Preparation method of TiFe0. 8Mn0. 2 alloy doped nano magnesium solid block tablet material as well as product and application thereof

Abstract

The invention discloses a preparation method of a TiFe0. 8Mn0. 2 alloy doped nano magnesium solid block tablet material as well as a product and application of the TiFe0. 8Mn0. 2 alloy doped nano magnesium solid block tablet material. The material is prepared from TiFe < 0.8 > Mn < 0.2 > and 5 wt.% of nano magnesium. According to the invention, nano magnesium is added, so that the room temperature (25 DEG C) heat conductivity of the TiFe0. 8Mn0. 2 alloy solid block tablet can be greatly improved, the hydrogen absorption and desorption activation energy of the alloy is greatly reduced, and meanwhile, the hydrogen storage capacity of the alloy solid block tablet is effectively improved to 1.69 wt.% from 1.44 wt.% by doping the nano magnesium, and is improved by about 17.36%. Mg is added, so that the heat transfer problem is effectively solved, the formability of the alloy solid block tablet is improved, and meanwhile, a new thought is provided for application of the Ti-based hydrogen storage alloy.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid hydrogen storage materials, and particularly relates to a preparation method, product and application of a TiFe0.8Mn0.2 alloy doped with nano magnesium solid block tablet material. Background Art

[0002] Currently, the mainstream technologies for hydrogen storage include high-pressure gaseous hydrogen storage, liquid hydrogen storage, and solid hydrogen storage. In the field of solid hydrogen storage, the technology of metal hydrides formed by the combination of metals and hydrogen is regarded as one of the best safe solutions for storing hydrogen at room temperature and appropriate pressures due to its high volumetric hydrogen storage density and excellent reversibility. Its volumetric hydrogen storage density is similar to that of liquid hydrogen, perfectly meeting the hydrogen storage requirements in various energy utilization scenarios. Common solid hydrogen storage materials include intermetallic compounds such as AB, AB 2 、AB 5 type. The AB-type intermetallic compound TiFe can form compounds such as TiFeH and TiFeH 2 after hydrogen absorption, and can achieve a reversible mass hydrogen storage density of 1.86 wt.% at room temperature. In addition, due to the abundance and low cost of titanium and iron resources, it shows great potential in mobile fuel cell systems and large-scale fixed hydrogen storage systems.

[0003] However, TiFe-based alloys need to be activated, that is, heated above 670K under a hydrogen pressure of 3MPa to achieve complete initial hydrogen absorption. To improve its market applicability, it is crucial to optimize the activation and hydrogen absorption and desorption performance. For this reason, researchers have tried various optimization strategies, such as element doping, surface modification, high-pressure torsion, and mechanical alloying. Among them, element doping is particularly effective. The alloying research of Mn in TiFe alloys has been quite in-depth, and it is regarded as an ideal doping element.

[0004] In addition, when the hydrogen storage material is assembled into the tank, the thermal conductivity of the material and its solid block tablets also has an important impact on the hydrogen absorption and desorption performance. Temperature changes will change the equilibrium pressure, thereby affecting the hydrogen absorption kinetics. For example, if heat cannot be effectively discharged during the hydrogen absorption process, the temperature will rise, the hydrogen platform pressure will increase accordingly, and then the driving force for hydrogen absorption will be reduced. The hydrogen desorption process is also restricted by the thermal conductivity. Summary of the Invention

[0005] Object of the Invention: The technical problem to be solved by the present invention is to provide a preparation method of a TiFe 0.8 Mn 0.2 alloy doped with nano magnesium solid block tablet material.

[0006] The technical problem to be solved by the present invention is to provide a TiFe with high thermal conductivity, strong hydrogen storage performance and good formability prepared by the above method 0.8 Mn0.2 Alloy-doped nano magnesium solid block tablet material.

[0007] The technical problem to be finally solved by the present invention is to provide TiFe 0.8 Mn 0.2 The application of alloy-doped nano magnesium solid block tablet material in the preparation or as a hydrogen storage material.

[0008] Technical solution: To solve the above technical problems, the present invention provides a preparation method of TiFe 0.8 Mn 0.2 Alloy-doped nano magnesium solid block tablet material, including the following steps:

[0009] (1) Preparation of TiFe 0.8 Mn 0.2 Nano magnesium alloy powder: Uniformly mix and ball mill nano magnesium powder with TiFe 0.8 Mn 0.2 Alloy powder to obtain alloy powder;

[0010] (2) Preparation of TiFe 0.8 Mn 0.2 Nano magnesium solid block tablets: Load the alloy powder prepared in step (1) into a tablet press mold and press it with a powder press to obtain.

[0011] Among them, the preparation of TiFe 0.8 Mn 0.2 Alloy powder includes: Take alloy component elements Ti, Fe, Mn to prepare raw materials, place them in a vacuum induction melting furnace for melting to form a uniform alloy ingot, and then crush and grind it into powder with a mesh size of 100-200.

[0012] Among them, the particle size of the TiFe 0.8 Mn 0.2 Nano magnesium alloy powder in step (1) is 100-200 mesh.

[0013] Among them, the mass percentage of the nano magnesium powder in the alloy powder in step (1) is 1-10%, and preferably, the mass percentage of the nano magnesium powder in the alloy powder is 5%.

[0014] Among them, the ball milling conditions in step (1) are: the mass ratio of ball to material is 20:1, the ball milling process is a rotation speed of 400-500 revolutions per minute, pause for 6 minutes after forward ball milling for 30 minutes, and then reverse ball milling for 30 minutes, and the total time is 66 minutes.

[0015] Among them, the pressure applied by the powder press in step (2) is 10 MPa - 20 Mpa, and the pressure holding time is 1-5 minutes.

[0016] Among them, the pressure applied by the powder press in step (2) is 10 MPa to 15 MPa, and the pressure holding time is 1 to 5 minutes.

[0017] The content of the present invention further includes TiFe 0.8 Mn 0.2 alloy-doped nano-magnesium solid block tablet material.

[0018] Among them, the TiFe 0.8 Mn 0.2 The thermal conductivity of the alloy-doped nano-magnesium solid block tablet material is 2 to 10 W·(m·K) -1 As a preference, the thermal conductivity of the TiFe 0.8 Mn 0.2 alloy-doped nano-magnesium solid block tablet material is 7.058 W·(m·K) -1 .

[0019] The content of the present invention further includes the application of the TiFe 0.8 Mn 0.2 alloy-doped nano-magnesium solid block tablet material in the preparation of hydrogen storage materials.

[0020] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0021] (1) The thermal conductivity of the TiFe 0.8 Mn 0.2 alloy-doped nano-magnesium solid block tablet material of the present invention at room temperature (25 °C) is as high as 7.058 W·(m·K) -1 , compared with the TiFe 0.8 Mn 0.2 alloy solid block tablet of 0.984 W·(m·K) -1 has achieved a substantial increase.

[0022] (2) The hydrogen absorption activation energy of the TiFe 0.8 Mn 0.2 alloy-doped nano-magnesium solid block tablet material of the present invention is -8.1 kJ·mol -1 , and the hydrogen desorption activation energy is 14.9 kJ·mol -1 , compared with the hydrogen absorption and desorption activation energies of the TiFe 0.8 Mn 0.2 alloy solid block tablet, which are -27.5 kJ·mol -1 and 30.9 kJ·mol -1 respectively, has achieved a substantial reduction.

[0023] (3) The TiFe 0.8 Mn 0.2The hydrogen storage capacity of the alloy-doped nano magnesium solid block tablet material has been increased to 1.69 wt.%, compared with 1.44 wt.% of the TiFe 0.8 Mn 0.2 alloy solid block tablet, an increase of about 17.36%.

[0024] In summary, the addition of nano magnesium in the present invention not only effectively solves the heat transfer problem and improves the formability of the alloy solid block tablet, but also provides a new idea for the application of Ti-based hydrogen storage alloys. Description of the Drawings

[0025] Figure 1 For TiFe 0.8 Mn 0.2 and TiFe 0.8 Mn 0.2 -5 wt.% nano magnesium XRD and TEM diagrams;

[0026] Figure 2 For TiFe 0.8 Mn 0.2 Alloy solid block tablet thermal conductivity vs. molding pressure diagram;

[0027] Figure 3 For TiFe 0.8 Mn 0.2 Alloy solid block tablet diagrams at different molding pressures;

[0028] Figure 4 For the effect of different element doping on the thermal conductivity of TiFe 0.8 Mn 0.2 Alloy solid block tablet;

[0029] Figure 5 For TiFe 0.8 Mn 0.2 and TiFe 0.8 Mn 0.2 -5 wt.% nano magnesium isothermal hydrogen absorption and desorption curves;

[0030] Figure 6 For TiFe 0.8 Mn 0.2 and TiFe 0.8 Mn 0.2 -5 wt.% nano magnesium hydrogen absorption and desorption activation energy diagram;

[0031] Figure 7 For TiFe 0.8 Mn 0.2 and TiFe 0.8 Mn 0.2 -5 wt.% nano magnesium compressive strength comparison diagram. Detailed Embodiments

[0032] The present invention will be further described in detail below.

[0033] Example 1 TiFe 0.8 Mn 0.2 Preparation and Characterization of Alloy Solid Block Tablets

[0034] This example studied the variation of the thermal conductivity of TiFe 0.8 Mn 0.2 alloy solid block tablets with the molding pressure.

[0035] 1. Take alloy component elements Ti, Fe, and Mn to prepare TiFe 0.8 Mn 0.2 alloy raw materials, place them in a vacuum induction melting furnace for melting to form a uniform alloy ingot, and then crush and grind it into TiFe 0.8 Mn 0.2 alloy powder with a mesh size of 100 - 200.

[0036] 2. Take 1 g of TiFe 0.8 Mn 0.2 alloy powder, uniformly mix it in a glove box, load it into a 100 - ml ball - milling jar, and use the QM - 3SP2S all - around planetary ball mill from Nanjing University Instrument Factory for ball milling. The mass ratio of balls to materials is 20:1, the ball - milling process is a rotation speed of 400 - 500 revolutions per minute, pause for 6 minutes after forward ball - milling for 30 minutes, and then reverse ball - milling for 30 minutes, with a total time of 66 minutes. Then scrape out the ball - milled alloy powder, take 0.8 g - 1 g of the powder and load it into a 12.7 - mm circular tablet - pressing mold, and apply pressures of 10 MPa, 15 MPa, and 20 MPa respectively on a HYP - 15 powder tablet press for molding.

[0037] 3. Place the TiFe 0.8 Mn 0.2 alloy solid block tablets prepared under 3 different pressures in a flash - method thermal conductivity meter (LFA467, NETZSCH) to measure the thermal conductivity of the alloy solid block tablets. The test temperature range is 25 °C - 100 °C, the heating rate is 5 - 20 K·min -1 , the laser voltage is 250 V, and the pulse width is 0.60 milliseconds. High - purity argon gas is used as a protective atmosphere during the test to prevent sample oxidation. The XRD and TEM diagrams of TiFe 0.8 Mn 0.2 alloy powder are shown in Figure 1 .

[0038] Figure 2 For TiFe 0.8 Mn 0.2Variation diagram of the thermal conductivity of the alloy solid block tablets with the molding pressure. It can be seen that as the temperature increases, the thermal conductivity continuously increases; and as the molding pressure increases, the thermal conductivity also continuously increases. When the molding pressure is 20 MPa, the thermal conductivity of the sample is the largest, reaching 1.326 W·(m·K) at 373 K -1 。 Figure 3 TiFe 0.8 Mn 0.2 Alloy solid block tablets under different molding pressures. It can be seen that when the molding pressure is 20 MPa, the formability of the sample is poor and cracks are prone to appear at the edges. Therefore, 15 MPa is selected as the molding pressure.

[0039] Example 2 Influence of different element doping on TiFe 0.8 Mn 0.2 Alloy solid block tablets

[0040] This example studies the influence of different element doping on the thermal conductivity of TiFe 0.8 Mn 0.2 Alloy solid block tablets.

[0041] 1. Add 5 wt.% of other elements (Mg, nano-Mg, Cu, Al, Zn or C powder) to the TiFe 0.8 Mn 0.2 Alloy powder, mix evenly in a glove box and load it into a 100 ml ball milling jar, and use the QM-3SP2S all-round planetary ball mill of Nanjing University Instrument Factory for ball milling. Among them, the ball-to-material mass ratio is 20:1, the ball milling process is a rotation speed of 400 - 500 revolutions per minute, forward ball milling for 30 minutes and then pausing for 6 minutes, and then reverse ball milling for 30 minutes, with a total time of 66 minutes. Among them, the XRD and TEM diagrams of TiFe 0.8 Mn 0.2 and TiFe 0.8 Mn 0.2 -5 wt.% nano-Mg alloy powder are shown in Figure 1 。Among them Figure 1 a is the XRD diagram of TiFe 0.8 Mn 0.2 and TiFe 0.8 Mn 0.2 -5 wt.% nano-Mg; Figure 1 b is the TEM diagram of TiFe 0.8 Mn 0.2 -5 wt.% nano-Mg, and the inset is its selected area electron diffraction pattern; Figure 1 c is the HRTEM diagram of TiFe 0.8 Mn 0.2 -5 wt.% nano-Mg, and the corresponding inset (marked by a solid circle) is the enlarged selected area (marked by a dashed circle); Figure 1d is TiFe 0.8 Mn 0.2 HRTEM images of TiFeMn with -5 wt.% nano-Mg, and the corresponding inset is the magnified selected area. From Figure 1 it can be seen that the crystal structure of TiFeMn remains the same as that of TiFe, and the addition of Mg does not change the crystal structure. However, the interplanar spacing and unit cell parameters will increase, which helps to improve the hydrogen absorption capacity and rate.

[0042] 2. Subsequently, scrape out the ball-milled alloy powder, and take 0.5 - 1 g of the powder and put it into a 12.7-mm circular tablet die, and apply a pressure of 15 MPa on the HYP-15 powder press to form tablets.

[0043] 3. Place the prepared TiFe 0.8 Mn 0.2 alloy solid tablets doped with different elements in a laser flash thermal conductivity analyzer (LFA467, NETZSCH) to measure the thermal conductivity of the alloy solid tablets. The test temperature range is 25°C to 100°C, the heating rate is 10 K·min -1 , the laser voltage is 250 V, and the pulse width is 0.60 ms. High-purity argon gas is used as the protective atmosphere during the test to prevent the sample from oxidation.

[0044] Figure 4 Figure showing the effect of different element doping on the thermal conductivity of TiFe 0.8 Mn 0.2 alloy solid tablets. It can be seen that among a series of elements, the addition of Mg can effectively improve the thermal conductivity of the hydrogen storage material. In addition, comparing TiFe 0.8 Mn 0.2 alloys added with 5 wt.% ordinary magnesium powder and nano-magnesium powder, the smaller the particle size of the magnesium powder, the greater the thermal conductivity.

[0045] Example 3 Hydrogen absorption and desorption properties of TiFe 0.8 Mn 0.2 and TiFe 0.8 Mn 0.2 -5 wt.% nano-magnesium alloy solid tablets

[0046] This example studies the hydrogen absorption and desorption properties of TiFe 0.8 Mn 0.2 and TiFe 0.8 Mn 0.2 -5 wt.% nano-magnesium alloy solid tablets.

[0047] 1. Take 1 g of TiFe 0.8 Mn 0.2 alloy powder and 1 g of TiFe 0.8 Mn 0.2-5 wt.% nano-magnesium powder (0.95 g TiFe 0.8 Mn 0.2 + 0.05 g nano-magnesium) was separately loaded into two 100 ml ball milling jars in a glove box and ball milled using a QM-3SP2S all-round planetary ball mill from Nanjing University Instrument Factory. The mass ratio of balls to materials was 20:1, and the ball milling process was a rotational speed of 400 - 500 revolutions per minute. After ball milling forward for 30 minutes, it was paused for 6 minutes, and then ball milled backward for 30 minutes, with a total time of 66 minutes. Subsequently, the ball milled alloy powder was scraped out, and 0.75 g of the powder was separately loaded into a 10.0 mm circular tablet pressing die and formed under a pressure of 15 MPa on a HYP-15 powder tablet press. Subsequently, the hydrogen storage performance test of the alloy solid block tablets was carried out on a Sievert-type gas-solid reaction test device developed by the New Energy Materials and Technology Laboratory of Yangzhou University. The temperatures for the isothermal hydrogen absorption and desorption kinetic performance tests were 30 °C, 50 °C, and 70 °C respectively, the hydrogen absorption test pressure was 3.5 MPa, and the hydrogen desorption test pressure was 0.01 MPa.

[0048] Figure 5 is TiFe 0.8 Mn 0.2 and TiFe 0.8 Mn 0.2 -5 wt.% nano-magnesium isothermal hydrogen absorption and desorption curve graphs. It can be seen that in the temperature range of 30 - 70 °C, the saturated hydrogen absorption amounts of both at a hydrogen pressure of 3.5 MPa increase with the decrease of temperature, and the saturated hydrogen absorption amount reaches the highest at 30 °C, being 1.44 wt.% and 1.69 wt.% respectively. Compared with the pure TiFe 0.8 Mn 0.2 alloy solid block tablets, the saturated hydrogen absorption amounts of the TiFe 0.8 Mn 0.2 alloy solid block tablets doped with nano-magnesium have increased at each experimental temperature, and the hydrogen absorption and desorption rates have both increased. Figure 6 is TiFe 0.8 Mn 0.2 and TiFe 0.8 Mn 0.2 -5 wt.% nano-magnesium hydrogen absorption and desorption data fitting graph and the calculated hydrogen absorption and desorption activation energy graph. It can be seen that after doping with nano-magnesium, the activation energy of the TiFe 0.8 Mn 0.2 alloy has decreased significantly. The hydrogen absorption activation energy has decreased by 19.4 kJ·mol -1 . The dehydrogenation activation energy has decreased by 16 kJ·mol -1 . In terms of improving the kinetic performance of the TiFe 0.8 Mn 0.2 alloy, the addition of nano-magnesium can effectively reduce the TiFe 0.8 Mn 0.2The energy barrier of the alloy and the reduction in the activation energies of hydrogen absorption and dehydrogenation can be attributed to the significant increase in the thermal conductivity of the entire system after doping with nano magnesium.

[0049] Example 4 TiFe 0.8 Mn 0.2 and TiFe 0.8 Mn 0.2 Compressive strength of the TiFe

[0050] This example studied the TiFe 0.8 Mn 0.2 and TiFe 0.8 Mn 0.2 -5wt.% nano magnesium alloy solid block tablets in terms of compressive strength.

[0051] Weigh out 1.8 g of the ball-milled TiFe 0.8 Mn 0.2 and TiFe 0.8 Mn 0.2 -5wt.% nano magnesium alloy powders, load them into a 12.7 mm circular tablet press die, and apply a pressure of 15 MPa on a HYP-15 powder tablet press to form tablets. Place the two alloy solid block tablets obtained separately on an electronic universal testing machine (Instron 5982) and conduct compressive strength tests at a compression rate of 1 mm / min.

[0052] Figure 7 For the comparison chart of the compressive strength of TiFe 0.8 Mn 0.2 and TiFe 0.8 Mn 0.2 -5wt.% nano magnesium, it can be seen that after doping with nano magnesium, the elastic modulus of the TiFe 0.8 Mn 0.2 alloy solid block tablets increased from the original 1169.524 MPa to 1983.135 MPa, indicating that its plasticity became significantly worse and the strength increased.

Claims

1. A TiFe 0.8 Mn 0.2 The method for preparing alloy-doped nano-magnesium solid block tablet material is characterized by: The following steps are involved: (1) TiFe 0.8 Mn 0.2 Preparation of nano magnesium alloy powder: Nano magnesium powder and TiFe 0.8 Mn 0.2 The alloy powders are uniformly mixed and ball-milled to obtain alloy powders; (2) TiFe 0.8 Mn 0.2 Preparation of nano-magnesium solid block tablets: The alloy powder prepared in step (1) is loaded into a tablet pressing mold and tableted using a powder tablet press.

2. TiFe according to claim 1 0.8 Mn 0.2 The method for preparing alloy-doped nano-magnesium solid block tablet material is characterized by: The TiFe 0.8 Mn 0.2 The preparation of alloy powder includes: preparing raw materials with alloy component elements Ti, Fe and Mn, placing them in a vacuum induction melting furnace for melting to form a uniform alloy ingot, and then crushing and grinding them into powders of 100-200 meshes.

3. TiFe according to claim 1 0.8 Mn 0.2 The method for preparing alloy-doped nano-magnesium solid block tablet material is characterized by: The TiFe 0.8 Mn 0.2 The particle size of nano magnesium alloy powder is 100~200 mesh.

4. TiFe according to claim 1 0.8 Mn 0.2 The method for preparing alloy-doped nano-magnesium solid block tablet material is characterized by: The mass percentage of the nano magnesium powder in step (1) to the alloy powder is 1-10%.

5. TiFe according to claim 1 0.8 Mn 0.2 The method for preparing alloy-doped nano-magnesium solid block tablet material is characterized by: The ball milling conditions in step (1) are as follows: the ball-to-material mass ratio is 1:1-100:1, the ball milling process is a rotation speed of 400-500 rpm, forward ball milling for 10-60 minutes, followed by a 6-minute pause, and then reverse ball milling for 10-60 minutes, for a total time of 66 minutes.

6. TiFe according to claim 1 0.8 Mn 0.2 The method for preparing alloy-doped nano-magnesium solid block tablet material is characterized by: The powder tablet press in step (2) applies a pressure of 10 MPa to 20 MPa, and the pressure holding time is 1 to 5 minutes.

7. The TiFe according to claim 1 0.8 Mn 0.2 The method for preparing alloy-doped nano-magnesium solid block tablet material is characterized by: The powder tablet press in step (2) applies a pressure of 10 MPa to 15 MPa, and the pressure holding time is 1 to 5 minutes.

8. TiFe prepared by the method according to any one of claims 1 to 6 0.8 Mn 0.2 Alloy doped nano-magnesium solid block tablet material.

9. TiFe according to claim 8 0.8 Mn 0.2 Alloy doped nano magnesium solid block tablet material, characterized in that: The TiFe 0.8 Mn 0.2 The thermal conductivity of alloy-doped nano-magnesium solid block tablet material is 2~10 W∙(m·K) -1 .

10. The TiFe according to claim 8 0.8 Mn 0.2 Application of alloy-doped nano-magnesium solid block tablet materials in the preparation of hydrogen storage materials.

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