CN114425622A - A kind of powder metallurgy composite material and preparation method thereof - Google Patents

Abstract

The application belongs to the technical field of powder metallurgy, and particularly discloses a powder metallurgy composite material and a preparation method thereof, wherein the preparation method comprises the steps of respectively carrying out low-energy ball milling on copper powder and aluminum powder to obtain smaller powder, and then respectively carrying out cold pressing to obtain a copper sheet blank and an aluminum sheet blank; sequentially placing the sheet blank in acetone, ethanol, water and dilute hydrochloric acid in an oxygen-free box to remove a surface oxidation film by ultrasonic treatment, and then sequentially cleaning with water, ethanol and acetone and drying in the air; transferring the copper sheet blank into a tubular furnace, introducing methane, hydrogen and argon to perform in-situ vapor deposition of graphene, transferring the deposited graphene-copper sheet blank into an oxygen-free box to be stacked with the aluminum sheet blank at intervals, and then sealing, coating and discharging the box; after hot-pressing sintering is carried out in a sintering machine, the mixture is put into a vacuum furnace to be densified and sintered in an argon atmosphere. The method can effectively reduce the material cost of the copper material.

Description

A kind of powder metallurgy composite material and preparation method thereof

technical field

The application belongs to the technical field of powder metallurgy, and specifically relates to a powder metallurgy composite material and a preparation method thereof.

Background technique

As good conductors of heat, copper and aluminum are widely used in various electronic products, especially heat dissipation substrates. Due to the relatively high price of copper, the thermal conductivity of aluminum is relatively low, so if the two can be mixed in a certain proportion The composite material with low cost and good heat dissipation effect can be obtained. The advantage of the powder metallurgy method is to prepare metal composite materials with a simple shape and structure like a heat dissipation substrate at a lower cost, but the disadvantage of powder metallurgy is the porosity of the prepared material. Higher, more grain boundaries lead to lower heat transfer efficiency, limiting the application prospects of powder metallurgy methods.

Therefore, the existing technology still needs to be further developed and improved.

SUMMARY OF THE INVENTION

In view of various deficiencies in the prior art, in order to solve the above problems, a powder metallurgy composite material and a preparation method thereof are proposed. This application provides the following technical solutions:

A powder metallurgy composite material comprises aluminum flakes and copper flakes that are laminated and compounded in sequence, and single-layer graphene is attached to the surface of the copper flakes.

Further, the outermost layer of the composite material is copper foil.

A preparation method of powder metallurgy composite material, comprising:

The copper powder and aluminum powder are respectively subjected to low-energy ball milling to obtain powders with smaller size, which are then cold-pressed into copper sheet blanks and aluminum sheet blanks respectively;

In an oxygen-free box, the sheet blanks are placed in acetone, ethanol, water, and dilute hydrochloric acid in sequence to remove the surface oxide film by ultrasonic, and then sequentially washed with water, ethanol and acetone, and air-dried;

Transfer the copper flake blanks to a tube furnace, conduct in-situ vapor deposition of graphene through methane, hydrogen and argon, transfer the deposited graphene-copper flake blanks to an oxygen-free box and stack the aluminum flake blanks at intervals, Then seal and wrap it out of the box;

After hot-pressing sintering in a sintering machine, it is put into a vacuum furnace for densification and sintering in an argon atmosphere.

Further, the rotating speed of the low-energy ball milling is 100-150 r/min, anhydrous ethanol is used as a dispersant, and the ball milling time is 4 hours.

Further, the thickness of the sheet blank after cold pressing is 0.5-1 mm.

Further, when ultrasonically removing the oxide film on the surface, the sheet blank was ultrasonicated in acetone, ethanol and water for 5 min respectively, and in dilute hydrochloric acid for 10 min.

Further, the gas flow ratio of methane, hydrogen and argon is 1:30:30-1:5:5, and the vapor deposition temperature is 1050°C.

Further, the gas flow rate of the methane was 5 sccm at first during the vapor deposition, and increased to 30 sccm after 10 minutes.

Further, the temperature of the hot pressing sintering is 700-900° C., the pressure is 500 kgf/cm ² , and the hot pressing sintering time is 4 minutes.

Further, the densification sintering temperature is 1100° C., and the densification sintering time is 30 minutes.

Beneficial effects:

1. By compounding copper sheets and aluminum sheets, the heat dissipation efficiency is improved and the material cost is reduced;

2. By vapor-depositing graphene on the surface of the copper sheet, the oxidation of the surface of the copper sheet is prevented and the thermal conductivity is improved;

3. Improve the thermal conductivity by removing the oxide layer of the sheet blank;

4. Processed and synthesized in an oxygen-free environment to avoid secondary formation of oxide layer;

5. By controlling the air flow ratio, the deposition of thin-layer graphene can be realized to make up for the thermal conductivity loss between the copper sheet and the aluminum sheet grain boundary.

Description of drawings

1 is a schematic flow chart of a powder metallurgy composite material and a preparation method thereof in a specific embodiment of the present application;

Fig. 2 is the Raman spectrum of vapor deposition product in the specific embodiment of the present application;

FIG. 3 shows different thermal conductivities corresponding to different sintering temperatures in specific embodiments of the present application.

Detailed ways

In order to make those skilled in the art better understand the technical solutions of the present application, the technical solutions of the present application will be described clearly and completely below with reference to the accompanying drawings of the present application. Other similar embodiments obtained without creative work shall fall within the scope of protection of the present application. In addition, the directional terms mentioned in the following embodiments, such as "up", "down", "left", "right", etc., are only the directions of reference to the drawings. Therefore, the directional terms used are used to illustrate rather than limit the present invention. Apply to create.

A powder metallurgy composite material comprises aluminum flakes and copper flakes that are laminated and compounded in sequence, and single-layer graphene is attached to the surface of the copper flakes.

Further, the outermost layer of the composite material is copper foil.

As shown in Figure 1, a method for preparing a powder metallurgy composite material includes:

S1. The copper powder and the aluminum powder are respectively subjected to low-energy ball milling to obtain powder with a smaller size, and then cold-pressed into a copper sheet blank and an aluminum sheet blank respectively;

S2. In an oxygen-free box, place the sheet blanks in acetone, ethanol, water, and dilute hydrochloric acid in sequence to remove the surface oxide film by ultrasonic, and then sequentially wash and dry through water, ethanol and acetone;

S3. Transfer the copper flake blank to the tube furnace, conduct in-situ vapor deposition of graphene through methane, hydrogen and argon, and transfer the deposited graphene-copper flake blank to the oxygen-free box to be spaced from the aluminum flake blank Stacked, then sealed and wrapped out of the box; after etching the graphene-copper flake blank with sulfuric acid solution, it was found that a transparent film floated above the solution, which was detected as graphene by Raman, as shown in Figure 2.

S4. After hot-pressing sintering in the sintering machine, it is put into a vacuum furnace for densification and sintering in an argon atmosphere.

Further, the rotating speed of the low-energy ball milling is 100-150 r/min, anhydrous ethanol is used as a dispersant, and the ball milling time is 4 hours.

Further, the thickness of the sheet blank after cold pressing is 0.5-1 mm.

Further, when ultrasonically removing the oxide film on the surface, the sheet blank was ultrasonicated in acetone, ethanol and water for 5 min respectively, and in dilute hydrochloric acid for 10 min.

Further, the gas flow ratio of methane, hydrogen and argon is 1:30:30-1:5:5, and the vapor deposition temperature is 1050°C.

Further, the gas flow rate of the methane was 5 sccm at first during the vapor deposition, and increased to 30 sccm after 10 minutes.

Further, the temperature of the hot pressing sintering is 700-900° C., the pressure is 500 kgf/cm ² , and the hot pressing sintering time is 4 minutes.

Further, the densification sintering temperature is 1100° C., and the densification sintering time is 30 minutes.

Use the laser flash point method of the LFA1000 thermal conductivity tester to test and analyze the thermal conductivity of the heat dissipation materials prepared in the following examples.

Example 1

A preparation method of powder metallurgy composite material, comprising:

S1. The copper powder and the aluminum powder are respectively subjected to low-energy ball milling, the rotation speed is 100-150r/min, and absolute ethanol is used as a dispersant, and the ball milling time is 4h. Aluminum sheet blank, the thickness of the sheet blank after cold pressing is 0.5-1mm;

S2. In an oxygen-free box, place the sheet blanks in acetone, ethanol, water, and dilute hydrochloric acid in sequence to remove the surface oxide film by ultrasonic waves. When ultrasonically removing the surface oxide film, the sheet blanks are ultrasonicated in acetone, ethanol, and water for 5 minutes respectively, and then in dilute hydrochloric acid. Ultrasound in hydrochloric acid for 10 min, then successively washed with water, ethanol and acetone for 30 s, and air-dried;

S3. Transfer the copper sheet blank to the tube furnace, and conduct in-situ vapor deposition of graphene through methane, hydrogen and argon. The gas flow rates of methane, hydrogen and argon are 5 sccm, 150 sccm and 150 sccm, respectively, and change after 10 minutes. For 30sccm, 150sccm and 150sccm, the vapor deposition temperature is 1080 ℃, the deposited graphene-copper sheet blanks are transferred to an oxygen-free box and stacked with the aluminum sheet blanks at intervals, and then sealed and wrapped out of the box;

S4. After hot-pressing sintering in the sintering machine, put it into a vacuum furnace for densification and sintering in an argon atmosphere. The hot-pressing sintering temperature is 700°C, the pressure is 500kgf/cm ² , the hot-pressing sintering time is 4 minutes, and the densification and sintering temperature is 1100 ℃, densification sintering time 30min. The thermal conductivity is 50W/mK.

Example 2

A preparation method of powder metallurgy composite material, comprising:

S1. The copper powder and the aluminum powder are respectively subjected to low-energy ball milling, the rotation speed is 100-150r/min, and absolute ethanol is used as a dispersant, and the ball milling time is 4h. Aluminum sheet blank, the thickness of the sheet blank after cold pressing is 0.5-1mm;

S2. In an oxygen-free box, place the sheet blanks in acetone, ethanol, water, and dilute hydrochloric acid in sequence to remove the surface oxide film by ultrasonic waves. When ultrasonically removing the surface oxide film, the sheet blanks are ultrasonicated in acetone, ethanol, and water for 5 minutes respectively, and then in dilute hydrochloric acid. Ultrasound in hydrochloric acid for 10 min, then successively washed with water, ethanol and acetone for 30 s, and air-dried;

S3. Transfer the copper sheet blank to the tube furnace, and conduct in-situ vapor deposition of graphene through methane, hydrogen and argon. The gas flow rates of methane, hydrogen and argon are 5 sccm, 150 sccm and 150 sccm, respectively, and change after 10 minutes. For 30sccm, 150sccm and 150sccm, the vapor deposition temperature is 1080 ℃, the deposited graphene-copper sheet blanks are transferred to an oxygen-free box and stacked with the aluminum sheet blanks at intervals, and then sealed and wrapped out of the box;

S4. After hot-pressing sintering in a sintering machine, put it into a vacuum furnace for densification and sintering under an argon atmosphere. The hot-pressing sintering temperature is 750°C, the pressure is 500kgf/cm ² , the hot-pressing sintering time is 4 minutes, and the densifying sintering temperature is 1100 ℃, densification sintering time 30min. The thermal conductivity is 54W/mK.

Example 3

A preparation method of powder metallurgy composite material, comprising:

S1. The copper powder and the aluminum powder are respectively subjected to low-energy ball milling, the rotation speed is 100-150r/min, and absolute ethanol is used as a dispersant, and the ball milling time is 4h. Aluminum sheet blank, the thickness of the sheet blank after cold pressing is 0.5-1mm;

S2. In an oxygen-free box, place the sheet blanks in acetone, ethanol, water, and dilute hydrochloric acid in sequence to remove the surface oxide film by ultrasonic waves. When ultrasonically removing the surface oxide film, the sheet blanks are ultrasonicated in acetone, ethanol, and water for 5 minutes respectively, and then in dilute hydrochloric acid. Ultrasound in hydrochloric acid for 10 min, then successively washed with water, ethanol and acetone for 30 s, and air-dried;

S3. Transfer the copper sheet blank to the tube furnace, and conduct in-situ vapor deposition of graphene through methane, hydrogen and argon. The gas flow rates of methane, hydrogen and argon are 5 sccm, 150 sccm and 150 sccm, respectively, and change after 10 minutes. For 30sccm, 150sccm and 150sccm, the vapor deposition temperature is 1080 ℃, the deposited graphene-copper sheet blanks are transferred to an oxygen-free box and stacked with the aluminum sheet blanks at intervals, and then sealed and wrapped out of the box;

S4. After hot-pressing sintering in the sintering machine, put it into a vacuum furnace for densification and sintering in an argon atmosphere. The hot-pressing sintering temperature is 800°C, the pressure is 500kgf/cm ² , the hot-pressing sintering time is 4 minutes, and the densification and sintering temperature is 1100 ℃, densification sintering time 30min. The thermal conductivity is 57W/mK.

Example 4

A preparation method of powder metallurgy composite material, comprising:

S1. The copper powder and the aluminum powder are respectively subjected to low-energy ball milling, the rotation speed is 100-150r/min, and absolute ethanol is used as a dispersant, and the ball milling time is 4h. Aluminum sheet blank, the thickness of the sheet blank after cold pressing is 0.5-1mm;

S2. In an oxygen-free box, place the sheet blanks in acetone, ethanol, water, and dilute hydrochloric acid in sequence to remove the surface oxide film by ultrasonic waves. When ultrasonically removing the surface oxide film, the sheet blanks are ultrasonicated in acetone, ethanol, and water for 5 minutes respectively, and then in dilute hydrochloric acid. Ultrasound in hydrochloric acid for 10 min, then successively washed with water, ethanol and acetone for 30 s, and air-dried;

S3. Transfer the copper sheet blank to the tube furnace, and conduct in-situ vapor deposition of graphene through methane, hydrogen and argon. The gas flow rates of methane, hydrogen and argon are 5 sccm, 150 sccm and 150 sccm, respectively, and change after 10 minutes. For 30sccm, 150sccm and 150sccm, the vapor deposition temperature is 1080 ℃, the deposited graphene-copper sheet blanks are transferred to an oxygen-free box and stacked with the aluminum sheet blanks at intervals, and then sealed and wrapped out of the box;

S4. After hot-pressing sintering in a sintering machine, put it into a vacuum furnace for densification and sintering in an argon atmosphere. The hot-pressing sintering temperature is 850°C, the pressure is 500kgf/cm ² , the hot-pressing sintering time is 4 minutes, and the densification and sintering temperature is 1100 ℃, densification sintering time 30min. The thermal conductivity is 59W/mK.

Example 5

A preparation method of powder metallurgy composite material, comprising:

S1. The copper powder and the aluminum powder are respectively subjected to low-energy ball milling, the rotation speed is 100-150r/min, and absolute ethanol is used as a dispersant, and the ball milling time is 4h. Aluminum sheet blank, the thickness of the sheet blank after cold pressing is 0.5-1mm;

S2. In an oxygen-free box, place the sheet blanks in acetone, ethanol, water, and dilute hydrochloric acid in sequence to remove the surface oxide film by ultrasonic waves. When ultrasonically removing the surface oxide film, the sheet blanks are ultrasonicated in acetone, ethanol, and water for 5 minutes respectively, and then in dilute hydrochloric acid. Ultrasound in hydrochloric acid for 10 min, then successively washed with water, ethanol and acetone for 30 s, and air-dried;

S3. Transfer the copper sheet blank to the tube furnace, and conduct in-situ vapor deposition of graphene through methane, hydrogen and argon. The gas flow rates of methane, hydrogen and argon are 5 sccm, 150 sccm and 150 sccm, respectively, and change after 10 minutes. For 30sccm, 150sccm and 150sccm, the vapor deposition temperature is 1080 ℃, the deposited graphene-copper sheet blanks are transferred to an oxygen-free box and stacked with the aluminum sheet blanks at intervals, and then sealed and wrapped out of the box;

S4. After hot-pressing sintering in the sintering machine, put it into a vacuum furnace for densification and sintering in an argon atmosphere. The hot-pressing sintering temperature is 900°C, the pressure is 500kgf/cm ² , the hot-pressing sintering time is 4 minutes, and the densifying sintering temperature is 1100 ℃, densification sintering time 30min. The thermal conductivity is 58W/mK.

Example 6

A preparation method of powder metallurgy composite material, comprising:

S1. The copper powder and the aluminum powder are respectively subjected to low-energy ball milling, the rotation speed is 100-150r/min, and absolute ethanol is used as a dispersant, and the ball milling time is 4h. Aluminum sheet blank, the thickness of the sheet blank after cold pressing is 0.5-1mm;

S2. In an oxygen-free box, place the sheet blanks in acetone, ethanol, water, and dilute hydrochloric acid in sequence to remove the surface oxide film by ultrasonic waves. When ultrasonically removing the surface oxide film, the sheet blanks are ultrasonicated in acetone, ethanol, and water for 5 minutes respectively, and then in dilute hydrochloric acid. Ultrasound in hydrochloric acid for 10 min, then successively washed with water, ethanol and acetone for 30 s, and air-dried;

S3. Transfer the copper sheet blank to the tube furnace, and conduct in-situ vapor deposition of graphene through methane, hydrogen and argon. The gas flow rates of methane, hydrogen and argon are 5 sccm, 150 sccm and 150 sccm, respectively, and change after 10 minutes. For 30sccm, 150sccm and 150sccm, the vapor deposition temperature is 1080 ℃, the deposited graphene-copper sheet blanks are transferred to an oxygen-free box and stacked with the aluminum sheet blanks at intervals, and then sealed and wrapped out of the box;

S4. After hot-pressing sintering in the sintering machine, put it into a vacuum furnace for densification and sintering in an argon atmosphere. The hot-pressing sintering temperature is 950°C, the pressure is 500kgf/cm ² , the hot-pressing sintering time is 4 minutes, and the densification and sintering temperature is 1100 ℃, densification sintering time 30min. The thermal conductivity is 57W/mK.

Comparative ratio

A preparation method of powder metallurgy composite material, comprising:

S1. The copper powder and the aluminum powder are respectively subjected to low-energy ball milling, the rotation speed is 100-150r/min, and absolute ethanol is used as a dispersant, and the ball milling time is 4h. Aluminum sheet blank, the thickness of the sheet blank after cold pressing is 0.5-1mm;

S2. In an oxygen-free box, place the sheet blanks in acetone, ethanol, water, and dilute hydrochloric acid in sequence to remove the surface oxide film by ultrasonic waves. When ultrasonically removing the surface oxide film, the sheet blanks are ultrasonicated in acetone, ethanol, and water for 5 minutes respectively, and then in dilute hydrochloric acid. Ultrasound in hydrochloric acid for 10 min, then successively washed with water, ethanol and acetone for 30 s, and air-dried;

S3. Stack the copper sheet blanks and the aluminum sheet blanks at intervals in the oxygen-free box, and then seal and wrap them out of the box;

S4. After hot-pressing sintering in a sintering machine, put it into a vacuum furnace for densification and sintering in an argon atmosphere. The hot-pressing sintering temperature is 850°C, the pressure is 500kgf/cm ² , the hot-pressing sintering time is 4 minutes, and the densification and sintering temperature is 1100 ℃, densification sintering time 30min. Thermal conductivity is 48W/mK.

Figure 3 shows the test results of the above thermal conductivity. In the comparative example without adding graphene, the thermal conductivity is low because the copper grain boundary cannot be completely fused with the aluminum grain boundary, and the addition of graphene fills the The gaps in the copper grain boundaries make the heat at the grain boundaries quickly transfer out through the graphene. With the increase of the sintering temperature, the density of the composite material increases continuously, which is conducive to the fusion between the grain boundaries, thereby reducing the number of gaps and improving the thermal conductivity. However, when the temperature reaches a certain level, the grain boundaries will no longer be fused and the density will not increase. At this time, continuing to heat up will lead to thermal cracks in the sintered structure, resulting in a decrease in thermal conductivity.

It will be apparent to those skilled in the art that the present application is not limited to the details of the above-described exemplary embodiments, but that the present application can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. Accordingly, the embodiments are to be regarded in all respects as illustrative and not restrictive, and the scope of the application is to be defined by the appended claims rather than the foregoing description, which is therefore intended to fall within the scope of the claims. All changes that come within the meaning and scope of equivalents to are included in this application.

The application has been described in detail above. The above is only the preferred embodiment of the application, and should not limit the scope of implementation of the application, that is, all equivalent changes and modifications made according to the scope of the application should still belong to this application application coverage.

Claims (10)

1. a powder metallurgy composite material, is characterized in that, comprises the aluminum flake and copper flake that are laminated and compounded successively, and the surface of described copper flake is attached with monolayer graphene. 2 . The powder metallurgy composite material according to claim 1 , wherein the outermost layer of the composite material is copper flakes. 3 . 3. A method for preparing powder metallurgy composite material as claimed in claim 1, characterized in that, comprising: The copper powder and aluminum powder are respectively subjected to low-energy ball milling to obtain powders with smaller size, which are then cold-pressed into copper sheet blanks and aluminum sheet blanks respectively; In an oxygen-free box, the sheet blanks are placed in acetone, ethanol, water, and dilute hydrochloric acid in sequence to remove the surface oxide film by ultrasonic, and then sequentially washed with water, ethanol and acetone, and air-dried; Transfer the copper flake blanks to a tube furnace, conduct in-situ vapor deposition of graphene through methane, hydrogen and argon, transfer the deposited graphene-copper flake blanks to an oxygen-free box and stack the aluminum flake blanks at intervals, Then seal and wrap it out of the box; After hot-pressing sintering in a sintering machine, it is put into a vacuum furnace for densification and sintering in an argon atmosphere. 4 . The method for preparing a powder metallurgy composite material according to claim 3 , wherein the rotating speed of the low-energy ball milling is 100-150 r/min, anhydrous ethanol is used as a dispersant, and the ball milling time is 4 h. 5 . 5 . The method for preparing a powder metallurgy composite material according to claim 3 , wherein the thickness of the cold-pressed sheet blank is 0.5-1 mm. 6 . 6 . The method for preparing a powder metallurgy composite material according to claim 3 , wherein when ultrasonically removing the surface oxide film, the sheet blank is ultrasonicated in acetone, ethanol and water for 5 minutes, and in dilute hydrochloric acid for 10 minutes. 7 . 7 . The method for preparing a powder metallurgy composite material according to claim 3 , wherein the gas flow ratio of methane, hydrogen and argon is 1:30:30-1:5:5, and the vapor deposition temperature is 1050° C. 8 . . 8 . The method for preparing a powder metallurgy composite material according to claim 7 , wherein the gas flow rate of the methane is first 5 sccm during vapor deposition, and is increased to 30 sccm after 10 minutes. 9 . 9 . The method for preparing a powder metallurgy composite material according to claim 3 , wherein the temperature of the hot-pressing sintering is 700-900° C., the pressure is 500 kgf/cm ² , and the hot-pressing sintering time is 4 minutes. 10 . 10 . The method for preparing a powder metallurgy composite material according to claim 3 , wherein the densification and sintering temperature is 1100° C. and the densification and sintering time is 30 minutes. 11 .

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