Method for preparing block nano-porous aluminum with macroscopic size based on phase separation principle

Abstract

The invention discloses a method for preparing block nano-porous aluminum with a macroscopic size based on a phase separation principle. The method comprises the following steps: step 1, preparing aluminum and zinc raw materials; 2, the aluminum and zinc raw materials prepared in the step 1 are heated and smelted into alloy ingots, and then the alloy ingots cooled to the room temperature are hot-rolled into alloy sheets; 3, the alloy sheet obtained in the step 2 is subjected to solution treatment, water quenching is conducted after solution treatment is completed, and the alloy sheet obtained after water quenching is placed in a drying box to be subjected to aging treatment; 4, the alloy sheet obtained in the step 3 is ground through abrasive paper, the alloy sheet is placed in a corrosion solution to be corroded after being polished, and a sample is obtained; and 5, the sample obtained after corrosion in the step 4 is put into deionized water to be cleaned and then is cleaned with acetone, then the sample is put into a vacuum drying box to be vacuumized, the sample is taken out after acetone is naturally volatilized, and the nano-porous aluminum block is obtained after vacuum preservation.

Description

Technical Field

[0001] The invention belongs to the technical field of metal material preparation, and in particular relates to a method for preparing bulk nanoporous aluminum with macroscopic size based on the phase separation principle. Background Art

[0002] Nanoporous metals have the characteristics of high specific surface area, low density, and high catalytic activity due to their nano-sized ligaments and pore structures. They are widely used in catalysis, energy storage, sensing and other fields.

[0003] The existing method for preparing nanoporous aluminum is basically to remove the active members in the alloy in an anhydrous ionic liquid by dealloying to obtain nanoporous aluminum. However, the strict requirements of the anhydrous ionic liquid system on the environment and the high cost of the anhydrous ionic liquid system make the existing nanoporous Al preparation have the disadvantages of high preparation cost and harsh environment. Therefore, it is of great significance to the progress of nanoporous Al preparation technology to efficiently prepare nanoporous Al under simple environmental requirements.

[0004] Aqueous solution is cheap, easy to obtain and can be used to prepare various corrosive solutions. Therefore, the main preparation method of existing nanoporous metal materials is to remove the active components in the alloy by corrosion in the aqueous solution, and then the inert components are self-assembled into a porous material of inert components by diffusion. Due to its amphoteric properties, aluminum can be corroded in acid solution, alkaline solution, and even in pure aqueous solution. Therefore, aluminum is often used as an active component for corroding and preparing nanoporous metals. It is removed during the corrosion process of the alloy to prepare other various nanoporous metal materials. That is, it is difficult to prepare porous Al by corrosion in aqueous solution, and nanoporous Al can be dissolved into the aqueous solution at a relatively fast corrosion rate even in pure water due to its huge specific surface area and high activity. Therefore, even if a porous Al thin layer of submicron thickness can be formed on the surface of the alloy by corrosion, as the subsequent corrosion proceeds to the inside of the alloy, the nanoporous thin layer formed on the surface will also dissolve due to its high activity, so that nanoporous Al foil with micron thickness cannot be obtained, and nanoporous Al bulk materials with a thickness of more than millimeter thickness cannot be obtained. Therefore, up to now, there has been no report on the preparation of nanoporous Al based on the corrosion method in aqueous solution, let alone the preparation of nanoporous Al bulk based on the corrosion method in aqueous solution. Summary of the invention

[0005] The purpose of the present invention is to provide a method for preparing bulk nanoporous aluminum with macroscopic size based on the phase separation principle, so as to solve the problems of high cost and harsh corrosive environment conditions in the existing nanoporous Al preparation methods.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is: a method for preparing a bulk nanoporous aluminum with a macroscopic size based on the phase separation principle, which is specifically implemented according to the following steps:

[0007] Step 1, preparing aluminum and zinc raw materials, wherein the weight proportion of aluminum raw materials is 17%-40%;

[0008] Step 2, heating and smelting the aluminum and zinc raw materials prepared in step 1 into alloy ingots, and then hot-rolling the alloy ingots cooled to room temperature into alloy sheets;

[0009] Step 3, subjecting the alloy sheet obtained in step 2 to a solution treatment, and then subjecting the alloy sheet to water quenching after the solution treatment, and placing the alloy sheet after the water quenching in a drying oven for an aging treatment;

[0010] Step 4, polishing the alloy sheet obtained in step 3 with sandpaper, and placing it in a corrosion solution for corrosion after polishing to obtain a sample;

[0011] Step 5, wash the sample obtained after corrosion in step 4 in deionized water, then wash it with acetone, and then place it in a vacuum drying oven and evacuate it to -0.1MPa. After the acetone evaporates naturally, take out the sample and obtain a nanoporous aluminum block after vacuum storage.

[0012] As a preferred technical solution of the present invention, in step 1, the aluminum raw material is an industrial pure aluminum ingot or aluminum plate with a purity greater than 99.5%; the zinc raw material is an industrial pure zinc ingot with a purity greater than 99.5%.

[0013] As a preferred technical solution of the present invention, in step 2, the smelting temperature is 720°C-750°C.

[0014] As a preferred technical solution of the present invention, in step 2, the hot rolling temperature of the alloy is 450°C-480°C, and the thickness of the alloy sheet obtained by rolling is 1.1mm-2.0mm.

[0015] As a preferred technical solution of the present invention, in step 3, the solution temperature is 370°C-400°C, and the solution time is 4h-10h; the alloy after solution is an atomically uniform single-phase Al solid solution, in which the Zn atoms are at the lattice position of the Al crystal.

[0016] As a preferred technical solution of the present invention, in step 3, the aging temperature is 50°C-150°C, and the aging time is 5h-10h; after aging, the Zn atoms dissolved in the alloy are completely dissolved from the Al crystals to form nanoscale and / or submicron-scale Zn phase grains and Al phase grains, and the Zn phase grains are interconnected, and the Al phase grains are also interconnected.

[0017] As a preferred technical solution of the present invention, in step 4, the sandpaper used for grinding is 600 mesh, 1000 mesh, 2000 mesh or 3000 mesh sandpaper.

[0018] As a preferred technical solution of the present invention, in step 4, the thickness of the polished alloy sheet is 1.0 mm-1.5 mm.

[0019] As a preferred technical solution of the present invention, in step 4, the temperature during corrosion is 0°C-25°C, and the reaction time is 24h-30h.

[0020] As a preferred technical solution of the present invention, in step 4, the corrosion solution is sulfuric acid with a concentration of 0.05 mol / L-0.5 mol / L.

[0021] The beneficial effects of the present invention are as follows: the bulk nanoporous aluminum prepared by the method of preparing bulk nanoporous aluminum with macroscopic size based on the phase separation principle of the present invention has a microstructure composed of nanoscale and / or submicron pore struts and pores, the pore structure is uniform and continuous, the macroscopic size is centimeter-level, and it has the advantages of complete structure, high porosity, and large specific surface area. At the same time, the size of nano / submicron pores and pore struts can be regulated by controlling the composition of the precursor alloy, the aging temperature, the aging time, etc., to obtain a bulk nanoporous aluminum with a high specific surface area. The preparation of bulk nanoporous aluminum by the present invention has the advantages of low preparation cost, short cycle, simple experimental conditions, and simple operation process, which is of great significance to the advancement of nanoporous Al bulk preparation technology and the wide application of nanoporous Al. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the metallographic microstructure of the alloy after solid solution;

[0023] Figure 2 This is the metallographic microstructure diagram (OM diagram) of the alloy after aging;

[0024] Figure 3 is the SEM image of the microstructure of nanoporous Al;

[0025] Figure 4 is the macroscopic shape and size diagram of nanoporous Al;

[0026] Figure 5 is the XRD pattern of bulk nanoporous aluminum. DETAILED DESCRIPTION

[0027] The present invention provides a method for preparing a bulk nanoporous aluminum with a macroscopic size based on the phase separation principle, which is specifically implemented according to the following steps:

[0028] Step 1, preparing aluminum and zinc raw materials, wherein the weight proportion of aluminum raw materials is 17%-40%;

[0029] Step 2, heating the aluminum and zinc raw materials prepared in step 1 to 720° C.-750° C. to melt into alloy ingots, and then heating the alloy ingots cooled to room temperature to 450° C.-480° C. to hot-roll them into alloy sheets with a thickness of 1.1 mm-2.0 mm;

[0030] Step 3, heating the alloy sheet obtained in step 2 to 370°C-400°C for solution treatment, the solution time is 4h-10h, water quenching is performed after the solution treatment, and the alloy sheet after water quenching is placed in a drying oven at a temperature of 50°C-150°C for 5h-10h for aging treatment;

[0031] Step 4, grinding the alloy sheet obtained in step 3 with 600 mesh, 1000 mesh, 2000 mesh, and 3000 mesh sandpaper, and then polishing to obtain an alloy sheet with a thickness of 1.0 mm-1.5 mm, and then placing the polished alloy sheet in a sulfuric acid corrosion solution with a temperature of 0° C.-25° C. and a concentration of 0.05 mol / L-0.5 mol / L for corrosion for 24 h-30 h to obtain a sample;

[0032] Step 5, wash the sample obtained after corrosion in step 4 in deionized water, then wash it with acetone, and then place it in a vacuum drying oven and evacuate it to -0.1MPa. After the acetone evaporates naturally, take out the sample and obtain a nanoporous aluminum block after vacuum storage.

[0033] The present invention takes the aging of aluminum alloy as a reference, and the aluminum-zinc alloy is aged after solid solution. The solid solution phase mixed evenly at the atomic level will be separated into aluminum phase grains and zinc phase grains during the aging process. The corrosion rate of aluminum in sulfuric acid and hydrochloric acid is much lower than the reaction rate of zinc and acid under the same conditions. At the same time, the size of the Al phase grains and the Zn phase grains formed during the aging process are controlled, so that the Zn phase grains are completely corroded and dissolved during the corrosion process, and holes with the same size and shape as the Zn phase grains are formed at the original positions of the Zn phase grains. At the same time, the amount of aluminum phase grains connected after aging in the alloy is small, and most of them are retained to form the pore walls (pore ridges) of the nanoporous Al block. In this way, the reaction rate difference is used to selectively remove the zinc phase grains in the alloy after aging, and the aluminum phase grains in the alloy after aging are retained, thereby obtaining a bulk nanoporous aluminum with a macroscopic size.

[0034] In the process of preparing nanoporous aluminum, the present invention can adjust the alloy composition, aging temperature, aging time, etc. to control the pore size, pore structure, specific surface area, etc. of the bulk nanoporous aluminum prepared by the final reaction.

[0035] Figure 1This is the metallographic microstructure diagram (OM diagram) of the alloy after solid solution. From the diagram, it can be seen that the grain boundaries formed by corrosion (the thin black lines, as shown by the arrows in the figure) indicate that the alloy is a single-phase solid solution. Figure 2 This is the metallographic microstructure diagram (OM diagram) of the alloy after aging. From the diagram, we can see the black and white areas, where the white area is the Al phase area and the black area is the Zn phase area. Figure 3 This is a SEM image of the microstructure of nanoporous aluminum. The white part in the image is the pore wall (pore ridge) of the porous Al, which has a thickness of about 200nm. The area between adjacent pore walls is the pore, whose size varies from tens of nanometers to hundreds of nanometers. Figure 4 The macroscopic shape and size diagram of nanoporous Al. It can be seen from the figure that the length and width of the block of nanoporous Al are at the cm level (this figure is only for display and does not mean that its size is limited to the cm level), and the thickness is at the millimeter level. Figure 5 This is the XRD diagram of the nanoporous Al bulk. It can be seen from the figure that the diffraction peak coincides with the standard diffraction peak of Al.

[0036] The method of preparing a bulk nanoporous aluminum with a macroscopic size based on the phase separation principle of the present invention, through the design of alloy composition and the control of heat treatment process, firstly makes Al and alloy element Me in the alloy realize atomic level composition homogenization, and obtains a solid solution with uniform composition; then, through aging, Al and alloy element Me in the alloy are separated to form separate Al phase grains and Me phase grains, and Al phase grains are interconnected, and Me phase grains are interconnected, that is, the alloy before corrosion presents separated Al grains and Me phase grains, and the size of Al phase grains is controlled at the same time, so that it will not be completely dissolved in the subsequent corrosion process; finally, the alloy completely separated from Al and alloy element Me is corroded in an aqueous solution of sulfuric acid, so that the separated alloy element Me phase grains are completely dissolved in the aqueous solution to form interconnected pores, and the interconnected Al phase is left to form a nanoporous Al block. The present invention provides a simple, convenient and low-cost preparation of nanoporous Al blocks, which has important practical significance for enriching the preparation method of nanoporous Al, improving the preparation technology progress of nanoporous Al blocks, and promoting the wide application of nanoporous Al blocks.

[0037] Example 1

[0038] The present invention provides a method for preparing a bulk nanoporous aluminum with a macroscopic size based on the phase separation principle, which is specifically implemented according to the following steps:

[0039] Step 1, preparing aluminum and zinc raw materials, wherein the weight proportion of aluminum raw materials is 17%;

[0040] Step 2, heating the aluminum and zinc raw materials prepared in step 1 to 720° C. to melt into an alloy ingot, and then heating the alloy ingot cooled to room temperature to 450° C. to hot-roll it into an alloy sheet with a thickness of 1.1 mm;

[0041] Step 3, heating the alloy sheet obtained in step 2 to 370° C. for solution treatment for 10 hours, water quenching after solution treatment, and placing the alloy sheet after water quenching in a drying oven at a temperature of 50° C. for 10 hours for aging treatment;

[0042] Step 4, the alloy sheet obtained in step 3 is successively ground with 600 mesh, 1000 mesh, 2000 mesh, and 3000 mesh sandpaper, and then polished to obtain an alloy sheet with a thickness of 1.0 mm, and then the polished alloy sheet is placed in a sulfuric acid corrosion solution with a temperature of 0° C. and a concentration of 0.05 mol / L for corrosion for 24 hours to obtain a sample;

[0043] Step 5, wash the sample obtained after corrosion in step 4 in deionized water, then wash it with acetone, and then place it in a vacuum drying oven and evacuate it to -0.1MPa. After the acetone evaporates naturally, take out the sample and obtain a nanoporous aluminum block after vacuum storage.

[0044] After testing, the specific surface area of ​​the bulk nanoporous aluminum material prepared in this embodiment is 10.0 m 2 / g

[0045] Example 2

[0046] The present invention provides a method for preparing a bulk nanoporous aluminum with a macroscopic size based on the phase separation principle, which is specifically implemented according to the following steps:

[0047] Step 1, preparing aluminum and zinc raw materials, with the weight of aluminum raw materials accounting for 40%;

[0048] Step 2, heating the aluminum and zinc raw materials prepared in step 1 to 750° C. to melt into alloy ingots, and then heating the alloy ingots cooled to room temperature to 480° C. to hot-roll them into alloy sheets with a thickness of 2.0 mm;

[0049] Step 3, heating the alloy sheet obtained in step 2 to 400°C for solution treatment for 4 hours, water quenching after solution treatment, and placing the alloy sheet after water quenching in a drying oven at a temperature of 150°C for 5 hours for aging treatment;

[0050] Step 4, the alloy sheet obtained in step 3 is successively ground with 600 mesh, 1000 mesh, 2000 mesh, and 3000 mesh sandpaper, and then polished to obtain an alloy sheet with a thickness of 1.5 mm, and then the polished alloy sheet is placed in a sulfuric acid corrosion solution with a temperature of 25° C. and a concentration of 0.5 mol / L for corrosion for 24 hours to obtain a sample;

[0051] Step 5, wash the sample obtained after corrosion in step 4 in deionized water, then wash it with acetone, and then place it in a vacuum drying oven and evacuate it to -0.1MPa. After the acetone evaporates naturally, take out the sample and obtain a nanoporous aluminum block after vacuum storage.

[0052] After testing, the specific surface area of ​​the bulk nanoporous aluminum material prepared in this embodiment is 12.78m 2 / g

[0053] Example 3

[0054] The present invention provides a method for preparing a bulk nanoporous aluminum with a macroscopic size based on the phase separation principle, which is specifically implemented according to the following steps:

[0055] Step 1, preparing aluminum and zinc raw materials, with the weight proportion of aluminum raw materials being 35%;

[0056] Step 2, heating the aluminum and zinc raw materials prepared in step 1 to 740° C. to melt into alloy ingots, and then heating the alloy ingots cooled to room temperature to 460° C. to hot-roll them into alloy sheets with a thickness of 1.5 mm;

[0057] Step 3, heating the alloy sheet obtained in step 2 to 380° C. for solution treatment for 7 hours, water quenching after solution treatment, and placing the alloy sheet after water quenching in a drying oven at a temperature of 100° C. for 7 hours for aging treatment;

[0058] Step 4, the alloy sheet obtained in step 3 is successively ground with 600 mesh, 1000 mesh, 2000 mesh, and 3000 mesh sandpaper, and then polished to obtain an alloy sheet with a thickness of 1.3 mm, and then the polished alloy sheet is placed in a sulfuric acid corrosion solution with a temperature of 10° C. and a concentration of 0.20 mol / L for corrosion for 26 hours to obtain a sample;

[0059] Step 5, wash the sample obtained after corrosion in step 4 in deionized water, then wash it with acetone, and then place it in a vacuum drying oven and evacuate it to -0.1MPa. After the acetone evaporates naturally, take out the sample and obtain a nanoporous aluminum block after vacuum storage.

[0060] After testing, the specific surface area of ​​the bulk nanoporous aluminum material prepared in this embodiment is 15.69m 2 / g

[0061] Example 4

[0062] The present invention provides a method for preparing a bulk nanoporous aluminum with a macroscopic size based on the phase separation principle, which is specifically implemented according to the following steps:

[0063] Step 1, preparing aluminum and zinc raw materials, wherein the weight proportion of aluminum raw materials is 22%;

[0064] Step 2, heating the aluminum and zinc raw materials prepared in step 1 to 740° C. to melt into an alloy ingot, and then heating the alloy ingot cooled to room temperature to 470° C. to hot-roll it into an alloy sheet with a thickness of 1.6 mm;

[0065] Step 3, heating the alloy sheet obtained in step 2 to 390° C. for solution treatment for 6 hours, water quenching after solution treatment, and placing the alloy sheet after water quenching in a drying oven at 80° C. for 8 hours for aging treatment;

[0066] Step 4, the alloy sheet obtained in step 3 is successively ground with 600 mesh, 1000 mesh, 2000 mesh, and 3000 mesh sandpaper, and then polished to obtain an alloy sheet with a thickness of 1.2 mm, and then the polished alloy sheet is placed in a sulfuric acid corrosion solution with a temperature of 5° C. and a concentration of 0.10 mol / L for corrosion for 27 hours to obtain a sample;

[0067] Step 5, wash the sample obtained after corrosion in step 4 in deionized water, then wash it with acetone, and then place it in a vacuum drying oven and evacuate it to -0.1MPa. After the acetone evaporates naturally, take out the sample and obtain a nanoporous aluminum block after vacuum storage.

[0068] After testing, the specific surface area of ​​the bulk nanoporous aluminum material prepared in this embodiment is 20.95m 2 / g.

Claims

1. A method for preparing a bulk nanoporous aluminum with a macroscopic size based on the phase separation principle, characterized in that: Follow the steps below to implement it: Step 1, preparing aluminum and zinc raw materials, wherein the weight proportion of aluminum raw materials is 17%-40%; Step 2, heating and smelting the aluminum and zinc raw materials prepared in step 1 into alloy ingots, and then hot-rolling the alloy ingots cooled to room temperature into alloy sheets; Step 3, subjecting the alloy sheet obtained in step 2 to a solution treatment, and then subjecting the alloy sheet to water quenching after the solution treatment, and placing the alloy sheet after the water quenching in a drying oven for aging treatment; Step 4, polishing the alloy sheet obtained in step 3 with sandpaper, and placing it in a corrosion solution for corrosion after polishing to obtain a sample; Step 5, wash the sample obtained after corrosion in step 4 in deionized water, then wash it with acetone, and then place it in a vacuum drying oven and evacuate it to -0.1MPa. After the acetone evaporates naturally, take out the sample and obtain a nanoporous aluminum block after vacuum storage.

2. The method for preparing a bulk nanoporous aluminum having a macroscopic size based on the phase separation principle according to claim 1, characterized in that: In step 1, the aluminum raw material is an industrial pure aluminum ingot or aluminum plate with a purity greater than 99.5%; the zinc raw material is an industrial pure zinc ingot with a purity greater than 99.5%.

3. The method for preparing a bulk nanoporous aluminum having a macroscopic size based on the phase separation principle according to claim 2, characterized in that: In the step 2, the smelting temperature is 720°C-750°C.

4. The method for preparing a bulk nanoporous aluminum having a macroscopic size based on the phase separation principle according to claim 3, characterized in that: In step 2, the hot rolling temperature of the alloy is 450° C.-480° C., and the thickness of the alloy sheet obtained by rolling is 1.1 mm-2.0 mm.

5. The method for preparing a bulk nanoporous aluminum with a macroscopic size based on the phase separation principle according to claim 4, characterized in that: In step 3, the solution temperature is 370° C.-400° C., and the solution time is 4 h-10 h; the alloy after solution is an atomically uniform single-phase Al solid solution, in which the Zn atoms are located at the lattice point position of the Al crystal.

6. The method for preparing bulk nanoporous aluminum with macroscopic size based on the phase separation principle according to claim 5, characterized in that: In step 3, the aging temperature is 50°C-150°C, and the aging time is 5h-10h; after aging, the Zn atoms dissolved in the alloy are completely dissolved from the Al crystals to form nanoscale and / or submicron-scale Zn phase grains and Al phase grains, and the Zn phase grains are interconnected, and the Al phase grains are also interconnected.

7. The method for preparing bulk nanoporous aluminum with macroscopic size based on the phase separation principle according to claim 6, characterized in that: In step 4, the sandpaper used for grinding is 600 mesh, 1000 mesh, 2000 mesh, and 3000 mesh sandpaper, respectively.

8. The method for preparing a bulk nanoporous aluminum with a macroscopic size based on the phase separation principle according to claim 7, characterized in that: In step 4, the thickness of the polished alloy sheet is 1.0 mm to 1.5 mm.

9. The method for preparing a bulk nanoporous aluminum with a macroscopic size based on the phase separation principle according to claim 8, characterized in that: In step 4, the temperature during corrosion is 0°C-25°C, and the reaction time is 24h-30h.

10. The method for preparing bulk nanoporous aluminum with macroscopic size based on the phase separation principle according to claim 9, characterized in that: In step 4, the corrosion solution is sulfuric acid with a concentration of 0.05 mol / L-0.5 mol / L.

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