CN112435845A - Integrated co-fired inductor and preparation method thereof - Google Patents
Integrated co-fired inductor and preparation method thereof Download PDFInfo
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/24—Magnetic cores
- H01F27/255—Magnetic cores made from particles
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- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/28—Coils; Windings; Conductive connections
- H01F27/2823—Wires
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/33—Arrangements for noise damping
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/34—Special means for preventing or reducing unwanted electric or magnetic effects, e.g. no-load losses, reactive currents, harmonics, oscillations, leakage fields
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F37/00—Fixed inductances not covered by group H01F17/00
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
- H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
- H01F41/0206—Manufacturing of magnetic cores by mechanical means
- H01F41/0246—Manufacturing of magnetic circuits by moulding or by pressing powder
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/34—Special means for preventing or reducing unwanted electric or magnetic effects, e.g. no-load losses, reactive currents, harmonics, oscillations, leakage fields
- H01F2027/348—Preventing eddy currents
Abstract
The invention provides an integrated co-fired inductor and a preparation method thereof, wherein the preparation method comprises the following steps: the magnetic powder is filled in the die cavity in batches, at least one wire is embedded into the magnetic powder of one layer when the two adjacent layers are different in type, two ends of the wire extend out of the die cavity, then compression molding and heat treatment are sequentially carried out to obtain the magnetic core, and the wire extending out of the magnetic core is bent and tinned to obtain the co-fired inductor. The manufacturing method provided by the invention adopts an integrated molding process to manufacture the inductor, avoids the assembly process of too many components, carries out heat treatment after integrated molding, fully releases stress, reduces the hysteresis loss of materials, reduces the loss of devices under the light-load working condition, has no extra gap between a lead and a magnetic core, uniformly distributes air gaps in the magnetic core, and reduces the vibration noise of eddy current loss.
Description
Technical Field
The invention belongs to the technical field of inductors, and relates to an integrated co-fired inductor and a preparation method thereof.
Background
In recent years, with the large-scale use of mobile devices, home appliances, automobiles, industrial devices, data center servers, communication base station servers, and other devices, energy consumption has become a key consideration. As the size, multi-function, high-performance, and power-saving of the module have been advanced, the size, thickness, and high-performance of the mounted electronic components have been further required. Improving efficiency in DC-DC converters and reducing heat generation are key conditions for miniaturization of electronic components. In particular, as the DC-DC converter IC performs high-speed conversion and the inductor used therein has become lower in impedance, the core power supply circuit is increasingly required to be smaller and thinner, to have a low DC impedance, to handle a large current, and to have high reliability.
The third generation semiconductor is used for power devices, and is gradually the mainstream, especially, the technology of gallium nitride (GaN) and silicon carbide (SiC) is relatively mature, and the third generation semiconductor is suitable for manufacturing high-frequency high-power devices with high temperature resistance, high pressure resistance and large current resistance, wherein the power semiconductor is the main application field of the power semiconductor. Gallium nitride has a remarkable advantage in a high-frequency circuit, is a powerful competitor in current mobile communication, is mainly focused in military fields such as a base station power amplifier, aerospace and the like in the current application scene, and gradually moves to the field of consumer electronics. The physical property of the silicon carbide material is superior to that of silicon and other materials, the forbidden bandwidth of the silicon carbide single crystal is about 3 times of that of the silicon material, the thermal conductivity is 3.3 times of that of the silicon material, the electronic saturation migration speed is 2.5 times of that of the silicon, and the breakdown field strength is 5 times of that of the silicon, so that the silicon carbide single crystal has irreplaceable advantages in high-temperature, high-voltage, high-frequency and high-power electronic devices. With the successful application of silicon carbide power semiconductors in the high-end vehicle market such as Tesla, the automobile field will be the main power for the growth of silicon carbide in the future.
The power semiconductor is the core of electric energy conversion and circuit control in the electronic device, and is the core component for realizing the functions of voltage, frequency, direct current and alternating current conversion and the like in the electronic device. Power ICs, IGBTs, MOSFETs, diodes are the four most widely used power semiconductor products. Electronic components such as inductance and capacitance, which coordinate with power semiconductors to improve the power conversion efficiency of power supplies, also need to be matched with the development trend of third generation semiconductors. High-frequency, large-current, high-saturation-current and high-reliability inductors are also necessary components of the energy-efficient power supply.
In a traditional high-current-resistant inductor, a soft magnetic material is generally made into a discrete component, then a coil is placed on a magnetic core, and high saturation superposed current of an inductor device is realized by designing an air gap. This form of inductance tends to be relatively large in size due to the need for air gaps and tissue, especially in the thickness direction which tends to exceed 3mm and even reach 7 mm. This is because the soft magnetic ferrite material itself has a high magnetic permeability, but because of its low saturation magnetic induction, it is easily saturated in an external field, and in order to improve the saturation current resistance, it is necessary to open an air gap to reduce the effective magnetic permeability. The increased air gap increases the size of the device, and requires assembly and tolerance matching in the manufacturing process, which has a certain effect on the yield of product production.
The metal magnetic powder core material has the characteristics of high saturation magnetic induction intensity, high temperature stability, impact resistance and low noise, and the development is rapid in recent years, and particularly in the field of integrally formed inductors, the application of metal soft magnetic materials such as FeSiCr, carbonyl iron, iron nickel and the like is rapidly advanced. The integrally formed inductor is made of soft magnetic metal material, and the coil is integrally formed after being placed in the metal powder core.
CN205230770U discloses vertical slim heavy current inductor, this inductor include magnetic core, lower magnetic core and set up at last magnetic core, the inductance coil between the magnetic core down, inductance coil is by flat type copper metal wire coiling back, and two upper and lower flat pins that stretch out bend into 90 degrees, and two flat pin directions are relative direction, go up the magnetic core and be the square body, lower magnetic core is provided with accomodates inductance coil recess, and the recess middle part sets up a reference column that is used for fixed inductance coil. The inductance element adopts enameled wires for the coil due to winding, so that the forming pressure is not easy to be overlarge, otherwise, the insulating layer of the coil is easy to be damaged to cause interlayer short circuit. Secondly, stress anisotropy is generated in the magnetic core material due to stress caused by the molding pressure, thereby increasing the hysteresis loss of the material. In view of this, some people have developed a DUI type inductor product, i.e. the metal powder core is made into U piece and I piece, and after the magnetic powder core is sintered, the flat copper wire is sandwiched between the U piece and I piece to assemble the inductor.
CN110718359A discloses a manufacturing structure and method of a surface mount integrated inductor, which adopts a mixture of magnetic powder and thermosetting resin to perform pre-forming into two sets of identical pressing plate main bodies, the pressing plate main bodies have pressing surfaces, specifically, the pressing surfaces are high at two sides and low in the middle. In a forming die, two groups of pressing plate main bodies are respectively placed right above and right below a built-in coil, the pressing surface of each pressing plate main body needs to face the built-in coil, two poles of the built-in coil need to respectively exceed the range of two end parts of each pressing plate main body, and the two groups of pressing plate main bodies and the built-in coil are integrally formed into a blank body by adopting pressurization or heating. Two poles of the built-in coil are exposed outside the blank after molding, and external electrodes are formed at two ends of the blank.
However, when the inductor is manufactured in the mode, a plurality of components need to be assembled together, and an air gap is easily additionally introduced between the coil and the magnetic core, so that the effective magnetic conductivity is reduced.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide an integrated co-fired inductor and a preparation method thereof.
In order to achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the present invention provides a method for preparing an integrated co-fired inductor, where the method includes:
the magnetic powder is filled in the die cavity in batches, at least one wire is embedded into the magnetic powder of one layer when the two adjacent layers are different in type, two ends of the wire extend out of the die cavity, then compression molding and heat treatment are sequentially carried out to obtain the magnetic core, and the wire extending out of the magnetic core is bent and tinned to obtain the co-fired inductor.
The manufacturing method provided by the invention adopts an integrated molding process to manufacture the inductor, avoids the assembly process of too many components, carries out heat treatment after integrated molding, fully releases stress, reduces the hysteresis loss of materials, reduces the loss of devices under the light-load working condition, has no extra gap between a lead and a magnetic core, uniformly distributes air gaps in the magnetic core, and reduces the vibration noise of eddy current loss. Meanwhile, in the die pressing process, different powder materials are added in a mode of feeding in batches for multiple times, so that the deformation of the wire in the pressing process is reduced to the minimum, the anti-saturation capacity of the magnetic core material is increased, the respective advantages of different magnetic powder materials are fully exerted, the characteristics of the device are better exerted, the soft magnetic materials with positive temperature coefficients and negative temperature coefficients are matched for use, and the temperature stability of the device can be effectively improved.
As a preferred technical scheme of the invention, the magnetic powder is prepared by adopting the following method: and the soft magnetic powder is subjected to insulation coating, secondary coating and granulation treatment in sequence to obtain the magnetic powder.
Preferably, the soft magnetic powder comprises FeSiCr, FeSi, FeNi, FeSiAl, carbonyl iron powder, carbonyl iron nickel powder, FeNiMo, Fe-based amorphous nanocrystalline material, Co-based amorphous nanocrystalline soft magnetic material or Ni-based amorphous nanocrystalline soft magnetic material.
As a preferred technical solution of the present invention, the insulation coating adopts a coating process including phosphating, acidifying, oxidizing or nitriding, and further preferably, the soft magnetic powder is subjected to insulation coating by using phosphating treatment.
The insulation coating process refers to a coating process of a metal soft magnetic material, improves the insulation property and the corrosion resistance of the surface of the metal soft magnetic powder, and comprises surface treatment such as phosphorization, acidification, slow oxidation, nitridation and the like; the insulativity between the metal soft magnetic powder is improved mainly by adding a powder material with high resistivity or growing a coating layer with high resistivity in situ on the surface of the metal soft magnetic particle, and the coating layer comprises materials such as silicon dioxide, aluminum oxide, magnesium oxide, kaolin, zirconium oxide, mica powder and the like. Different coating methods and coating processes are adopted for different types of metal soft magnetic alloy powder, so that the optimal coating effect is achieved.
Preferably, the phosphating treatment comprises: and mixing and stirring the soft magnetic powder and the diluted phosphoric acid, and drying to obtain the phosphatized soft magnetic powder.
Preferably, the phosphoric acid is diluted with acetone.
The mass ratio of phosphoric acid to acetone is preferably 1 (60-70), and may be, for example, 1:60, 1:61, 1:62, 1:63, 1:64, 1:65, 1:66, 1:67, 1:68, 1:69 or 1:70, but is not limited to the enumerated values, and other unrecited values within the numerical range are also applicable.
Preferably, the phosphoric acid and acetone are mixed and stirred for 1-6 min, for example, 1mi, 2min, 3min, 4min, 5min or 6 min; and then standing for 5-10 min for later use, such as 5min, 6min, 7min, 8min, 9min or 10min, but not limited to the values listed, and other values not listed in the range of the values are also applicable.
Preferably, the soft magnetic powder is mixed with diluted phosphoric acid and stirred for 30-60 min, such as 30min, 35min, 40min, 45min, 50min, 55min or 60min, but not limited to the values listed, and other values not listed in the range of the values are also applicable.
Preferably, the drying temperature is 90 to 110 ℃, for example, 90 ℃, 92 ℃, 94 ℃, 96 ℃, 98 ℃, 100 ℃, 103 ℃, 104 ℃, 106 ℃, 108 ℃ or 110 ℃, but is not limited to the recited values, and other values not recited in the range of the values are also applicable.
Preferably, the drying time is 1 to 1.5 hours, for example, 1.0 hour, 1.1 hour, 1.2 hours, 1.3 hours, 1.4 hours or 1.5 hours, but not limited to the recited values, and other values not recited in the range of the values are also applicable.
As a preferable technical solution of the present invention, the secondary coating includes: the coating material is mixed and stirred with the soft magnetic powder coated in an insulating way.
Preferably, the coating is 2 to 10 wt% of the soft magnetic powder, for example, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt% or 10 wt%, but is not limited to the recited values, and other values not recited within the range of the recited values are also applicable.
Preferably, the coating comprises phenolic resin, epoxy resin or silicone resin.
Preferably, the coating material is mixed with the soft magnetic powder and stirred for 40-60 min, such as 40min, 42min, 44min, 46min, 48min, 50min, 52min, 54min, 56min, 58min or 60min, but not limited to the values listed, and other values not listed in the range of the values are also applicable.
As a preferable aspect of the present invention, the granulation process includes: and granulating the soft magnetic powder after secondary coating, and airing, drying and cooling the granulated soft magnetic powder in sequence to obtain the magnetic powder.
Preferably, the granulation process is performed in a 40-60 mesh granulator, such as a 40 mesh, 42 mesh, 44 mesh, 46 mesh, 48 mesh, 50 mesh, 52 mesh, 54 mesh, 56 mesh, 58 mesh or 60 mesh granulator, but not limited to the listed values, and other values not listed in the range of values are also applicable.
Preferably, the airing time is less than or equal to 3 hours, for example, 0.5 hour, 1 hour, 1.5 hour, 2 hours, 2.5 hours or 3 hours, but the airing time is not limited to the listed values, and other values not listed in the numerical range are also applicable.
Preferably, the soft magnetic powder after air-drying is passed through a 30-50 mesh sieve and then dried, and may be, for example, 30 mesh, 32 mesh, 34 mesh, 36 mesh, 38 mesh, 40 mesh, 42 mesh, 44 mesh, 46 mesh, 48 mesh or 50 mesh, but is not limited to the above-mentioned values, and other values not listed in the above-mentioned range are also applicable.
Preferably, the drying temperature is 50 to 70 ℃, for example, 50 ℃, 52 ℃, 54 ℃, 56 ℃, 58 ℃, 60 ℃, 62 ℃, 64 ℃, 66 ℃, 68 ℃ or 70 ℃, but not limited to the values listed, and other values not listed in the range of the values are also applicable.
Preferably, the drying time is 0.8 to 1.2 hours, for example, 0.8 hour, 0.9 hour, 1.0 hour, 1.1 hour or 1.2 hours, but is not limited to the recited values, and other values not recited in the range of the values are also applicable.
Preferably, the cooling process is natural cooling.
Preferably, the magnetic powder is obtained by sieving the cooled soft magnetic powder with a 30-50 mesh sieve and then adding an auxiliary material to the sieved soft magnetic powder, for example, 30 mesh, 32 mesh, 34 mesh, 36 mesh, 38 mesh, 40 mesh, 42 mesh, 44 mesh, 46 mesh, 48 mesh or 50 mesh, but not limited to the recited values, and other values not recited in the range of the values are also applicable.
Preferably, the auxiliary material comprises magnesium oxide, lubricating powder or demolding powder.
As a preferred technical scheme of the invention, the first magnetic powder, the second magnetic powder and the first magnetic powder are filled into the die cavity in three batches in sequence.
Preferably, the wire is embedded in the second magnetic powder.
As a preferred technical solution of the present invention, the conducting wire is a bare wire without an enameled wire.
Preferably, the conducting wire is a copper wire.
Preferably, the wire is a flat wire with a rectangular cross section.
Preferably, the shape of the wire is a straight wire or a special-shaped wire.
Preferably, the shape of the shaped conductor comprises an S shape, an L shape, a U shape, a W shape or an E shape.
Preferably, the conducting wires are laid in one layer of magnetic powder at intervals side by side on a horizontal plane.
The inductor designed by the invention requires low direct current resistance, the copper wire and the metal soft magnetic material are subjected to high-temperature heat treatment together, the flat copper wire without the enameled wire is adopted, the high-temperature heat treatment can be carried out, the loss of the powder core is further reduced, and the shape of the copper wire can be designed according to the requirement, such as I type, S type, L type, U type, W type, E type and the like. The molding process of one mold and one piece can be adopted, and the row pressing molding can also be carried out in a lead frame fixing mode.
As a preferable technical scheme of the invention, the mould pressing mode is hot pressing or cold pressing.
According to the characteristics of the granulated powder and the requirements of inductance, a hot-press forming mode can be adopted. During hot briquetting, required pressure is littleer, and the magnetic core can be inseparabler contact and the pressure that needs is littleer with the wire after hot briquetting, but the hot pressing can bring the suppression efficiency and reduce.
Preferably, the hot-pressing pressure is more than or equal to 800MPa/cm2For example, it may be 800MPa/cm2、810Mpa/cm2、820Mpa/cm2、830Mpa/cm2、840Mpa/cm2、850Mpa/cm2、860Mpa/cm2、870Mpa/cm2、880Mpa/cm2、890Mpa/cm2Or 900MPa/cm2More preferably 2000MPa/cm2。
In the present invention, since there is no limitation of the enameled wire, the molding pressure of the magnetic powder can be used to obtain a magnetic core with higher density, preferably a pressure of more than 800Mpa/cm2Even up to 2000MPa/cm2The optimum pressure for the inductor is selected based on die life and press capacity.
Preferably, the hot pressing temperature is 90 to 180 ℃, for example, 90 ℃, 100 ℃, 110 ℃, 120 ℃, 130 ℃, 140 ℃, 150 ℃, 160 ℃, 170 ℃ or 180 ℃, but is not limited to the recited values, and other values not recited in the range of the values are also applicable.
Preferably, the hot pressing time is 5 to 100s, for example, 5s, 10s, 20s, 30s, 40s, 50s, 60s, 70s, 80s, 90s, or 100s, but is not limited to the values listed, and other values not listed in the range of the values are also applicable.
Preferably, the heat treatment is an annealing treatment.
Preferably, the heat treatment process is performed under a protective atmosphere.
Preferably, the gas used in the protective atmosphere is nitrogen and/or an inert gas.
Preferably, the heat treatment temperature is 650 to 850 ℃, for example, 650 ℃, 660 ℃, 670 ℃, 680 ℃, 690 ℃, 700 ℃, 710 ℃, 720 ℃, 730 ℃, 740 ℃, 750 ℃, 760 ℃, 770 ℃, 780 ℃, 790 ℃, 800 ℃, 910 ℃, 920 ℃, 930 ℃, 940 ℃ or 950 ℃, but is not limited to the recited values, and other values not recited in the range of values are also applicable.
Preferably, the heat treatment time is 30 to 50min, for example, 30min, 32min, 34min, 36min, 38min, 40min, 42min, 44min, 46min, 48min or 50min, but is not limited to the values listed, and other values not listed in the range of the values are also applicable.
The invention carries out heat treatment on the pressed green body inductor to densify the magnetic core, obtains higher saturation magnetic induction intensity, higher magnetic conductivity and lower loss, and simultaneously improves the intensity of the inductor. Different heat treatment temperatures are selected for different materials. For example, for amorphous metal soft magnetic powder such as FeSiB, FeSiBCr, fenisibbc, etc., the heat treatment temperature cannot exceed the crystallization temperature of the powder; for the nanocrystalline gold soft magnetic alloy powder, the heat treatment temperature is higher than the crystallization temperature but not higher than the grain growth temperature, and the specific heat treatment temperature is set as a heat treatment process according to a curve tested by a differential scanning calorimeter; for the gas atomization or water-gas combined atomization or multi-stage atomization of FeSiAl, FeNi, FeNiMo, FeSi and other soft magnetic powder, high-temperature heat treatment is selected according to the collocation of the powder, and the heat treatment temperature is higher than 650 ℃ and lower than 850 ℃. In the heat treatment, the heat treatment may be performed under the protection of an inert gas such as nitrogen or argon, or under the protection of a reducing gas such as hydrogen or a mixed gas of hydrogen and nitrogen. Because the invention adopts the conducting wire without the enameled wire, and the shape of the conducting wire is I-shaped, S-shaped, L-shaped, U-shaped, W-shaped, E-shaped and the like, the conducting wires are not contacted with each other, and the short circuit problem among the conducting wires is avoided.
In a second aspect, the invention provides a co-fired inductor prepared by the preparation method according to the first aspect, where the co-fired inductor includes a magnetic core and at least one conducting wire located inside the magnetic core, the magnetic core includes at least two magnetic powder layers stacked in sequence, the two adjacent magnetic powder layers adopt different types of magnetic powder, the conducting wire is located in one of the magnetic powder layers, two ends of the conducting wire extend out of the magnetic core, and the conducting wire extending out of the magnetic core is bent and then attached to the outer wall of the magnetic core.
As a preferred technical solution of the present invention, the conducting wire is a bare wire without an enameled wire.
Preferably, the conducting wire is a copper wire.
Preferably, the wire is a flat wire with a rectangular cross section.
Preferably, the shape of the wire is a straight wire or a special-shaped wire.
Preferably, the shape of the shaped conductor comprises an S shape, an L shape, a U shape, a W shape or an E shape.
Preferably, the conducting wires are laid in one layer of magnetic powder at intervals side by side on a horizontal plane.
Compared with the prior art, the invention has the beneficial effects that:
the manufacturing method provided by the invention adopts an integrated molding process to manufacture the inductor, avoids the assembly process of too many components, carries out heat treatment after integrated molding, fully releases stress, reduces the hysteresis loss of materials, reduces the loss of devices under the light-load working condition, has no extra gap between a lead and a magnetic core, uniformly distributes air gaps in the magnetic core, and reduces the vibration noise of eddy current loss. Meanwhile, in the die pressing process, different powder materials are added in a mode of feeding in batches for multiple times, so that the deformation of the wire in the pressing process is reduced to the minimum, the anti-saturation capacity of the magnetic core material is increased, the respective advantages of different magnetic powder materials are fully exerted, the characteristics of the device are better exerted, the soft magnetic materials with positive temperature coefficients and negative temperature coefficients are matched for use, and the temperature stability of the device can be effectively improved.
Drawings
Fig. 1 is a schematic structural diagram of a co-fired inductor prepared in embodiment 1 of the present invention;
fig. 2 is a schematic structural diagram of a co-fired inductor prepared in embodiment 2 of the present invention;
fig. 3 is a schematic structural diagram of a co-fired inductor prepared in embodiment 3 of the present invention;
fig. 4 is a schematic structural diagram of a co-fired inductor prepared in embodiment 4 of the present invention;
fig. 5 is a schematic structural diagram of a co-fired inductor prepared in embodiment 5 of the present invention;
wherein, 1-a conducting wire; 2-a first magnetic powder layer; 3-a second magnetic powder layer; 4-a third magnetic powder layer; 5-a fourth magnetic powder layer; 6-fifth magnetic powder layer.
Detailed Description
It is to be understood that in the description of the present invention, the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be taken as limiting the present invention. Furthermore, the terms "first", "second", etc. 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," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.
It should be noted that, in the description of the present invention, unless otherwise explicitly specified or limited, the terms "disposed," "connected" and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art through specific situations.
The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings.
Example 1
The embodiment provides a preparation method of an integrated co-fired inductor, which comprises the following steps:
(1) filling 0.2g of first magnetic powder into a die cavity, removing an enameled wire from a flat copper wire 1 with a rectangular cross section, placing the flat copper wire 1 on the surface of the first magnetic powder, enabling two ends of the wire 1 to extend out of the die cavity, enabling the wire 1 to be a straight wire 1, enabling the length of the straight wire 1 to be 14mm, enabling the width of the straight wire 1 to be 2.6mm, enabling the wire 1 to be 0.3mm in thickness, vibrating the die cavity, embedding the straight wire 1 into the first magnetic powder, and leveling the first magnetic powder; then 0.6g of second magnetic powder is filled into the die cavity, the die cavity is vibrated, and the second magnetic powder is leveled; finally, filling 0.2g of first magnetic powder into the die cavity, vibrating the die cavity, and leveling the first magnetic powder;
(2) carrying out compression molding on the magnetic powder filled in the mold cavity, wherein the compression molding mode is hot pressing, and the hot pressing pressure is 300Mpa/cm2Hot pressing temperature is 180 ℃, and hot pressing time is 30 s;
(3) after forming, carrying out annealing heat treatment in a nitrogen atmosphere to obtain the magnetic core, wherein the heat treatment temperature is 700 ℃, and the heat treatment time is 30 min;
(4) and sequentially carrying out impregnation spraying and bending tinning on the lead 1 extending out of the magnetic core to obtain the co-fired inductor with the size of 11.0mm multiplied by 5.0mm multiplied by 2.0mm, wherein the impregnation treatment is vacuum impregnation, and the spraying liquid adopted in the spraying process is epoxy resin.
The first magnetic powder in the step (1) is prepared by the following method:
(a) insulating and coating: diluting phosphoric acid by using acetone, wherein the mass ratio of the phosphoric acid to the acetone is 1:60, mixing and stirring the phosphoric acid and the acetone for 1min, and then standing for 5min for later use; mixing and stirring FeSi soft magnetic powder with the diameter of 20 mu m D50 with diluted phosphoric acid for 30min, and drying at 90 ℃ for 1h to obtain soft magnetic powder after phosphating treatment;
(b) secondary coating: mixing and stirring a coating material and the soft magnetic powder obtained in the step (c) for 40min, wherein the coating material is 2 wt% of the soft magnetic powder, and the coating material is phenolic resin;
(c) and (3) granulation treatment: and granulating the soft magnetic powder subjected to secondary coating in a 40-mesh granulator, airing for 2 hours after granulation, sieving the aired soft magnetic powder with a 30-mesh sieve, drying at 50 ℃ for 0.8 hour, naturally cooling, sieving with the 30-mesh sieve, and adding magnesium oxide into the sieved soft magnetic powder to obtain the first magnetic powder.
The second magnetic powder is prepared by the same operation steps and process parameters as the first magnetic powder, and the difference is that the soft magnetic powder adopted in the step (a) is replaced by FeSiAl magnetic powder, the FeSiAl magnetic powder is subjected to insulation coating, secondary coating and granulation treatment to obtain the second magnetic powder, and the process parameters adopted in the operation steps are completely the same.
As shown in fig. 1, in the prepared co-fired inductor, a first magnetic powder layer 2, a second magnetic powder layer 3 and a third magnetic powder layer 4 are respectively formed by sequentially filling the first magnetic powder, the second magnetic powder and the first magnetic powder into a mold cavity, and a wire 1 is located in the first magnetic powder layer 2. And (3) carrying out inductance characteristic test on the prepared co-fired inductor, and measuring initial inductance L (0A) as 150nH, saturation current 90A and temperature rise current 85A. A12V-1V voltage reduction circuit is adopted to carry out efficiency test, the frequency of a switching power supply is 500kHz during the test, the efficiency reaches 81.5 percent when the electronic load is 5A, and the efficiency reaches 90.3 percent when the electronic load is 25A.
Example 2
The embodiment provides a preparation method of an integrated co-fired inductor, which comprises the following steps:
(1) filling 0.3g of first magnetic powder into the die cavity, vibrating the die cavity, and leveling the first magnetic powder; filling 0.5g of second magnetic powder, removing the enameled wire from a flat copper wire 1 with a rectangular cross section, placing the flat copper wire 1 on the surface of the second magnetic powder, enabling two ends of the wire 1 to extend out of the die cavity, enabling the wire 1 to be S-shaped, 10mm in length, 2.6mm in width and 0.30mm in thickness, vibrating the die cavity, embedding the wire 1 into the second magnetic powder, and leveling the second magnetic powder; finally, filling 0.3g of first magnetic powder, vibrating the die cavity, and leveling the first magnetic powder;
(2) carrying out compression molding on the magnetic powder filled in the mold cavity, wherein the compression molding mode is hot pressing, and the hot pressing pressure is 400Mpa/cm2Hot pressing temperature is 180 ℃, and hot pressing time is 30 s;
(3) after molding, carrying out annealing heat treatment in an inert atmosphere to obtain the magnetic core, wherein the heat treatment temperature is 650 ℃, and the heat treatment time is 50 min;
(4) sequentially carrying out impregnation spraying and bending tinning on the lead 1 extending out of the magnetic core to obtain a co-fired inductor with the size of 8.0mm multiplied by 6.0mm multiplied by 1.9mm, wherein the impregnation treatment is vacuum impregnation, and the spraying liquid adopted in the spraying process is epoxy resin;
the first magnetic powder in the step (1) is prepared by the following method:
(a) insulating and coating: diluting phosphoric acid by using acetone, wherein the mass ratio of the phosphoric acid to the acetone is 1:63, mixing and stirring the phosphoric acid and the acetone for 3min, and then standing for 6min for later use; mixing and stirring the FeNi soft magnetic powder and diluted phosphoric acid for 40min, and drying at 95 ℃ for 1.2h to obtain phosphatized soft magnetic powder;
(b) secondary coating: mixing and stirring a coating material and the soft magnetic powder obtained in the step (c) for 45min, wherein the coating material is 5 wt% of the soft magnetic powder, and the coating material is epoxy resin;
(c) and (3) granulation treatment: and granulating the soft magnetic powder subjected to secondary coating in a 43-mesh granulator, airing for 2.3 hours after granulation is finished, sieving the aired soft magnetic powder with a 35-mesh sieve, drying at 55 ℃ for 1 hour, naturally cooling, sieving with the 35-mesh sieve, and adding lubricating powder into the sieved soft magnetic powder to obtain the first magnetic powder.
The second magnetic powder is prepared by the same operation steps and process parameters as the first magnetic powder, and the difference is that the soft magnetic powder adopted in the step (a) is replaced by FeSiAl soft magnetic powder, the FeSiAl soft magnetic powder is subjected to insulation coating, secondary coating and granulation treatment to obtain the second magnetic powder, and the process parameters adopted in the operation steps are completely the same.
As shown in fig. 2, in the prepared co-fired inductor, a first magnetic powder layer 2, a second magnetic powder layer 3 and a third magnetic powder layer 4 are respectively formed by sequentially filling the first magnetic powder, the second magnetic powder and the first magnetic powder into the mold cavity, and the wire 1 is located in the second magnetic powder layer 3. And (3) carrying out inductance characteristic test on the prepared co-fired inductor, and measuring initial inductance L (0A) 160nH, saturation current 95A and temperature rise current 90A. A12V-1V voltage reduction circuit is adopted to carry out efficiency test, the frequency of a switching power supply is 500kHz during the test, the efficiency reaches 81.6% when the electronic load is 5A, and the efficiency reaches 90.6% when the electronic load is 25A.
Example 3
The embodiment provides a preparation method of an integrated co-fired inductor, which comprises the following steps:
(1) filling 0.2g of first magnetic powder into the die cavity, vibrating the die cavity, and leveling the first magnetic powder; then 0.6g of second magnetic powder is filled, the die cavity is vibrated, and the second magnetic powder is smoothed; finally, 0.2g of first magnetic powder is filled, a flat copper wire 1 with a rectangular cross section is placed on the surface of the first magnetic powder after enameled wires are removed, two ends of the wire 1 extend out of the die cavity, the wire 1 is w-shaped, 18mm in length, 2.8mm in width and 0.26mm in thickness, the die cavity is vibrated, the wire 1 is embedded into the first magnetic powder, and the first magnetic powder is leveled;
(2) carrying out compression molding on the magnetic powder filled in the mold cavity, wherein the compression molding mode is hot pressing, and the hot pressing pressure is 400Mpa/cm2Hot pressing temperature is 180 ℃, and hot pressing time is 30 s;
(3) after molding, carrying out annealing heat treatment in a nitrogen atmosphere to obtain the magnetic core, wherein the heat treatment temperature is 690 ℃, and the heat treatment time is 40 min;
(4) sequentially carrying out impregnation spraying and bending tinning on the lead 1 extending out of the magnetic core to obtain a co-fired inductor with the size of 7.5mm multiplied by 6.5mm multiplied by 1.8mm, wherein the impregnation treatment is vacuum impregnation, and the spraying liquid adopted in the spraying process is epoxy resin;
the first magnetic powder in the step (1) is prepared by the following method:
(a) insulating and coating: diluting phosphoric acid by using acetone, wherein the mass ratio of the phosphoric acid to the acetone is 1:65, mixing and stirring the phosphoric acid and the acetone for 5min, and then standing for 8min for later use; mixing and stirring the Fe powder with the diameter of 10 mu m D50 with the diluted phosphoric acid for 50min, and drying the mixture for 1.3h at the temperature of 100 ℃ to obtain soft magnetic powder after phosphating treatment;
(b) secondary coating: mixing and stirring a coating material and the soft magnetic powder obtained in the step (c) for 55min, wherein the coating material is 7 wt% of the soft magnetic powder, and the coating material is silicon resin;
(c) and (3) granulation treatment: and granulating the soft magnetic powder subjected to secondary coating in a 50-mesh granulator, airing for 2.5 hours after granulation is finished, sieving the aired soft magnetic powder with a 40-mesh sieve, drying at 63 ℃ for 1.1 hours, naturally cooling, sieving with the 40-mesh sieve, and adding demolding powder into the sieved soft magnetic powder to obtain the first magnetic powder.
The second magnetic powder is prepared by the same operation steps and process parameters as the first magnetic powder, and the difference is that the soft magnetic powder adopted in the step (a) is replaced by FeSiAl soft magnetic powder, the FeSiAl soft magnetic powder is subjected to insulation coating, secondary coating and granulation treatment to obtain the second magnetic powder, and the process parameters adopted in the operation steps are completely the same.
As shown in fig. 3, in the prepared co-fired inductor, the first magnetic powder, the second magnetic powder and the first magnetic powder sequentially filled in the mold cavity form a first magnetic powder layer 2, a second magnetic powder layer 3 and a third magnetic powder layer 4, respectively, and the wire 1 is located in the third magnetic powder layer 4. And (3) carrying out inductance characteristic test on the prepared co-fired inductor, and measuring initial inductance L (0A) as 150nH, saturation current 100A and temperature rise current 90A. A12V-1V voltage reduction circuit is adopted to carry out efficiency test, the frequency of a switching power supply is 500kHz during the test, the efficiency reaches 80.8% when the electronic load is 5A, and the efficiency reaches 91.2% when the electronic load is 25A.
Example 4
The embodiment provides a preparation method of an integrated co-fired inductor, which comprises the following steps:
(1) filling 0.2g of first magnetic powder into a die cavity, removing an enameled wire from a flat copper wire 1 with a rectangular cross section, placing the flat copper wire 1 on the surface of the first magnetic powder, enabling two ends of the wire 1 to extend out of the die cavity, enabling the wire 1 to be a straight wire 1, enabling the length of the straight wire 1 to be 10mm, enabling the width of the straight wire 1 to be 2.0mm, enabling the straight wire 1 to be 0.36mm in thickness, vibrating the die cavity, embedding the straight wire 1 into the first magnetic powder, and leveling the first magnetic; then 0.6g of second magnetic powder is filled into the die cavity, the die cavity is vibrated, and the second magnetic powder is leveled; finally, filling 0.2g of third magnetic powder into the die cavity, vibrating the die cavity and leveling the third magnetic powder;
(2) carrying out compression molding on the magnetic powder filled into the mold cavity, wherein the compression molding mode is cold pressing, and the cold pressing pressure is 500Mpa/cm2The cold pressing temperature is 180 ℃, and the cold pressing time is 30 s;
(3) after molding, carrying out annealing heat treatment in a nitrogen atmosphere to obtain the magnetic core, wherein the heat treatment temperature is 850 ℃, and the heat treatment time is 30 min;
(4) sequentially carrying out impregnation spraying and bending tinning on the lead 1 extending out of the magnetic core to obtain a co-fired inductor with the size of 8.0mm multiplied by 5.0mm multiplied by 3.0mm, wherein the impregnation treatment is vacuum impregnation, and the spraying liquid adopted in the spraying process is epoxy resin;
the first magnetic powder in the step (1) is prepared by the following method:
(a) insulating and coating: diluting phosphoric acid by using acetone, wherein the mass ratio of the phosphoric acid to the acetone is 1:70, mixing and stirring the phosphoric acid and the acetone for 6min, and then standing for 10min for later use; mixing FeNi powder with the diameter of 10 mu m D50 with diluted phosphoric acid, stirring for 60min, and drying at 110 ℃ for 1.5h to obtain soft magnetic powder after phosphating treatment;
(b) secondary coating: mixing and stirring a coating material and the soft magnetic powder obtained in the step (c) for 60min, wherein the coating material is 10 wt% of the soft magnetic powder, and the coating material is silicon resin;
(c) and (3) granulation treatment: and granulating the soft magnetic powder subjected to secondary coating in a 60-mesh granulator, airing for 3 hours after granulation is finished, sieving the aired soft magnetic powder with a 50-mesh sieve, drying at 70 ℃ for 1.2 hours, naturally cooling, sieving with the 50-mesh sieve, and adding magnesium oxide auxiliary materials into the sieved soft magnetic powder to obtain the first magnetic powder.
The second magnetic powder is prepared by the same operation steps and process parameters as the first magnetic powder, and the difference is that the soft magnetic powder adopted in the step (a) is replaced by FeSiAl soft magnetic powder, the FeSiAl soft magnetic powder is subjected to insulation coating, secondary coating and granulation treatment to obtain the second magnetic powder, and the process parameters adopted in the operation steps are completely the same.
The third magnetic powder is prepared by the same operation steps and process parameters as the first magnetic powder, except that the soft magnetic powder adopted in the step (a) is replaced by FeSi soft magnetic powder with the D50 being 20 mu m, the FeSi soft magnetic powder is subjected to insulation coating, secondary coating and granulation treatment to obtain the third magnetic powder, and the process parameters adopted in the operation steps are completely the same.
As shown in fig. 4, in the prepared co-fired inductor, a first magnetic powder layer 2, a second magnetic powder layer 3 and a third magnetic powder layer 4 are respectively formed by sequentially filling the first magnetic powder, the second magnetic powder and the third magnetic powder into the mold cavity, and the wire 1 is located in the first magnetic powder layer 2. And (3) carrying out inductance characteristic test on the prepared co-fired inductor, and measuring initial inductance L (0A) of 120nH, saturation current of 70A and temperature rise current of 65A. A12V-1V voltage reduction circuit is adopted to carry out efficiency test, the frequency of a switching power supply is 500kHz during the test, the efficiency reaches 79.5 percent when the electronic load is 5A, and the efficiency reaches 88.3 percent when the electronic load is 25A.
Example 5
The embodiment provides a preparation method of an integrated co-fired inductor, which comprises the following steps:
(1) filling 0.2g of first magnetic powder into a die cavity, removing an enameled wire from a flat copper wire 1 with a rectangular cross section, placing the flat copper wire 1 on the surface of the first magnetic powder, enabling two ends of the wire 1 to extend out of the die cavity, enabling the wire 1 to be a straight wire 1, enabling the length of the straight wire 1 to be 14mm, enabling the width of the straight wire 1 to be 2.2mm, enabling the wire 1 to be 0.35mm in thickness, vibrating the die cavity, embedding the straight wire 1 into the first magnetic powder, and leveling the first magnetic powder; then, 0.3g of second magnetic powder, 0.5g of third magnetic powder, 0.3g of second magnetic powder and 0.2g of first magnetic powder are sequentially filled, and after the magnetic powder is filled each time, the die cavity is vibrated and the surface of the magnetic powder is smoothed;
(2) the magnetic powder filled in the die cavity is subjected to compression molding, the compression molding mode is cold pressing, and the cold pressing pressure is 1600Mpa/cm2；
(3) After molding, carrying out annealing heat treatment in a nitrogen atmosphere to obtain the magnetic core, wherein the heat treatment temperature is 690 ℃, and the heat treatment time is 40 min;
(4) sequentially carrying out impregnation spraying and bending tinning on the lead 1 extending out of the magnetic core to obtain a co-fired inductor (shown in figure 1) with the size of 10.0mm multiplied by 5.0mm multiplied by 2.0mm, wherein the impregnation treatment is vacuum impregnation, and the spraying liquid adopted in the spraying process is epoxy resin;
the first magnetic powder in the step (1) is prepared by the following method:
(a) insulating and coating: diluting phosphoric acid by using acetone, wherein the mass ratio of the phosphoric acid to the acetone is 1:65, mixing and stirring the phosphoric acid and the acetone for 5min, and then standing for 8min for later use; mixing and stirring FeSi soft magnetic powder with the diameter of 20 mu m D50 with diluted phosphoric acid for 50min, and drying at 100 ℃ for 1.3h to obtain phosphatized soft magnetic powder;
(b) secondary coating: mixing and stirring a coating material and the soft magnetic powder obtained in the step (c) for 55min, wherein the coating material is 7 wt% of the soft magnetic powder, and the coating material is phenolic resin;
(c) and (3) granulation treatment: and granulating the soft magnetic powder subjected to secondary coating in a 50-mesh granulator, airing for 2.5 hours after granulation is finished, sieving the aired soft magnetic powder with a 40-mesh sieve, drying at 63 ℃ for 1.1 hours, naturally cooling, sieving with the 40-mesh sieve, and adding magnesium oxide into the sieved soft magnetic powder to obtain the first magnetic powder.
The second magnetic powder is prepared by the same operation steps and process parameters as the first magnetic powder, except that the soft magnetic powder adopted in the step (a) is replaced by FeNi soft magnetic powder with the D50 being 10 mu m, the FeNi soft magnetic powder is subjected to insulation coating, secondary coating and granulation treatment to obtain the second magnetic powder, and the process parameters adopted in the operation steps are completely the same.
The third magnetic powder is prepared by the same operation steps and process parameters as the first magnetic powder, and the difference is that the soft magnetic powder adopted in the step (a) is replaced by FeSiAl magnetic powder, the FeSiAl magnetic powder is subjected to insulation coating, secondary coating and granulation treatment to obtain the third magnetic powder, and the process parameters adopted in the operation steps are completely the same.
As shown in fig. 5, in the prepared co-fired inductor, a first magnetic powder layer 2, a second magnetic powder layer 3, a third magnetic powder layer 4, a fourth magnetic powder layer 5 and a fifth magnetic powder layer 6 are respectively formed by sequentially filling the first magnetic powder, the second magnetic powder, the third magnetic powder, the second magnetic powder and the first magnetic powder into the mold cavity, and the wire 1 is located in the first magnetic powder layer 2. And (3) carrying out inductance characteristic test on the prepared co-fired inductor, and measuring initial inductance L (0A) 165nH, saturation current 105A and temperature rise current 90A. A12V-1V voltage reduction circuit is adopted to carry out efficiency test, the frequency of a switching power supply is 500kHz during the test, the efficiency reaches 82.0% when the electronic load is 5A, and the efficiency reaches 91.5% when the electronic load is 25A.
Comparative example 1
The embodiment provides a preparation method of an integrated co-fired inductor, which comprises the following steps:
(1) filling 1g of magnetic powder into a die cavity, removing an enameled wire from a flat copper wire 1 with a rectangular cross section, and embedding the flat copper wire 1 into the magnetic powder, wherein the shape of the wire 1 is a straight wire 1, the length of the wire 1 is 14mm, the width of the wire 1 is 2.6mm, and the thickness of the wire 1 is 0.3 mm;
(2) carrying out compression molding on the magnetic powder filled in the mold cavity, wherein the compression molding mode is hot pressing, and the hot pressing pressure is 400Mpa/cm2Hot pressing temperature is 160 ℃, and hot pressing time is 25 s;
(3) after forming, carrying out annealing heat treatment in a nitrogen atmosphere to obtain the magnetic core, wherein the heat treatment temperature is 700 ℃, and the heat treatment time is 30 min;
(4) sequentially carrying out impregnation spraying and bending tinning on the lead 1 extending out of the magnetic core to obtain a co-fired inductor with the size of 11.0mm multiplied by 5.0mm multiplied by 2.0mm, wherein the impregnation treatment is vacuum impregnation, and the spraying liquid adopted in the spraying process is epoxy resin;
the magnetic powder in the step (1) is prepared by adopting the following method:
(a) insulating and coating: diluting phosphoric acid by using acetone, wherein the mass ratio of the phosphoric acid to the acetone is 1:60, mixing and stirring the phosphoric acid and the acetone for 1min, and then standing for 5min for later use; mixing and stirring FeSi soft magnetic powder with the diameter of 20 mu m D50 with diluted phosphoric acid for 30min, and drying at 90 ℃ for 1h to obtain soft magnetic powder after phosphating treatment;
(b) secondary coating: mixing and stirring a coating material and the soft magnetic powder obtained in the step (c) for 40min, wherein the coating material is 2 wt% of the soft magnetic powder, and the coating material is phenolic resin;
(c) and (3) granulation treatment: and granulating the soft magnetic powder subjected to secondary coating in a 40-mesh granulator, airing for 2 hours after granulation, sieving the aired soft magnetic powder with a 30-mesh sieve, drying at 50 ℃ for 0.8 hour, naturally cooling, sieving with the 30-mesh sieve, and adding magnesium oxide auxiliary materials into the sieved soft magnetic powder to obtain the magnetic powder.
And (3) carrying out inductance characteristic test on the prepared co-fired inductor, and measuring initial inductance L (0A) of 140nH, saturation current of 50A and temperature rise current of 40A. A12V-1V voltage reduction circuit is adopted to carry out efficiency test, the frequency of a switching power supply is 500kHz during the test, the efficiency reaches 82.3% when the electronic load is 5A, and the efficiency reaches 88.3% when the electronic load is 25A.
The applicant declares that the above description is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and it should be understood by those skilled in the art that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are within the scope and disclosure of the present invention.
Claims (10)
1. A preparation method of an integrated co-fired inductor is characterized by comprising the following steps:
the magnetic powder is filled in the die cavity in batches, at least one wire is embedded into the magnetic powder of one layer when the two adjacent layers are different in type, two ends of the wire extend out of the die cavity, then compression molding and heat treatment are sequentially carried out to obtain the magnetic core, and the wire extending out of the magnetic core is bent and tinned to obtain the co-fired inductor.
2. The method of claim 1, wherein the magnetic powder is prepared by the following method: the soft magnetic powder is subjected to insulation coating, secondary coating and granulation treatment in sequence to obtain the magnetic powder;
preferably, the soft magnetic powder comprises FeSiCr, FeSi, FeNi, FeSiAl, carbonyl iron powder, carbonyl iron nickel powder, FeNiMo, Fe-based amorphous nanocrystalline material, Co-based amorphous nanocrystalline soft magnetic material or Ni-based amorphous nanocrystalline soft magnetic material.
3. The method according to claim 1 or 2, wherein the insulation coating is performed by a coating process including phosphating, acidification, oxidation or nitridation, and further preferably, the soft magnetic powder is subjected to insulation coating by phosphating;
preferably, the phosphating treatment comprises: mixing and stirring the soft magnetic powder and the diluted phosphoric acid, and drying to obtain the soft magnetic powder after phosphating;
preferably, the phosphoric acid is diluted with acetone;
preferably, the mass ratio of the phosphoric acid to the acetone is 1 (60-70);
preferably, the phosphoric acid and acetone are mixed and stirred for 1-6 min, and then are kept stand for 5-10 min for later use;
preferably, the soft magnetic powder and the diluted phosphoric acid are mixed and stirred for 30-60 min;
preferably, the drying temperature is 90-110 ℃;
preferably, the drying time is 1-1.5 h.
4. The method of any one of claims 1-3, wherein the secondary coating comprises: mixing and stirring the coating material and the insulated and coated soft magnetic powder;
preferably, the coating material is 2-10 wt% of the soft magnetic powder;
preferably, the coating material comprises phenolic resin, epoxy resin or silicon resin;
preferably, the coating material and the soft magnetic powder are mixed and stirred for 40-60 min.
5. The process according to any one of claims 1 to 4, wherein the granulation treatment comprises: granulating the soft magnetic powder after secondary coating, and sequentially airing, drying and cooling the granulated soft magnetic powder to obtain the magnetic powder;
preferably, the granulation process is carried out in a 40-60 mesh granulator;
preferably, the airing time is less than or equal to 3 hours;
preferably, the aired soft magnetic powder is sieved by a sieve with 30-50 meshes, and then is dried;
preferably, the drying temperature is 50-70 ℃;
preferably, the drying time is 0.8-1.2 h;
preferably, the cooling process is natural cooling;
preferably, the cooled soft magnetic powder is sieved by a 30-50-mesh sieve, and then auxiliary materials are added into the sieved soft magnetic powder to obtain the magnetic powder;
preferably, the auxiliary material comprises magnesium oxide, lubricating powder or demolding powder.
6. The production method according to any one of claims 1 to 5, wherein the first magnetic powder, the second magnetic powder and the first magnetic powder are filled into the cavity in three batches in order;
preferably, the wire is embedded in the second magnetic powder.
7. The method according to any one of claims 1 to 6, wherein the wire is a bare wire without a lacquered wire;
preferably, the conducting wire is a copper wire;
preferably, the lead is a flat lead with a rectangular cross section;
preferably, the shape of the wire is a straight wire or a special-shaped wire;
preferably, the shape of the shaped conductor comprises an S shape, an L shape, a U shape, a W shape or an E shape;
preferably, the conducting wires are laid in one layer of magnetic powder at intervals side by side on a horizontal plane.
8. The method according to any one of claims 1 to 7, wherein the molding is hot or cold pressing;
preferably, the hot-pressing pressure is more than or equal to 800MPa/cm2More preferably 2000MPa/cm2；
Preferably, the hot pressing temperature is 90-180 ℃;
preferably, the hot pressing time is 5-100 s;
preferably, the heat treatment is an annealing treatment;
preferably, the heat treatment process is carried out under a protective atmosphere;
preferably, the gas used in the protective atmosphere is nitrogen and/or inert gas;
preferably, the heat treatment temperature is 650-850 ℃;
preferably, the heat treatment time is 30-50 min.
9. A co-fired inductor prepared by the preparation method according to any one of claims 1 to 8, wherein the co-fired inductor comprises a magnetic core and at least one wire positioned inside the magnetic core, the magnetic core comprises at least two magnetic powder layers which are sequentially stacked, the magnetic powder types adopted by two adjacent magnetic powder layers are different, the wire is positioned in one of the magnetic powder layers, two ends of the wire extend out of the magnetic core, and the wire extending out of the magnetic core is bent and then clings to the outer wall of the magnetic core.
10. The co-fired inductor of claim 9, wherein the wire is bare wire without enameled wire;
preferably, the conducting wire is a copper wire;
preferably, the lead is a flat lead with a rectangular cross section;
preferably, the shape of the wire is a straight wire or a special-shaped wire;
preferably, the shape of the shaped conductor comprises an S shape, an L shape, a U shape, a W shape or an E shape;
preferably, the conducting wires are laid in one layer of magnetic powder at intervals side by side on a horizontal plane.
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| CN202011412397.7A CN112435845A (en) | 2020-12-04 | 2020-12-04 | Integrated co-fired inductor and preparation method thereof |
| DE112021006315.4T DE112021006315T5 (en) | 2020-12-04 | 2021-11-24 | INTEGRATED CO-BURNED INDUCTOR AND PRODUCTION PROCESS THEREOF |
| US18/255,538 US20240029952A1 (en) | 2020-12-04 | 2021-11-24 | Integrated co-fired inductor and preparation method therefor |
| KR1020237020410A KR20230109700A (en) | 2020-12-04 | 2021-11-24 | Integrated co-fired inductor and its manufacturing method |
| PCT/CN2021/132664 WO2022116874A1 (en) | 2020-12-04 | 2021-11-24 | Integrated co-fired inductor and preparation method therefor |
| JP2023534000A JP2023552400A (en) | 2020-12-04 | 2021-11-24 | Integral co-fired inductor and its manufacturing method |
| TW110144074A TWI815227B (en) | 2020-12-04 | 2021-11-25 | Integrated co-fired inductor and preparation method threrof |
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| CN113661549A (en) * | 2021-06-30 | 2021-11-16 | 东莞顺络电子有限公司 | Integrally formed inductor and manufacturing method thereof |
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