Copper-modified reduced graphene oxide reinforced magnesium-based composite material and preparation process thereof

Abstract

The invention discloses a copper-modified reduced graphene oxide reinforced magnesium-based composite material and a preparation process thereof, and belongs to the field of magnesium alloy materials. Copper particles are uniformly deposited on the surface of reduced graphene oxide by adopting a chemical plating technology to form strong interface bonding. Ethanol serves as a medium to achieve uniform distribution of copper-modified reduced graphene oxide in a magnesium matrix, extrusion forming is conducted on composite powder, and the copper-modified reduced graphene oxide reinforced magnesium-based composite material is obtained. The method is simple in process and low in cost, the copper-modified reduced graphene oxide is uniformly distributed in a magnesium matrix, and the mechanical property of the magnesium-based composite material is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of the preparation of metal matrix composites, and particularly relates to a method for preparing a copper-modified reduced graphene oxide reinforced magnesium matrix composite material. Background Art

[0002] Magnesium and its alloys have become an ideal choice for lightweight due to their lightweight, high specific strength, good damping properties, excellent heat dissipation and thermal conductivity. However, the low strength, low elastic modulus and insufficient corrosion resistance of magnesium and magnesium alloys limit their wide application. Adding reinforcing bodies with excellent properties to the magnesium matrix to prepare magnesium matrix composites can overcome this limitation. Graphene has become one of the ideal reinforcing bodies for magnesium matrix composites due to its special structure, excellent mechanical properties, special electrical and thermal properties, etc., and has attracted extensive attention from researchers.

[0003] To give full play to the excellent comprehensive properties of graphene, when preparing graphene-reinforced magnesium matrix composites, it is necessary to solve the problems that graphene has a large specific surface area, high free energy, a serious tendency of self-aggregation, and it is difficult to form good dispersion in the magnesium matrix, as well as the problem that graphene and magnesium are non-wetting systems and there is no interfacial reaction between them, resulting in weak interfacial bonding between graphene and the magnesium matrix. Researchers mostly use ultrasonic treatment and mechanical stirring methods to improve the above problems, but they have little effect on high graphene content, and the formed weak interfacial bonding is mainly physical adsorption, which cannot fully play the strengthening effect of graphene as an ideal reinforcing body. Modifying the surface of graphene can improve the dispersion of graphene in the magnesium matrix and the interfacial bonding strength with the magnesium matrix, but it relies on strong alkalis and has potential safety hazards, and uses more chemical reagents and is easy to introduce impurities.

[0004] Patent CN107058832A combines ultrasonic dispersion, mechanical stirring and ball milling to uniformly disperse graphene and magnesium powder, and then prepares graphene-reinforced magnesium matrix composites through sintering. However, ball milling is easy to damage the structure of graphene and reduce the strengthening effect of graphene. Patent CN116144967A uses an organic chemical reduction method to modify the surface of graphene, and then prepares magnesium nanoparticle-coated graphene-reinforced magnesium matrix composites through hot pressing sintering, realizing the uniform dispersion of graphene in the magnesium matrix and enhancing the interfacial bonding strength of the composite material. However, chemical reagents such as bromoethane, tetrahydrofuran, iodine and sodium hydride are used in the surface modification process, which is easy to introduce impurities. Summary of the Invention

[0005] The present invention aims to solve the problems of poor dispersion of graphene and insufficient interfacial bonding strength between graphene and the matrix in the preparation of graphene-reinforced magnesium matrix composites, and proposes a preparation method for enhancing the performance of magnesium matrix composites by using copper-modified reduced graphene oxide.

[0006] A preparation method of a copper-modified reduced graphene oxide reinforced magnesium matrix composite material proposed by the present invention comprises the following steps:

[0007] (1) Disperse graphite oxide in deionized water and ultrasonically prepare a graphene oxide suspension;

[0008] (2) Prepare a copper ammonia solution. Under stirring, drop the copper ammonia solution into the graphene oxide suspension. After stirring evenly, add hydrazine hydrate and react in a water bath heating environment;

[0009] (3) Filter and wash the reaction product obtained in step (2), and perform drying to obtain copper-modified reduced graphene oxide;

[0010] (4) Weigh a certain mass of the copper-modified reduced graphene oxide obtained in step (3) and magnesium powder or / and magnesium alloy powder, stir and mix them with absolute ethanol as a medium, and obtain copper-modified reduced graphene oxide / magnesium matrix composite powder after complete drying;

[0011] (5) Put the copper-modified reduced graphene oxide / magnesium composite powder obtained in step (4) into a mold for hot extrusion;

[0012] (6) Extrude the blank obtained in step (5) after setting the temperature and heat preservation time to obtain a copper-modified reduced graphene oxide / magnesium matrix composite material.

[0013] In the step (1), the graphite oxide has a sheet diameter of 0.5 - 15 μm, a thickness of 1 - 10 nm, a purity of ≥ 99.0 wt.%, the concentration of graphite oxide is 0.1 - 2 mg / ml, the ultrasonic power is 300 - 600 W, and the time is 100 - 200 min.

[0014] In the step (2), the concentration of CuSO4·5H2O in the copper ammonia solution is 2 - 8 mg / ml, the pH is adjusted to 10 - 11 with ammonia water, the mass ratio of graphite oxide to CuSO4·5H2O is 1:4, the stirring rate is 300 - 900 rpm, the concentration of hydrazine hydrate in the reaction solution is 0.05 - 0.2 mg / ml, the reaction temperature is 80 - 95 °C, and the time is 3 - 6 h.

[0015] In the step (3), the drying temperature is 50 - 70 °C, and the drying time is 5 - 7 h.

[0016] In the step (4), the magnesium powder or / and magnesium alloy powder is one or several of pure magnesium, ZK series or AZ series magnesium alloy powders, the particle size is 200 - 400 mesh, and the impurity content is ≤ 0.5 wt.%; the water bath temperature is 70 - 90 °C, the stirring rate is 300 - 900 rpm, and the stirring time is 1 - 3 h.

[0017] In step (5), the hot extrusion temperature is 250-330 °C, the extrusion pressure is 600-900 MPa, and the extrusion rate is 1-10 mm / s.

[0018] In step (6), the heat preservation temperature is 280-350 °C, the time is 10-40 min, and the extrusion ratio is 10-25.

[0019] The content of copper-modified reduced graphene oxide in the composite material is 0.1-1.5 wt.%.

[0020] The core advantages of the present invention are reflected in the following aspects:

[0021] Copper is used to modify the surface of graphene oxide, which has significant cost advantages compared with noble metals such as nickel and silver, effectively reducing the material preparation cost. Through copper modification to modify the surface of graphene oxide, the self-aggregation of graphene and its interfacial wettability with the magnesium alloy matrix are significantly improved, forming excellent interfacial bonding, thereby significantly enhancing the mechanical properties of the composite material. During the preparation process of the composite powder, uniform dispersion of copper-modified reduced graphene oxide in the magnesium alloy powder is achieved. At the same time, the hot extrusion process is used to effectively refine the grains, and a magnesium-based composite material with uniform structure and excellent properties is prepared. The preparation process of the present invention has good reliability and repeatability, is simple and controllable in operation, has significant process advantages compared with the prior art, and the prepared composite material has excellent performance. Description of the Drawings

[0022] Figure 1 It is the scanning electron microscope image of the copper-modified reduced graphene oxide obtained in Example 4 of the present invention, and copper particles uniformly cover the surface of graphene.

[0023] Figure 2 It is the energy spectrum analysis of the copper-modified reduced graphene oxide obtained in Example 4 of the present invention, indicating that copper particles are successfully loaded on the surface of reduced graphene oxide.

[0024] Figure 3 It is the fracture morphology of the composite material prepared in Example 4 of the present invention after room temperature tensile testing. The fracture shows ductile fracture characteristics, indicating good interfacial bonding. Detailed Embodiments

[0025] The present invention is further illustrated by the following specific examples. The examples are only used to illustrate the correlation mechanism between the material preparation process parameters and the microstructure and macroscopic properties of the composite material, and should not be regarded as a limitation on the claims of the patent right of the present invention.

[0026] Example 1:

[0027] (1) Dissolve 0.5 mg / ml of graphite oxide (flake diameter 1 - 5 μm, thickness 1 - 3 nm, purity ≥ 99.0 wt.%) in deionized water, and configure a graphene oxide suspension with an ultrasonic power of 400 W and an ultrasonic time of 150 min;

[0028] (2) Prepare a copper ammonia solution with a concentration of 4 mg / ml of CuSO4·5H2O and a pH of 10 - 11. The mass ratio of graphite oxide to CuSO4·5H2O is 1:4. Under magnetic stirring at 500 rpm, drop the copper ammonia solution into the graphene oxide suspension. After stirring evenly, add 0.1 mg / ml of hydrazine hydrate and react in a water bath heating environment at 90 °C for 4 h;

[0029] (3) Filter and wash the reaction product obtained in step (2), and dry it at 60 °C for 6 h to obtain copper-modified reduced graphene oxide;

[0030] (4) Weigh 40 mg of the copper-modified reduced graphene oxide obtained in step (3), add it to absolute ethanol and disperse it by ultrasonic treatment. Then add 39.96 g of AZ91 magnesium alloy powder (particle size 200 - 250 mesh, impurity content ≤ 0.5 wt.%, Al: 9.07 wt.%, Zn: 1.04 wt.%, the rest is Mg). The water bath temperature is 80 °C, the stirring rate is 600 rpm, and the stirring time is 2 h. After complete drying, obtain copper-modified reduced graphene oxide / AZ91 magnesium matrix composite powder.

[0031] (5) Put the copper-modified reduced graphene oxide / AZ91 magnesium matrix composite powder obtained in step (4) into a mold. The hot extrusion temperature is 250 °C, the extrusion pressure is 900 MPa, and the extrusion rate is 1 mm / s.

[0032] (6) Keep the blank obtained in step (5) at a temperature of 280 °C for 40 min, and perform extrusion at an extrusion ratio of 10 to obtain 0.1 wt.% copper-modified reduced graphene oxide / AZ91 magnesium matrix composite material.

[0033] Example 2:

[0034] (1) Dissolve 0.3 mg / ml of graphite oxide (flake diameter 5 - 10 μm, thickness 2 - 6 nm, purity ≥ 99.5 wt.%) in deionized water, and configure a graphene oxide suspension with an ultrasonic power of 500 W and an ultrasonic time of 130 min;

[0035] (2) Prepare a copper ammonia solution with a concentration of 6 mg / ml of CuSO4·5H2O and a pH of 10 - 11. The mass ratio of graphite oxide to CuSO4·5H2O is 1:4. Under magnetic stirring at 600 rpm, drop the copper ammonia solution into the graphite oxide suspension. After stirring evenly, add 0.05 mg / ml of hydrazine hydrate and react for 3 h in a water bath heating environment at 95 °C;

[0036] (3) Filter and wash the reaction product obtained in step (2), and dry it at 70 °C for 5 h to obtain copper-modified reduced graphite oxide;

[0037] (4) Weigh 0.2 g of the copper-modified reduced graphite oxide obtained in step (3), add it to absolute ethanol for ultrasonic dispersion, and then add 39.8 g of ZK61 magnesium alloy powder (particle size 300 - 400 mesh, impurity content ≤ 0.5 wt.%, Zn: 5.73 wt.%, Zr: 0.81 wt.%, the rest is Mg). The water bath temperature is 90 °C, the stirring rate is 500 rpm, and the stirring time is 2 h. After complete drying, obtain copper-modified reduced graphite oxide / ZK61 magnesium matrix composite powder.

[0038] (5) Put the copper-modified reduced graphite oxide / ZK61 magnesium matrix composite powder obtained in step (4) into a mold. The hot extrusion temperature is 280 °C, the extrusion pressure is 800 MPa, and the extrusion rate is 4 mm / s.

[0039] (6) Keep the blank obtained in step (5) at a temperature of 320 °C for 25 min, and perform extrusion at an extrusion ratio of 15 to obtain 0.5 wt.% copper-modified reduced graphite oxide / ZK61 magnesium matrix composite material.

[0040] Example 3:

[0041] (1) Dissolve 1 mg / ml of graphite oxide (flake diameter 10 - 15 μm, thickness 3 - 8 nm, purity ≥ 99.5 wt.%) in deionized water, and configure a graphite oxide suspension with an ultrasonic power of 600 W and an ultrasonic time of 170 min;

[0042] (2) Prepare a copper ammonia solution with a concentration of 7 mg / ml of CuSO4·5H2O and a pH of 10 - 11. The mass ratio of graphite oxide to CuSO4·5H2O is 1:4. Under magnetic stirring at 700 rpm, drop the copper ammonia solution into the graphite oxide suspension. After stirring evenly, add 0.15 mg / ml of hydrazine hydrate and react for 6 h in a water bath heating environment at 80 °C;

[0043] (3) Filter and wash the reaction product obtained in step (2), and dry it at 50 °C for 7 h to obtain copper-modified reduced graphite oxide;

[0044] (4) Weigh 0.4 g of the copper-modified reduced graphene oxide obtained in step (3), add it to anhydrous ethanol and disperse it by ultrasonic treatment. Then add 39.6 g of pure Mg powder (particle size 200 - 260 mesh, impurity content ≤ 0.5 wt.%). The water bath temperature is 70 °C, the stirring rate is 900 rpm, and the stirring time is 3 h. After complete drying, a copper-modified reduced graphene oxide / Mg-based composite powder is obtained.

[0045] (5) Put the copper-modified reduced graphene oxide / Mg-based composite powder obtained in step (4) into a mold. The hot extrusion temperature is 310 °C, the extrusion pressure is 600 MPa, and the extrusion rate is 6 mm / s.

[0046] (6) Keep the blank obtained in step (5) at a temperature of 340 °C for 15 min, and perform extrusion at an extrusion ratio of 20 to obtain a 1 wt.% copper-modified reduced graphene oxide / Mg-based composite material.

[0047] Example 4:

[0048] (1) Dissolve 2 mg / ml of graphite oxide (flake diameter 1 - 5 μm, thickness 4 - 10 nm, purity ≥ 99.5 wt.%) in deionized water, and configure a graphene oxide suspension with an ultrasonic power of 600 W and an ultrasonic time of 190 min.

[0049] (2) Prepare a copper ammonia solution with a concentration of CuSO4·5H2O of 8 mg / ml and a pH of 10 - 11. The mass ratio of graphite oxide to CuSO4·5H2O is 1:4. Under magnetic stirring at 300 rpm, drop the copper ammonia solution into the graphene oxide suspension. After stirring evenly, add 0.2 mg / ml of hydrazine hydrate and react in a 90 °C water bath heating environment for 4 h.

[0050] (3) Filter and wash the reaction product obtained in step (2), and dry it at 60 °C for 6 h to obtain copper-modified reduced graphene oxide.

[0051] (4) Weigh 0.6 g of the copper-modified reduced graphene oxide obtained in step (3), add it to anhydrous ethanol and disperse it by ultrasonic treatment. Then add 39.4 g of AZ31 magnesium alloy powder (particle size 250 - 300 mesh, impurity content ≤ 0.2 wt.%, Al: 3.35 wt.%, Zn: 1.27 wt.%, the rest is Mg). The water bath temperature is 90 °C, the stirring rate is 300 rpm, and the stirring time is 1 h. After complete drying, a copper-modified reduced graphene oxide / AZ31 magnesium-based composite powder is obtained.

[0052] (5) Put the copper-modified reduced graphene oxide / AZ31 magnesium-based composite powder obtained in step (4) into a mold. The hot extrusion temperature is 330 °C, the extrusion pressure is 800 MPa, and the extrusion rate is 10 mm / s.

[0053] (6) Keep the blank obtained in step (5) at a temperature of 350 °C for 10 min, and perform extrusion at an extrusion ratio of 25 to obtain 1.5 wt.% copper-modified reduced graphene oxide / AZ31 magnesium matrix composite material.

[0054] The mechanical properties of the copper-modified reduced graphene oxide-reinforced magnesium matrix composites prepared in Examples 1-4 are shown in Table 1.

[0055] Table 1 Mechanical properties of the copper-modified reduced graphene oxide-reinforced magnesium matrix composites in the examples

[0056]

[0057] The above are only the preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. It should be emphasized that as long as it does not deviate from the core concept and basic principle of the present invention, any addition, modification, equivalent replacement or improvement based on the technical essence of the present invention will be regarded as falling within the protection scope defined by the claims of the present invention.

Claims

1. A preparation method of a copper-modified reduced graphene oxide reinforced magnesium matrix composite material, characterized in that It includes the following steps: (1) Disperse graphite oxide in deionized water and configure a graphene oxide suspension by ultrasonic treatment; (2) Prepare a copper ammonia solution. Under stirring, drop the copper ammonia solution into the graphene oxide suspension. After stirring evenly, add hydrazine hydrate and react in a water bath heating environment; (3) Filter and wash the reaction product obtained in step (2), and perform drying to obtain copper-modified reduced graphene oxide; (4) Weigh a certain mass of the copper-modified reduced graphene oxide obtained in step (3) and mix it with magnesium powder or / and magnesium alloy powder by stirring with absolute ethanol as a medium. After complete drying, obtain a copper-modified reduced graphene oxide / magnesium-based composite powder; (5) Put the copper-modified reduced graphene oxide / magnesium composite powder obtained in step (4) into a mold for hot extrusion; (6) Extrude the blank obtained in step (5) after setting the temperature and holding time to obtain a copper-modified reduced graphene oxide / magnesium-based composite material.

2. The method according to claim 1, wherein In step (1), the graphite oxide has a sheet diameter of 0.5 - 15 μm, a thickness of 1 - 10 nm, and a purity of ≥99.0 wt.%; in step (1), the concentration of graphite oxide is 0.1 - 2 mg / ml, the ultrasonic power is 300 - 600 W, and the time is 100 - 200 min.

3. The method according to claim 1, wherein In step (2), the concentration of CuSO4·5H2O in the copper ammonia solution is 2 - 8 mg / ml, and the pH is adjusted to 10 - 11 with ammonia water.

4. The method according to claim 1, wherein In step (2), the mass ratio of graphite oxide to CuSO4·5H2O is 1:4, and the concentration of hydrazine hydrate in the reaction solution is 0.05 - 0.2 mg / ml; in step (2), the stirring rate is 300 - 900 rpm, the reaction temperature is 80 - 95 °C, and the time is 3 - 6 h.

5. The method according to claim 1, wherein In step (3), the drying temperature is 50 - 70 °C, and the drying time is 5 - 7 h.

6. The method according to claim 1, characterized in that, In step (4), the magnesium powder or / and magnesium alloy powder is one or several of pure magnesium, ZK series or AZ series magnesium alloy powders, with a particle size of 200 - 400 mesh and an impurity content of ≤0.5 wt.%; the water bath temperature is 70 - 90 °C, the stirring rate is 300 - 900 rpm, and the stirring time is 1 - 3 h.

7. The method according to claim 1, characterized in that In step (5), the hot extrusion temperature is 250 - 330 °C, the extrusion pressure is 600 - 900 MPa, and the extrusion rate is 1 - 10 mm / s.

8. The method according to claim 1, characterized in that, In step (6), the holding temperature is 280 - 350 °C, the time is 10 - 40 min, and the extrusion ratio is 10 - 25.

9. The method according to claim 1, wherein The content of copper-modified reduced graphene oxide in the composite material is 0.1 - 1.5 wt.%.

10. A copper-modified reduced graphene oxide-reinforced magnesium-based composite material prepared by the method according to any one of claims 1 - 9.

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