CN106957972B - A kind of foamed aluminium radical hydrogen manufacturing material and preparation method thereof - Google Patents

Abstract

A foamed aluminum-based hydrogen production material and a preparation method thereof. Firstly, after the aluminum is completely melted, the temperature is lowered, and magnesium is immediately pressed into the melt; secondly, gallium, tin, indium or bismuth or 47 are sequentially added to the aluminum alloy melt any one of the low-melting-point alloys, stir evenly, remove the residue on the surface of the melt, let it stand still, so that the metal elements are fully alloyed and can be evenly distributed in the molten aluminum, and finally, lower the temperature and transfer to the aluminum alloy melt obtained in step 2 Add tackifier and stir, then add titanium hydride particles to make it evenly distributed, let it stand under a certain pressure, and cool it quickly to obtain a foamy aluminum alloy. The prepared foamy aluminum alloy can improve the reaction rate of aluminum water. The activity and reaction rate make the aluminum alloy and water react more completely, and have the characteristics of high hydrogen production efficiency and simple method.

Description

A kind of aluminum foam base hydrogen production material and preparation method thereof

technical field

The invention belongs to the technical field of new energy, and in particular relates to a foamed aluminum-based hydrogen production material and a preparation method thereof.

Background technique

Hydrogen has a heat of combustion three times higher than hydrocarbon fuels, and the product of its combustion in air is water. However, due to its low density and high activity, there are many problems in actual transportation and storage. At present, this problem has been successfully solved by in-situ hydrogen production by reacting metal and water. The metals used include hydrogen production materials based on Mg, Al, and Zn. Among them, because aluminum is rich in sources, cheap, and has the highest hydrogen production, and its reaction products are aluminum oxides and hydroxides, which are convenient for recycling.

The reason why pure aluminum does not react even in boiling water is that there is a dense oxide film on its surface, which prevents the contact between aluminum and water. Scholars from various countries have done a lot of research on this. In order to prevent the formation of an oxide film on the aluminum surface, around 1960 Woodall et al. discovered that an Al-Ga alloy could react with water under normal conditions. In 2005, Kravchenko et al. found that aluminum alloys were added Some low-melting point metals can produce amalgam phenomenon to prevent the formation of its oxide film, so that the alloy and water react, and some people are committed to using mechanical ball milling to improve the rate and output of aluminum water reaction. In 2012, Hu Xiaoyang et al prepared a water-reactive Al-Sn alloy foil (Hydrogen generation through rolling using Al-Sn alloy) by cold rolling method, but the method is complicated and the production equipment is expensive. In 2014, Chen Kai et al. A novel method to prepare Al-Ga alloy with intergranular penetrating is used to prepare Al-Ga alloy with intergranular penetrating by infiltrating gallium into the aluminum alloy grain boundary. This process needs to be carried out under a low-temperature protective atmosphere, and the hydrogen production rate is low.

Contents of the invention

In order to overcome the shortcomings of the above-mentioned prior art, the object of the present invention is to provide a foamed aluminum-based hydrogen production material and a preparation method thereof. The prepared foamed aluminum alloy can improve the activity and reaction rate of the aluminum water reaction, so that the aluminum alloy and The water reaction is relatively complete, and has the characteristics of high hydrogen production efficiency and simple method.

In order to achieve the above object, the technical scheme that the present invention takes is:

A foamed aluminum-based hydrogen production material, its raw material composition and its mass fraction are: aluminum 75-90%, magnesium 2-10%, gallium 2-4%, tin 3.5-7%, indium or bismuth or 47 degrees low melting point 0.5-2% of any alloy, 0.9-3.8% of tackifier, 1-4% of titanium hydride.

A method for preparing a foamed aluminum-based hydrogen production material, the steps of which are as follows:

Step 1: After completely melting aluminum with a mass fraction of 75-90%, lower the temperature to 710-730°C, and immediately press 2-10% magnesium into the melt;

Step 2: adding 2-4% gallium, 3.5-7% tin and 0.5-2% indium or bismuth or any one of 47-degree low-melting point alloys to the aluminum alloy melt in sequence, stirring evenly, Remove the residue on the surface of the molten aluminum and let it stand to make the metal elements fully alloyed and evenly distributed in the molten aluminum;

Step 3: Lower the temperature to 680-690°C, add 0.9-3.8% by mass fraction of tackifier to the aluminum alloy melt obtained in Step 2 and stir, then add 1-4% by mass fraction of hydrogenated Titanium particles make it evenly distributed, let stand under the pressure of 5-10MPa for 10 minutes, and cool to 50-100°C within 30 minutes.

The magnesium added in the step 1 is block.

The metal gallium, tin, indium or bismuth or the 47-degree low melting point alloy added in the second step are all block.

The resting temperature in the second step is 710-730° C., and the resting time is 10-20 min.

The stirring time of the second step is 5 min.

The thickener is calcium powder or magnesium powder.

The present invention adopts the melt foaming method to make foamed aluminum alloy. In the preparation process, titanium hydride (TiH ₂ ) is selected as the foaming agent, and calcium powder or magnesium powder is selected as the tackifier. CaO, CaAl ₂ O ₄ or Al ₄ Ca are formed in the aluminum, these compounds can increase the viscosity of the aluminum liquid, and the formed substances can play an activation role in the aluminum-water reaction, greatly improving the reaction between aluminum and water rate; by adding magnesium and low-melting point metals to increase the activity of aluminum, so that it can react with water at room temperature; the composition of the material is highly adjustable, the preparation method is simple and feasible, and the specific surface area of the foamed metal is Large, can greatly improve the reaction rate of aluminum water, according to the hydrogen production rate of the block aluminum alloy produced in general is 60-80mL/g·min, while the hydrogen production rate of the foamed aluminum produced by this method is 120mL/g·min, the production The hydrogen efficiency has been increased by 50%, which solves the problem of low hydrogen production rate at room temperature. It has the characteristics of high efficiency, simple, fast and portable hydrogen method, and can be applied to batteries, power vehicles and other fields.

Description of drawings

Figure 1 is a hydrogen production rate diagram of the reaction of 1.0 g of this foamed aluminum alloy in water at 50°C.

Fig. 2 is a BSE imaging diagram of the foamed aluminum alloy prepared in Example 1.

Fig. 3 is a microscopic scan diagram of the foamed aluminum alloy prepared in Example 1.

FIG. 4 is a partially enlarged view of point A in FIG. 3 .

Figure 5(a) is the energy spectrum of point c in Figure 4; Figure 5(b) is the energy spectrum of point d in Figure 4; Figure 5(c) is the energy spectrum of point e in Figure 4.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings and embodiments.

Embodiment one

Step 1: Place aluminum with a mass fraction of 84.1% in an electric furnace at 750°C. After it is completely melted, cool down to 715°C, and immediately press block magnesium with a mass fraction of 2% into the melt to prevent it from Surface combustion, considering the burning loss of magnesium at high temperature, the amount of magnesium added can be 1.1 times of the theoretical amount added;

Step 2: Add block-shaped gallium, 7% tin, and 1% indium in sequence to the aluminum alloy melt, stir evenly, remove residues generated on the surface of the melt, and stand at 710°C for 15 minutes. Stir for 5 minutes, so that the metal elements are fully alloyed and can be evenly distributed in the molten aluminum;

Step 3: Cool down to 685°C, add magnesium powder with a mass fraction of 0.9% to the aluminum alloy melt obtained in Step 2 and stir, then add titanium hydride particles with a mass fraction of 1% and a particle size of 20 μm, and stir rapidly after adding The distribution is uniform, and the titanium hydride is allowed to stand for 10 minutes under a pressure of 10 MPa to make the titanium hydride foam, and cooled to 80° C. within 30 minutes to obtain a foamed aluminum alloy.

It can be seen from FIG. 1 that the initial hydrogen production rate of the foamed aluminum alloy prepared in Example 1 is 120 mL/g·min, which is relatively high.

Figure 2 is the metallographic diagram of the obtained sample. It can be seen from the BSE imaging diagram that the white part in the diagram is the second phase composed of low melting point alloy. It can be seen that the second phase is evenly distributed and has a skeleton shape, which will promote the reaction Carry it out completely.

It can be seen from Figure 3 and Figure 4 that there are mainly two second phases in the figure, one is bright white point c phase, the other is dark white point d phase, and the matrix phase is dark gray phase.

It can be seen from Figure 5 that Figure 5(a) shows that the bright white second phase is Mg ₂ Sn intermetallic compound, Figure 5(b) shows that the gray-white second phase is gallium-rich phase, and Figure 5(c) It shows that the matrix phase is Al-Mg-Ga solid solution phase, and the surface is easily oxidized.

Embodiment two

Step 1: Place aluminum with a mass fraction of 82% in an electric furnace at 750°C. After it is completely melted, cool down to 710°C, and immediately press 3% block magnesium into the melt to prevent its Burning on the surface, considering the burning loss of magnesium at high temperature, the amount of magnesium added can be 1.1 times of the theoretical amount added;

Step 2: Add block-shaped gallium, 5% tin, and 2% bismuth in sequence to the aluminum alloy melt, stir evenly, remove residues generated on the surface of the melt, and stand at 730°C for 20 minutes. Stir for 5 minutes, so that the metal elements are fully alloyed and can be evenly distributed in the molten aluminum;

Step 3: Cool down to 690°C, add magnesium powder with a mass fraction of 2% to the aluminum alloy melt obtained in Step 2 and stir, then add titanium hydride particles with a mass fraction of 3% and a particle size of 20 μm, and stir rapidly after adding The distribution is uniform, and the titanium hydride is allowed to stand for 10 minutes under a pressure of 7 MPa to make the titanium hydride foam, and cooled to 100° C. within 30 minutes to obtain a foamed aluminum alloy.

Embodiment three

Step 1: Place aluminum with a mass fraction of 78.7% in an electric furnace at 750°C. After it is completely melted, cool down to 730°C, and immediately press 10% mass fraction of magnesium into the melt to prevent its Burning on the surface, considering the burning loss of magnesium at high temperature, the amount of magnesium added can be 1.1 times of the theoretical amount added;

Step 2: Add block-like gallium, 3.5% tin and 0.5% 47-degree low-melting-point alloy to the aluminum alloy melt in turn, stir evenly, remove the residue generated on the surface of the melt, and heat it at 720°C Stand still for 10 minutes, stir for 5 minutes, so that the metal elements are fully alloyed and can be evenly distributed in the molten aluminum;

Step 3: Cool down to 688°C, add calcium powder with a mass fraction of 3.8% to the aluminum alloy melt obtained in Step 2 and stir, then add titanium hydride particles with a mass fraction of 1.5% and a particle size of 20 μm, and stir rapidly after adding to make it distributed Evenly, stand under the pressure of 5MPa for 10 minutes to make the titanium hydride foam, and cool to 50°C within 30 minutes to obtain a foamy aluminum alloy.

Claims (7)

1. A foam aluminum-based hydrogen production material, characterized in that its raw material composition and its mass fraction are: aluminum 75-90%, magnesium 2-10%, gallium 2-4%, tin 3.5-7%, indium or 0.5-2% of bismuth or 47-degree low melting point alloy, 0.9-3.8% of tackifier, 1-4% of titanium hydride. 2. A preparation method for foamed aluminum-based hydrogen production material, characterized in that the steps are as follows: Step 1: After completely melting the aluminum with a mass fraction of 75-90%, lower the temperature to 710-730°C, and immediately press into the melt with a mass fraction of 2-10% magnesium; Step 2: adding 2-4% gallium, 3.5-7% tin and 0.5-2% indium or bismuth or any one of 47-degree low-melting point alloys to the aluminum alloy melt in sequence, stirring evenly, Remove the residue on the surface of the molten aluminum and let it stand to make the metal elements fully alloyed and evenly distributed in the molten aluminum; Step 3: Lower the temperature to 680-690°C, add 0.9-3.8% by mass fraction of tackifier to the aluminum alloy melt obtained in Step 2 and stir, then add 1-4% by mass fraction of hydrogenated Titanium particles make it evenly distributed, let stand under the pressure of 5-10MPa for 10 minutes, and cool to 50-100°C within 30 minutes. 3. The preparation method of a foamed aluminum-based hydrogen production material according to claim 2, wherein the magnesium added in the step 1 is block. 4. The preparation method of a foamed aluminum-based hydrogen production material according to claim 2, wherein the metal gallium, tin, indium or bismuth or the 47-degree low-melting point alloy added in the step 2 are all block . 5 . The preparation method of a foamed aluminum-based hydrogen production material according to claim 2 , characterized in that, the resting temperature in the second step is 710-730° C., and the resting time is 10-20 min. 6. The preparation method of a foamed aluminum-based hydrogen production material according to claim 2, characterized in that, the stirring time of the second step is 5 minutes. 7. The preparation method of a foamed aluminum-based hydrogen production material according to claim 2, wherein the tackifier is calcium powder or magnesium powder.