CN112853144A

CN112853144A - Preparation method of diamond/graphene/metal composite material

Info

Publication number: CN112853144A
Application number: CN202011640888.7A
Authority: CN
Inventors: 张阳; 楚晴晴; 郑辉; 陈伟; 郑梁; 郑鹏
Original assignee: Hangzhou Dianzi University
Current assignee: Hangzhou Dianzi University
Priority date: 2020-12-31
Filing date: 2020-12-31
Publication date: 2021-05-28

Abstract

The invention belongs to a preparation technology of a metal-based composite material, and discloses a preparation method of a diamond/graphene/metal composite material. Firstly, preparing a carbon-containing high polymer material into a solution; adding the solution into the metal powder for multiple times, grinding, mixing uniformly and drying; mixing the dried powder and the diamond in a ball mill to uniformly mix the diamond and the metal powder coated with the carbon-containing high polymer material; putting the mixed powder into a self-made mould, carrying out heat treatment in a microwave plasma furnace, and then cooling in a nitrogen atmosphere; and placing the mixed powder block subjected to microwave treatment into a graphite mold, and sintering in a hot-pressing furnace. The method is simple to operate and low in cost, can realize the preparation of the high-thermal-conductivity composite material, and expands the application range of the composite material in the preparation of the high-thermal-conductivity electronic packaging material.

Description

Preparation method of diamond/graphene/metal composite material

Technical Field

The invention belongs to the technical field of materials, and particularly relates to a method for preparing a diamond/graphene/metal composite material by taking a carbon-containing high polymer material as a carbon source so as to prepare a high-heat-conductivity electronic packaging material.

Background

With the increasing demand of the current market for high thermal conductive electronic packaging materials, diamond is more and more concerned by people due to its superior physical properties, and metal has good thermal conductivity and isotropic thermal conductivity, so that diamond/metal matrix composite becomes a hot spot of current research. However, the interface bonding force between the diamond and part of metal is weak, and even valence bond bonding cannot be formed, so that a large gap defect exists between the diamond and the metal, and heat and electricity conduction is hindered. At present, aiming at the problem of diamond/metal interface, many researches are carried out to improve the interface bonding force between diamond and metal by metalizing the surface of diamond or alloying the surface of metal, but whether the interface structure of the carbide layer is formed by metalizing the surface of diamond or alloying the surface of metal (W/Ti/Cr/Mo), the formed interface structure of the carbide layer can scatter heat in the process of conduction, and the increase of the thermal conductivity of the composite material is not outstanding enough. Therefore, the patent designs a method for preparing the diamond/graphene/metal interface composite material to solve the problem of an interface between diamond and metal, and a carbon-containing high polymer material is converted into graphene to be tightly coated on the surface of copper particles under the treatment of microwave plasma, so that a good copper powder/graphene interface structure is formed. Meanwhile, diamond and graphene are allotropes, and the wettability between the diamond and the graphene is good. And tightly compounding the graphene and the diamond together at high temperature and high pressure to finally form the copper/graphene/diamond composite material. In addition, the graphene is a two-dimensional nano material with high heat conductivity and excellent performance, and is used as an interface material between diamond and a metal material, so that the wettability between the diamond and the metal is improved, and the heat conductivity of the diamond/metal composite material is improved.

Disclosure of Invention

The invention aims to provide a composite material taking graphene as a diamond/metal interface to solve the problem of the interface structure of the existing metal-based diamond composite material. The method provides a good idea for solving the interface problem of the heat-conducting and electricity-conducting composite material. Has higher innovation and higher exploration value. And the obtained composite material can be used as an electronic packaging material with high thermal conductivity.

The invention provides a preparation method of a diamond/graphene/metal composite material, which comprises the following steps:

(1) preparing carbon-containing polymer solution such as fibroin solution, glucose solution, etc.;

(2) soaking diamond in 0.5mol/L dilute sulfuric acid for 30min, and oven drying. And then soaking in 0.5mol/L sodium hydroxide solution for 30min to remove impurities of the diamond, drying, performing ultrasonic treatment in deionized water for 30min to remove residual acid-base solution, and drying for 20 min. The drying is carried out in vacuum, and the drying temperature is 90 ℃;

(3) quantitatively adding the solution prepared in the step (1) into copper powder, adding 0.5ml of the solution into the metal powder each time by using a liquid transfer gun, fully grinding the solution in a mortar, and drying the powder in a vacuum drying oven;

(4) adding the metal/polymer mixed material treated in the step (3) and the diamond treated in the step (2) into a ball milling tank, wherein the particle size of the diamond is 100-300 microns, the mass fraction of the metal/polymer mixed material is 40-60%, performing dry mixing on powder in a ball mill, the ball milling speed is 225r/min, and the ball milling time is 2 hours;

(5) and (4) placing the sample treated in the step (4) into a self-made mold, treating the sample in a nitrogen atmosphere by using a microwave plasma technology, and then cooling the sample in the nitrogen atmosphere and taking out the sample.

(6) And (3) putting the sample prepared in the step (5) into a graphite grinding tool, carrying out hot-pressing sintering in a hot-pressing furnace, wherein the hot-pressing temperature is 900-1100 ℃, the pressure is 30-50 MPa, and the pressure is maintained to 300 ℃ in the cooling process to obtain the diamond/graphene/copper blocky composite material.

Compared with the prior art, the invention has the following technical effects: a graphene interface layer formed by microwave conversion of a carbon-containing high polymer material is formed between diamond and metal powder. At present, the method for improving the interface bonding of diamond and metal is mainly to improve the wettability between diamond and metal by metallizing or alloying the surface of diamond to form a carbide layer between metal and diamond. According to the invention, a carbon-containing polymer solution is converted into graphene under a certain preparation process to serve as an interface filling layer between metal and diamond, and a carbon-containing polymer material is converted into graphene to be tightly coated on the surface of copper particles under the treatment of microwave plasma, so that a good copper powder/graphene interface structure is formed. Meanwhile, diamond and graphene are allotropes, and the wettability between the diamond and the graphene is good. And tightly compounding the graphene and the diamond together at high temperature and high pressure to finally form the copper/graphene/diamond composite material. In addition, the graphene is a two-dimensional nano material with high heat conductivity and excellent performance, and is used as an interface material between diamond and a metal material, so that the wettability between the diamond and the metal is improved, and the heat conductivity of the diamond/metal composite material is improved.

The main equipment used by the invention is as follows: microwave plasma ovens and autoclave ovens.

Drawings

Fig. 1 is a flow chart in a sample making process.

Fig. 2 is an electron micrograph of the hot pressed sample, from which it is seen that the diamond is uniformly distributed in the copper powder. The diamond and the copper powder are tightly combined.

FIG. 3 is an electron microscope image and a Raman image of the sample after hot pressing, wherein three different structures of diamond, graphene and copper powder can be seen from the electron microscope image, and the graphene is located between the copper powder and the diamond, so that the diamond and the copper powder are tightly combined. From the raman graph, the D peak, G peak and 2D peak of graphene, and the peak of diamond can be seen. It can be seen that the carbon-containing polymer material shows better crystallinity after being converted into graphene.

FIG. 4 is a graphical representation of measured thermal conductivity data.

Detailed Description

The experimental procedures used in the following examples are all conventional ones unless otherwise specified.

Materials, reagents and the like used in the following examples are commercially available unless otherwise specified.

Example 1:

(1) preparation of carbon-containing Polymer solution

The silk fibroin solution is adopted in the embodiment, namely, silk is put into the sodium carbonate solution with good proportioning to be boiled, degummed and dried; putting the dried silk into a lithium bromide solution according to a ratio for fusing; and then dialyzing the solution after fusing, and finally centrifuging to obtain the fibroin solution.

(2) Cleaning of diamond

Putting diamond into 0.5mol/L sodium hydroxide solution for ultrasonic treatment for 30min, then ultrasonic treatment for 30min in 0.5mol/L dilute sulfuric acid solution, then ultrasonic treatment for 10min in deionized water, and finally drying in a vacuum drying oven, wherein the drying temperature is set to 90 ℃.

(3) The metal powder used in this example was copper powder. Putting 5g of copper powder with the particle size of 5 mu m into a mortar, adding 4ml of the fibroin solution obtained in the step (1) into the mortar by 0.5ml each time, fully and uniformly mixing, and then putting into a vacuum drying oven for drying at the drying temperature of 60 ℃ for 10 min. The above process was then repeated 4 times.

(4) Mixing the diamond cleaned in the step (2) with the mixed powder obtained in the step (3) according to a volume ratio of 0.45: putting the mixture into a ball milling tank according to the proportion of 0.55, and ball milling for 2 hours at the rotating speed of 225 r/min.

(5) And (4) putting the mixed powder of the diamond/fibroin/copper obtained in the step (4) into a self-made circular quartz mould with the diameter of 22mm for capping.

(6) And (5) putting the covered sample in the step (5) into a plasma microwave oven. Introducing nitrogen, keeping the microwave power at 1200W for 1 h.

(7) And (4) putting the sample obtained in the step (6) into a graphite mold, and then putting the mold into a hot-pressing furnace, wherein the temperature of the hot-pressing furnace is 1000 ℃, and the pressure is 50 MPa.

From the above example 1, the present invention relates to the preparation of graphene as an interface composite between diamond and copper, and a circular thin sheet with a diameter of 22mm and a thickness of 2mm is obtained, and the circular thin sheet is an electronic packaging material with high thermal conductivity and excellent performance. The measured thermal conductivity data is shown in FIG. 4, and the thermal conductivity reaches about 468W/mk. The nitrogen-doped graphene prepared by the invention plays a key role in preparing a high-thermal-conductivity electronic packaging material as an interface filling material of diamond/copper.

The above description of the embodiments is only intended to facilitate the understanding of the method of the invention and its core idea. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A preparation method of a diamond/graphene/metal composite material is characterized by comprising the following steps:

(1) preparing a carbon-containing high polymer material into a solution;

(2) adding metal powder into the solution prepared in the step (1) for multiple times, grinding and drying in vacuum, wherein the mass fraction of copper powder in the dried mixed powder is 80-99%, and the mass fraction of a carbon-containing polymer material is 1-20%; uniformly adding the solution prepared in the step (1) into metal powder for multiple times, fully milling in a bowl mill for 5min, and drying in a vacuum drying oven for 10 min;

(3) putting the diamond and the mixed powder obtained in the step (2) into a ball milling tank, and carrying out dry mixing on the mixed powder in a ball mill, wherein the particle size of the diamond is 100-300 mu m, the ball milling speed is 225r/min, and the ball milling time is 2 hours;

(4) putting the mixed powder obtained in the step (3) into a self-made mold, performing microwave treatment in a nitrogen atmosphere by using a microwave plasma technology, wherein the microwave power is 800-1200W, the heating time is 30-60 min, and finally cooling in the nitrogen atmosphere to obtain a diamond/graphene/copper mixed powder block;

(5) putting the mixed powder block obtained in the step (4) into a graphite mold, and carrying out hot pressing in a hot pressing furnace; sintering at 900-1100 ℃ for 1h under the pressure of 40-50 MPa, cooling to room temperature, and taking out; wherein the pressure is maintained to 300 ℃ in the process of temperature reduction; and forming the mixed powder block at high temperature and high pressure to form a diamond/graphene/copper tightly combined structure with graphene as an interface, and finally obtaining a diamond/graphene/copper block.