEL-1(D50 ═ 5um), 3.5 parts by weight of adhesive and 15 parts by weight of acetone, wherein the adhesive consists of resin and curing agent in a mass ratio of 100:6, the resin is cyanate, and the curing agent is 4,4' -diaminodiphenyl sulfone.

The preparation method of the soft magnetic composite material comprises the following steps: dissolving cyanate ester and 4,4' -diaminodiphenyl sulfone in the adhesive in acetone, uniformly mixing, pouring into carbonyl iron powder, uniformly stirring, granulating, and baking at 60 ℃ for 1 hour to obtain the soft magnetic composite material of the comparative example.

Comparative example 4

This comparative example differs from example 4 in that no carboxyl-terminated nitrile rubber was used as auxiliary additive.

The comparative example provides a soft magnetic composite material, which comprises, by weight, 100 parts of 500-mesh iron-silicon-chromium powder, 3.5 parts of an adhesive and 12 parts of acetone, wherein the adhesive comprises a resin and a curing agent in a mass ratio of 100:15, the resin is epoxy resin E51, and the curing agent is m-phenylenediamine.

The preparation method of the soft magnetic composite material comprises the following steps: dissolving epoxy resin E51 and m-phenylenediamine in the adhesive in acetone, uniformly mixing, pouring into 500-mesh iron-silicon-chromium powder, uniformly stirring, granulating, and baking at 60 ℃ for 1 hour to obtain the soft magnetic composite material of the comparative example.

Comparative example 5

This comparative example differs from example 4 in the small amount of the auxiliary additive carboxyl-terminated nitrile rubber.

The comparative example provides a soft magnetic composite material, which comprises, by weight, 100 parts of 500 parts of iron-silicon-chromium powder, 3.5 parts of an adhesive, 0.05 part of an auxiliary additive and 12 parts of acetone, wherein the adhesive comprises a resin and a curing agent in a mass ratio of 100:6, the resin is epoxy resin E51, and the curing agent is m-phenylenediamine.

The preparation method of the soft magnetic composite material comprises the following steps: dissolving epoxy resin E51, m-phenylenediamine and auxiliary additives in the adhesive in acetone, uniformly mixing, pouring into iron-silicon-chromium powder, uniformly stirring, granulating, and baking at 60 ℃ for 1h to prepare the soft magnetic composite material of the comparative example.

Comparative example 6

This comparative example differs from example 4 in that an excess of the auxiliary additive carboxyl-terminated nitrile rubber is added.

The comparative example provides a soft magnetic composite material, which comprises, by weight, 100 parts of 500-mesh iron-silicon-chromium powder, 3.5 parts of an adhesive and 3.5 parts of an auxiliary additive, wherein the adhesive comprises a resin and a curing agent in a mass ratio of 100:15, the resin is epoxy resin E51, and the curing agent is m-phenylenediamine.

The preparation method of the soft magnetic composite material comprises the following steps: dissolving epoxy resin E51, m-phenylenediamine and auxiliary additives in the adhesive in acetone, uniformly mixing, pouring into iron-silicon-chromium powder, uniformly stirring, granulating, and baking at 60 ℃ for 1h to prepare the soft magnetic composite material of the comparative example.

Discussion of test and results

The soft magnetic composite materials obtained in the above-described examples and comparative examples were subjected to detection of magnetic permeability before and after storage for one month at room temperature of 25 ℃ respectively, and a magnetic permeability decrease rate was calculated.

	Permeability H/m before storage	Permeability H/m after storage for 1 month	Rate of decrease in magnetic permeability
				Example 1	32.5	30.8	5.23％
Example 2	35.4	34.8	1.82％
				Example 3	27.2	26.3	3.3％
Example 4	29.5	29.1	1.3％
				Comparative example 1	32.8	30.1	8.20％
Comparative example 2	36.5	33.62	7.9％
				Comparative example 3	28.1	25.5	9.3％
Comparative example 4	31.2	28.2	9.5％
				Comparative example 5	30.8	28.1	8.7％
Comparative example 6	27.8	27.4	1.3％

After the magnetic permeability of the soft magnetic composite materials obtained in the embodiments 1 to 4 and the comparative examples 1 to 4 is detected before and after being stored for one month at room temperature, the magnetic permeability reduction rate obtained by the comparative example preparation under the condition of not adding the auxiliary additive is obviously increased, and the fact that the addition of the auxiliary additive can effectively reduce the further crosslinking of the resin and the curing agent and can effectively reduce the magnetic permeability loss of the soft magnetic composite materials is proved.

As can be seen from comparison of example 4, comparative example 5 and comparative example 6, the permeability can be improved by adding a small amount of the auxiliary additive, but the permeability is remarkably reduced after storage for one month; the addition of an excessive amount of auxiliary additives can effectively reduce the permeability loss of the soft magnetic composite material, but can sacrifice the permeability of a certain soft magnetic composite material.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, so as to understand the technical solutions of the present invention specifically and in detail, but not to be understood as the limitation of the protection scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. It should be understood that the technical solutions provided by the present invention and obtained by logical analysis, reasoning or limited experiments by those skilled in the art are all within the scope of the appended claims. Therefore, the protection scope of the patent of the invention is subject to the content of the appended claims, and the description can be used for explaining the content of the claims.