阅读说明：本技术 一种石墨烯增强多孔铝基复合材料的制备方法 (Preparation method of graphene reinforced porous aluminum-based composite material ) 是由 赵占勇 段瑞斌 张立正 白培康 谭勇生 崔向中 刘琦 于 2019-10-31 设计创作，主要内容包括：本发明公开了一种石墨烯增强多孔铝基复合材料的制备方法,是以2,6-二异氰酸己酸甲酯对石墨烯进行表面处理,并经水合肼还原得到改性石墨烯,通过外加电场在改性石墨烯表面充分吸附气体后,于六甲基磷酰胺中与铝合金粉球磨混合,采用选择性激光熔化成形制备得到石墨烯增强多孔铝基复合材料。本发明制备方法提高了石墨烯在铝基体中的分散均匀性,提高了石墨烯与铝基体的界面结合性能,制备得到了一种内部孔结构丰富且均匀的多孔金属复合材料。(The invention discloses a preparation method of a graphene reinforced porous aluminum-based composite material, which comprises the steps of carrying out surface treatment on graphene by 2, 6-diisocyanatohexanoic acid methyl ester, reducing by hydrazine hydrate to obtain modified graphene, fully adsorbing gas on the surface of the modified graphene by an external electric field, carrying out ball milling mixing with aluminum alloy powder in hexamethylphosphoramide, and carrying out selective laser melting forming to obtain the graphene reinforced porous aluminum-based composite material. The preparation method provided by the invention improves the dispersion uniformity of graphene in the aluminum matrix, improves the interface bonding performance of graphene and the aluminum matrix, and prepares the porous metal composite material with rich and uniform internal pore structure.)

1. A preparation method of a graphene reinforced porous aluminum matrix composite material comprises the following steps:

1) adding graphene into benign organic solvent solution of 2, 6-diisocyanato methyl hexanoate, and carrying out surface treatment in the presence of an organic tin catalyst;

2) taking hydrazine hydrate as a reducing agent, and carrying out a reduction reaction on the graphene subjected to surface treatment to obtain modified graphene;

3) placing modified graphene in a closed system, introducing gas, and enabling the surface of the modified graphene to fully adsorb the gas under the action of an external negative electric field;

4) dispersing modified graphene adsorbing gas in hexamethylphosphoramide, adding aluminum alloy powder, performing ball milling in a ball mill, and drying to obtain modified graphene/aluminum alloy powder mixed powder;

5) and carrying out selective laser melting forming on the modified graphene/aluminum alloy powder mixed powder in an inert environment to form the graphene reinforced porous aluminum-based composite material.

2. The method for preparing the graphene reinforced porous aluminum-based composite material according to claim 1, wherein the modified graphene/aluminum alloy powder mixed powder which is laid to have a thickness of 0.05-0.07 mm is scanned layer by a laser with a power of 260-300W to perform selective laser melting forming.

3. The preparation method of the graphene reinforced porous aluminum-based composite material according to claim 1, wherein the mass ratio of the graphene to the methyl 2, 6-diisocyanatohexanoate is 1: 40-60.

4. The method for preparing the graphene reinforced porous aluminum-based composite material according to claim 1, wherein the methyl 2, 6-diisocyanatohexanoate is prepared into a benign organic solvent solution with a concentration of 10-30 wt%.

5. The method for preparing a graphene-reinforced porous aluminum-based composite material according to claim 1, wherein the benign organic solvent of methyl 2, 6-diisocyanatohexanoate is any one of butanone, acetone and diethyl ether.

6. The preparation method of the graphene reinforced porous aluminum-based composite material according to claim 1, wherein the mass ratio of hydrazine hydrate to surface-treated graphene is 1-10: 10.

7. The preparation method of the graphene reinforced porous aluminum-based composite material according to claim 1, wherein the hydrazine hydrate is prepared into a hydrazine hydrate aqueous solution with a concentration of 10-30 wt%.

8. The preparation method of the graphene reinforced porous aluminum-based composite material according to claim 1, wherein the reduction reaction time is 1-2 h.

9. The preparation method of the graphene reinforced porous aluminum-based composite material according to claim 1, wherein the modified graphene is subjected to gas adsorption in a closed system at a temperature of 30-40 ℃ and with the addition of a negative electric field of- (0.5-1.5) V/Å.

10. The preparation method of the graphene reinforced porous aluminum-based composite material as claimed in claim 1, wherein the mass ratio of the modified graphene capable of adsorbing gas, hexamethylphosphoramide and aluminum alloy powder is 1: 50-70: 90-100.

Technical Field

The invention belongs to the technical field of metal matrix composite materials, relates to an aluminum matrix composite material, and particularly relates to a preparation method of a graphene reinforced porous aluminum matrix composite material.

Background

In recent years, the development and application of metal porous materials have been receiving increasing attention. Porous metal is a new type of engineering material consisting of a rigid skeleton and internal pores, with excellent physical properties and good mechanical properties. The composite material has a plurality of excellent physical properties such as small density, large rigidity, large specific surface area, good energy absorption and vibration reduction performance, good noise reduction effect, high electromagnetic shielding performance and the like, and is widely applied to the fields of aviation, electronics, medical materials, biochemistry and the like.

The porous aluminum alloy material has the structural characteristics of small density, high porosity, large specific surface area, selective fluid permeability and the like, so that the porous aluminum alloy material has high damping performance, excellent thermophysical performance, excellent circulation performance, excellent acoustic and electromagnetic performance and wide application prospect, and is concerned at home and abroad.

With the development of aerospace technology, higher requirements are put on material properties. The single performance of the porous aluminum alloy material can not meet the actual requirement, and the metal-based composite material with better comprehensive performance is produced at the same time and is developed rapidly. The graphene has the advantages of high strength, high toughness, high conductivity and the like, and can be added into the aluminum alloy to effectively improve the comprehensive performance of the aluminum alloy, so that the graphene has important application potential in the aspects of mechanics, optics, thermodynamics, electrics and the like. Therefore, graphene/aluminum-based composite materials have become an important composite material.

CN 105081310a discloses a method for preparing graphene reinforced aluminum matrix composite, which disperses graphene in aluminum matrix by means of electrostatic self-assembly. CN 105296786a discloses a preparation method of an aluminum-based graphene heat-conducting composite material sample, which is to coat graphene on the outer layer of metal particles, and prepare an aluminum-based graphene composite material by heating and casting. CN 106607323A relates to a preparation process of an aluminum-based graphene composite material, wherein a graphene coating liquid is coated on an aluminum foil through a poly (phenol-oxygen) resin, and then the composite material is obtained through drying and curing.

The common problems of the graphene aluminum-based composite materials prepared by the various methods are as follows: the poor wettability between graphene and an aluminum matrix causes that graphene is difficult to be uniformly dispersed in an aluminum alloy, thereby affecting the mechanical property of the composite material.

Disclosure of Invention

The invention aims to provide a preparation method of a graphene reinforced porous aluminum-based composite material, which aims to solve the problems of poor wettability between graphene and an aluminum matrix and difficulty in pore-forming of the porous aluminum-based composite material.

The preparation method of the graphene reinforced porous aluminum-based composite material comprises the following steps:

1) adding graphene into benign organic solvent solution of 2, 6-diisocyanato methyl hexanoate, and carrying out surface treatment in the presence of an organic tin catalyst;

2) taking hydrazine hydrate as a reducing agent, and carrying out a reduction reaction on the graphene subjected to surface treatment to obtain modified graphene;

3) placing modified graphene in a closed system, introducing gas, and enabling the surface of the modified graphene to fully adsorb the gas under the action of an external negative electric field;

4) dispersing modified graphene adsorbing gas in hexamethylphosphoramide, adding aluminum alloy powder, performing ball milling in a ball mill, and drying to obtain modified graphene/aluminum alloy powder mixed powder;

5) and carrying out selective laser melting forming on the modified graphene/aluminum alloy powder mixed powder in an inert environment to form the graphene reinforced porous aluminum-based composite material.

According to the invention, the advantage of large specific surface area of graphene is utilized, gas is adsorbed on the surface of graphene, and then the gas-adsorbed graphene is mixed with aluminum alloy powder and then subjected to selective laser melting forming. In the forming process, gas adsorbed on the surface of the graphene can form bubbles, and the bubbles can be solidified in the alloy due to the fact that the solidification speed of the molten aluminum matrix is high, so that the graphene reinforced porous aluminum matrix composite is prepared.

In the preparation method, the selective laser melting forming is to scan the modified graphene/aluminum alloy powder mixed powder by using a laser with power of 260-300W.

Preferably, the modified graphene/aluminum alloy powder mixed powder is laid to a thickness of 0.05-0.07 mm for layer-by-layer scanning forming.

More preferably, the scanning speed is 4-8 m/s.

Specifically, in the surface treatment process of graphene, the mass ratio of the graphene to 2, 6-diisocyanatohexanoic acid methyl ester is 1: 40-60.

More specifically, the invention preferably prepares the 2, 6-diisocyanatohexanoic acid methyl ester into benign organic solvent solution with the concentration of 10-30 wt%.

More preferably, the benign organic solvent of methyl 2, 6-diisocyanatohexanoate may be any one of butanone, acetone and diethyl ether.

The organic tin catalyst can be any one of stannous octoate, dibutyltin bis (dodecyl sulfur) and dibutyltin dilaurate.

The surface treatment process of the graphene can be carried out under the condition of ultrasonic stirring, and the ultrasonic stirring time is preferably 1-2 h.

Further, in the reduction reaction of the surface-treated graphene by using hydrazine hydrate, the mass ratio of the hydrazine hydrate to the surface-treated graphene is 1-10: 10.

Furthermore, the hydrazine hydrate is preferably prepared into a hydrazine hydrate aqueous solution with the concentration of 10-30 wt% for use.

The time of the reduction reaction is preferably 1-2 h.

And ultrasonically cleaning the modified graphene obtained by the reduction reaction with acetone, and then drying the modified graphene in vacuum at the temperature of 60-80 ℃.

Furthermore, the modified graphene is subjected to gas adsorption in a closed system under the conditions that the temperature is 30-40 ℃ and a negative electric field is applied, wherein the negative electric field is (0.5-1.5) V/Å.

Furthermore, the time for gas adsorption is preferably 0.5-1.5 h.

Further, the gas is an inert gas, preferably nitrogen or argon.

The flow rate of the introduced gas is preferably 30-50 ml/min.

In the preparation method of the present invention, preferably, the modified graphene capable of adsorbing gas, hexamethylphosphoramide, and aluminum alloy powder are mixed in a mass ratio of 1: 50-70: 90-100 and ball milled.

Further, the ball milling is specifically carried out for 1-3 h at a ball-material ratio of 4-6: 1 and a rotation speed of 150-210 rpm in a ball mill.

And (3) drying the materials obtained by ball milling at 40-60 ℃ for 1-3 h in vacuum to prepare modified graphene/aluminum alloy powder mixed powder.

According to the preparation method of the graphene reinforced porous aluminum-based composite material, 2, 6-diisocyanatohexanoic acid methyl ester is adopted to carry out surface treatment on graphene, so that the stability of the graphene is improved compared with other isocyanates, and meanwhile, the dispersibility of the graphene and aluminum alloy powder in the ball milling process is effectively improved due to the use of hexamethylphosphoramide.

The graphene reinforced porous aluminum-based composite material prepared by the method solves the problem of poor wettability between graphene and an aluminum matrix, improves the dispersion uniformity of the graphene in the aluminum matrix, overcomes the agglomeration problem of the graphene, improves the interface bonding property of the graphene and the aluminum matrix, and improves the mechanical property of the composite material.

Meanwhile, the porous metal composite material with rich and uniform internal pore structure is prepared by utilizing the characteristic that the two-dimensional crystal structure of the graphene has larger surface area and pore structure and can be fully contacted with gas and combining the characteristic with a 3D printing technology.

Drawings

Fig. 1 is a gold phase diagram of an internal organization structure of a graphene reinforced porous aluminum-based composite prepared in example 1.

Fig. 2 is a high-power scanning electron microscope image of the internal tissue structure of the graphene-reinforced porous aluminum-based composite prepared in example 1.

Detailed Description

The following examples further describe embodiments of the present invention. The following examples are only for illustrating the technical solutions of the present invention more clearly, and do not limit the scope of the present invention. Various changes, modifications, substitutions and alterations to these embodiments will be apparent to those skilled in the art without departing from the principles and spirit of this invention.

The aluminum alloy powder used in the examples of the present invention was an aluminum alloy having a trade name of AlSi10 Mg.