Method for establishing a cure profile for soft magnetic composite material

Abstract

The application provides a method for preparing a soft magnetic composite material curing curve, comprising the following steps: preparing a magnetic ring, wherein the material of the magnetic ring comprises a soft magnetic composite material; heating the magnetic ring at different temperature values; testing the crushing strength of the magnetic ring at different heating times at each temperature value; determining the optimal curing time of the soft magnetic composite material at the temperature value according to the crushing strength; and preparing a soft magnetic composite material curing curve according to the crushing strength and the optimal curing time. The soft magnetic composite material curing curve prepared according to the application can shorten the curing time of the soft magnetic composite material, thereby improving the production efficiency. The application also provides a soft magnetic composite material curing curve prepared by the preparation method.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of soft magnetic composite material curing, in particular to a method for formulating a soft magnetic composite material curing curve. BACKGROUND

[0002] With the rapid development of 5G technology and new energy vehicle industry, the market demand for inductance components also increases exponentially. The integrally formed inductance is widely used in the electronic industry due to its excellent magnetic shielding structure, excellent magnetic properties and small volume. The soft magnetic composite material used in the integrally formed inductance is formed by mixing the soft magnetic metal with the high molecular resin, then the soft magnetic composite material is molded into an inductance green body, and then the oven is used for gradient heating to make the high molecular resin in the soft magnetic composite material cure and cross-link, thereby improving the adhesion between the soft magnetic composite materials to achieve optimal mechanical properties.

[0003] At present, the temperature and time of the gradient heating method are generally revised according to the Tg reaction curve of the high molecular resin alone, and the weight of the high molecular resin in the soft magnetic composite material accounts for only 6% to 10% of the weight of the soft magnetic composite material. However, according to the above scheme, the curing time of the soft magnetic composite material is between 12 to 24 hours, and the production efficiency is low. Therefore, under the premise of ensuring the appearance characteristics of the product, the method for reasonably formulating the soft magnetic composite material curing curve also ensures the accuracy of the development. SUMMARY

[0004] Therefore, it is necessary to provide a reasonable method for formulating a soft magnetic composite material curing curve to improve production efficiency.

[0005] The present application provides a method for formulating a soft magnetic composite material curing curve, comprising the following steps:

[0006] Preparation of a magnetic ring, wherein the material of the magnetic ring comprises a soft magnetic composite material;

[0007] Heating the magnetic ring at different temperature values;

[0008] Testing the crushing strength of the magnetic ring at each temperature value and different heating times;

[0009] According to the crushing strength, determining the optimal curing time of the soft magnetic composite material at the temperature value; and

[0010] Formulating a soft magnetic composite material curing curve according to the crushing strength and the optimal curing time.

[0011] In some embodiments, determining the optimal curing time of the soft magnetic composite material at the temperature value according to the crushing strength comprises the following steps:

[0012] At the same temperature value, comparing the curing time when the crushing strength increases and stabilizes in a predetermined range at different heating times, the shortest curing time is determined as the optimal curing time of the soft magnetic composite material at the same temperature value.

[0013] In some embodiments, the method for preparing the magnetic ring comprises:

[0014] Mixing an organic resin system, a diluent and iron powder to obtain a paste;

[0015] Extruding and granulating the paste to obtain a semi-finished product;

[0016] Drying the semi-finished product to obtain the soft magnetic composite material; and

[0017] Pressing and forming the soft magnetic composite material to obtain the magnetic ring.

[0018] In some embodiments, the organic resin system comprises at least one of an epoxy resin system, a phenolic resin system, a cyanate ester system and a silicone resin system.

[0019] In some embodiments, the iron powder comprises at least one of carbonyl iron powder, iron silicon chromium powder, iron silicon aluminum powder and iron silicon powder.

[0020] In some embodiments, the mass ratio of the iron powder, the organic resin system and the diluent is 100:(6-10):(10-15).

[0021] In some embodiments, the device for extruding and granulating the paste is an extrusion granulator.

[0022] In some embodiments, the device for testing the crushing strength is a pressure crushing device.

[0023] In some embodiments, the temperature value comprises 25-180℃, and / or the heating time comprises 0-120min.

[0024] In some embodiments, the temperature value comprises 25℃, 80℃, 100℃, 120℃, 140℃, 160℃, 170℃ and 180℃, and / or the heating time comprises 0min, 10min, 30min, 60min, 90min and 120min.

[0025] The application determines the rationality of the gradient temperature value and the heating time by directly testing the crushing strength of the soft magnetic composite material at different gradient temperature values and different heating times, so as to reasonably formulate the curing curve of the soft magnetic composite material. The curing of the soft magnetic composite material according to the curing curve of the soft magnetic composite material formulated by the application can shorten the curing time of the soft magnetic composite material, thereby improving the production efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 DSC graph of the epoxy resin system in the application.

[0027] Figure 2 Curing curve graph of the soft magnetic composite material formulated by Example 1 of the application.

[0028] Figure 3 Curing curve graph of the soft magnetic composite material formulated by Example 2 of the application.

[0029] Figure 4 Curing curve graph of the soft magnetic composite material formulated by Example 3 of the application.

[0030] Figure 5 Curing curve graph of the soft magnetic composite material formulated by Example 4 of the application.

[0031] Figure 6 Curing curve graph of the soft magnetic composite material formulated by Example 5 of the application.

[0032] Figure 7 Curing curve graph of the soft magnetic composite material formulated by Comparative Example 1 of the application.

[0033] Figure 8 Curing curve graph of the soft magnetic composite material formulated by Comparative Example 2 of the application.

[0034] Figure 9 Curing curve graph of the soft magnetic composite material formulated by Comparative Example 3 of the application. DETAILED DESCRIPTION

[0035] In order to facilitate the understanding of the application, the application will be described more fully below with reference to the accompanying drawings. The preferred embodiments of the application are shown in the drawings. However, the application can be realized in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the application more thorough and comprehensive.

[0036] Unless otherwise defined, 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 application belongs. The terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0037] The application provides a method for preparing a soft magnetic composite material curing curve, comprising the following steps:

[0038] Step S11, referring to Figure 1 The organic resin system is mixed with a diluent to obtain a mixed solution.

[0039] Specifically, the organic resin system and the diluent are poured into a container for stirring and dissolving to obtain the mixed solution.

[0040] In an embodiment, the organic resin system comprises at least one of an epoxy resin system, a phenolic resin system, a cyanate ester system, and a silicone resin system. Specifically, the organic resin system can have a curing agent in addition to the corresponding organic resin, such as a trimellitic anhydride curing agent, etc.

[0041] Step S12, mixing iron powder and the mixed solution to obtain a paste.

[0042] Specifically, the iron powder and the mixed solution are mixed and stirred in a sealed container to form a semi-dry paste.

[0043] In an embodiment, the iron powder comprises at least one of carbonyl iron powder, iron silicon chromium powder, iron silicon aluminum powder, and iron silicon powder.

[0044] In an embodiment, the mass ratio of the iron powder, the organic resin system, and the diluent can be 100:(6-10):(10-15).

[0045] It should be noted that in steps S11 and S12, the organic resin system, the diluent, and the iron powder do not have a strict mixing order. That is, the organic resin system and the diluent can be mixed first, and then the iron powder is mixed, or the organic resin system and the iron powder can be mixed first, and then the diluent is mixed. The application does not limit the mixing order of the organic resin system, the diluent, and the iron powder.

[0046] Step S13, extruding and granulating the paste to obtain a semi-finished product.

[0047] Specifically, the paste can be extrusion granulated in an extrusion granulator to obtain the semi-product. According to needs, semi-products with different particle sizes can be obtained.

[0048] Step S14, screen the semi-product with a screen to obtain qualified products.

[0049] Screening the semi-product with a screen is to remove particles with inappropriate particle sizes in the semi-product to obtain particles with appropriate particle sizes, i.e., the qualified products.

[0050] Step S15, dry the qualified products to obtain soft magnetic composites.

[0051] Specifically, the qualified products can be dried using a drying device.

[0052] In an embodiment, the drying temperature can be 60°C, and the drying time can be 60 min. In other embodiments, the drying temperature and the drying time can be adjusted according to needs.

[0053] Step S16, press-form the soft magnetic composites to obtain magnetic rings.

[0054] Specifically, the soft magnetic composites can be press-formed using a magnetic ring mold to obtain the magnetic rings.

[0055] In an embodiment, the forming pressure of the magnetic rings in the press-forming can be 5 MPa. In other embodiments, the forming pressure of the magnetic rings in the press-forming can be adjusted according to needs.

[0056] In an embodiment, the outer diameter R of the magnetic ring can be 7 cm, and the inner diameter r of the magnetic ring can be 4 cm.

[0057] Step S17, heat the magnetic rings at different temperature values.

[0058] Specifically, the magnetic rings can be placed on a specific heating device to be heated at different gradient temperature values.

[0059] In an embodiment, the temperature values include 25°C-180°C. Specifically, the temperature values include 25°C, 80°C, 100°C, 120°C, 140°C, 160°C, 170°C, and 180°C.

[0060] Step S18, test the crushing strength of the magnetic rings at different heating times at each of the temperature values.

[0061] Specifically, a pressure crushing device can be used to test the crushing strength of the magnetic rings at different heating times at each of the gradient temperature values.

[0062] In an embodiment, the heating time comprises 0-120 min. Specifically, the heating time comprises 0 min, 10 min, 30 min, 60 min, 90 min and 120 min.

[0063] Generally, at the same gradient temperature value, the breaking strength of the magnetic ring increases obviously at first, then increases slowly, and finally tends to a predetermined range with the increase of the heating time.

[0064] Step S19, judging the optimal curing time of the soft magnetic composite material at the temperature value according to the breaking strength.

[0065] Specifically, at the same temperature value, the curing time when the breaking strength increases and stabilizes in the predetermined range at different heating times is compared, and the shortest curing time is determined as the optimal curing time of the soft magnetic composite material at the same temperature value. For example, when the temperature value is 100℃, the predetermined range is 15-18 MPa.

[0066] Step S20, formulating the soft magnetic composite material curing curve according to the breaking strength and the optimal curing time.

[0067] The method for formulating the soft magnetic composite material curing curve is described in detail through specific steps as follows.

[0068] Firstly, 7-8 parts of an epoxy resin system (i.e. epoxy resin E51 and trimellitic anhydride, wherein the DES diagram of the epoxy resin system is shown in Figure 1 ) and 6-15 parts of a diluent are poured into a container for stirring and dissolving to obtain a mixed solution.

[0069] Secondly, 100 parts of iron powder with a D50 of 10 μm (material Fe 92 Si 3.5 Cr 4.5 ) and the above mixed solution are mixed to obtain a paste.

[0070] Thirdly, the above paste is extruded and granulated in an extrusion granulator to obtain a semi-finished product.

[0071] Fourthly, the above semi-finished product is sieved by a screen to obtain a qualified product.

[0072] Fifthly, the above qualified product is dried to obtain a soft magnetic composite material.

[0073] Sixthly, the above soft magnetic composite material is pressed and formed using a magnetic ring mold to obtain a magnetic ring.

[0074] Seventh step, the above magnetic ring is placed on a specific heating device to heat at a temperature of 25℃, 80℃, 100℃, 120℃, 140℃, 160℃, 170℃ and 180℃.

[0075] Eighth step, the breaking strength of the magnetic ring heated at the above different gradient temperature values for 0min, 10min, 30min, 60min, 90min and 120min is tested respectively, and the test results are shown in Table 1. The unit of the breaking strength is MPa.

[0076] Table 1

[0077] 25℃ 80℃ 100℃ 120℃ 140℃ 160℃ 170℃ 180℃ 0 min 8.5 8.7 10.3 11.4 13.3 15.6 16.5 16.3 10 min 9.1 12.7 16.8 20.2 25.7 29.8 28.4 30.2 30 min 8.3 13.1 15.7 21.5 32.4 37.9 38.9 39.6 60 min 8.7 12.9 17.1 22.3 33.4 45.7 47.8 49.3 90 min 8.7 12.7 16.5 23.1 32.9 54.2 53.5 55.7 120 min 8.2 13.2 17.3 21.7 31.7 53.1 54.3 54.8

[0078] Ninth step, the optimal curing time of the soft magnetic composite material at the gradient temperature value is determined according to the breaking strength.

[0079] Tenth step, the soft magnetic composite material curing curve is formulated according to the breaking strength and the optimal curing time of the soft magnetic composite material.

[0080] The present application determines the rationality of the gradient temperature value and the heating time by directly testing the breaking strength of the soft magnetic composite material at different gradient temperature values and different heating times, thereby reasonably formulating the soft magnetic composite material curing curve. The soft magnetic composite material is cured according to the soft magnetic composite material curing curve formulated by the present application, which can shorten the curing time of the soft magnetic composite material, thereby improving the production efficiency.

[0081] The present application is further illustrated by specific examples and comparative examples.

[0082] Example 1

[0083] First step, 7-8 parts of epoxy resin system (i.e. epoxy resin E51 and trimellitic anhydride) and 6-15 parts of diluent are poured into a container for stirring and dissolving to obtain a mixed solution.

[0084] Second step, 100 parts of iron powder with a D50 of 10μm (material Fe 92 Si 3.5 Cr 4.5 ) and the above mixed solution are mixed to obtain a paste.

[0085] Third step, the above paste is extruded in an extrusion granulator to obtain a semi-finished product.

[0086] Fourth step, the above semi-finished product is sieved by a screen to obtain a qualified product.

[0087] Fifth step, the above qualified product is dried to obtain a soft magnetic composite material.

[0088] Sixth step, using the magnetic ring mold to press the above soft magnetic composite material into shape, to get the magnetic ring.

[0089] Seventh step, the above magnetic ring is cured according to the curing curve in the table, wherein the temperature value and heating time are as follows: 80℃*10min+100℃*10min+120℃*10min+140℃*30min+160℃*90min. Figure 2

[0090] Example 2

[0091] First step, pour 7-8 parts of epoxy resin system (i.e. epoxy resin E51 and trimellitic anhydride) and 6-15 parts of diluent into a container for stirring and dissolving to obtain a mixed solution.

[0092] Second step, mix 100 parts of iron powder (material Fe 92 Si 3.5 Cr 4.5 ) with a D50 of 10μm and the above mixed solution to obtain a paste.

[0093] Third step, extrude the above paste in an extrusion granulator to obtain a semi-finished product.

[0094] Fourth step, screen the above semi-finished product on a screen to obtain a qualified product.

[0095] Fifth step, dry the above qualified product to obtain a soft magnetic composite material.

[0096] Sixth step, use the magnetic ring mold to press the above soft magnetic composite material into shape to obtain a magnetic ring.

[0097] Seventh step, the above magnetic ring is cured according to the curing curve in the table, wherein the temperature value and heating time are as follows: 80℃*10min+100℃*10min+120℃*10min+140℃*30min+170℃*90min. Figure 3

[0098] Example 3

[0099] First step, pour 7-8 parts of epoxy resin system (i.e. epoxy resin E51 and trimellitic anhydride) and 6-15 parts of diluent into a container for stirring and dissolving to obtain a mixed solution.

[0100] Second step, mix 100 parts of iron powder (material Fe 92 Si 3.5 Cr 4.5 ) with a D50 of 10μm and the above mixed solution to obtain a paste.​​

[0101] Third step, the above paste in the extrusion granulator extrusion granulation, get semi-finished product.

[0102] Fourth step, the above semi-finished product sieve screening, get qualified product.

[0103] Fifth step, drying the above qualified product, get soft magnetic composite material.

[0104] Sixth step, using magnetic ring mold the above soft magnetic composite material compression molding, get magnetic ring.

[0105] Seventh step, the above magnetic ring according to the curing curve in the solidification, wherein the temperature value and heating time is: 80℃*10min + 100℃*10min + 120℃*10min + 140℃*30min + 180℃*90min. Figure 4

[0106] Example 4

[0107] First step, according to the weight part, 7-8 parts of epoxy resin system (i.e. epoxy resin E51 and trimellitic anhydride) and 6-15 parts of diluent into the container for stirring solution, to get mixed solution.

[0108] Second step, according to the weight part, 100 parts of D50 is 10 microns of iron powder (material for Fe 92 Si 3.5 Cr 4.5 ) and the above mixed solution, get paste.

[0109] Third step, the above paste in the extrusion granulator extrusion granulation, get semi-finished product.

[0110] Fourth step, the above semi-finished product sieve screening, get qualified product.

[0111] Fifth step, drying the above qualified product, get soft magnetic composite material.

[0112] Sixth step, using magnetic ring mold the above soft magnetic composite material compression molding, get magnetic ring.

[0113] Seventh step, the above magnetic ring according to the curing curve in the solidification, wherein the temperature value and heating time is: 80℃*10min + 100℃*10min + 120℃*10min + 140℃*30min + 160℃*90min + 170℃*90min. Figure 5

[0114] Example 5

[0115] ​​First step, 7-8 parts of epoxy resin system (i.e. epoxy resin E51 and trimellitic anhydride) and 6-15 parts of diluent are poured into a container for stirring and dissolving to obtain a mixed solution.

[0116] Second step, 100 parts of iron powder (material Fe 92 Si 3.5 Cr 4.5 with D50 of 10 μm and the above mixed solution are mixed to obtain a paste.

[0117] Third step, the above paste is extrusion granulated in an extrusion granulator to obtain a semi-finished product.

[0118] Fourth step, the above semi-finished product is screened by a screen to obtain a qualified product.

[0119] Fifth step, the above qualified product is dried to obtain a soft magnetic composite material.

[0120] Sixth step, the above soft magnetic composite material is pressed and formed using a magnetic ring mold to obtain a magnetic ring.

[0121] Seventh step, the above magnetic ring is cured according to the curing curve in Table 1, wherein the temperature value and heating time are specifically: 80℃*10min+100℃*10min+120℃*10min+140℃*30min+160℃*90min+180℃*90min. Figure 6

[0122] Comparative Example 1

[0123] First step, 7-8 parts of epoxy resin system (i.e. epoxy resin E51 and trimellitic anhydride) and 6-15 parts of diluent are poured into a container for stirring and dissolving to obtain a mixed solution.

[0124] Second step, 100 parts of iron powder (material Fe 92 Si 3.5 Cr 4.5 with D50 of 10 μm and the above mixed solution are mixed to obtain a paste.

[0125] Third step, the above paste is extrusion granulated in an extrusion granulator to obtain a semi-finished product.

[0126] Fourth step, the above semi-finished product is screened by a screen to obtain a qualified product.

[0127] Fifth step, the above qualified product is dried to obtain a soft magnetic composite material.

[0128] Sixth step, the above soft magnetic composite material is pressed and formed using a magnetic ring mold to obtain a magnetic ring. ​

[0129] The seventh step is to cure the magnetic ring according to the curing curve in the table 1, wherein the temperature value and heating time are as follows: 80℃*10min+100℃*10min+120℃*10min+140℃*30min+160℃*90min+170℃*90min+180℃*90min. Figure 7 The seventh step is to cure the magnetic ring according to the curing curve in the table 1, wherein the temperature value and heating time are as follows: 80℃*10min+100℃*10min+120℃*10min+140℃*30min+160℃*90min+170℃*90min+180℃*90min.

[0130] Comparative Example 2

[0131] The first step is to pour 7-8 parts of the epoxy resin system (i.e. epoxy resin E51 and trimellitic anhydride) and 6-15 parts of the diluent into a container for stirring and dissolving to obtain a mixed solution.

[0132] The second step is to mix 100 parts of iron powder (material Fe 92 Si 3.5 Cr 4.5 ) with a D50 of 10 μm and the above mixed solution to obtain a paste.

[0133] The third step is to extrude the paste in an extrusion granulator to obtain a semi-finished product.

[0134] The fourth step is to screen the semi-finished product on a screen to obtain a qualified product.

[0135] The fifth step is to dry the qualified product to obtain a soft magnetic composite material.

[0136] The sixth step is to press and form the soft magnetic composite material using a magnetic ring mold to obtain a magnetic ring.

[0137] The seventh step is to cure the magnetic ring according to the curing curve in the table 1, wherein the temperature value and heating time are as follows: 80℃*10min+100℃*10min+120℃*10min+140℃*30min+160℃*90min+170℃*90min+180℃*90min. Figure 8

[0138] Comparative Example 3

[0139] The first step is to pour 7-8 parts of the epoxy resin system (i.e. epoxy resin E51 and trimellitic anhydride) and 6-15 parts of the diluent into a container for stirring and dissolving to obtain a mixed solution.

[0140] The second step is to mix 100 parts of iron powder (material Fe 92 Si 3.5 Cr 4.5 ) with a D50 of 10 μm and the above mixed solution to obtain a paste. ​

[0141] Thirdly, the paste is extruded in an extrusion granulator to obtain a semi-finished product.

[0142] Fourthly, the semi-finished product is sieved by a screen to obtain a qualified product.

[0143] Fifthly, the qualified product is dried to obtain a soft magnetic composite material.

[0144] Sixthly, the soft magnetic composite material is pressed into a magnetic ring using a magnetic ring mold.

[0145] Seventhly, the magnetic ring is cured according to a curing curve in the table 1, wherein the temperature value and the heating time are specifically as follows: 80℃*50min+100℃*50min+120℃*50min+140℃*50min+160℃*120min+170℃*120min+180℃*120min. Figure 9

[0146] The inductance, saturation change rate, permeability and strength of the cured magnetic rings prepared in the examples 1-5 and the comparative examples 1-3 are tested, and the test results are shown in the following table 2.

[0147] The inductance test is specifically as follows: the inductance of the cured magnetic ring is tested using an inductance tester (Zhenxin Precision ZX8526A).

[0148] The saturation change rate test is specifically as follows: the change rate of the inductance of the magnetic ring after being electrified with 20A direct current compared with the inductance before being electrified.

[0149] The permeability test is specifically as follows: the permeability is calculated through the formula: L=N^2*μ*Ae / le.

[0150] The strength test is specifically as follows: the strength of the cured magnetic ring is tested by applying a certain pressure to the cured magnetic ring.

[0151] Table 2

[0152]

[0153] From the test results in the table 2, it can be seen that the inductance, saturation change rate, permeability and strength of the cured magnetic rings prepared in the examples 1-5 are substantially the same as those of the cured magnetic rings prepared in the comparative examples 1-3. This indicates that the inductance, saturation change rate, permeability and strength of the cured magnetic ring prepared in the present application meet the requirements while reducing the curing time of the soft magnetic composite material, thereby improving the production efficiency.

[0154] ​Any combination of the technical features in the above-described embodiments can be made, and for the sake of brevity, not all possible combinations are described, however, as long as the combination of the technical features does not exist in contradiction, it shall be considered within the scope of the present disclosure.

[0155] The above-described embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it shall not be understood as a limitation on the patent scope of the present application. It shall be pointed out that, for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the present application, and these shall be within the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. A method of developing a cure curve for a soft magnetic composite material, characterized by, The method comprises the following steps: Preparation of a magnetic ring, wherein the material of the magnetic ring comprises a soft magnetic composite material; Heating the magnetic ring at different temperature values; Testing the crushing strength of the magnetic ring at each temperature value and different heating times; Determining the optimal curing time of the soft magnetic composite material at the temperature value according to the crushing strength; and Formulating a soft magnetic composite material curing curve according to the crushing strength and the optimal curing time; Wherein, determining the optimal curing time of the soft magnetic composite material at the temperature value according to the crushing strength comprises the following steps: At the same temperature value, comparing the curing time when the crushing strength increases and stabilizes in a predetermined range at different heating times, and determining the shortest curing time as the optimal curing time of the soft magnetic composite material at the same temperature value.

2. The method of claim 1, wherein the soft magnetic composite curing curve is determined by: The preparation method of the magnetic ring comprises: Mixing an organic resin system, a diluent and iron powder to obtain a paste; Extruding and granulating the paste to obtain a semi-finished product; Drying the semi-finished product to obtain the soft magnetic composite material; and Pressing the soft magnetic composite material to form the magnetic ring.

3. The method of claim 2, wherein the soft magnetic composite curing curve is determined by: The forming pressure of the magnetic ring in the pressing forming is 5Mpa; And / or, the drying temperature is 60℃, and the drying time is 60min; And / or, the outer diameter R of the magnetic ring is 7cm, and the inner diameter r of the magnetic ring is 4cm.

4. The method for determining the curing curve of the soft magnetic composite material as described in claim 2, characterized in that, The organic resin system comprises at least one of an epoxy resin system, a phenolic resin system, a cyanate ester system and a silicone resin system.

5. The method for determining the curing curve of the soft magnetic composite material as described in claim 2, characterized in that, The iron powder comprises at least one of carbonyl iron powder, iron silicon chromium powder, iron silicon aluminum powder and iron silicon powder.

6. The method of claim 2, wherein the soft magnetic composite curing curve is determined by: The mass ratio of the iron powder, the organic resin system and the diluent is 100:(6~10):(10~15).

7. The method for determining the curing curve of the soft magnetic composite material as described in claim 2, characterized in that, The device for extruding and granulating the paste is an extrusion granulator.

8. The method of claim 1, wherein the soft magnetic composite curing curve is determined by: The device for testing the crushing strength is a pressure crushing device.

9. The method of establishing a soft magnetic composite material curing curve according to any one of claims 1 to 8, wherein, The temperature value comprises 25℃~180℃, and / or the heating time comprises 0~120min.

10. The method of claim 9, wherein the soft magnetic composite curing curve is determined by: The temperature value comprises 25℃, 80℃, 100℃, 120℃, 140℃, 160℃, 170℃ and 180℃, and / or the heating time comprises 0min, 10min, 30min, 60min, 90min and 120min.

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