CN111863411A - A kind of integrated magnetic device and preparation method thereof - Google Patents

Abstract

The invention relates to an integrated magnetic device and a preparation method thereof, comprising magnetic ceramics and one or more sets of conductive coils; the conductive coils are wound by metal wires; the magnetic ceramics and the conductive coils are sintered; The integrated magnetic device because the conductive coil is sintered inside the magnetic ceramic, the magnetic ceramic can enhance the magnetic induction effect and magnetic shielding function at the same time, there is no gap between the coil and the magnetic core, which minimizes the leakage of the electromagnetic field of the conductive coil. It also shields the interference of the external electromagnetic field on the conductive coil; at the same time, compared with the existing magnetic devices such as metal magnetic powder integrated inductance, molded inductance, etc., it has the advantages of high magnetic permeability, high resistivity, low eddy current loss, etc., especially in the It has broad application prospects in high frequency circuits (greater than 100KHz).

Description

A kind of integrated magnetic device and preparation method thereof

technical field

The invention belongs to the technical field of electronic components, and particularly relates to an integrated magnetic device and a preparation method thereof.

Background technique

Magnetic devices include transformers, inductors, mutual inductors, filters, etc., which are made by winding one or more sets of copper wires on magnetic materials, and are extremely important components in the electronics industry. When alternating current flows through the coil, energy is temporarily stored in the magnetic field induced inside the coil and core. According to the law of electromagnetic induction, the alternating magnetic field can induce alternating electric and magnetic fields, and radiate to the outside of the device. These outwardly radiated electromagnetic fields can interfere or degrade other electronic devices around the magnetic device. In addition, electric and magnetic fields from other electronic components on the circuit board can also interfere with and degrade the performance of magnetic devices. Electronic equipment is developing rapidly towards high frequency, integration and low power consumption. The electromagnetic interference phenomenon of magnetic devices is becoming more and more serious, and the demand for magnetic devices with shielding function is increasing.

In order to solve the electromagnetic interference problem of the above-mentioned open magnetic devices, the widely used method is to form a Drum Core around the coil in the middle of the I-shaped magnetic core, and add a magnetic or metal shield outside the device, between the shield, the coil and the magnetic core. Filling plastic sealant (usually epoxy resin). However, in this design, the shielding cover occupies a large amount of internal space of the device, and the electromagnetic field can still leak from the assembly gap between the magnetic core, the coil and the shielding cover, and the processing of the shielding cover is complicated, the efficiency is low, and the labor intensity of the workers is high. Another solution is to place the enameled wire coil in the insulated metal magnetic powder and form it integrally by die casting, and the coil is densely surrounded by the magnetic powder to achieve the shielding function. However, this method needs to press the metal magnetic powder and the coil under very high pressure. The insulating layer of the metal magnetic powder and the insulating varnish of the coil are very easily damaged, resulting in a short circuit between the magnetic core and the coil. The resistivity of the metal magnetic powder is also very low and high. Serious eddy current loss occurs at high frequency (greater than 100KHz), and due to powder compression molding, there are a large number of air gaps inside, and the magnetic permeability of the device is very low (less than 80).

In view of the above technical problems, it is necessary to improve.

SUMMARY OF THE INVENTION

Aiming at the problems existing in the existing magnetic devices, the present invention provides an integrated magnetic device and a preparation method thereof.

In order to achieve the above purpose, the technical solution adopted in the present invention is: an integrated magnetic device, comprising magnetic ceramics and one or more groups of conductive coils; the conductive coils are wound by metal wires; the magnetic ceramics and the conductive coils are sintered made.

As a preferred mode of the present invention, the conductive coil includes but is not limited to round enameled wire, flat enameled wire, pure metal copper wire, metal aluminum wire, and metal silver wire.

As a preferred mode of the present invention, the magnetic ceramics are manganese-zinc ferrite, nickel-zinc ferrite, nickel-copper-zinc ferrite, manganese-copper-zinc ferrite, lithium-zinc ferrite and magnesium-zinc ferrite one of the body.

As a preferred mode of the present invention, the shape of the magnetic device is a rod shape, a rectangular parallelepiped shape, a sheet shape, a pot shape, a ring shape, a tube shape, a PM shape, a PQ shape, an E shape, a T shape, a U shape and the above shapes. any combination of .

As a preferred mode of the present invention, the magnetic device has at least one connection terminal.

A preparation method of an integrated magnetic device, comprising the following steps:

Step (1): Preparation of magnetic ceramic pre-sintered powder, mixing oxide raw materials uniformly, and pre-sintering at 700-1000° C. for 0.5-5 h to obtain magnetic ceramic pre-sintered powder;

Step (2): Slurry preparation, mixing pre-fired powder with dopant, solvent, adhesive, dispersant and plasticizer uniformly, and ball milling to obtain slurry;

Step (3): the coil is solidified, the slurry is first placed in the mold, and then the coil is immersed in the slurry, so that the slurry is evenly filled between the coils, and cured at 60-120° C. for 0.5-3 hours to obtain a green blank;

Step (4): Debinding and sintering, debinding the green body at 250-500°C for 0.5-5h, and sintering at 850-1200°C for 1-6h.

As a preferred mode of the present invention, in the preparation of the magnetic ceramic pre-sintered powder in the step (1), the oxide raw materials are iron oxide, and zinc oxide, manganese oxide, manganese carbonate, copper oxide, nickel oxide, magnesium oxide, One or more of lithium oxide; the oxide raw material is one of the following combinations: iron oxide, zinc oxide, manganese oxide, or iron oxide, zinc oxide, manganese oxide, copper oxide, or iron oxide, zinc oxide, Nickel oxide, or iron oxide, zinc oxide, nickel oxide and copper oxide; the mole fraction of iron oxide is 45-55%, and the mole fraction of copper oxide is 1-15%.

As a preferred mode of the present invention, in the preparation of the slurry in the step (2), the dopant is cobalt oxide, titanium oxide, tin oxide, calcium oxide, silicon oxide, bismuth oxide, vanadium oxide one or more of molybdenum oxides, molybdenum oxides and lanthanum oxides, and the mole fraction of the total amount of doping is 0.1 to 5%; the solvent is water, ethanol, methyl ethyl ketone, acetone, butanone, cyclohexanone, diethyl ether One or more of toluene, the volume fraction is 5-40% of the slurry; the adhesive is epoxy resin, W-6C magnetic powder glue, phenolic resin, polyvinyl alcohol, polyvinyl butyral , a kind of glass powder, which is 5-30% of the mass fraction of the slurry; the dispersant is a kind of castor oil, herring oil, phosphate ester, glyceryl trioleate, and triethanolamine, and the volume fraction is 0.2 to 5% of the slurry. Described plasticizer is a kind of in glycerol, dioctyl phthalate, polyethylene glycol, dibutyl phthalate, ortho-dibutyl phthalate, and the binder/plasticizer weight ratio is 0.5 to 1.0.

As a preferred mode of the present invention, one of ultrasonic vibration, mechanical stirring, and natural immersion can be used in the coil solidification process of the step (3), so that the slurry is evenly filled between the coils.

As a preferred mode of the present invention, the sintering in step (4) is one of pressureless sintering, warm pressing sintering, hot pressing sintering, spark plasma sintering, and microwave sintering, and the sintering atmosphere is vacuum, air, and nitrogen. , Argon or balanced oxygen partial pressure sintering.

The beneficial effects of the present invention are:

In the integrated magnetic device obtained by the present invention, the conductive coil is sintered inside the magnetic ceramic, and the magnetic ceramic has the functions of enhancing the magnetic induction effect and magnetic shielding at the same time. The leakage of the electromagnetic field also shields the interference of the external electromagnetic field to the conductive coil. At the same time, compared with the existing magnetic devices such as metal magnetic powder integrally formed inductors and molded inductors, it has the advantages of high permeability, high resistivity, and low eddy current loss, especially in high-frequency circuits (greater than 100KHz) It has a wide range of applications. prospect.

Description of drawings

1 is a schematic structural diagram of Embodiment 1 of the present invention;

2 is a schematic structural diagram of Embodiment 2 of the present invention;

3 is a schematic structural diagram of Embodiment 3 of the present invention;

Reference numerals in the figure: magnetic ceramic 1 , conductive coil 2 .

Detailed ways

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

Example: As shown in Figure 1, an integrated magnetic device includes a magnetic ceramic 1 and a conductive coil 2; the conductive coil 2 is wound by a metal wire; the magnetic ceramic 1 and the conductive coil 2 are sintered; The apparent density is above 4.4g/ ^cm3 ;

Wherein, the conductive coil 2 includes but is not limited to round enameled wire, flat enameled wire, pure metal copper wire, metal aluminum wire, metal silver wire; magnetic ceramic 1 is manganese zinc ferrite, nickel zinc ferrite, nickel copper zinc ferrite One of the ferrite, manganese-copper-zinc ferrite, lithium-zinc ferrite and magnesium-zinc ferrite.

The conductive coils 2 are one or more groups, and their materials include but are not limited to round enameled wires, flat enameled wires, pure metal copper wires, metal aluminum wires, and metal silver wires.

The application of the integrated magnetic device of the present invention includes but is not limited to transformers, inductors, filters, reactors, transformers, etc., the resistivity is higher than 10 ⁶ μΩ·cm, the use frequency is higher than 100KHz, and the magnetic permeability is higher than 60 .

The shape of the magnetic device is rod shape, cuboid shape, sheet shape, pot shape, ring shape, tube shape, PM shape, PQ shape, E shape, T shape, U shape and any combination of the above shapes.

The magnetic device has at least one connection terminal.

A preparation method of an integrated magnetic device, comprising the following steps:

Step (1): Preparation of magnetic ceramic pre-sintered powder, mixing oxide raw materials uniformly, and pre-sintering at 700-1000° C. for 0.5-5 h to obtain magnetic ceramic pre-sintered powder; Preparation of magnetic ceramic pre-sintered powder in step (1) Among them, the oxide raw material is iron oxide, and one or more of zinc oxide, manganese oxide, manganese carbonate, copper oxide, nickel oxide, magnesium oxide, and lithium oxide; the oxide raw material is one of the following combinations: Iron, zinc oxide, manganese oxide, or iron oxide, zinc oxide, manganese oxide, copper oxide, or iron oxide, zinc oxide, nickel oxide, or iron oxide, zinc oxide, nickel oxide, and copper oxide; iron oxide mole fraction 45 ~ 55%, and the mole fraction of copper oxide is 1 ~ 15%.

Step (2); slurry preparation, mix the pre-fired powder with dopant, solvent, adhesive, dispersant, and plasticizer uniformly, and ball-mill to obtain slurry; in the slurry preparation of step (2), mix The doping agent is one or more of cobalt oxide, titanium oxide, tin oxide, calcium oxide, silicon oxide, bismuth oxide, vanadium oxide, molybdenum oxide and lanthanum oxide, and the total amount of doping The mole fraction is 0.1-5%; the solvent is one or more of water, ethanol, methyl ethyl ketone, acetone, butanone, cyclohexanone and xylene, and the volume fraction is 5-40% of the slurry; The adhesive is one of epoxy resin, W-6C magnetic powder glue, phenolic resin, polyvinyl alcohol, polyvinyl butyral, and glass powder, which is 5-30% of the mass fraction of the slurry; The dispersant is one of castor oil, herring oil, phosphoric acid ester, glyceryl trioleate and triethanolamine, and the volume fraction is 0.2-5% of the slurry. Described plasticizer is a kind of in glycerol, dioctyl phthalate, polyethylene glycol, dibutyl phthalate, ortho-dibutyl phthalate, and the binder/plasticizer weight ratio is 0.5 to 1.0.

Step (3): the coil is solidified, the slurry is first placed in the mold, and then the coil is immersed in the slurry, so that the slurry is evenly filled between the coils, and cured at 60-120° C. for 0.5-3 hours to obtain a green blank; During the solidification process of the coils in step (3), one of ultrasonic vibration, mechanical stirring and natural immersion methods can be used to make the slurry evenly filled between the coils.

Step (4): Debinding and sintering, debinding the green body at 250-500°C for 0.5-5h, and sintering at 850-1200°C for 1-6h; the sintering in step (4) is pressureless sintering, warm-pressing sintering, One of hot pressing sintering, spark plasma sintering and microwave sintering, and the sintering atmosphere is vacuum, air, nitrogen, argon or balanced oxygen partial pressure sintering.

The specific operation is as follows: Mix the raw materials of iron oxide, zinc oxide, nickel oxide and copper oxide evenly, and pre-fire at 700 ° C for 2 hours to obtain magnetic ceramic pre-fired powder; mix the pre-fired powder with dopants cobalt oxide and titanium oxide. , ethanol solvent, polyvinyl butyral adhesive, castor oil dispersant, dibutyl phthalate plasticizer are mixed evenly, ball milled to obtain slurry; The set of copper coils (constituting a four-terminal transformer) is immersed in the slurry, and the slurry is evenly filled between the coils by ultrasonic vibration, and cured at 80 °C for 1 hour to obtain a green billet; the green billet is degummed at 250 °C for 2 hours, 980 °C Sintered in air for 4h. The final prepared dual-winding four-terminal integrated transformer; specifically, in the figure, 1 is a magnetic ceramic base, 2 is a conductive coil sintered in the ceramic base, and the conductive coil is a copper coil.

Embodiment 2;

As shown in Figure 2; the raw materials of iron oxide, zinc oxide, manganese oxide, and copper oxide are mixed uniformly, and pre-fired at 750 ° C for 3 hours to obtain magnetic ceramic pre-fired powder; the pre-fired powder is mixed with dopants cobalt oxide, tin Oxide, calcium oxide, silicon oxide, bismuth oxide, acetone solvent, polyvinyl alcohol adhesive, phosphate ester dispersant, o-xylene dibutyl ester plasticizer are mixed uniformly, and ball milled to obtain slurry; The slurry is placed in the mold, and then a group of copper coils (forming a two-terminal inductor) are immersed in the slurry, and the slurry is evenly filled between the coils by ultrasonic vibration, and cured at 90 ° C for 1.5 hours to obtain a green billet; The green billet was degummed at 300°C for 2h, and sintered in nitrogen at 1000°C for 3h; the single-winding two-terminal integrated inductor was finally prepared; specifically, in the figure, No. 3 is the base of the second magnetic ceramic in Example 2 , No. 4 is the second conductive coil sintered in the second ceramic matrix in Example 2, and the second conductive coil is a copper coil.

For other contents in this embodiment, reference may be made to Embodiment 1.

Example 3:

As shown in Figure 3; the raw materials of iron oxide, zinc oxide and nickel oxide are mixed uniformly, and pre-fired at 850 ° C for 3 hours to obtain magnetic ceramic pre-fired powder; the pre-fired powder is mixed with dopants cobalt oxide, vanadium oxide, Molybdenum oxide, xylene solvent, epoxy resin adhesive, triethanolamine, dioctyl phthalate plasticizer are mixed evenly, and ball milled to obtain slurry; The copper coil (constituting a two-terminal inductor) is naturally immersed in the slurry, so that the slurry is evenly filled between the coils, and cured at 100 ° C for 2 hours to obtain a green blank; the green blank is degummed at 350 ° C for 2 hours, and 1020 ° C. Vacuum sintering for 3 hours; the single-winding two-terminal integrated flat inductor is finally prepared. Specifically, in the figure, No. 5 is the substrate of the third magnetic ceramic in Example 3, No. 6 is the third conductive coil sintered in the third ceramic substrate in Example 3, and the third conductive coil is a copper coil.

For other contents in this embodiment, reference may be made to Embodiment 1.

The above description of the disclosed embodiments enables any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention; thus , the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. An integrated magnetic device, characterized in that; comprises a magnetic ceramic (1) and one or more groups of conductive coils (2); the conductive coil (2) is formed by winding a metal wire; the magnetic ceramic (1) and the conductive coil (2) are sintered.

2. An integrated magnetic device as claimed in claim 1, wherein: the conductive coil (2) comprises, but is not limited to, a round enameled wire, a flat enameled wire, a pure metal copper wire, a metal aluminum wire and a metal silver wire.

3. An integrated magnetic device as claimed in claim 1, wherein: the magnetic ceramic (1) is one of manganese zinc ferrite, nickel copper zinc ferrite, manganese copper zinc ferrite, lithium zinc ferrite and magnesium zinc ferrite.

4. An integrated magnetic device as claimed in claim 1, 2 or 3, wherein: the magnetic device is in the shape of a bar, a rectangular parallelepiped, a sheet, a can, a ring, a tube, a PM, a PQ, an E, a T, a U, and any combination of the above.

5. An integrated magnetic device as claimed in claim 4, wherein: the magnetic device has at least one connection terminal.

6. The preparation method of the integrated magnetic device is characterized by comprising the following steps of:

step one; preparing magnetic ceramic pre-sintering powder, namely uniformly mixing oxide raw materials, and pre-sintering at 700-1000 ℃ for 0.5-5 h to obtain the magnetic ceramic pre-sintering powder;

step two; preparing slurry, namely uniformly mixing the pre-sintered powder with a doping agent, a solvent, an adhesive, a dispersing agent and a plasticizer, and performing ball milling to obtain slurry;

step three; curing the coil, namely placing the slurry into a mold, immersing the coil into the slurry to uniformly fill the slurry between the coils, and curing at 60-120 ℃ for 0.5-3 h to obtain a raw blank;

step four; and (3) binder removal and sintering, namely binder removal and sintering of the raw blank at 250-500 ℃ for 0.5-5 h and sintering at 850-1200 ℃ for 1-6 h.

7. The method for preparing an integrated magnetic device according to claim 6, wherein in the preparation of the magnetic ceramic pre-firing powder in the step (I), the oxide raw material is iron oxide and one or more of zinc oxide, manganese carbonate, copper oxide, nickel oxide, magnesium oxide and lithium oxide; the oxide raw material is one of the following combinations: iron oxide, zinc oxide, manganese oxide, or iron oxide, zinc oxide, manganese oxide, copper oxide, or iron oxide, zinc oxide, nickel oxide, and copper oxide; the iron oxide is 45-55% in mole fraction, and the copper oxide is 1-15% in mole fraction.

8. The method for preparing an integrated magnetic device according to claim 6, wherein the dopant in the slurry preparation of the second step is one or more of cobalt oxide, titanium oxide, tin oxide, calcium oxide, silicon oxide, bismuth oxide, vanadium oxide, molybdenum oxide and lanthanum oxide, and the total doping amount is 0.1-5% by mole; the solvent is one or more of water, ethanol, methyl ethyl ketone, acetone, butanone, cyclohexanone and xylene, and the volume fraction of the solvent is 5-40% of the slurry; the adhesive is one of epoxy resin, W-6C magnetic powder glue, phenolic resin, polyvinyl alcohol, polyvinyl butyral and glass powder and accounts for 5-30% of the mass of the slurry; the dispersing agent is one of castor oil, herring oil, phosphate ester, triolein glyceride and triethanolamine, and the volume fraction of the dispersing agent is 0.2-5% of the slurry. The plasticizer is one of glycerol, dioctyl phthalate, polyethylene glycol, dibutyl phthalate and o-xylene dibutyl ester, and the weight ratio of the binder to the plasticizer is 0.5-1.0.

9. The method as claimed in claim 6, wherein one of ultrasonic vibration, mechanical agitation and natural immersion is used in the process of curing the coil in step (iii) to uniformly fill the slurry between the coils.

10. The method of claim 6, wherein the sintering of step (IV) is one of pressureless sintering, warm-pressing sintering, hot-pressing sintering, spark plasma sintering, and microwave sintering, and the sintering atmosphere is vacuum, air, nitrogen, argon, or equilibrium oxygen partial pressure sintering.

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