CN114360837A - Method for manufacturing magnetic element - Google Patents

Method for manufacturing magnetic element Download PDF

Info

Publication number
CN114360837A
CN114360837A CN202110529198.2A CN202110529198A CN114360837A CN 114360837 A CN114360837 A CN 114360837A CN 202110529198 A CN202110529198 A CN 202110529198A CN 114360837 A CN114360837 A CN 114360837A
Authority
CN
China
Prior art keywords
coil
composite material
magnetic
equal
soft magnetic
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202110529198.2A
Other languages
Chinese (zh)
Inventor
郭峰
付邦良
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Kunshan Citong New Material Technology Co ltd
Original Assignee
Kunshan Citong New Material Technology Co ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Kunshan Citong New Material Technology Co ltd filed Critical Kunshan Citong New Material Technology Co ltd
Publication of CN114360837A publication Critical patent/CN114360837A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
    • H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
    • H01F1/20—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of particles, e.g. powder
    • H01F1/22—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of particles, e.g. powder pressed, sintered, or bound together
    • H01F1/24—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of particles, e.g. powder pressed, sintered, or bound together the particles being insulated
    • 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
    • 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
    • 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
    • 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
    • H01F41/0253—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 for manufacturing permanent magnets

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical & Material Sciences (AREA)
  • Dispersion Chemistry (AREA)
  • Soft Magnetic Materials (AREA)
  • Coils Or Transformers For Communication (AREA)

Abstract

The application relates to the technical field of semiconductors, and particularly discloses a preparation method of a magnetic element. The preparation method comprises winding a wire to form a coil; placing the coil in a mold; filling a magnetic composite material into the mould, wherein the magnetic composite material comprises a soft magnetic metal material and an adhesive, the soft magnetic metal material and the adhesive are mixed according to a preset proportion, the relative density of the soft magnetic metal material is more than or equal to 0.5, and the relative density is the ratio of tap density to true density; and applying a preset pressure to the mold to enable the magnetic composite material to flow and form a magnetic body for coating the coil, wherein the preset pressure is less than the plastic deformation strength of the magnetic composite material and the plastic deformation strength of the coil. During actual pressing, the magnetic composite material can have higher forming density only by using smaller pressure without using larger pressure, and the problems that the magnetic composite material and a coil structure are damaged due to larger pressure and the like are avoided.

Description

Method for manufacturing magnetic element
Technical Field
The invention relates to the technical field of semiconductors, in particular to a preparation method of a magnetic element.
Background
Magnetic components such as inductors are widely used in various intelligent hardware systems, such as smart phones, smart televisions, smart home appliances, tablet computers, notebook computers, various communication terminals and servers, as one of the main passive components around the chip, and the main functions of the magnetic components include conversion, storage and filtering of electromagnetic signals and energy.
Taking an inductor as an example, a conventional inductor includes a coil and a magnetic body covering the coil, and the coil is generally placed in a mold, and the empty space inside and around the coil is filled with metal soft magnetic powder and is formed by pressing. In the pressing process, in order to ensure the stability of the structure, the pressing pressure is often larger and can reach 500MPa, 600MPa, 800MPa or even higher. However, such a high pressing pressure often damages the soft magnetic metal powder and the internal coil structure, resulting in problems such as overall deformation of the coil structure, further causing problems such as attenuation of initial voltage resistance of the coil, short circuit of the inductor, and the like, and reducing reliability of the inductor. Similarly, the same problems exist in the preparation of other magnetic elements of similar construction.
Disclosure of Invention
In view of the above, it is necessary to provide a method for manufacturing a magnetic element, which solves the problem of low reliability of the magnetic element due to excessive pressing pressure during the manufacturing process of the magnetic element.
According to an aspect of the present application, there is provided a method of manufacturing a magnetic element, the method including:
winding a conducting wire to form a coil;
placing the coil in a mold;
filling a magnetic composite material into the mould, wherein the magnetic composite material comprises a soft magnetic metal material and an adhesive, the soft magnetic metal material and the adhesive are mixed according to a preset proportion, the relative density of the soft magnetic metal material is more than or equal to 0.5, and the relative density is the ratio of tap density to true density;
and applying preset pressure intensity to the mold to enable the magnetic composite material to flow and form a magnetic body wrapping the coil, wherein the preset pressure intensity is smaller than the plastic deformation intensity of the magnetic composite material and the plastic deformation intensity of the coil.
In one embodiment, the preset pressure is greater than or equal to 1.0MPa and less than or equal to 15.0 MPa.
In one embodiment, the soft magnetic metal material accounts for more than or equal to 92% and less than or equal to 97% of the magnetic composite material by weight, and the binder accounts for more than or equal to 3% and less than or equal to 8% of the magnetic composite material by weight.
In one embodiment, the soft magnetic metal material includes a mixture of several materials not all having the same particle size, and a ratio of a maximum particle size to a minimum particle size among the particle sizes of the several materials is 8 or less.
In one embodiment, the soft magnetic metal material comprises carbonyl iron powder, reduced iron powder, atomized Fe(100-x-y)SixCryThe powder, atomized iron-based amorphous soft magnetic powder, atomized iron-based amorphous nanocrystalline powder, atomized iron-silicon-aluminum alloy powder and atomized iron-nickel alloy powder, wherein x is more than or equal to 3.5 and less than or equal to 6.5, and y is more than or equal to 0 and less than or equal to 6.5.
In one embodiment, the surface of the soft magnetic metal material has an insulating thin film including a complex salt of one or two or more of phosphate, silicate, borate, chromate, permanganate, nitrate, and aluminate.
In one embodiment, the adhesive includes one or a mixture of two or more of epoxy resin, phenolic resin, cyanate resin, bismaleimide resin and silicone resin, or one or a mixture of two or more of modified substances of the above resin materials.
In one embodiment, the molding density of the magnetic composite material is greater than or equal to 5g/cm3And is less than or equal to 6.2g/cm3。
In one embodiment, after the step of winding the wire to form the coil, the method for manufacturing the magnetic element further comprises:
and coating hot melt adhesive on the periphery of the coil formed by winding.
In one embodiment, in the step of placing the coil in the mold, two ends of the coil are respectively connected with electrode plates, so that the coil is limited by the electrode plates.
In the preparation process of the magnetic element, the magnetic composite material formed by the soft magnetic metal material with the relative density of more than or equal to 0.5 is used as the pressing material, so that the magnetic composite material is pressed by the pressure intensity which is less than the plastic deformation intensity of the magnetic composite material and the plastic deformation intensity of the coil without adopting too high pressing pressure intensity during pressing, the magnetic composite material after pressing and forming can be ensured to have enough forming density, the deformation or damage of the magnetic composite material and the internal coil structure caused by too high pressure intensity can be avoided, the situations of short circuit of the magnetic element and attenuation of the initial pressure resistance of the coil can be prevented, and the reliability of the magnetic element can be improved.
Drawings
Fig. 1 is a block flow diagram of a method for manufacturing a magnetic element according to an embodiment of the present disclosure;
FIG. 2 is a block flow diagram of one embodiment of a method of making a magnetic composite material provided in an example of the present application;
FIG. 3 is a block flow diagram of another embodiment of a method of making a magnetic composite material provided in the examples herein;
Detailed Description
To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
The terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
With the gradual development and mutual fusion of network technology, computer technology, communication technology and artificial intelligence technology, people begin to enter the fourth industrial revolution era; the era is mainly characterized in that close connection and information interaction are established between people and people, between objects and between people and objects, so that new life styles such as smart phones, smart homes, smart cities and the like appear, and along with the gradual breakthrough of related bottleneck technologies, intelligent transportation (including internet automobiles, intelligent parking and the like), AI robots, even the early and late AI robots, the society, agriculture and industry, and related internet of things can appear. The complex connections depend on the information transmission, communication and processing of a hardware system, can be an information transmitting end, an information receiving end and a cloud end, and the key of the intelligent hardware is a chip and related components.
Among them, magnetic components such as inductors (e.g., power inductors) are widely used in various intelligent hardware systems, such as smart phones, smart tvs, smart appliances, tablet computers, notebook computers, various communication terminals and servers, as one of the main passive components around the chip, and the main functions of the magnetic components include conversion, storage and filtering of electromagnetic signals and energy. The power inductor comprises a coil winding, wherein the coil winding is preset in a die, and the vacant space inside and around the coil winding is filled and pressed and molded through metal soft magnetic powder, so that an inductor structure is obtained, and the inductor structure has excellent EMI interference resistance and a completely closed magnetic structure.
However, in the conventional process of pressing the metallic soft magnetic powder, in order to increase the forming density of the metallic soft magnetic powder, the pressing is often performed with a higher pressure, for example, 500MPa or 600MPa or 800MPa, or even higher. Although such a high pressure can ensure a sufficiently high molding density of the metallic soft magnetic powder, it is easy to damage the metallic soft magnetic powder itself and the coil structure covered therein, so that the coil structure is deformed as a whole, the sectional area of the wire constituting the coil is deformed and scratched, and further, problems such as attenuation of the initial withstand voltage of the coil, short circuit of the magnetic element, and the like occur, thereby reducing the reliability of the magnetic element.
In order to solve the above problems, the present application provides a method for manufacturing a magnetic element, wherein the magnetic element may be a magnetic element formed by combining a coil and a magnetic material, such as an inductor or a transformer.
Referring to fig. 1, a method for manufacturing a magnetic element provided in an embodiment of the present application includes the following steps:
and step S40, winding the conducting wire to form a coil.
Step S42, placing the coil in a mold.
And S44, filling a magnetic composite material into the mould, wherein the magnetic composite material comprises a soft magnetic metal material and an adhesive, the soft magnetic metal material and the adhesive are mixed according to a preset proportion, the relative density of the soft magnetic metal material is more than or equal to 0.5, and the relative density is the ratio of tap density to true density.
Step S46, applying a preset pressure to the mold to make the magnetic composite material flow and form a magnetic body wrapping the coil, the preset pressure being less than the plastic deformation strength of the magnetic composite material and the plastic deformation strength of the coil.
In the preparation process of the magnetic element, the magnetic composite material formed by the soft magnetic metal material with the relative density of more than or equal to 0.5 is used as the pressing material, so that the magnetic composite material is pressed by the pressure intensity which is less than the plastic deformation intensity of the magnetic composite material and the plastic deformation intensity of the coil without adopting too high pressing pressure intensity during pressing, the magnetic composite material after pressing and forming can be ensured to have enough forming density, the deformation or damage of the magnetic composite material and the internal coil structure caused by too high pressure intensity can be avoided, the situations of short circuit of the magnetic element and attenuation of the initial pressure resistance of the coil can be prevented, and the reliability of the magnetic element can be improved.
The mixing of the soft magnetic metal material and the binder enables the soft magnetic metal material to have a certain fluidity, so that the magnetic composite material formed by mixing can be applied to a pressing process.
Tap density refers to the mass per unit volume measured after the powder in the container has been tapped under specified conditions, and true density refers to the actual mass per unit volume of solid material in an absolutely dense state of the material, i.e., the density after removal of internal voids or voids between particles. The ratio of tap density to true density is defined herein as the relative density of the soft magnetic metal material, the higher the relative density, the higher the compacted density of the soft magnetic metal material, and correspondingly, the higher the fill factor when the magnetic composite material is placed in a mold for pressing. The relative density of the soft magnetic metal material in the application is more than or equal to 0.5, when the soft magnetic metal material is actually pressed, the magnetic composite material has higher forming density only by small pressure without adopting large pressure, and the problems that the magnetic composite material and a coil structure are damaged due to large pressure and the like are avoided.
Wherein, the relative compactness of the soft magnetic metal material can be 0.5, 0.6, 0.7 and the like.
In one embodiment, the preset pressure is greater than or equal to 1MPa and less than or equal to 15 MPa. In the conventional scheme, the magnetic element is formed by adopting pressing pressure of 500MPa, 600MPa, 800MPa or even higher, which undoubtedly causes certain damage to the structure of the magnetic element. In the application, the magnetic composite material with relatively high density is adopted, and the magnetic element can be molded only by adopting the pressure less than or equal to 15MPa, so that the magnetic composite material and the internal coil structure are not deformed or damaged, the situations of short circuit of the magnetic element and attenuation of the initial pressure resistance of the coil are prevented, and the reliability of the magnetic element is improved.
The direct-current voltage resistance of the magnetic element prepared by the preparation method can reach more than 1000V/cm.
The predetermined mixing ratio of the soft magnetic metal material and the binder is not unique, and the mixing ratio of the soft magnetic metal material and the binder can be considered comprehensively from two aspects, namely, the fluidity of the magnetic composite material after mixing and the inductance performance of the magnetic composite material after mixing. In one embodiment, the soft magnetic metal material accounts for more than or equal to 92% and less than or equal to 97% of the magnetic composite material by weight, and the binder accounts for more than or equal to 3% and less than or equal to 8% of the magnetic composite material by weight. The soft magnetic metal material and the adhesive are mixed according to the mixing ratio, and the prepared magnetic composite material can be compatible with good fluidity and excellent inductance performance.
For example, the soft magnetic metal material accounts for 92% by weight of the magnetic composite material, and the binder accounts for 8% by weight of the magnetic composite material, or the soft magnetic metal material accounts for 95% by weight of the magnetic composite material, and the binder accounts for 5% by weight of the magnetic composite material, or the soft magnetic metal material accounts for 97% by weight of the magnetic composite material, and the binder accounts for 3% by weight of the magnetic composite material. Of course, the magnetic composite material may further include an auxiliary material such as a coupling agent, a toughening agent, or a leveling agent, so as to optimize the mixing effect between the metal magnetic material and the binder, or the flexibility of the magnetic composite material, for example, the magnetic composite material further includes a toughening agent, a leveling agent, a mold release agent, and the like, in which case, the weight percentage of the soft magnetic metal material in the magnetic composite material may be 95%, the weight percentage of the binder in the magnetic composite material may be 3%, and the weight percentage of the other auxiliary agents in the magnetic composite material may be 2%. Of course, there are other proportion distribution methods, which are not listed here, and it is only necessary that the weight percentage of the binder in the magnetic composite material is between 92% and 97%, and the weight percentage of the binder in the magnetic composite material is between 3% and 8%.
In one embodiment, the soft magnetic metal material includes a mixture of a plurality of materials not all having the same particle size, and a ratio of a maximum particle size to a minimum particle size among the particle sizes of the plurality of materials is 8 or less. That is, in this application, including the multiple material that the particle size is not of uniform size among the soft magnetic metal material, when mixing the material of different particle sizes, can realize higher tap density, and then promote relative density. Also, applicants have found that when the ratio of the maximum particle size to the minimum particle size of the particle sizes of several materials in the mixture is defined to be 8 or less, e.g., 8 or 7 or 6, etc., the tap density can be maintained at a higher value.
In this embodiment, the particle size of the several mixed materials in the soft magnetic metal material is between 10 micrometers and 80 micrometers.
In one embodiment, the soft magnetic metallic material includes carbonyl iron powder, reduced iron powder, atomized Fe(100-x-y)SixCryPowder and fogThe iron-based amorphous soft magnetic powder, the atomized iron-based amorphous nanocrystalline powder, the atomized iron-silicon-aluminum alloy powder and the atomized iron-nickel alloy powder are mixed, wherein x is more than or equal to 3.5 and less than or equal to 6.5, and y is more than or equal to 0 and less than or equal to 6.5. For example, the soft magnetic metallic material may include a mixture of carbonyl iron powder, reduced iron powder, and atomized iron powder, and may also include carbonyl iron powder, reduced iron powder, atomized iron powder, and atomized Fe(100-x-y)SixCryThe mixture of powders (x ═ 4 and y ═ 5) may further include reduced iron powder, atomized iron-based amorphous soft magnetic powder, atomized iron-based amorphous nanocrystalline powder, atomized iron-silicon-aluminum alloy powder, and a mixture of atomized iron-nickel alloy powder, which are not listed here.
In one embodiment, the surface of the soft magnetic metal material has an insulating thin film including a complex salt of one or two or more of phosphate, silicate, borate, chromate, permanganate, nitrate, and aluminate. The insulating film can be directly coated on the surface of the soft magnetic metal material in a physical coating mode, and can also be chemically reacted with the surface of the soft magnetic metal material, so that the surface of the soft magnetic metal material is modified to form the insulating film. The insulating thin film is a covalent bond or an ionic bond compound, so that the insulating thin film has good insulating property and heat-resistant property, and when the magnetic composite material is applied to an inductor structure, the insulating thin film can meet the requirements of heat aging resistance and voltage breakdown resistance in the use process of the inductor.
It should be noted that, because the soft magnetic metal material has higher relative density, the magnetic composite material can have higher molding density only with smaller pressure in the pressing process, which can prevent the magnetic composite material from being damaged due to larger pressure and also can prevent the insulating thin film structure on the surface of the soft magnetic metal material from being damaged.
In one embodiment, the thickness of the insulating film is 50 nm or less.
In one embodiment, the adhesive includes one or a mixture of two or more of epoxy resin, phenolic resin, cyanate ester resin, bismaleimide resin and silicone resin, or one or a mixture of two or more of modified substances of the above resin materials.
In one embodiment, the magnetic composite material has a molding density of 5g/cm or more3And is less than or equal to 6.2g/cm3. When the magnetic composite material is used in the process of pressing the inductor, on the basis of ensuring sufficiently high molding density, the pressing pressure of the magnetic composite material can be further reduced, the damage and deformation of the magnetic composite material in the pressing process can be reduced, and the deformation amount of the coil coated by the magnetic composite material can be reduced.
In step S40, the conductive wire may include a metal wire and an insulating layer (enameled wire) covering the metal wire, and the metal wire may include any one of a copper wire, an aluminum alloy, and a copper alloy. In addition, the cross-sectional shape of the coil may be circular or elliptical or rectangular, etc.
In one embodiment, before step S40, the core center pillar may be prepared in advance. Specifically, the core center pillar may be made of the magnetic composite material described above, or may be made of a soft magnetic metal material in the magnetic composite material. When the magnetic composite material is adopted to prepare the iron core center pillar, the molding pressure of the iron core center pillar is between 400 and 1500MPa, the higher the pressure is, the higher the magnetic conductivity is, the higher the strength and the density are, and the curing treatment is carried out according to the requirement after molding to finally prepare the iron core center pillar.
When the core center pillar is prepared, the coil may be wound around the core center pillar in step S40. The iron core center pillar is arranged in the coil, and deformation of the coil in the follow-up pressing process is reduced.
In one embodiment, after step S40, the method further includes:
and step S41, coating hot melt adhesive on the periphery of the coil formed by winding. The function of the hot melt adhesive is to shape the wound part of the coil when the coil is wound.
In one embodiment, in step S42, the coil may be placed in a mold, and both ends of the coil are respectively connected to the electrode plates, and the coil is fixed by the electrode plates connected to both ends, that is, the coil is limited by the electrode plates, so as to ensure that the distance from the coil to the inner wall of the mold is uniform, and then the mold is closed to form the mold cavity.
The connection mode between the two ends of the coil and the electrode plate comprises any one of a welding mode, a solder paste sintering mode and an electroplating mode. The electrode plate partially extends out of the die, and after the magnetic body is formed by subsequent pressing, the electrode plate is bent to form an external connecting terminal of the magnetic element.
It should be noted that, the present application uses a molding transfer molding process to prepare the inductor. The adopted mould is divided into an upper mould and an upper mould, and the lower mould is provided with an area for placing the coil and a bin for placing the magnetic composite material. In step S42, the coil is placed in the area corresponding to the lower mold of the mold, and in step S44, the magnetic composite material is filled into the bin of the lower mold of the mold.
In step S46, a preset pressure is applied to the magnetic composite material in the bin by using the pressure principle, and the magnetic composite material is changed into a liquid state under the heating action, flows into a die cavity formed by the upper die and the lower die under extrusion until the die cavity is filled, and then the magnetic composite material covers the coil completely. Then, the pressure is maintained for 30 to 180 seconds to cure the thermosetting resin (i.e., the binder) in the magnetic composite material, thereby forming a magnetic body covering the coil, and finally, the mold is released.
In one embodiment, the shape of the finally formed magnetic body may include a rectangular parallelepiped or an elliptic cylinder. Specifically, the top corner of the rectangular parallelepiped may have a chamfered shape, and the elliptic cylinder may further include a cylindrical shape.
Because the relative density of the magnetic composite material is more than or equal to 0.5, namely, the magnetic composite material has higher relative density, high pressing pressure is not needed during forming, and the requirements of high density after the magnetic composite material is formed and no damage to the magnetic composite material and a coil can be met simultaneously by forming with lower pressure.
Referring to fig. 2, an embodiment of the present application further provides a method for preparing a magnetic composite material, where the method for preparing a magnetic composite material provided in this embodiment includes the following steps:
step S20, mixing a plurality of soft magnetic metal powder materials with different grain diameters to prepare a soft magnetic metal material with relative compactness more than or equal to 0.5, wherein the ratio of the maximum grain diameter to the minimum grain diameter in the grain diameters of the plurality of materials is less than or equal to 8.
And step S22, mixing the soft magnetic metal material and the adhesive according to a preset proportion to prepare the magnetic composite material.
In the preparation method, the soft magnetic metal material and the adhesive are mixed, so that the prepared magnetic composite material has certain fluidity and can be applied to a pressing process. Moreover, the relative density of the prepared soft magnetic metal material is more than or equal to 0.5, so that when the magnetic composite material is applied to a pressing process, the magnetic composite material can have higher molding density only by smaller pressing pressure, and the problems that the magnetic composite material is damaged or deformed and the like due to larger pressure are avoided.
In one embodiment, in step S20, when soft magnetic metal powder materials with different particle sizes are mixed, a higher tap density can be achieved, and the relative compactness is improved. Also, applicants have found that when the ratio of the maximum particle size to the minimum particle size of the particle sizes of several soft magnetic metal powder materials in the mixture is defined as 8 or less, e.g., 8 or 7 or 6, etc., the tap density can be maintained at a high value, i.e., 0.5 or greater.
In one embodiment, the particle sizes of the several soft magnetic metal powder materials in the soft magnetic metal material are all between 10 microns and 80 microns.
For the relative compactness, reference may be made to the description of the magnetic composite material, which is not repeated herein.
In one embodiment, step S20 may be to mix carbonyl iron powder, reduced iron powder, atomized iron powder, and atomized Fe(100-x-y)SixCryAny several of the powder, atomized iron-based amorphous soft magnetic powder, atomized iron-based amorphous nanocrystalline powder, atomized iron-silicon-aluminum alloy powder and atomized iron-nickel alloy powder are mixed to prepare the soft magnetic metal material,wherein x is more than or equal to 3.5 and less than or equal to 6.5, and y is more than or equal to 0 and less than or equal to 6.5. When the materials are selected, the requirements that the particle sizes are not all the same and the ratio of the maximum particle size to the minimum particle size is less than or equal to 8 are met.
In one embodiment, in step S22, the binder may be greater than or equal to 3% and less than or equal to 8% by weight of the mixture, and the soft magnetic metal material may be greater than or equal to 92% and less than or equal to 97% by weight of the mixture. When the soft magnetic metal material and the adhesive are mixed uniformly, the required magnetic composite material can be prepared.
The adhesive comprises one or a mixture of more than two of epoxy resin, phenolic resin, cyanate resin, bismaleimide resin and silicon resin, or one or a mixture of more than two of modified substances of the resin materials.
Referring to fig. 3, in one embodiment, after step S20 and before step S22, the method for preparing the magnetic composite material provided by the present application further includes the following steps:
step S21, performing surface modification treatment on the soft magnetic metal material to form an insulating thin film on the surface of the soft magnetic metal material, wherein the insulating thin film includes one or more compound salts of phosphate, silicate, borate, chromate, permanganate, nitrate and aluminate.
The surface modification treatment of the soft magnetic metal material aims to form an insulating film on the surface of the soft magnetic metal material, and the insulating film can be directly coated on the surface of the soft magnetic metal material in a physical coating mode or can be subjected to chemical reaction with the surface of the soft magnetic metal material, so that the insulating film is formed after the surface of the soft magnetic metal material is modified. The insulating thin film is a covalent bond or an ionic bond compound, so that the insulating thin film has good insulating property and heat-resistant property, and when the magnetic composite material is applied to an inductor structure, the insulating thin film can meet the requirements of heat aging resistance and voltage breakdown resistance in the use process of the inductor.
In one embodiment, the thickness of the insulating film is 50 nm or less.
Referring to fig. 2, in one embodiment, after step S22, the method further includes the following steps:
and step S24, preparing the magnetic composite material into feed material, wherein the shape of the feed material comprises any one or more of irregular powder, cake and viscous fluid.
The molding density of the magnetic composite material prepared by the preparation method is more than or equal to 5g/cm3And is less than or equal to 6.2g/cm3。
The embodiment of the application also provides a magnetic element, and the magnetic element provided by the embodiment comprises a coil and a magnetic body wrapping the coil, wherein the magnetic body is made of the magnetic composite material.
Because the relative density of the soft magnetic metal material in the magnetic composite material is more than or equal to 0.5, when the magnetic composite material is pressed, the magnetic composite material can have higher molding density only by lower pressure without adopting higher pressure, the problems that the magnetic composite material and a coil structure coated with the magnetic composite material are damaged or deformed and the like due to higher pressure are avoided, the situations of short circuit of a magnetic element and attenuation of the initial pressure resistance of the coil are further prevented, and the reliability of the magnetic element is improved.
In one embodiment, the coil is an air-core coil having a core leg inside, i.e., the coil is disposed around the core leg. Preferably, the height of the core center pillar is equal to or greater than the height of the coil and equal to or less than 80% of the height of the magnetic body.
In one embodiment, the center pillar of the core is made of the magnetic composite material, and may also be made of other magnetic composite materials, which is not limited herein.
As an alternative embodiment, the central column of the iron core is made of a soft magnetic metal material, and can be a ferrosilicon magnetic powder core, an amorphous magnetic powder core, a sendust magnetic powder core, and the like.
In the embodiment, the compression fracture strength of the central column of the iron core is more than or equal to 15MPa, and the deformation is 0.1-1%.
In one embodiment, the coil is formed by winding enameled wires, the enameled wires at the outermost periphery of the coil are coated with hot melt adhesive, and the hot melt adhesive is used for shaping the wound part of the coil when the coil is wound.
In one embodiment, two ends of the coil are respectively connected to corresponding external electrodes, and the external electrodes extend out of the magnetic body to serve as external connection terminals of the inductor.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims (10)

1. A method of making a magnetic element, the method comprising:
winding a conducting wire to form a coil;
placing the coil in a mold;
filling a magnetic composite material into the mould, wherein the magnetic composite material comprises a soft magnetic metal material and an adhesive, the soft magnetic metal material and the adhesive are mixed according to a preset proportion, the relative density of the soft magnetic metal material is more than or equal to 0.5, and the relative density is the ratio of tap density to true density;
and applying preset pressure intensity to the mold to enable the magnetic composite material to flow and form a magnetic body wrapping the coil, wherein the preset pressure intensity is smaller than the plastic deformation intensity of the magnetic composite material and the plastic deformation intensity of the coil.
2. The method according to claim 1, wherein the predetermined pressure is 1.0MPa or more and 15.0MPa or less.
3. The method of claim 1, wherein the soft magnetic metal material is greater than or equal to 92% and less than or equal to 97% by weight of the magnetic composite material, and the binder is greater than or equal to 3% and less than or equal to 8% by weight of the magnetic composite material.
4. The method of claim 1, wherein the soft magnetic metal material comprises a mixture of a plurality of materials that are not all the same in particle size, and a ratio of a maximum particle size to a minimum particle size among the plurality of materials is 8 or less.
5. A method of manufacturing a magnetic component as claimed in claim 1, wherein the soft magnetic metallic material comprises carbonyl iron powder, reduced iron powder, atomized Fe(100-x-y)SixCryThe powder, atomized iron-based amorphous soft magnetic powder, atomized iron-based amorphous nanocrystalline powder, atomized iron-silicon-aluminum alloy powder and atomized iron-nickel alloy powder, wherein x is more than or equal to 3.5 and less than or equal to 6.5, and y is more than or equal to 0 and less than or equal to 6.5.
6. The method of manufacturing a magnetic device according to claim 1, wherein the surface of the soft magnetic metal material has an insulating thin film comprising a complex salt of one or two or more of phosphate, silicate, borate, chromate, permanganate, nitrate, and aluminate.
7. The method of manufacturing a magnetic element according to claim 1, wherein the adhesive includes one or a mixture of two or more of an epoxy resin, a phenol resin, a cyanate resin, a bismaleimide resin, and a silicone resin, or one or a mixture of two or more of modified products of the respective resin materials.
8. The method of claim 1, wherein the magnetic composite material has a molding density of 5.0g/cm or more3And is less than or equal to 6.2g/cm3。
9. The method of claim 1, wherein after the step of winding the wire to form the coil, the method further comprises:
and coating hot melt adhesive on the periphery of the coil formed by winding.
10. The method according to claim 1, wherein in the step of placing the coil in a mold, both ends of the coil are respectively connected to electrode tabs so as to limit the coil by the electrode tabs.
CN202110529198.2A 2020-10-12 2021-05-14 Method for manufacturing magnetic element Pending CN114360837A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN2020110839545 2020-10-12
CN202011083954.5A CN112331441A (en) 2020-10-12 2020-10-12 Composite material and preparation method thereof, inductor and preparation method thereof

Publications (1)

Publication Number Publication Date
CN114360837A true CN114360837A (en) 2022-04-15

Family

ID=74314809

Family Applications (5)

Application Number Title Priority Date Filing Date
CN202011083954.5A Withdrawn CN112331441A (en) 2020-10-12 2020-10-12 Composite material and preparation method thereof, inductor and preparation method thereof
CN202110529180.2A Pending CN114360835A (en) 2020-10-12 2021-05-14 Magnetic element
CN202110529191.0A Pending CN114360836A (en) 2020-10-12 2021-05-14 Magnetic composite material
CN202110528227.3A Pending CN114360834A (en) 2020-10-12 2021-05-14 Preparation method of magnetic composite material
CN202110529198.2A Pending CN114360837A (en) 2020-10-12 2021-05-14 Method for manufacturing magnetic element

Family Applications Before (4)

Application Number Title Priority Date Filing Date
CN202011083954.5A Withdrawn CN112331441A (en) 2020-10-12 2020-10-12 Composite material and preparation method thereof, inductor and preparation method thereof
CN202110529180.2A Pending CN114360835A (en) 2020-10-12 2021-05-14 Magnetic element
CN202110529191.0A Pending CN114360836A (en) 2020-10-12 2021-05-14 Magnetic composite material
CN202110528227.3A Pending CN114360834A (en) 2020-10-12 2021-05-14 Preparation method of magnetic composite material

Country Status (1)

Country Link
CN (5) CN112331441A (en)

Also Published As

Publication number Publication date
CN114360835A (en) 2022-04-15
CN112331441A (en) 2021-02-05
CN114360836A (en) 2022-04-15
CN114360834A (en) 2022-04-15

Similar Documents

Publication Publication Date Title
JP2014013803A (en) Inductor
JP4099340B2 (en) Manufacturing method of coil-embedded dust core
CN112582134A (en) Preparation method of high-reliability molded inductor and molded inductor thereof
KR101671048B1 (en) Permanently laminated flux concentrator assembly and flexible flux concentrator assembly
CN102623121B (en) Method for manufacturing iron-silicon material and Mu-90 iron-silicon magnetic powder core
JP7089576B2 (en) Manufacturing method of integrated chip inductor consisting of metal magnetic powder core
JPH09120926A (en) High-current thin inductor and manufacture thereof
EP2584574A1 (en) Reactor
CN102810392B (en) Thin closed magnetic circuit inductor and manufacturing method thereof
CN101377975A (en) Integral inductor and preparation method thereof
TW201712699A (en) Dust core, method for producing said dust core, electric/electronic component provided with said dust core, and electric/electronic device on which said electric/electronic component is mounted
KR20170061586A (en) Compressed powder core, method of manufacturing the compressed powder core, inductor comprising the compressed powder core and electronic-electric device mounted with the inductor
WO2022077150A1 (en) Magnetic composite material and preparation method therefor, and inductor and manufacturing method therefor
CN113223844B (en) Powder coating method
CN104064320B (en) A kind of preparation method of electromagnetic oven filter inductance
CN114360837A (en) Method for manufacturing magnetic element
CN110323028A (en) Coil component, electronic device, metallic magnetic powder and auxiliary device
CN116670314A (en) Magnetic powder for manufacturing magnet, magnet and magnetic element
KR102069475B1 (en) Green powder core, the manufacturing method of the green powder core, the electrical / electronic component provided with this powder core, and the electrical / electronic device in which the electrical / electronic component was mounted.
JP7392275B2 (en) Composite particles, cores and inductor elements
CN114078620A (en) Electric element and manufacturing method thereof
TW202036614A (en) Method for manufacturing inductor
JP6087708B2 (en) Winding element manufacturing method
CN111755200A (en) Composite magnetic particles comprising metal magnetic particles
CN217485249U (en) Magnetic powder injection molding inductor with prefabricated magnetic core

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination