WO2023024571A1

WO2023024571A1 - Composite heat conductive material and electronic device

Info

Publication number: WO2023024571A1
Application number: PCT/CN2022/091299
Authority: WO
Inventors: 方浩明; 徐焰; 郑坤
Original assignee: 华为技术有限公司
Priority date: 2021-08-26
Filing date: 2022-05-06
Publication date: 2023-03-02
Also published as: CN115734557A

Abstract

The present application provides an electronic device comprising an electronic element (210) and a heat sink (55) provided on the electronic element (210). The surface of the heat sink (55) facing the electronic element (210) is provided with a magnetic layer (231), and the magnetic layer (231) comprises a permanent magnet material. A composite heat conductive material (100) is incorporated between the electronic element (210) and the heat sink (55). The composite heat conductive material (100) comprises an organic matrix (10) and a heat conductive filler, wherein the heat conductive filler is distributed in the organic matrix (10), and the heat conductive filler comprises ferromagnetic particles (33). The present application further provides a composite heat conductive material (100). A magnetic attraction effect is generated between the magnetic layer (231) on the surface of the heat sink (55) and the composite heat conductive material (100) containing the ferromagnetic particles (33), thereby reducing the probability of glue overflowing in a vertical flow manner before the gelatinous composite heat conductive material (100) is cured in the process of forming the composite heat conductive material (100) by means of glue dispensing.

Description

Composite Thermally Conductive Materials and Electronic Devices

Cross References to Related Applications

This application claims the priority of a Chinese patent with application number 202110991016.3 and application title "Composite Thermal Conductive Material and Electronic Equipment" filed with the China Patent Office on August 26, 2021, the entire contents of which are incorporated herein by reference.

technical field

The present application relates to the field of thermally conductive materials, in particular to a composite thermally conductive material and electronic equipment using the composite thermally conductive material.

Background technique

The heat generated by heat-generating power devices in electronic equipment, such as chips, usually requires the use of heat sinks to spread the heat to the outside. From a microscopic point of view, the contact interface between the chip and the heat sink is uneven, and the interface heat-conducting material is usually used to fill the gap between the chip and the heat sink to reduce the contact thermal resistance. Interface thermally conductive materials usually include thermally conductive silicone grease, thermally conductive pads, thermally conductive gels, phase change thermally conductive materials, thermally conductive adhesives, etc.; and according to different application scenarios, different types of interface thermally conductive materials with different thermal conductivity can be used. However, when the gel-like interface heat-conducting material is provided on the contact interface between the chip and the heat sink, the problem of overflow of the gel-like interface heat-conducting material is very likely to occur. The process mechanism of the gel-like interface heat-conducting material overflowing: When the heat sink is assembled, the gel-like interface heat-conducting material is compressed and spreads around. When it overflows out of the chip package, it is initially suspended due to its own weight; When the yield deformation strength of its own is exceeded, the gel-like interface thermal material will collapse and contact the surface of the circuit board or the surrounding device housing.

If the interface thermal conductive material itself conducts electricity, it will lead to short circuit failure of the circuit board component parts in contact with it. If the interface thermal conduction material itself is insulated, but contains conductive particles inside, it may lead to insufficient dielectric strength of the circuit board components in contact with it. Even if the interface heat conduction material itself is insulated and does not contain conductive particles inside, when there is a high-frequency or high-speed signal in the circuit board component in contact with it, the impedance mismatch caused by the contact of the interface heat conduction material may cause electrical signal changes of the circuit board component and other defects. .

Contents of the invention

The first aspect of the embodiment of the present application provides an electronic device, including:

Electronic component;

A heat sink is arranged on the electronic component, and the surface of the heat sink facing the electronic component is provided with a magnetic layer, and the magnetic layer contains a permanent magnetic material;

A composite thermally conductive material, combined between the electronic component and the heat sink, the composite thermally conductive material includes an organic matrix and a thermally conductive filler, wherein the thermally conductive filler is distributed in the organic matrix, and the thermally conductive filler includes iron magnetic particles.

In the electronic device described in the first aspect of the present application, by arranging a magnetic layer on the surface of the heat sink and setting ferromagnetic particles in the composite heat-conducting material, a gap between the magnetic layer on the surface of the heat sink and the composite heat-conducting material containing ferromagnetic particles is generated. The magnetic adsorption effect reduces the probability of glue overflow and sag in the gel-like composite heat-conducting material before curing during the dispensing process.

In the embodiment of the present application, the ferromagnetic particles are selected from Fe ₃ O ₄ particles, CaLaCo particles, AlNiCo particles, NdFeB particles, SmCo particles, BiFeO ₃ particles, FeCrCo particles, NiOFe ₂ O ₃ particles, CuOFe ₂ O ₃ particles, At least one of MgOFe ₂ O ₃ particles, MnBi particles, CrO ₂ particles, Fe powder, Co powder, and Ni powder.

In the embodiment of the present application, the thermally conductive filler further includes non-magnetic particles.

In the embodiment of the present application, the material of the non-magnetic particles includes at least one of aluminum oxide, aluminum nitride, boron nitride, zinc oxide, magnesium oxide, graphite, carbon nanotubes, graphene, diamond, and non-magnetic metal powder. kind.

In the embodiment of the present application, the non-magnetic particles include large-diameter particles, and the average particle diameter of the large-diameter particles is larger than the average particle diameter of the ferromagnetic particles.

The large-diameter particles generally have the largest average particle diameter among the thermally conductive fillers, and the thermal conductivity of the large-diameter particles is higher than that of the ferromagnetic particles, preferably the highest among the thermally conductive fillers.

In the embodiment of the present application, the average particle size of the large particle size particles is 20 μm or more.

The average particle size of the large particle size particles is usually the largest among the thermally conductive fillers. In some embodiments, the average particle diameter of the large-diameter particles is 40 μm-250 μm, more preferably 60 μm-160 μm.

In the implementation manner of the present application, the volume percentage of the large-diameter particles in the composite heat-conducting material is 35%-55%.

In the embodiment of the present application, at least part of the large-diameter particles are attached to the surface of the bonding medium, and at least part of the ferromagnetic particles are bonded to the surface of the large-diameter particles through the bonding medium.

The ferromagnetic particles are bonded to the surface of the large particle size particles through the bonding medium, which can ensure that the overall heat conduction effect and magnetic performance of the composite heat conduction material are better.

In the embodiment of the present application, the bonding medium is an organic bonding material, the bonding medium and the organic matrix are selected from the same polymer system, and the molecular weight of the bonding medium is lower than that of the organic matrix .

In the embodiment of the present application, the thermal conductivity of the large-diameter particles is higher than the thermal conductivity of the ferromagnetic particles.

In an embodiment of the present application, the large-diameter particles include at least one of aluminum nitride, diamond, aluminum powder, silver powder, copper powder, aluminum-coated silver, and aluminum-coated copper.

In the implementation manner of the present application, the volume percentage of the thermally conductive filler in the composite thermally conductive material is greater than 70%.

Considering factors such as high heat conduction efficiency compounding, heat conduction network construction, viscosity and dispensable fluidity, etc., the volume percentage of the heat conduction filler in the composite heat conduction material is greater than 70%, more preferably 80% to 90% .

In the implementation manner of the present application, the volume percentage of the ferromagnetic particles in the composite heat-conducting material is 10%-30%.

In order to balance the magnetic properties and thermal conductivity of the composite heat-conducting material, the volume percentage of the ferromagnetic particles in the composite heat-conducting material is 10%-30%.

In the embodiment of the present application, the organic matrix is selected from at least one of a silicone system, an epoxy system, an acrylic system, a polyurethane system, and a polyimide system.

In an embodiment of the present application, a coating that reacts with the organic matrix is further provided on the magnetic layer, and the coating includes a silane coupling agent.

The silane coupling agent has a graft reaction with the surface of the heat sink to realize the connection with the heat sink, and the silane coupling agent exposes a functional group that can react with the organic matrix. When the overflowing gel-like composite heat-conducting material contacts the coating on the surface of the radiator, a chemical bond can be formed to increase the interaction force between the composite heat-conducting material and the radiator, thereby preventing the gel-like composite heat-conducting material from flowing vertically.

In the embodiment of the present application, the general structural formula of the silane coupling agent is:

R ³ /R ¹ represents one of R ³ and R ¹ , wherein R ¹ is an unsubstituted or substituted monovalent hydrocarbon group, R ² is an alkyl or alkoxy group, and R ³ is a hydrogen-containing functional group or a vinyl functional group , X is an alkyl group.

In an embodiment of the present application, a groove is formed on the surface of the heat sink facing the electronic component, and the magnetic layer is embedded in the groove.

The magnetic layer is a magnet structure embedded in the groove, and the magnet structure is not limited to designs such as back-shaped, cross-shaped, I-shaped, square, etc., and the shape of the groove matches the shape of the magnetic layer of the magnet structure . The magnetic layer of the magnet structure can also be designed in a mosaic type such as a convex platform type and a concave platform type.

The second aspect of the embodiment of the present application provides a composite heat-conducting material, including:

organic matrix;

A thermally conductive filler distributed in the organic matrix, the thermally conductive filler comprising:

Ferromagnetic particles;

Non-magnetic particles, the non-magnetic particles include large-diameter particles, and the average particle diameter of the large-diameter particles is larger than the average particle diameter of the ferromagnetic particles.

The composite thermal conductive material has high thermal conductivity and is magnetic.

The third aspect of the embodiment of the present application provides an electronic device, which includes an electronic component and a cured product of the composite thermally conductive material described in the second aspect of the embodiment of the present application disposed on the electronic component.

In the embodiment of the present application, the electronic component is a chip, and the electronic device further includes a heat sink disposed on the electronic component, an interface heat conducting material is disposed between the electronic component and the heat sink, and the interface The thermally conductive material is a cured product of the composite thermally conductive material described in the second aspect of the embodiment of the present application.

The composite heat-conducting material has high thermal conductivity and is magnetic, and can be used as an interface heat-conducting material, so that the heat dissipation effect of electronic components is good.

Description of drawings

FIG. 1 is a schematic structural diagram of a chip provided with a heat sink.

FIG. 2 is a schematic structural diagram of a packaged chip.

Fig. 3A is a partial schematic view of the electronic device according to the embodiment of the present application before dispensing glue.

FIG. 3B is a partial schematic diagram of an electronic device according to an embodiment of the present application.

Fig. 4 is a schematic diagram of the composite heat-conducting material of the first embodiment of the present application.

FIG. 5 is a schematic diagram of a composite thermally conductive material according to a second embodiment of the present application.

FIG. 6A and FIG. 6B are two schematic diagrams of the radiator of the present application, respectively.

Fig. 7 is a flow chart of the preparation of the composite heat-conducting material of the present application.

Fig. 8 is another preparation flow chart of the composite heat-conducting material of the present application.

Description of main component symbols

电路板 circuit board	5151
芯片 chip	5353
散热器 heat sink	5555
界面导热材料interface thermal material	5757
散热盖 Cooling cover	5959
电子元件 Electronic component	210210
磁性层 magnetic layer	231231
凹槽 groove	551551
涂层 coating	233233
复合导热材料Composite thermal conductive material	100100
有机基体 organic matrix	1010
铁磁性颗粒 ferromagnetic particles	3333
非磁性颗粒 non-magnetic particles	3030
大粒径颗粒 large particle size	3131
粘接介质 Bonding medium	3232
小粒径颗粒 Small particle size	30a30a
中粒径颗粒 Medium particle size	30b30b

Detailed ways

Embodiments of the present application are described below with reference to the drawings in the embodiments of the present application. Unless otherwise specified, the data ranges involved in this application shall include the end values.

Electronic devices are usually provided with many electronic components that generate heat, such as chips. High temperature will have a harmful effect on the stability, reliability and life of electronic components. For example, excessive temperature will endanger the junction of semiconductors, damage the connection interface of the circuit, increase the resistance of the conductor and cause mechanical stress damage. As shown in FIG. 1 , a heating power device or a heating module is arranged on the circuit board 51 . In this embodiment, the heat generating power device is a chip 53 as an example for illustration. The chip 53 is provided with a heat sink 55 . However, there are usually fine uneven spaces between the contact interface of the chip 53 and the heat sink 55. If the chip 53 and the heat sink 55 are directly mounted together, there will be a lot of air gaps between the chip 53 and the heat sink 55. Because the thermal conductivity of air is only 0.024W/(m·K), it is a bad conductor of heat, which will cause the contact thermal resistance between the electronic component 210 and the heat sink 55 to be very large, which seriously hinders the conduction of heat, and finally causes the heat sink 55 to be damaged. Ineffective. Therefore, between chip 53 and heat sink 55, be filled with interface heat-conducting material 57, to get rid of the air gap between chip 53 and heat sink 55, between chip 53 and heat sink 55, establish effective heat conduction path, can significantly reduce Contact thermal resistance, so that the role of the radiator 55 can be fully brought into play.

The chip 53 can be a bare chip or a ball grid array (BGA) packaged chip with a heat dissipation cover disposed thereon. BGA package chip as shown in Figure 2, between the chip 53 and the heat dissipation cover 59 is also filled with an interface heat conduction material 57, and the interface heat conduction material 57 is used to reduce the contact heat between the chip 53 and the heat dissipation cover 59 resistance, so that the heat generated by the chip 53 can be effectively conducted to the heat dissipation cover 59 .

However, when the pre-cured interface heat-conducting material (gel-like heat-conducting material) is applied between the chip 53 and the heat sink 55, the glue-like heat-conducting material is prone to the problem of glue overflowing, and then the chip 53 Components on the perimeter and/or on the circuit board 51 are in direct contact, leading to a series of undesirable problems.

Therefore, as shown in FIG. 3A and FIG. 3B , the present application provides an electronic device, including an electronic component 210 and a heat sink 55 disposed on the electronic component 210 . A magnetic layer 231 is disposed on the surface of the heat sink 55 facing the electronic component 210 , and the magnetic layer 231 contains a permanent magnetic material. A composite heat conducting material 100 is disposed between the electronic component 210 and the surface of the radiator 55 having the magnetic layer 231 . Electronic components 210 are provided on the circuit board 51 . The electronic component 210 can be a chip, but not limited thereto. As shown in FIG. 4 and FIG. 5 , the composite heat-conducting material 100 includes an organic matrix 10 and a heat-conducting filler distributed in the organic matrix 10 , and the heat-conducting filler includes ferromagnetic particles 33 . In this way, magnetic adsorption occurs between the magnetic layer 231 on the surface of the heat sink 55 and the composite thermally conductive material 100 containing ferromagnetic particles 33, reducing the amount of the composite thermally conductive material 100 (colloidal composite thermally conductive material 100) before curing in the dispensing process. ) the probability of glue overflow and sag flow.

The ferromagnetic particles 33 are Fe ₃ O ₄ particles, CaLaCo particles, AlNiCo particles, NdFeB particles, SmCo particles, BiFeO ₃ particles, FeCrCo particles, NiOFe ₂ O ₃ particles (including blended NiO and Fe ₂ O ₃ ), CuOFe ₂ O ₃ particles (comprising blended CuO and Fe ₂ O ₃ ), MgOFe ₂ O ₃ particles (comprising blended MgO and Fe ₂ O ₃ ), MnBi particles, CrO ₂ particles, Fe powder, Co powder and Ni at least one of the powders. The size of the ferromagnetic particles 33 may be nanoscale, with a particle diameter ranging from 10 nm to 1000 nm. From the perspective of thermal conductivity, it is preferable that the ferromagnetic particles 33 are pure metals such as Fe, Co, Ni and the like with high thermal conductivity.

The thermally conductive filler also includes non-magnetic particles 30 . The material of described nonmagnetic particle 30 comprises aluminum oxide, aluminum nitride, boron nitride, zinc oxide, magnesium oxide, graphite, carbon nanotube, graphene, diamond and nonmagnetic metal powder (such as aluminum powder, silver powder, copper powder) Powder, etc.) at least one.

According to the particle size, the non-magnetic particles 30 include large particle size particles 31, the average particle size of the large particle size particles 31 is larger than the average particle size of the ferromagnetic particles 33, usually the average particle size of the thermally conductive filler biggest. In some embodiments, the thermal conductivity of the large-diameter particles 31 is higher than that of the ferromagnetic particles 33 , for example greater than 200 W/mK, preferably the highest thermal conductivity among the thermally conductive fillers. The material of the large-diameter particles 31 is selected from at least one of aluminum nitride, diamond, aluminum powder, silver powder, copper powder, aluminum-coated silver particles, and aluminum-coated copper particles.

In some embodiments, the ferromagnetic particles 33 are randomly distributed in the organic matrix 10 . In some other embodiments, based on the consideration of thermal conductivity and magnetic performance, as shown in FIG. 4 , the surface of the large-diameter particles 31 is attached with a bonding medium 32, and at least part of the ferromagnetic particles 33 pass through the bonding medium. 32 is bonded to the surface of the large-diameter particles 31. That is, it is possible that all the ferromagnetic particles 33 are bonded to the surface of the large-diameter particles 31 through the bonding medium 32; 31, while other ferromagnetic particles 33 are randomly dispersed in the organic matrix 10, as shown in FIG. 5 . Generally, the larger the particle diameter difference between the large-diameter particles 31 and the ferromagnetic particles 33 is, the more ferromagnetic particles 33 can be adhered to the surface of the same large-diameter particle 31, which will generally make composite heat conduction The packing density of the thermally conductive filler in material 100 is greater. In addition, according to the coating effect of the ferromagnetic particles 33 and the requirements of magnetic applications, the volume percentage of the ferromagnetic particles 33 randomly distributed in the organic matrix 10 may be 0%-20%. In addition, as shown in FIG. 5 , in some embodiments, the thermally conductive particles adhered to the surface of the large-diameter particles 31 include not only ferromagnetic particles 33 , but also other average particle sizes smaller than the large-diameter particles 31 . Other non-magnetic particles 30 of diameter. The random distribution mentioned in this application means that the distribution of the ferromagnetic particles 33 in the organic matrix 10 is not bound by the bonding medium 32 . The shape of the large-diameter particles 31 shown in FIG. 4 and FIG. 5 is spherical, which is only for illustration, but not limited thereto. For example, the large-diameter particles 31 may be polyhedral diamonds.

In addition to the above-mentioned large-diameter particles 31, the non-magnetic particles 30 can also optionally include other heat-conducting particles with a variety of particle size distributions, such as small-diameter particles 30a and medium-diameter particles 30b, as shown in Figure 4 and Figure 5 shows. In some embodiments, when the particle diameter ratio of the large-diameter particles 31 to a heat-conducting particle with the smallest average particle diameter is greater than 50, the heat-conducting filler includes three or more heat-conducting particles with different average particle diameters.

Considering factors such as high heat conduction efficiency compounding, heat conduction network construction, viscosity and dispensable fluidity, etc., the volume percentage of the heat conduction filler in the composite heat conduction material 100 is greater than 70%, more preferably 80% to 90%. %. From the perspective of dispensing and better reliability, the volume fraction of the thermally conductive filler in the composite thermally conductive material 100 should not exceed 92%.

In order to balance the magnetic properties and thermal conductivity, the volume percentage of the ferromagnetic particles 33 in the composite thermal conductive material 100 is 10%-30%.

In some embodiments, the average particle diameter of the large-diameter particles 31 is above 20 μm, preferably 40 μm-250 μm, more preferably 60 μm-160 μm. The volume fraction of the large-diameter particles 31 in the composite heat-conducting material 100 is 35%-55%.

The organic matrix 10 , which can also be called a polymer matrix, is used as a continuous phase to fix the dispersed phase (such as various thermal conductive fillers) in the composite thermal conductive material 100 in the organic matrix 10 to form a macroscopic composite thermal conductive material 100 . The organic matrix 10 is selected from at least one of silicone systems, epoxy systems, acrylic systems, polyurethane systems, and polyimide systems. When the composite thermal conductive material 100 is used in a product, for example, when used in the application scene in FIG. 1 , the composite thermal conductive material 100 is a cured product, and curing mainly refers to the curing of the organic matrix 10 .

The organic matrix 10 is curable polymer, including silicone polymer, epoxy polymer, urethane polymer, phenolic polymer, unsaturated polyester, polyimide polymer, acrylonitrile Butadiene rubber, ethylene-propylene-diene rubber, ethylene-propylene rubber, natural rubber, polybutadiene rubber, polyisoprene rubber, polyester, polyurethane, etc.

In some embodiments, the material of the organic matrix 10 is preferably organic silicon such as silicone rubber, silicone oil, silicone resin, or epoxy resin, more preferably silicone. The silicone can be any one of the condensation curing type silicone system and the addition reaction curing type silicone system, preferably an addition reaction curing type silicone system, and more preferably an addition polymerization reaction curing type silicone rubber . In this application, silicone oil is a popular name for organopolysiloxane.

Among them, the addition reaction-curable silicone rubber includes two major types of basic silicone oil components, such as alkenyl-containing organopolysiloxane and hydrogen-containing (Si-H group)-containing organopolysiloxane. Coupling agent, coupling agent, catalyst, inhibitor and other functional additives.

Among them, the alkenyl-containing organopolysiloxane may include vinyl two-terminal polydimethylsiloxane, vinyl two-terminal polyphenylmethylsiloxane, vinyl two-terminal dimethylsiloxane-dimethicone Phenylsiloxane copolymer, vinyl two-terminal dimethylsiloxane-phenylmethylsiloxane copolymer, vinyl two-terminal dimethylsiloxane-diethylsiloxane copolymer, etc. base two-terminal organopolysiloxane.

The viscosity of the alkenyl group-containing organopolysiloxane at 25° C. is preferably not less than 5 mPa·s and not more than 10000 mPa·s, preferably not less than 30 mPa·s and not more than 500 mPa·s.

Among them, the number of hydrogen atoms bonded to silicon atoms on the hydrogen group-containing organopolysiloxane molecule is 2 or more, preferably 2 to 50. For example, methylhydrogensiloxane-dimethylsiloxane copolymer, polymethylhydrogensiloxane, polyethylhydrogensiloxane, methylhydrogensiloxane-phenylmethylsiloxane copolymer and other hydrogen-containing organopolysiloxanes. Among them, the molar ratio of the hydrogen group-containing organopolysiloxane to the alkenyl group-containing organopolysiloxane is preferably 0.3-3.

The viscosity of the hydrogen group-containing organopolysiloxane at 25°C is not particularly limited, but is preferably 1 mPa·s or more and 1000 mPa·s or less, and can be mixed and cured with an alkenyl group-containing organopolysiloxane to form physical properties good polymer. The viscosities of the above-mentioned organopolysiloxanes are all measured with a rotational viscometer.

In addition, in the case of using a curable silicone polymer as the organic matrix 10 , it needs to be used in combination with a noble metal catalyst. The noble metal catalysts may be platinum-based catalysts, palladium-based catalysts, rhodium-based catalysts, and the like. Preferably, platinum-based catalysts are used, such as platinum-based catalysts such as elemental platinum, oxyplatinic acid, platinum-olefin complexes, platinum-alcohol complexes, and platinum coordination compounds. The content of the above catalyst is 0.1 ppm to 300 ppm, preferably 0.1 ppm to 200 ppm.

In order to increase the shelf life and pot life of the composite thermal conductive material 100 and prevent active functional groups such as Si-H groups from being consumed in advance due to side reactions (hydrosilylation reaction) at room temperature, inhibitors need to be added to the composite thermal conductive material 100 . Inhibitors can be various acetylenic compounds such as 1-ethynyl-1-cyclohexanol and 3-butyn-1-ol, triallyl isocyanurate and derivatives of triallyl isocyanurate, etc. Nitrogen compounds, organic phosphorus compounds such as triphenylphosphine, etc. The content of the above-mentioned inhibitor is 0.01wt%-5wt% of the composite heat-conducting material 100, preferably 0.1wt%-1wt%.

The bonding medium 32 tightly binds the ferromagnetic particles 33 on the surface of the large-diameter particles 31 . The process of the adhesive medium 32 exerting tight fixation can be completed before the large-diameter particles 31 are added to the organic matrix 10, for example, the ferromagnetic particles 33 are coated on the surface of the large-diameter particles 31 by the adhesive medium 32 in advance, or This may be done after the large size particles 31 have been added in the organic matrix 10 .

The thickness of the adhesive medium 32 covering the large-diameter particles 31 is usually less than 10 μm, preferably less than 1 μm.

The adhesive medium 32 can be made of the same material as the organic matrix 10, or can be made of a different material. The adhesive medium 32 may be an inorganic adhesive. Inorganic binders can be clay, phosphate, silicate, etc. The inorganic binder can be added with a solvent to adjust the viscosity before coating the ferromagnetic particles 33 . Adhesive medium 32 also can be organic adhesive, organic adhesive can be polyvinyl alcohol (Polyvinyl Alcohol, PVA), ethylene-vinyl acetate copolymer (Ethylene Vinyl Acetate, EVA), polyvinyl butyral (Polyvinyl Butyral, PVB) and other commonly used adhesive materials for granulation of ceramic powders, solvents can be added to significantly reduce the viscosity of the organic adhesive to achieve uniform dispersion of large ferromagnetic particles 33 in the organic adhesive solution. The bonding medium 32 can adhere the ferromagnetic particles 33 to the surface of the large-diameter particles 31 through chemical bonding forces such as covalent bonds, ionic bonds, or metal bonds.

In some embodiments, the adhesive medium 32 is made of the same material as the organic matrix 10 , that is, the adhesive medium 32 and the organic matrix 10 use the same polymer system. For example, if the material of the organic matrix 10 is silicone, the material of the bonding medium 32 is also silicone. Taking the organic matrix 10 of silicone as an example, the adhesive medium 32 is organosiloxane composed of a certain number of repeated -O-Si-bonds.

In some embodiments, the number of silicon-oxygen bonds of the organosiloxane material bonding the ferromagnetic particles 33 is lower than the number of silicon-oxygen bonds of the organic silicon host molecule of the organic matrix 10, that is, the molecular weight of the silicone oil for bonding Lower than the molecular weight of the silicone oil matrix. That is, the molecular weight of the organic adhesive medium 32 is lower than that of the organic matrix 10 .

The surfaces of the large-diameter particles and the ferromagnetic particles all contain a certain amount of -OH active functional groups. When the large-diameter particles are diamond particles, the bonding silicone oil forms adhesion between the large-diameter particles through the C-O-Si bond, wherein the carbon atoms come from diamond. The bonding silicone oil forms adhesion with small-diameter particles through the -O-Si bond.

In some embodiments, the silicone oil of the adhesive medium 32 may have the same terminal reactive functional group as the end of the polysiloxane molecular chain of the silicone oil of the organic matrix 10, for example, for the addition polymerization silicone system, it may be ethylene Base silicone oil, also can be hydrogen base silicone oil. When the silicone oil of the bonding medium 32 is vinyl silicone oil, at least two vinyl silicone oils with different molecular weights are added to the silicone matrix. When the silicone oil of the adhesive medium 32 is hydrogen-based silicone oil, at least two kinds of hydrogen-based silicone oils with different molecular weights are added to the silicone matrix.

In some embodiments, the adhesive silicone oil can be that the other end of the polysiloxane molecular chain is a functional group that can react with the -OH functional group, such as carboxyl, epoxy, carbonyl, double bond, amine, acid chloride, Ester group, hydroxyl group, halogen group, etc.

In some embodiments, the adhesive silicone oil can also be that the other end of the polysiloxane molecular chain is an inactive functional group, such as an alkyl group. In this case, a silane coupling agent that can react with the terminal functional group of the adhesive silicone oil, such as a vinyl silane coupling agent and a hydrogen silane coupling agent, can also be added to the silicone matrix.

In some embodiments, the adhesive silicone oil may also include a terminal functional group that is an active functional group and can react with the -OH functional group, such as carboxyl, epoxy, carbonyl, double bond, amine, acid chloride, ester group, hydroxyl group, halo group, etc.

The adhesion and fixation of the adhesive silicone oil to the large-diameter particles 31 and the ferromagnetic particles 33 can be carried out simultaneously with the curing reaction of the main silicone matrix, or can be carried out separately in advance.

The magnetic layer 231 can be formed on the surface of the heat sink 55 by means of magnetic paint coating or whole magnet embedding. The magnetic coating can be composed of permanent magnet material powder, film-forming base material, additives, solvents, etc.; the powder of permanent magnet material can be AlNiCo permanent magnet alloy, FeCrCo permanent magnet alloy, permanent magnet ferrite, at least one of magnetic materials. Rare earth permanent magnet materials can be conventional materials such as NdFeB, SmCo, AlNiCo, etc. For the way of inlaying magnets, as shown in Figure 6A and Figure 6B, the surface of the heat sink 55 is provided with a groove 551, and the groove 551 is used to inlay the magnetic layer 231 of the magnet structure, and the magnet structure is not limited to that shown in Figure 6A. The back shape shown, the cross shape shown in FIG. 6B , and other I-shaped, square and other designs, the shape of the groove 551 matches the shape of the magnetic layer 231 of the magnet structure. The magnetic layer 231 of the magnet structure can also be designed in a mosaic type such as a convex platform type and a concave platform type.

In some embodiments, as shown in FIG. 3A and FIG. 3B , the magnetic layer 231 is further provided with a coating 233 that reacts quickly with the organic matrix 10 , and the coating 233 includes a silane coupling agent. The coating 233 mainly includes a silane coupling agent, and can be formed on the radiator 55 by coating. When the gel-like composite heat-conducting material 100 overflows, it reacts with the coating 233 on the surface of the heat sink 55 (for example, a cross-linking reaction), thereby increasing the interaction force between the composite heat-conducting material 100 and the heat sink 55 . For example, when the organic matrix 10 adopts a vinyl-terminated addition type silicone system, the coating 233 can be a hydrogen-containing silane coupling agent. When the organic matrix 10 adopts curable epoxy resin, the coating 233 can be an amino-containing silane coupling agent. The methoxane of the silane coupling agent will undergo a graft reaction with the surface of the heat sink 55 to achieve connection with the heat sink 55 , while the silane coupling agent exposes a functional group capable of reacting with the organic matrix 10 . When the overflowing jelly-like composite heat-conducting material 100 contacts the coating 233 on the surface of the heat sink 55 , a chemical bond can be formed, thereby preventing the jelly-like composite heat-conducting material 100 from flowing vertically and overflowing.

In some embodiments, the general structural formula of the silane coupling agent is:

R ³ /R ¹ represents one of R ³ and R ¹ , wherein R ¹ is an unsubstituted or substituted monovalent hydrocarbon group, R ² is an alkyl group or an alkoxy group, and R ³ is a reactive functional group, for example is a hydrogen-containing functional group or a vinyl functional group, and X is an alkyl group. The silane coupling agent is a silane coupling agent containing at least one hydrogen atom directly bonded to a silicon atom in one molecule.

Generally speaking, a curable silicone system is used as the organic matrix 10 for the composite thermally conductive material 100 , and the composite thermally conductive material 100 contains a certain amount of inhibitor to prevent the composite thermally conductive material 100 from curing immediately after dispensing. Therefore, in order to achieve the adhesion effect between the composite thermally conductive material 100 and the coating 233 , the key is to adjust the catalyst type and content of the composite thermally conductive material 100 and the coating 233 coated on the surface of the radiator 55 . Generally, the inhibitor content in the composite thermal conductive material 100 is relatively low, usually 0-0.1 wt%, and the catalyst content is relatively high, which may be 0.1 wt%-0.5 wt%. The concentration of the catalyst in the coating 233 coated on the surface of the radiator 55 may be 1 ppm˜1000 ppm. The catalyst may be a platinum-based catalyst, a palladium-based catalyst, a rhodium-based catalyst, or the like. Preferably, platinum-based catalysts are used, which can be known platinum-based catalysts such as elemental platinum, oxyplatinic acid, platinum-olefin complexes, platinum-alcohol complexes, and platinum coordination compounds.

In addition, commonly used additives such as antioxidants, heat stabilizers, colorants, flame retardants, and antistatic agents can also be added to the composite thermally conductive material 100 of the present application as required.

Please refer to FIG. 7 , the preparation method for the ferromagnetic particles 33 coating the surface of the large-diameter particles 31 includes the following steps.

Dispersion: uniformly disperse a plurality of large-diameter particles and a plurality of ferromagnetic particles in the bonding medium to form a slurry, and the particle diameter of the ferromagnetic particles is smaller than that of the large-diameter particles.

Granulating into balls: using the slurry to granulate into balls, so that the ferromagnetic particles are coated on the surface of the large-diameter particles 31 through the bonding medium.

Glue removal: remove the excess bonding medium, so that the ferromagnetic particles can be tightly combined with the large particle size particles. Debinding can be done by high temperature calcination.

Size screening: screen out the coated thermally conductive fillers whose size and particle size distribution meet the requirements through gauze filtration and air classification.

The composite heat-conducting material can be prepared by dispersing the above-mentioned large-diameter particles coated with ferromagnetic particles and other heat-conducting fillers in the organic polymer matrix.

Continuing to refer to FIG. 7 , in one embodiment, a typical process of manufacturing the composite heat-conducting material 100 includes the following steps.

Mixing: add the above-mentioned large-size particles coated with ferromagnetic particles, other fillers (such as small-size and medium-size fillers), functional additives, etc. to the organic matrix according to the specified formula design.

Stirring and dispersion: The random and uniform dispersion of the above fillers in the organic matrix is achieved by using high-speed stirring processes such as double planetary mixing, meshing dispersion, and homogenizer. Usually when stirring or after stirring, it is necessary to vacuum to remove the air bubbles in the paste mixture. The temperature setting in the mixing process is not particularly limited, and it may be above 10°C and below 150°C.

Curing: According to the formula design, the curing of the composite material is realized under the specified curing conditions, mainly referring to the curing of the organic matrix to make a composite heat-conducting material. The curing process is not particularly limited, and it is usually heating and curing. The typical heating and curing temperature is in the range of 100°C to 250°C, and the heating time is half an hour to several hours. Before curing, it can be coated as a pad or film according to product requirements. After curing, it can be packaged according to product requirements, such as sub-packaging or cutting.

As shown in Figure 4, the composite thermally conductive material 100 prepared by the above method includes an organic matrix 10 and a thermally conductive filler distributed in the organic matrix 10, the thermally conductive filler includes ferromagnetic particles 33 and nonmagnetic particles 30, so The non-magnetic particles 30 include large-diameter particles 31, the average particle diameter of the large-diameter particles 31 is greater than the average particle diameter of the ferromagnetic particles 33, and at least part of the surface of the large-diameter particles 31 is attached and bonded medium 32 , at least part of the ferromagnetic particles 33 are bonded to the surface of the large-diameter particles 31 through the bonding medium 32 .

The present application also provides another preparation method of the composite heat-conducting material 100, which does not need to carry out surface-coating ferromagnetic particles 33 on the large-size filler particles in advance, but directly realizes such ferromagnetic particles 33 when making the composite heat-conducting material 100 The effect of covering the surroundings of the large-diameter particles 31 is shown in FIG. 8 .

In this case, the adhesive medium 32 used can be a material homogeneous with the organic matrix 10. Taking the organic silicon matrix system as an example, the adhesive medium 32 is composed of -O-Si-bonds with a certain number of repetitions. of organosiloxanes.

The number of silicon-oxygen bonds of the organosiloxane material for bonding small particles is lower than the number of silicon-oxygen bonds as the main molecule of the silicone matrix, that is, the molecular weight of the silicone oil for bonding is lower than that of the main silicone oil.

The silicone oil for bonding can have the same terminal reactive functional group as the end of the polysiloxane molecular chain of the main silicone oil, for example, for the addition polymerization silicone system, it can be vinyl silicone oil or hydrogen silicone oil . When the adhesive silicone oil is vinyl silicone oil, at least two vinyl silicone oils with different molecular weights are added to the silicone matrix. When the adhesive silicone oil is hydrogen-based silicone oil, at least two hydrogen-based silicone oils with different molecular weights are added to the silicone matrix.

The adhesive silicone oil can be that the other end of the end of the polysiloxane molecular chain is a functional group that can react with the -OH functional group, such as a carboxyl group, an epoxy group, a carbonyl group, a double bond, an amine group, an acid chloride group, an ester group, a hydroxyl group, Halo, etc.

The adhesive silicone oil can also be that the other end of the polysiloxane molecular chain is an inactive functional group, such as an alkyl group. In this case, a silane coupling agent that can react with the terminal functional group of the adhesive silicone oil, such as a vinyl silane coupling agent and a hydrogen silane coupling agent, can also be added to the silicone matrix.

The adhesive silicone oil can also be only a terminal functional group that is an active functional group and can react with the -OH functional group, such as carboxyl, epoxy, carbonyl, double bond, amine, acid chloride, ester, hydroxyl, halogen Base etc.

The adhesion and fixation of the adhesive silicone oil and the large-diameter filler particles and nano-scale ferromagnetic particles 33 can be carried out simultaneously with the curing reaction of the main silicone matrix, or can be carried out separately in advance.

As shown in Figure 5, the composite thermally conductive material 100 prepared by the above method includes an organic matrix 10 and a thermally conductive filler distributed in the organic matrix 10, and the thermally conductive filler includes ferromagnetic particles 33 and nonmagnetic particles 30, so The non-magnetic particles 30 include large-diameter particles 31 and small-diameter particles 30a, the average particle diameter of the large-diameter particles 31 is larger than the average particle diameter of the ferromagnetic particles 33 and the small-diameter particles 30a, at least A bonding medium 32 is attached to the surface of part of the large particle size particles 31, and at least part of the ferromagnetic particles 33 and at least part of other small particle size particles 30a are bonded to the large particle size particles through the bonding medium 32. The surface of the diameter particle 31.

The present application also provides an electronic device, which includes an electronic component that generates heat during operation and a composite heat-conducting material covering the electronic component. In some embodiments, as shown in FIG. 1 , the electronic device further includes a circuit board 51 and a heat sink 55 . The electronic component is a chip 53, and the chip 53 is arranged on the circuit board 51, and the heat sink 55 is arranged on the side of the chip 53 away from the circuit board 51, and the composite heat conducting material 100 between the chip 53 and the heat sink 55 cured product.

It can be understood that the composite thermally conductive material 100 described in this application can also be used for heat conduction at the interface between a thermally conductive structural member (such as the above-mentioned chip uniform temperature substrate, thermally conductive plate) and another thermally conductive structural member, that is, a function in an electronic device Heat conduction between the structural housing of a module and the structural housing of another functional module.

The technical solutions of the embodiments of the present application will be further described below through specific examples.

Embodiment 1-4

Thermally conductive filler

Artificial diamond, untreated, Henan Huanghe Cyclone Co., Ltd., particle size range 120 μm ~ 150 μm, sphericity 0.9, polyhedral shape.

Alumina, untreated, Suzhou Jinyi New Material Technology Co., Ltd., the average particle size is 0.4 μm, the sphericity is 1, spherical body.

Alumina, untreated, Suzhou Jinyi New Material Technology Co., Ltd., the average particle size is 4 μm, the sphericity is 1, spherical body.

Nano-iron powder, untreated, Shanghai Metallurgical Powder Research Institute, average particle size 0.5μm, sphericity 1, spherical body.

Bonding medium 32: long carbon chain polysiloxane.

Diamond surface coating: disperse the above-mentioned artificial diamond and nano-iron powder particles in an acetone solution containing 2wt% long carbon chain polysiloxane, stir at 30°C for 30 minutes, granulate into balls, and heat at 70°C Heating at low temperature for 12 hours, removing the solvent, and obtaining artificial diamond coated with nano-iron powder. After surface modification, the sphericity of the obtained coated synthetic diamond was increased to 0.95.

Preparation of Composite Thermal Conductive Materials

Organic matrix 1: Vinyl-containing polyorganosiloxane, α, ω-divinyl polydimethylsiloxane, Jiangxi Lanxinghuo Silicone Co., Ltd., viscosity 100Pa·s.

Organic matrix 2: polyhydrogen-containing organosiloxane, silicone oil: α, ω-divinyl polydimethylsiloxane, Jiangxi Lanxinghuo Silicone Co., Ltd., viscosity 30Pa·s.

Platinum catalyst: Platinum-1,2-divinyltetramethyldisiloxane complex, Jiangxi Lanxinghuo Silicone Co., Ltd.

Inhibitor: Ethynyl-1-cyclohexanol, Jiangxi Lanxinghuo Silicone Co., Ltd.

Surface treatment agent: dodecyltrimethoxysilane, Jiangxi Lanxinghuo Silicone Co., Ltd.

Addition-reactive silicone resin is used as the polymer matrix, in which the vinyl ends are organopolysiloxane, the surface modifier is dodecyltrimethoxysilane, and the organic matrix 1 is used according to the volume fraction shown in Table 1. Adding diamond coated with nano-iron powder particles and thermally conductive filler, further adding reaction inhibitor in parts by mass and platinum catalyst to prepare component A thermally conductive material.

In addition, relative to the organic hydrogen-containing polysiloxane that constitutes the curing agent of the addition reaction silicone resin, the organic matrix 2 is used and the diamond coated with nanoparticles and the thermally conductive filler are added according to the volume fraction shown in Table 1 to prepare B component thermal conductive material, the difference between B component and A component is that the organic matrix is different.

Mix component A and component B at a mass ratio of 1:1 to produce a new type of thermally conductive material. Wherein, the curing condition is 80° C., and curing takes 2 hours. The proportioning ratio of the composite heat-conducting materials of Examples 1-4 and Comparative Example 1 is shown in Table 1, and physical performance tests are carried out, as shown in Table 1 for details.

The evaluation methods and measurement methods in Examples 1 to 4 and Comparative Example 1 are as follows.

radiator surface treatment

After the NdFeB magnet is attached to the aluminum radiator, the aluminum radiator is coated with an ethanol solution of 1 wt% hydrogen-terminated silane coupling agent, and after natural drying, a sizing comparison test is carried out. The specific examples are shown in Table 1. shown.

The evaluation methods and measurement methods in Examples 1-4 and Comparative Example 1 are as follows.

Thermal conductivity test

The Longwin interface thermal resistance tester is used to test according to the ASTM D5470 standard. Coat the heat-conducting composite material on a section of the copper rod, and gradually raise the temperature from normal temperature to 80°C under the pressure of 40psi, and use the steady-state heat transfer method to measure the thermal conductivity of the heat-conducting material under different thicknesses (0.5mm, 1.0mm, 1.5mm). Apply the thermal resistance, and then fit the intrinsic thermal conductivity of the colloid.

Liquidity test

Use a 30cc syringe with an inner diameter of 2.54±5%mm and a pressure of 90±5%PSI to measure the weight of the glue that flows out within 1min. The fluidity test was evaluated by the following evaluation criteria.

A: Fluidity>25g/min;

B: Fluidity 15～25g/min;

C: Fluidity <15g/min.

surface oxygen content

The diamond particles before and after coating were analyzed and measured by XPS, focusing on the C/O ratio on the diamond surface. The oxygen content was defined as the surface oxygen content of the diamond for evaluation.

porosity

Use a true density meter (Quantachrome, a fully automatic true density meter Ultrapyc 1200e) to measure the components of thermally conductive fillers such as diamond, alumina, etc., and silicone additives to obtain the actual density. The theoretical density (without voids) of the thermally conductive material is derived from the mixing recipe above. Then use a true density meter to measure the density of the mixed thermally conductive colloid to obtain the actual density. The internal porosity of the composite is obtained by dividing the actual density by the ratio of the theoretical density.

vertical flow

Apply 1.12 ml of thermal conductive gel to the dummy of 40mm*40mm*10mm, press it to a thickness of 0.5mm with a 100mm*100mm aluminum plate pressure head, and observe the volume of the gel that hangs out after 24 hours. The sag resistance test was evaluated by the following evaluation criteria. A: Fluidity<0.1ml; B: Fluidity0.1～0.4ml; C: Fluidity>0.4ml.

Table 1

From the results in Table 1, it can be seen that compared with Comparative Example 1, Examples 1-4 are anti-sag flow high thermal conductivity materials with a thermal conductivity greater than 15W/mK; and with a radiator with a special coating structure, the thermal conductivity can be significantly reduced The phenomenon of sagging and overflowing after gel sizing.

Embodiment 5～7

Thermally conductive filler

Nano-zinc oxide particles, untreated, Suzhou Jinyi New Material Technology Co., Ltd., with an average particle size of 0.3 μm, a sphericity of 0.8, and a spheroidal shape.

Micron iron powder, untreated, Shanghai Metallurgical Powder Research Institute, with an average particle size of 4 μm, a sphericity of 0.8, and a spheroidal body.

Micron silver powder, untreated, Guangzhou Hongwu Material Technology Co., Ltd., the average particle size is 25 μm, the sphericity is 1, spherical body.

Inhibitor: Ethynyl-1-cyclohexanol, Jiangxi Lanxinghuo Silicone Co., Ltd.

Addition reaction type silicone resin is used as the polymer matrix, in which the vinyl ends are organopolysiloxane, the surface modifier is dodecyltrimethoxysilane, organic matrix 1 is used and the volume fraction shown in Table 2 is used. Adding nano-zinc oxide, iron powder particles, micron silver powder, long carbon chain polysiloxane, dodecyltrimethoxysilane, further adding inhibitors and platinum catalysts to prepare A-component thermal conductivity materials through double planetary mixing.

In addition, relative to the organic hydrogen-containing polysiloxane (viscosity at 25°C: 100 mPa·s) constituting the curing agent of the addition-reactive silicone resin, organic matrix 2 was used and nanometers were added according to the volume fraction shown in Table 2. Iron powder particles and thermally conductive fillers are used to prepare component B thermally conductive materials. The difference between component B and component A is that the organic matrix is different.

Mix component A and component B at a mass ratio of 1:1, cure at 20psi, 150°C under high temperature and pressure to prepare a new type of thermally conductive material, and perform the above physical performance test. The specific examples are shown in Table 2 .

Table 2

From the results in Table 2, it can be known that the composite heat-conducting materials of Examples 5-7 are matched with a heat sink with a special coating structure, which can effectively reduce the phenomenon of sagging and overflowing of the heat-conducting gel after sizing.

It should be noted that the above is only a specific implementation of the application, but the scope of protection of the application is not limited thereto, and any person familiar with the technical field can easily think of changes or substitutions within the scope of the technology disclosed in the application , should be covered within the protection scope of the present application; in the case of no conflict, the implementation modes and the features in the implementation modes of the application can be combined with each other. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

An electronic device, characterized in that it comprises:

Electronic component;

A heat sink is arranged on the electronic component, and the surface of the heat sink facing the electronic component is provided with a magnetic layer, and the magnetic layer contains a permanent magnetic material;

a composite thermally conductive material, combined between the electronic component and the heat sink, the composite thermally conductive material includes an organic matrix and a thermally conductive filler,

Wherein, the thermally conductive filler is distributed in the organic matrix, and the thermally conductive filler includes ferromagnetic particles.
The electronic device according to claim 1, wherein the ferromagnetic particles are selected from Fe3O4 particles, CaLaCo particles, AlNiCo particles, NdFeB particles, SmCo particles, BiFeO3 particles, FeCrCo particles, NiOFe2O3 At least one of particles, CuOFe 2 O 3 particles, MgOFe 2 O 3 particles, MnBi particles, CrO 2 particles, Fe powder, Co powder, Ni powder.
The electronic device according to claim 1 or 2, wherein the thermally conductive filler further comprises non-magnetic particles.
The electronic device according to claim 3, wherein the material of the non-magnetic particles comprises aluminum oxide, aluminum nitride, boron nitride, zinc oxide, magnesium oxide, graphite, carbon nanotubes, graphene, diamond, at least one of non-magnetic metal powders.
The electronic device according to claim 3 or 4, wherein the non-magnetic particles include large-diameter particles, and the average particle diameter of the large-diameter particles is larger than the average particle diameter of the ferromagnetic particles.
The electronic device according to claim 5, wherein the average particle size of the large particle size particles is 20 μm or more.
The electronic device according to claim 5 or 6, characterized in that the volume percentage of the large-diameter particles in the composite heat-conducting material is 35%-55%.
The electronic device according to any one of claims 5 to 7, wherein at least part of the surface of the large-diameter particles is attached to a bonding medium, and at least part of the ferromagnetic particles pass through the bonding medium Adhering to the surface of the large particle size.
The electronic device according to claim 8, wherein the bonding medium is an organic bonding material, the bonding medium and the organic matrix are selected from the same polymer system, and the molecular weight of the bonding medium is lower than the molecular weight of the organic matrix.
The electronic device according to any one of claims 5 to 9, characterized in that the thermal conductivity of the large-diameter particles is higher than that of the ferromagnetic particles.
The electronic device according to any one of claims 5 to 10, wherein the large particle size particles include aluminum nitride, diamond, aluminum powder, silver powder, copper powder, aluminum-coated silver, aluminum-coated copper at least one of the
The electronic device according to any one of claims 1 to 11, wherein the volume percentage of the thermally conductive filler in the composite thermally conductive material is greater than 70%.
The electronic device according to any one of claims 1-12, characterized in that, the volume percentage of the ferromagnetic particles in the composite heat-conducting material is 10%-30%.
The electronic device according to any one of claims 1 to 13, wherein the organic matrix is selected from at least one of organosilicon systems, epoxy systems, acrylic systems, polyurethane systems, and polyimide systems .
The electronic device according to any one of claims 1 to 14, wherein the magnetic layer is also provided with a coating that reacts with the organic matrix, and the coating includes a silane coupling agent.
The electronic device according to claim 15, wherein the general structural formula of the silane coupling agent is:

R 3 /R 1 represents one of R 3 and R 1 , wherein R 1 is an unsubstituted or substituted monovalent hydrocarbon group, R 2 is an alkyl or alkoxy group, and R 3 is a hydrogen-containing functional group or a vinyl functional group , X is an alkyl group.
The electronic device according to claim 15, wherein a groove is opened on the surface of the heat sink facing the electronic component, and the magnetic layer is embedded in the groove.
A composite heat conducting material, characterized in that it comprises:

organic matrix;

A thermally conductive filler distributed in the organic matrix, the thermally conductive filler comprising:

Ferromagnetic particles;

Non-magnetic particles, the non-magnetic particles include large-diameter particles, and the average particle diameter of the large-diameter particles is larger than the average particle diameter of the ferromagnetic particles.
The composite heat-conducting material according to claim 18, characterized in that at least part of the large-diameter particles are attached to the surface of the bonding medium, and at least part of the ferromagnetic particles are bonded to the surface through the bonding medium. surface of large particles.
The composite heat conducting material according to claim 18 or 19, characterized in that the thermal conductivity of the large-diameter particles is higher than that of the ferromagnetic particles.
The composite heat-conducting material according to any one of claims 18 to 20, wherein the large particle size particles include aluminum nitride, diamond, aluminum powder, silver powder, copper powder, aluminum-coated silver, aluminum-coated at least one of copper.
The composite heat conducting material according to any one of claims 18 to 21, wherein the ferromagnetic particles are selected from Fe3O4 particles, CaLaCo particles, AlNiCo particles, NdFeB particles, SmCo particles, BiFeO3 particles, At least one of FeCrCo particles, NiOFe 2 O 3 particles, CuOFe 2 O 3 particles, MgOFe 2 O 3 particles, MnBi particles, CrO 2 particles, Fe powder, Co powder, and Ni powder.
The composite thermally conductive material according to any one of claims 18 to 22, characterized in that the volume percentage of the thermally conductive filler in the composite thermally conductive material is greater than 70%.
The composite heat-conducting material according to any one of claims 18-23, characterized in that the volume percentage of the ferromagnetic particles in the composite heat-conducting material is 10%-30%.
The composite thermally conductive material according to any one of claims 18 to 24, characterized in that, the average particle diameter of the large particle diameter particles is above 20 μm.
The composite heat-conducting material according to any one of claims 18-25, characterized in that the volume percentage of the large-diameter particles in the composite heat-conducting material is 35%-55%.
The composite thermal conductive material according to any one of claims 18 to 26, wherein the organic matrix is selected from at least one of organosilicon systems, epoxy systems, acrylic systems, polyurethane systems, and polyimide systems. kind.
An electronic device, characterized by comprising an electronic component and a cured product of the composite heat-conducting material according to any one of claims 18 to 27 arranged on the electronic component.
The electronic device according to claim 28, characterized in that, the electronic device further comprises a heat sink arranged on the electronic component, and the electronic device described in claims 18 to 27 is arranged between the electronic component and the heat sink. A cured product of any one of the composite heat-conducting materials.