阅读说明：本技术 一种高导热复合体及其制备方法 (High-thermal-conductivity complex and preparation method thereof ) 是由 王华涛 田聪 吴亚金 吴绪磊 钟博 于 2020-05-07 设计创作，主要内容包括：本发明提供一种高导热复合体及其制备方法,通过打孔、攻丝工艺将螺丝穿过高导热材料,并与外层基板和盖板形成高导热复合体。螺丝在复合体中形成纵向导热结构,可显著增强水平方向导热好、纵向导热差的材料的纵向导热。同时这种螺丝结构还可以增强高导热材料与外层基板和盖板连接,降低界面热阻。该方法简单、可靠、成本低廉,操作性强,利用这种方法制作的复合体热导率高、密度低、强度高、厚度可控,避免了高导热材料易磨损、掉渣、强度低等缺点,可应用于各类基板、冷板和机箱壳体等散热结构中。(The invention provides a high-thermal-conductivity complex and a preparation method thereof. The screw forms a longitudinal heat conduction structure in the composite body, so that the longitudinal heat conduction of the material with good horizontal heat conduction and poor longitudinal heat conduction can be obviously enhanced. Meanwhile, the screw structure can also enhance the connection of high-heat-conduction materials with the outer-layer substrate and the cover plate, and reduce the interface thermal resistance. The method is simple and reliable, low in cost and strong in operability, and the complex body manufactured by the method is high in thermal conductivity, low in density, high in strength and controllable in thickness, avoids the defects that high-heat-conducting materials are easy to wear, drop slag, low in strength and the like, and can be applied to heat dissipation structures of various substrates, cold plates, case shells and the like.)

1. A preparation method of a high-thermal-conductivity composite body comprises the following steps:

s101, processing: processing a substrate into a certain plane shape or a three-dimensional shape with a groove;

s102, punching: processing holes with certain diameter and quantity on the processed substrate and tapping to form screw holes;

s103, cutting: selecting a high heat conduction material and a cover plate, and cutting the high heat conduction material and the cover plate into the shape and the size consistent with the shape and the size of the substrate or the substrate groove;

s104, punching: punching and tapping holes in the high-heat-conduction material and the cover plate to form screw holes, wherein the positions and the number of the holes are consistent with those of the holes in the base plate;

s105, assembling: putting the high-heat-conduction material between the base plate and the cover plate to ensure that all the screw holes are aligned to form a complex;

s106, silk feeding: screwing screws into the assembled complex body, and penetrating through the cover plate, the high heat conduction material and the base plate;

s107, processing: removing the head and/or tail of the screw protruding from the surfaces of the substrate and the cover plate of the assembled complex to form a flat surface;

s108, pressing: and pressing the screwed composite body to form the final high-heat-conductivity composite body.

2. The method of claim 1,

the materials of the substrate and the cover plate in the step S101 and/or the step S103 comprise copper, aluminum, silver, magnesium, ceramics, plastics and composite materials thereof, and the materials of the substrate and the cover plate are the same or different and are selected from one or two of the materials.

3. The method of claim 1,

the holes formed in the step S102 and/or the step S104 are obtained by drilling with a drill bit or by laser drilling; the screw holes on the cover plate and the high heat conduction material are through holes, and the screw holes on the base plate are through holes or blind holes; the types, threads, thread pitches and diameters of the screw holes at the same position of the base plate and the cover plate are consistent; the diameter of the screw hole at the same position of the high-heat-conduction material and the substrate is 60-100% of that of the screw hole at the same position of the substrate, and the type, the thread and the thread pitch of the screw hole at the same position of the high-heat-conduction material and the substrate are consistent with those of the screw hole at the same position of the substrate; the specifications of the screw holes at different positions on the substrate are the same or different.

4. The method of claim 1,

the cutting in the step S103 refers to one or more methods of cutter cutting, laser cutting, yarn cutting, ultrasonic cutting, and hydraulic cutting.

5. The method of claim 1,

the type, the thread pitch and the diameter of the screw in the step S106 are the same as those of the screw hole at the corresponding position on the substrate; the material of the screw comprises silver, copper, aluminum and their alloy, and the material of each screw is the same or different and is selected from one or more of the materials.

6. The method of claim 1,

the diameter of the screw holes in the step S102 and/or the step S104 is 0.2-50mm, and the density of the screw holes is 1-20 per square centimeter.

7. The method of claim 1,

the high thermal conductive material in the step S103 comprises pyrolytic graphite and graphite composite materials, carbon fiber composite materials, graphene films and graphene composite materials, carbon nanotube films and carbon nanotube composite materials, and diamond composite materials; the horizontal thermal conductivity is more than 200W/(m.K), and the thickness of the high thermal conductive material is more than 0.1 mm.

8. The method of claim 1,

and S107, the equipment for processing the surface of the high-thermal-conductivity composite body comprises a milling machine, a grinding machine and a polishing machine.

9. The method of claim 1,

the pressing method in the step S108 comprises dry pressing, hot pressing and isostatic pressing, wherein the pressure is 0.1-200 MPa, the pressure maintaining time is 0.1-100 hours, and the temperature is 20-1000 ℃.

10. A high heat-conducting composite body is characterized in that,

the high thermal conductivity composite is prepared by the method of any one of claims 1 to 9.

Technical Field

The invention belongs to the technical field of material structure design, and relates to a high-thermal-conductivity complex and a preparation method thereof.

Background

Prior patent documents:

the application CN108925108A, accepted, discloses a heat conducting structure with aluminum alloy embedded in a graphene-based composite material substrate and a manufacturing method thereof.

With the rapid development of electronic technology, the volume of electronic components is continuously reduced, the integration level of chips is continuously increased, and the heat flux density is also increased. The high-power electronic components can generate a large amount of heat, and if effective heat management measures are not taken, the heat is transferred out, and the components can be damaged or even damaged. With the development of science and technology, many high thermal conductive materials including artificial graphite, pyrolytic graphite, graphene films, graphene composites and the like have appeared. Most of the high-heat-conducting materials are carbon materials with a laminated structure, the plane heat conductivity of the materials can reach 150-1800W/(m.K), and the materials are low in density and are heat-conducting materials with wide application prospects. However, the graphitized carbon materials have low interlayer bonding force, are easy to strip and remove slag, cannot meet the requirements of a plurality of precise electronic devices on the environment when being used independently, and have low strength so as to limit the application of the graphitized carbon materials in the field of aviation. The composite of the high heat conduction material and the outer layer matrix can avoid the defects of the high heat conduction material and expand the application range. Most of the high-thermal conductivity materials are anisotropic materials, the longitudinal thermal conductivity of the materials is less than 10W/(m.K), and the high-anisotropic thermal conductivity limits the conduction of heat in three-dimensional directions. The longitudinal heat conduction columns are added in the high heat conduction materials, so that the longitudinal heat conduction of the high heat conduction materials can be obviously improved, and the overall heat dissipation effect is improved.

The method of patent CN108925108A (patent document 1, a heat conduction structure with aluminum alloy embedded in a graphene-based composite substrate and a manufacturing method thereof) is to punch a hole on a graphene-based composite, metallize the graphene-based composite, plate copper on an aluminum block, and weld the aluminum block and the graphene-based composite to prepare a longitudinal heat conduction column structure. The process is complex, has large workload and high cost, and is not suitable for mass preparation. And the graphene-based composite material is not wrapped by a metal layer, is easy to wear and low in strength, and is not suitable for continuous work in a severe environment.

Disclosure of Invention

In order to solve the defect problem of the high-heat-conduction material and other various problems, the invention provides a preparation method of a high-heat-conduction composite. In the method, the screw column body serves as a longitudinal heat conduction column, heat of a heat source is rapidly transferred to the longitudinal direction, then the screw column body is connected with the high heat conduction material through threads, the heat is transferred to the whole plane of the high heat conduction material, the longitudinal heat conduction capability of the high heat conduction material can be greatly improved, and the integral heat dissipation capability of the composite body is further improved. Meanwhile, the screw can greatly improve the interlayer binding force of the high-heat-conduction material, the problems that the carbon-based heat-conduction material is easy to wear, slag falls, and has low strength and the like are solved by the base material on the periphery of the high-heat-conduction material, and the screw has high heat-conduction performance, low density and excellent mechanical property. The whole preparation process is simple, high-temperature welding is not needed, the problem that the thermal expansion coefficients of the carbon materials and the metal materials are not matched is avoided, and the connection is more reliable.

The invention aims to overcome the defects of the prior art and provide a high-heat-conductivity composite body and a longitudinal heat-conducting structure thereof, which have simple and reliable process and obviously improve the heat-radiating capacity.

In order to achieve the purpose, the invention adopts the following technical scheme:

a preparation method of a high-thermal-conductivity composite body comprises the following steps:

s101, processing: processing a substrate into a certain plane shape or a three-dimensional shape with a groove;

s102, punching: processing holes with certain diameter and quantity on the processed substrate and tapping to form screw holes;

s103, cutting: selecting a high heat conduction material and a cover plate, and cutting the high heat conduction material and the cover plate into the shape and the size consistent with the shape and the size of the substrate or the substrate groove;

s104, punching: punching and tapping holes in the high-heat-conduction material and the cover plate to form screw holes, wherein the positions and the number of the holes are consistent with those of the holes in the base plate;

s105, assembling: placing the high-heat-conductivity material between the substrate and the cover plate to ensure that all the screw holes are aligned to form a complex;

s106, silk feeding: screwing screws into the assembled complex body, and penetrating through the cover plate, the high heat conduction material and the base plate;

s107, processing: removing the head and/or tail of the screw protruding from the surfaces of the substrate and the cover plate of the assembled complex to form a flat plane;

s108, pressing: and pressing the screwed composite body to form the final high-heat-conductivity composite body.

Preferably, the materials of the substrate and the cover plate in the step S101 and/or the step S103 include copper, aluminum, silver, magnesium, ceramic, plastic and their composite materials, and the materials of the substrate and the cover plate are the same or different and are selected from one or two of the above materials.

Preferably, the hole formed in step S102 and/or step S104 is formed by drilling with a drill or by laser drilling; the screw holes on the cover plate and the high heat conduction material are through holes, and the screw holes on the base plate are through holes or blind holes; the types, threads, thread pitches and diameters of the screw holes at the same position of the base plate and the cover plate are consistent; the diameter of the screw hole at the same position of the high-heat-conduction material and the substrate is 60-100% of that of the screw hole at the same position of the substrate, and the type, the thread and the thread pitch of the screw hole at the same position of the high-heat-conduction material and the substrate are consistent with those of the screw hole at the same position of the substrate; the specifications of the screw holes at different positions on the substrate are the same or different.

Preferably, the cutting in the step S103 refers to one or more methods of cutter cutting, laser cutting, yarn cutting, ultrasonic cutting and hydraulic cutting.

Preferably, the type, thread, pitch and diameter of the screw in the step S106 are the same as those of the screw hole at the corresponding position on the substrate; the material of the screw comprises silver, copper, aluminum and their alloy, and the material of each screw is the same or different and is selected from one or more of the materials.

Preferably, the screw holes in the step S102 and/or the step S104 are located right below the heat source, in the middle of the composite and at the periphery of the composite, and have a diameter of 0.2-50mm and a density of 1-20 screw holes per square centimeter.

Preferably, in the step S103, the high thermal conductive material includes pyrolytic graphite and a graphite composite material, a carbon fiber composite material, a graphene film and graphene composite material, a carbon nanotube film and carbon nanotube composite material, and a diamond and diamond composite material; the horizontal thermal conductivity is more than 200W/(m.K), and the thickness of the high thermal conductive material is more than 0.1 mm.

Preferably, the equipment for processing the surface of the high thermal conductive composite in the step S107 includes a milling machine, a grinding machine and a polishing machine.

Preferably, the pressing method in the step S108 comprises dry pressing, hot pressing and isostatic pressing, wherein the pressure is 0.1MPa to 200MPa, the pressure maintaining time is 0.1 to 100 hours, and the temperature is 20 to 1000 ℃.

Further disclosed is a high thermal conductive composite prepared by one of the above methods.

According to the invention, the screw penetrates through the high-heat-conduction material and the substrate through a punching process to form a high-heat-conduction composite body, and meanwhile, the screw also serves as a longitudinal heat-conduction column. The main advantages are:

1) the manufacturing method is simple, reliable and strong in operability, can be applied to a plurality of high-thermal-conductivity materials with anisotropy, and has a good effect no matter the thickness of the materials;

2) since the carbon-based high thermal conductive material having a layered structure has high plane thermal conductivity (> 200W/(m.k)) and low density, which is an absolute advantage in terms of a heat dissipating material, but has low longitudinal thermal conductivity, a high thermal conductive composite having low density and good heat dissipating performance can be prepared by the method of the present invention. The screw heat-conducting column is in contact with the base material, so that heat is quickly transferred to the plane direction of the base material, and the heat-radiating capacity of the high-heat-conducting material is greatly improved;

3) in the method, the strength of the high-heat-conduction material can be effectively enhanced by the substrate shell and the screw heat-conduction column, and the substrate shell is also beneficial to protecting the high-heat-conduction material, so that the high-heat-conduction material has higher mechanical strength, better interlayer bonding force and excellent mechanical property, and is suitable for heat dissipation of aerospace or precise high-power electronic devices;

4) the number of the screw heat-conducting columns in the method is easy to control, and the screw heat-conducting columns are connected with the base material through threads, so that the contact area is larger, the combination is tighter, the contact thermal resistance is small, and the heat-radiating capacity of the base material is effectively improved.