阅读说明：本技术 结合超声电沉积制备高表面光洁度金刚石/铜复合材料的方法 (Method for preparing diamond/copper composite material with high surface finish by combining ultrasonic electrodeposition ) 是由 武高辉 芶华松 林秀 陈国钦 王平平 修子扬 杨文澍 张强 于 2020-07-20 设计创作，主要内容包括：结合超声电沉积制备高表面光洁度金刚石/铜复合材料的方法,涉及一种金刚石/铜复合材料的制备方法。目的是解决现有的高导热金刚石铜复合材料表面光洁度低的问题。方法：准备模具,涂覆脱模剂并干燥；在模具型腔内表面沉积打底层,再镀覆一层铜膜；将镀覆金属薄膜的单晶金刚石颗粒装填于型腔内,进行浸渗。本发明最终所得金刚石/铜复合材料的表面光洁度显著提高,制备工艺简单,可重复性好,产品稳定,批次一致性好。所得产品能够直接应用于大功率微波功放器件及大规模集成电路的热沉、散热片或外壳。本发明适用于高表面光洁度金刚石/铜复合材料的制备。(A method for preparing a diamond/copper composite material with high surface finish by combining ultrasonic electrodeposition relates to a method for preparing a diamond/copper composite material. The purpose is to solve the problem that the surface finish degree of the existing high-heat-conductivity diamond copper composite material is low. The method comprises the following steps: preparing a mould, coating a release agent and drying; depositing a priming layer on the inner surface of the die cavity, and plating a copper film; the metal film-coated single-crystal diamond particles are filled in a cavity and impregnated. The diamond/copper composite material finally obtained by the method has the advantages of obviously improved surface smoothness, simple preparation process, good repeatability, stable product and good batch consistency. The obtained product can be directly applied to heat sinks, radiating fins or shells of high-power microwave power amplifiers and large-scale integrated circuits. The invention is suitable for preparing the diamond/copper composite material with high surface smoothness.)

1. A method for preparing a diamond/copper composite material with high surface finish by combining ultrasonic electrodeposition is characterized by comprising the following steps: the method comprises the following steps:

firstly, preparing a mould, wherein the requirement of the mould is that the roughness of the inner surface of a cavity is less than 6.3 microns, the heat conductivity is more than 90W/mK, and the average thermal expansion coefficient in a temperature range of 25-100 ℃ is less than 6 × 10^-6/K；

Secondly, coating a release agent on the inner surface of the die cavity and drying;

depositing a copper film with the thickness of 0.8-1 mu m on the inner surface of the die cavity by adopting a magnetron sputtering method to serve as a priming layer, and plating a copper film with the thickness of 1-3 mm and the surface roughness of less than 1.5 mu m on the surface of the priming layer by adopting an ultrasonic electrodeposition method;

fourthly, filling the single crystal diamond particles coated with the metal film into the cavity of the die obtained in the third step to obtain a prefabricated body;

placing the prefabricated body in a crucible, placing the blocky base alloy on the upper part of the prefabricated body in the crucible, and placing the crucible in an air pressure infiltration furnace;

preheating a mould to 800-1000 ℃ under a protective atmosphere, then heating the blocky matrix alloy to 1100-1300 ℃ and preserving heat for 1-2 hours, and then melting the blocky matrix alloy; maintaining the temperature of the mold at 800-1000 ℃, increasing the air pressure in the air pressure infiltration furnace to 0.5-8 MPa, and maintaining the pressure for 5-30 min;

and sixthly, maintaining pressure and cooling in a stepped manner, cleaning the BN particles on the surface after demolding, and grinding or polishing to obtain the diamond copper composite material with high surface finish.

2. The method of producing a high surface finish diamond/copper composite in combination with ultrasonic electrodeposition as claimed in claim 1 wherein: step one, the release agent is alcohol dispersion liquid of BN particles; the concentration of BN particles in the alcohol was 0.05 g/mL.

3. The method of producing a high surface finish diamond/copper composite in combination with ultrasonic electrodeposition as claimed in claim 1 wherein: and fourthly, the size of the single crystal diamond particles is 100-400 mu m, and the metal film plated on the single crystal diamond particles is a Ti film or a W film.

4. The method of producing a high surface finish diamond/copper composite in combination with ultrasonic electrodeposition as claimed in claim 1 wherein: and fourthly, the volume of the single crystal diamond particles coated with the metal film is 60-80% of the die cavity.

5. The method of producing a high surface finish diamond/copper composite in combination with ultrasonic electrodeposition as claimed in claim 1 wherein: and fourthly, the thickness of the metal film is 50-200 nm.

6. The method of producing a high surface finish diamond/copper composite in combination with ultrasonic electrodeposition as claimed in claim 1 wherein: and fifthly, the matrix alloy is pure copper or copper alloy.

7. The method of producing a high surface finish diamond/copper composite material in combination with ultrasonic electrodeposition as claimed in claim 1 wherein: and fifthly, the volume of the blocky base alloy is 20-30 times of that of the prefabricated body.

8. The method of producing a high surface finish diamond/copper composite in combination with ultrasonic electrodeposition as claimed in claim 1 wherein: step six the pressure-maintaining stepped cooling process comprises the following steps: when the temperature in the furnace is higher than 300 ℃, cooling at the cooling speed of 4 ℃/min under 2-5 MPa; when the temperature in the furnace is 300-100 ℃, cooling at the speed of 2 ℃/min under the pressure of 2-5 MPa; when the temperature in the furnace reaches below 100 ℃, releasing the pressure and naturally cooling to the room temperature.

9. The method of producing a high surface finish diamond/copper composite in combination with ultrasonic electrodeposition as claimed in claim 1 wherein: step six the pressure-maintaining stepped cooling process comprises the following steps: when the temperature in the furnace is higher than 300 ℃, cooling at the cooling speed of 4 ℃/min under 3 MPa; when the temperature in the furnace is 600 ℃, cooling at the speed of 2 ℃/min under the pressure of 3 MPa; when the temperature in the furnace reaches below 100 ℃, releasing the pressure and naturally cooling to the room temperature.

10. The method of producing a high surface finish diamond/copper composite in combination with ultrasonic electrodeposition as claimed in claim 1 wherein: step six the pressure-maintaining stepped cooling process comprises the following steps: when the temperature in the furnace is higher than 300 ℃, cooling at the cooling speed of 4 ℃/min under 5 MPa; when the temperature in the furnace is 300 ℃, cooling at the speed of 2 ℃/min under the pressure of 5 MPa; when the temperature in the furnace reaches below 100 ℃, releasing the pressure and naturally cooling to the room temperature.

Technical Field

The invention relates to a preparation method of a diamond/copper composite material.

Background

With the increasing requirements of high thermal conductivity metal matrix composite material on dimensional accuracy and matching accuracy, the development of a preparation technology of diamond copper composite material with high surface finish and high thermal conductivity is urgent. At present, the method for improving the surface finish degree of metal matrix composite materials such as diamond/copper composite materials and the like is mainly realized by surface grinding in the later period, impurities and cutting stress are easily introduced into the surface grinding, and the required labor intensity is high. The diamond is arranged on the surface of the diamond copper composite material, so that the diamond copper composite material is very hard, and the grinding difficulty and the cost are very high.

The surface roughness of the existing high-thermal-conductivity diamond copper composite material without surface processing treatment (preparation state) is 2-3.6 microns, and the requirement of the technical fields of laser communication, electronic packaging and the like on high smoothness of a heat dissipation material cannot be met. The surface finish of the composite material is improved by a method of multiple grinding, for example, the patent number is CN201611226063.4, and the name is ' a surface processing method suitable for diamond/copper composite material ', and the patent method has higher requirements on grinding technology and consumes manpower cost '.

Disclosure of Invention

The invention provides a method for preparing a diamond/copper composite material with high surface finish by combining ultrasonic electrodeposition, aiming at solving the problem of low surface finish of the existing high-thermal-conductivity diamond/copper composite material.

The method for preparing the diamond/copper composite material with high surface finish by combining ultrasonic electrodeposition comprises the following steps:

firstly, preparing a mould, wherein the requirement of the mould is that the roughness of the inner surface of a cavity is less than 6.3 microns, the heat conductivity is more than 90W/mK, and the average thermal expansion coefficient in a temperature range of 25-100 ℃ is less than 6 × 10^-6/K；

Secondly, coating a release agent on the inner surface of the die cavity and drying;

depositing a copper film with the thickness of 0.8-1 mu m on the inner surface of the die cavity by adopting a magnetron sputtering method to serve as a priming layer, and plating a copper film with the thickness of 1-3 mm and the surface roughness of less than 1.5 mu m on the surface of the priming layer by adopting an ultrasonic electrodeposition method;

fourthly, filling the single crystal diamond particles coated with the metal film into the cavity of the die obtained in the third step to obtain a prefabricated body;

placing the prefabricated body in a crucible, placing the blocky base alloy on the upper part of the prefabricated body in the crucible, and placing the crucible in an air pressure infiltration furnace;

preheating a mould to 800-1000 ℃ under a protective atmosphere, then heating the blocky matrix alloy to 1100-1300 ℃ and preserving heat for 1-2 hours, and then melting the blocky matrix alloy; maintaining the temperature of the mold at 800-1000 ℃, increasing the air pressure in the air pressure infiltration furnace to 0.5-8 MPa, and maintaining the pressure for 5-30 min;

and sixthly, maintaining pressure and cooling in a stepped manner, cleaning the BN particles on the surface after demolding, and grinding or polishing to obtain the diamond copper composite material with high surface finish.

The principle and the beneficial effects of the invention are as follows:

1. the invention improves the air pressure infiltration preparation method of the high-heat-conductivity diamond/copper composite material, provides a preparation method of the high-heat-conductivity diamond/copper composite material with high surface smoothness, and is suitable for preparing the high-volume-fraction metal matrix composite material. Solves the problem of poor surface finish of the metal matrix composite in the prior art. The invention has the advantages of simple preparation process, good repeatability, stable product and good batch consistency. The obtained product can be directly applied to heat sinks, radiating fins or shells of high-power microwave power amplifiers and large-scale integrated circuits, and is particularly suitable for preparing high-thermal-conductivity diamond copper composite heat sink parts with bulges or steps.

2. The diamond/copper composite material prepared by the method has the volume fraction of the reinforcement body of 60-80%, the thermal conductivity of 750-870W/(mK) and the thermal diffusion coefficient of 320-367 mm²And/s, the surface roughness of the composite sample piece with the surface of 130mm × 130mm reaches 0.05-0.1 mu m, and the smoothness is improved.

3. According to the invention, the fine-grained copper layer with high surface finish is obtained on the inner surface of the die cavity by controlling the electrodeposition process, the temperature of the die in the step five is controlled to be 800-1000 ℃, and the melting point of copper is 1085 ℃, so that a copper film plated on the die by the electrodeposition method cannot flow down in the infiltration process, and the defect caused by too fast solidification of the infiltrated copper due to too low temperature is avoided; the copper film is plated on the inner surface of the die cavity of the die, so that the surface finish of the prepared diamond/copper composite material can be improved, and the surface finish of the finally obtained diamond/copper composite material is also obviously improved. After demoulding, only simple polishing is needed, so that the method has the advantages of high efficiency, time saving, labor saving and labor cost saving, and belongs to an in-situ preparation method of the metal-based composite material with high surface smoothness.

Drawings

FIG. 1 is a schematic view of a mold structure, in which 1 is a powder filling port, 2 is a cavity, 3 is a mold, and 4 is a copper-clad layer;

FIG. 2 is an Atomic Force Microscope (AFM) topography photograph of the surface of the diamond/copper composite material prepared in example 1;

fig. 3 is a surface afm profile photograph of a sample of the diamond/copper composite prepared in comparative example 1 after grinding.

The specific implementation mode is as follows:

the technical scheme of the invention is not limited to the specific embodiments listed below, and any reasonable combination of the specific embodiments is included.