Manufacturing method of integrally formed magnetic powder

Abstract

The invention relates to the technical field of powder metallurgy and magnetic materials, in particular to an integrally-formed magnetic powder manufacturing method which comprises the following manufacturing steps that firstly, soft magnetic powder is prepared; 2, sieving the soft magnetic powder to obtain sieved soft magnetic powder; 3, graphite fluoride is added into the soft magnetic powder obtained in the step 2; 4, volatile substances in the soft magnetic powder in the step 3 are volatilized, and magnetic powder is prepared; and 5, the magnetic powder is subjected to mold pressing and integrated forming, the soft magnetic powder with the small diameter is screened out by screening the soft magnetic powder, the friction force between the soft magnetic powder is reduced, the fluidity is improved, graphite fluoride has good lubricity, volatile substances in the soft magnetic powder are volatilized, and the powder fluidity is further improved. According to the invention, the powder fluidity can be enhanced, the stability of powder material mold pressing can be improved, and the precision and yield of products can be improved. The integrated inductor mold pressing method and the integrated inductor mold pressing device have the advantages of being convenient for enhancing the powder fluidity, improving the stability of powder material mold pressing and improving the product precision and yield.

Description

Technical Field

[0001] The invention belongs to the technical field of powder metallurgy and magnetic materials, and particularly relates to a method for manufacturing integrally formed magnetic powder. Background Art

[0002] Magnetic powder core is a soft magnetic material made of ferromagnetic powder and insulating medium. Since the diameter of ferromagnetic particles is very small and separated by non-magnetic electrical insulating film material, it has the characteristics of isolating eddy current, uniform distribution of powder core, no skin phenomenon, and relatively stable change of magnetic permeability with frequency, which is suitable for the production of high-frequency inductors. Iron powder core is a kind of commonly used soft magnetic powder core. Compared with other materials, it has the characteristics of high saturation flux density, excellent DC superposition performance, low price, etc., and is widely used.

[0003] At present, as a new type of inductor component, the one-piece molded inductor has the advantages of small size and strong current resistance, and is widely used in consumer electronics and other fields. The preparation technology of magnetic powder is the key technology for manufacturing one-piece molded inductors.

[0004] However, the fluidity of magnetic powder is unstable during production, resulting in uneven density of the inductor after molding and low precision of the inductor size. Therefore, an integrated molding magnetic powder manufacturing method is needed to solve the above problems. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a method for manufacturing an integrally formed magnetic powder to solve the problems in the existing market raised in the above background technology.

[0006] To achieve the above object, the technical solution of the present invention is as follows:

[0007] The method for manufacturing an integrally formed magnetic powder comprises the following steps:

[0008] Step 1: preparing soft magnetic powder;

[0009] Step 2: sieving the soft magnetic powder to obtain sieved soft magnetic powder;

[0010] Step 3: adding graphite fluoride to the soft magnetic powder in step 2;

[0011] Step 4: volatilize the volatile substances in the soft magnetic powder in step 3 to obtain magnetic powder;

[0012] Step 5: Molding the magnetic powder into an integrated unit.

[0013] Through the above technical scheme, the soft magnetic powder is screened to remove the soft magnetic powder with a smaller diameter, thereby reducing the friction between the soft magnetic powders and increasing the fluidity. Graphite fluoride has good lubricity and a smaller friction coefficient when dry or humid at high temperatures (400-500 degrees). The volatilization of volatile substances in the soft magnetic powder is beneficial to further enhance the powder fluidity, thereby avoiding uneven density of the one-piece molded inductor and affecting the conductive performance due to poor powder fluidity. The present application facilitates enhancing the powder fluidity, improving the stability of powder molding, and improving product accuracy and yield.

[0014] As a preferred embodiment of the present invention, the step 1 comprises the following steps:

[0015] S11, weigh FeSiCr5.5 alloy powder according to proportion, mix them at 80-100° C., and add surfactant and dispersant during the mixing process;

[0016] S12, adding the soft magnetic powder of s11 into a mixture of phosphate, nitrate and acetone, and heating to 120-150° C. and baking for 1-5 hours to obtain a magnetic powder with a coated insulating layer.

[0017] Through the above technical scheme, the addition of surfactant can effectively reduce the interaction force between metal powder particles and reduce the adsorption and aggregation between metal particles; the dispersant can improve the circulation and stability of metal powder; phosphates and nitrates react with the surface of metal powder at high temperature to passivate the abnormally sharp parts of the powder surface, solidify to form an oxide layer, and coat the outer surface of the soft magnetic powder particle core to form a coating layer, passivating the abnormally sharp parts of the original powder surface, and the generated oxide layer plays the role of insulating protection.

[0018] As a preferred embodiment of the present invention, the surfactant in step s11 includes any one of sodium dodecylbenzene sulfonate and polyethylene glycol octanoate; the dispersant is any one of ethylene acrylic acid, maleic acid, and tetraethylethylenediamine.

[0019] Through the above technical solution, the addition of surfactant can effectively reduce the interaction force between metal powder particles and reduce the adsorption and aggregation between metal particles; the dispersant can improve the circulation and stability of metal powder.

[0020] As a preferred embodiment of the present invention, step two also includes passing the soft magnetic powder in step one through a 90-130 mesh sieve, and obtaining two portions of powder after sieving. The first portion of powder has a soft magnetic powder diameter of 15-30 μm, and the second portion of powder has a diameter of less than 15 μm. The second powder having a mass ratio of 8% to the first powder is added to the first powder and stirred evenly to obtain the proportioned soft magnetic powder.

[0021] Through the above technical solution, the soft magnetic powder is screened to remove the soft magnetic powder with a smaller diameter, thereby reducing the friction between the soft magnetic powders and increasing the fluidity. Adding a finer second powder is beneficial to avoid the large gaps formed by the large particles of the first powder, which affects the density and performance of the one-piece molded inductor after molding, thereby maintaining the density and performance while enhancing the fluidity.

[0022] As a preferred embodiment of the present invention, step three comprises the following steps:

[0023] S31, adding 0.01-0.1% of graphite fluoride to the soft magnetic powder after heating and drying in S12;

[0024] S32. Stir the mixture of graphite fluoride and soft magnetic powder for 1 hour.

[0025] Through the above technical solution, the fluorinated graphite has good lubricity, and the friction coefficient is smaller in dry or wet high temperature (400-500 degrees), thereby reducing friction.

[0026] As a preferred embodiment of the present invention, step 4 includes the following preparation steps:

[0027] S411, placing the soft magnetic powder mixed and stirred in s32 in a sealing device;

[0028] S412, placing the sealing device in an environment of 0-5°C for 5-10 days;

[0029] S413, open the sealing device to remove the volatile gas.

[0030] Through the above technical solution, the soft magnetic powder is placed in a sealed bag or a sealed box with a certain amount of space left to facilitate the storage of volatile gases, avoiding oxidation of the powder due to long-term direct contact with air, and is placed at a low temperature of 0-5°C to facilitate better volatilization of the gas.

[0031] As a preferred embodiment of the present invention, step three includes the following preparation steps:

[0032] S421, placing the soft magnetic powder mixed and stirred in S32 in a vacuum device;

[0033] S422, placing the soft magnetic powder in a vacuum environment for 1-2 hours.

[0034] Through the above technical solution, the vacuum device is convenient for extracting volatile materials in the powder.

[0035] As a preferred embodiment of the present invention, step three includes the following preparation steps:

[0036] S431, placing the soft magnetic powder mixed and stirred in S32 in a nitrogen furnace;

[0037] S432. The temperature of the nitrogen furnace is 30-50°C, and the soft magnetic powder is placed for 0.5-1.5 hours.

[0038] Through the above technical solution, nitrogen can easily react with acetone to form acetone nitrogen, which is easy to emit, so that the acetone volatilizes.

[0039] The utility model relates to an integrally formed inductor, which is obtained by molding using an integrally formed magnetic powder manufacturing method.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] By sieving the soft magnetic powder, the soft magnetic powder with a smaller diameter is screened out, the friction between the soft magnetic powders is reduced, and the fluidity is increased. Graphite fluoride has good lubricity, and the friction coefficient is smaller when dry or humid at high temperature (400-500 degrees). The volatilization of volatile substances in the soft magnetic powder is beneficial to further enhance the powder fluidity, avoiding uneven molding density of the one-piece inductor due to poor powder fluidity, affecting the conductive performance, etc. The present application facilitates enhancing the powder fluidity, improving the stability of powder molding, and improving the product size accuracy and yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0043] Figure 1 It is a schematic diagram of the process of the present invention;

[0044] Figure 2 This is a schematic diagram of the process of Example 2 of the present invention. DETAILED DESCRIPTION

[0045] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] The present invention provides the following embodiments:

[0047] Embodiment 1:

[0048] The method for manufacturing an integrally formed magnetic powder comprises the following steps:

[0049] Step 1: preparing soft magnetic powder, wherein:

[0050] Step one includes the following steps:

[0051] S11, weighing FeSiCr5.5 alloy powder according to proportion and mixing at 80-100°C, and adding surfactant and dispersant during the mixing process, preferably weighing FeSiCr5.5 alloy powder according to proportion and mixing at 80°C, preferably weighing FeSiCr5.5 alloy powder according to proportion and mixing at 100°C;

[0052] S12, adding the soft magnetic powder of s11 into a mixture of phosphate, nitrate and acetone, and heating to 120-150°C and baking for 1-5 hours to obtain a magnetic powder with a coated insulating layer, preferably heating to 120°C and baking for 2 hours, preferably heating to 150°C and baking for 1 hour.

[0053] The addition of surfactants can effectively reduce the interaction force between metal powder particles and reduce the adsorption and aggregation between metal particles; dispersants can improve the circulation and stability of metal powders; phosphates and nitrates react with the surface of metal powders at high temperatures to passivate the abnormally sharp parts of the powder surface, solidify to form an oxide layer, and coat the outer surface of the soft magnetic powder particle core to form a coating layer, passivating the abnormally sharp parts of the original powder surface, and the generated oxide layer plays an insulating protection role.

[0054] As a preferred embodiment of the present invention, the surfactant in step s11 includes any one of sodium dodecylbenzene sulfonate and polyethylene glycol octanoate; the dispersant is any one of ethylene acrylic acid, maleic acid, and tetraethylethylenediamine. The addition of the surfactant can effectively reduce the interaction force between metal powder particles and reduce the adsorption and aggregation between metal particles; the dispersant can improve the circulation and stability of the metal powder.

[0055] Step 2: sieving the soft magnetic powder to obtain sieved soft magnetic powder, wherein:

[0056] Step 2 also includes passing the soft magnetic powder in step 1 through a 90-130 mesh sieve, preferably a 100 mesh sieve, to obtain two portions of powder after sieving, the first portion of powder is a soft magnetic powder with a diameter of 15-30 μm, preferably the first powder is a soft magnetic powder with a diameter of 20 μm, the second portion of powder is less than 15 μm in diameter, a second powder with a mass ratio of 8% to the first powder is added to the first powder and stirred evenly to obtain a proportioned soft magnetic powder, the soft magnetic powder is sieved to remove the soft magnetic powder with a smaller diameter, reduce the friction between the soft magnetic powders, and increase fluidity, and adding a finer second powder is beneficial to avoid larger gaps formed by larger first powder particles, affecting the density and performance of the one-piece molded inductor after molding, while enhancing fluidity while maintaining density and performance.

[0057] Step 3: Adding graphite fluoride to the soft magnetic powder in step 2, wherein:

[0058] Step three includes the following steps:

[0059] S31, adding 0.01-0.1% of graphite fluoride to the soft magnetic powder after heating and drying in S12;

[0060] S32. Stir the mixture of graphite fluoride and soft magnetic powder for 1 hour.

[0061] Graphite fluoride has good lubricity, and its friction coefficient is smaller when dry or wet at high temperature (400-500 degrees), thus reducing friction.

[0062] Step 4: volatilize the volatile substances in the soft magnetic powder in step 3 to obtain magnetic powder;

[0063] Step 5: Molding the magnetic powder into an integrated unit.

[0064] Embodiment 2:

[0065] Compared with Example 1, Example 2 has the following differences: Step 4 includes the following preparation steps:

[0066] S411, placing the soft magnetic powder mixed and stirred in s32 in a sealing device;

[0067] S412, placing the sealing device in an environment of 0-5°C for 5-10 days, preferably placing the sealing device in an environment of 0°C for 5 days, and placing the sealing device in an environment of 5°C for 10 days;

[0068] S413, open the sealing device to remove the volatile gas.

[0069] Place the soft magnetic powder in a sealed bag or box and leave some space to store the volatile gas, avoid oxidation of the powder due to long-term direct contact with air, and place it at a low temperature of 0-5℃ to facilitate better volatilization of the gas.

[0070] Embodiment 3:

[0071] Compared with Example 1, Example 3 has the following differences: Step 3 includes the following preparation steps:

[0072] S421, placing the soft magnetic powder mixed and stirred in S32 in a vacuum device;

[0073] S422, placing the soft magnetic powder in a vacuum environment for 1-2 hours.

[0074] The vacuum device facilitates the extraction of volatile materials in the powder.

[0075] Embodiment 4:

[0076] Compared with Example 1, Example 4 has the following differences: Step 3 includes the following preparation steps:

[0077] S431, placing the soft magnetic powder mixed and stirred in S32 in a nitrogen furnace;

[0078] S432. The temperature of the nitrogen furnace is 30-50°C, and the soft magnetic powder is placed for 0.5-1.5 hours.

[0079] Nitrogen is easy to react with acetone to form acetone nitrogen, which is easy to dissipate, causing the acetone to volatilize.

[0080] Embodiment 5:

[0081] The utility model relates to an integrally formed inductor, which is obtained by molding using an integrally formed magnetic powder manufacturing method.

[0082] Table 1 before improvement:

[0083]

[0084]

[0085]

[0086] Table 2 after improvement:

[0087]

[0088]

[0089]

[0090] The std data of pendulum thickness in Table 1 is: 0.011753, and the std data of center column height is: 0.012066;

[0091] The std data of pendulum thickness in Table 2 is: 0.005819, and the std data of center column height is: 0.004551;

[0092] By comparison, it can be concluded that the standard deviation of the thickness and center column height after the improvement of enhanced powder fluidity is lower than the standard deviation before the improvement, and the molding is more stable. Enhancing powder fluidity is beneficial to improving the stability of powder molding, improving product yield, and improving product accuracy.

[0093] By screening the soft magnetic powder, the soft magnetic powder with a smaller diameter is screened out, the friction between the soft magnetic powders is reduced and the fluidity is increased. Graphite fluoride has good lubricity and a smaller friction coefficient when dry or humid at high temperatures (400-500 degrees). Volatilizing the volatile substances in the soft magnetic powder is beneficial to further enhance the powder fluidity, avoiding uneven molding density of the one-piece inductor due to poor powder fluidity and affecting the conductive performance. The present application facilitates enhancing powder fluidity, improving the stability of powder molding, improving product yield, reducing complex production processes and processes, and being able to better serve and expand the market.

[0094] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for manufacturing an integrally formed magnetic powder, characterized in that: The production steps include: Step 1: preparing soft magnetic powder; Step 2: sieving the soft magnetic powder to obtain sieved soft magnetic powder; Step 3: adding graphite fluoride to the soft magnetic powder in step 2; Step 4: volatilize the volatile substances in the soft magnetic powder in step 3 to obtain magnetic powder; Step 5: Molding the magnetic powder into an integrated unit.

2. The method for manufacturing an integrally molded magnetic powder according to claim 1, characterized in that: The step 1 comprises the following steps: S11, weigh FeSiCr5.5 alloy powder according to proportion, mix them at 80-100° C., and add surfactant and dispersant during the mixing process; S12, adding the soft magnetic powder of s11 into a mixture of phosphate, nitrate and acetone, and heating to 120-150° C. and baking for 1-5 hours to obtain a soft magnetic powder with a coated insulating layer.

3. The method for manufacturing an integrally molded magnetic powder according to claim 2, characterized in that: The surfactant in step s11 includes any one of sodium dodecylbenzene sulfonate and polyethylene glycol octanoate; the dispersant is any one of ethylene acrylic acid, maleic acid, and tetraethylethylenediamine.

4. The method for manufacturing an integrally molded magnetic powder according to claim 2, characterized in that: Step 2 also includes passing the soft magnetic powder in step 1 through a 90-130 mesh sieve to obtain two portions of powder, the first portion of which has a soft magnetic powder diameter of 15-30 μm, and the second portion of which has a powder diameter of less than 15 μm. The second powder, which has a mass ratio of 8% of the first powder, is added to the first portion of powder and stirred evenly to obtain the proportioned soft magnetic powder.

5. The method for manufacturing an integrally molded magnetic powder according to claim 2, characterized in that: Step three includes the following steps: S31, adding 0.01-0.1% of graphite fluoride to the soft magnetic powder after heating and drying in S12; S32. Stir the mixture of graphite fluoride and soft magnetic powder for 1 hour.

6. The method for manufacturing an integrally molded magnetic powder according to claim 5, characterized in that: Step 4 includes the following preparation steps: S411, placing the soft magnetic powder mixed and stirred in S32 in a sealing device; S412, placing the sealing device in an environment of 0-5°C for 5-10 days; S413, open the sealing device to remove the volatile gas.

7. The method for manufacturing an integrally molded magnetic powder according to claim 5, characterized in that: Step three includes the following preparation steps: S421, placing the soft magnetic powder mixed and stirred in S32 in a vacuum device; S422, placing the soft magnetic powder in a vacuum environment for 1-2 hours.

8. The method for manufacturing an integrally molded magnetic powder according to claim 5, characterized in that: Step three includes the following preparation steps: S431, placing the soft magnetic powder mixed and stirred in S32 in a nitrogen furnace; S432. The temperature of the nitrogen furnace is 30-50°C, and the soft magnetic powder is placed for 0.5-1.5 hours.

9. An integrally formed inductor, characterized in that: The magnetic powder is obtained by molding the integrally molded magnetic powder manufacturing method according to any one of claims 1 to 8.

Images