An easily activated Ti-Fe-Ce-Mn-Zr-Al-Co-based hydrogen storage alloy and a preparation method thereof
By adding Ce, Mn, Zr, Al, and Co elements to TiFe alloy and subjecting it to short-time ball milling, nanocrystalline and multiphase structures are formed, solving the problem of TiFe alloy's difficulty in activation at room temperature. This significantly improves its activation performance and hydrogen absorption/desorption performance, making it suitable as a hydrogen storage material for fuel cell vehicles.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA IRON & STEEL RESEARCH INSTITUTE GROUP CO LTD
- Filing Date
- 2025-03-17
- Publication Date
- 2026-07-10
AI Technical Summary
Existing TiFe hydrogen storage alloys are difficult to activate at room temperature, have long activation cycles, and exhibit poor hydrogen absorption and desorption performance.
By adding Ce, Mn, Zr, Al and Co elements to TiFe alloy and combining it with short-time ball milling, nanocrystalline and multiphase structures are formed, generating a large number of grain boundaries and phase boundary defects, providing a fast channel for hydrogen diffusion, and optimizing the alloy composition to improve activation performance.
Rapid activation of Ti-Fe-Ce-Mn-Zr-Al-Co based hydrogen storage alloys under low activation conditions at room temperature was achieved, significantly improving hydrogen absorption and desorption performance, and demonstrating excellent hydrogen storage capacity and plateau pressure, making them suitable for use as hydrogen storage materials in fuel cell vehicles.
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Figure CN120249772B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of hydrogen storage alloy materials technology, and to a Ti-Fe-Mn-Zr-Al-Co based hydrogen storage alloy and its preparation method, particularly to an easily activated Ti-Fe-Mn-Zr-Al-Co based hydrogen storage alloy and its preparation method. Background Technology
[0002] In recent years, fuel cell vehicles (FCVs) fueled by hydrogen have been considered a feasible technology for addressing the environmental and energy problems caused by the excessive consumption of fossil fuels. Currently, lightweight high-pressure hydrogen storage tanks (35 MPa) are one of the main technologies for on-board hydrogen storage in fuel cell vehicles. On the other hand, hydrogen fuel cells require high-purity hydrogen. Therefore, developing efficient hydrogen purification and compression technologies is of great significance. It is well known that hydrogen storage alloys have the dual functions of purifying and compressing hydrogen. Therefore, metal hydride hydrogen compressors (MHHCs) have many advantages compared to traditional compressors. For example, they integrate compression and purification functions, cover a wide pressure range, allow quiet operating conditions, and promote the utilization of low-grade energy. For metal hydride hydrogen compressors, it is desirable for the hydrogen storage alloy to have a large hydrogen storage capacity, good pressure plateau characteristics, and good activation and kinetic characteristics. Most of the hydrogen storage alloys reported in the literature use AB5 type alloys.
[0003] Among all solid-state hydrogen storage materials, TiFe alloys possess advantages such as high capacity, ability to absorb and desorb hydrogen at room temperature, low cost, and abundant resources, making them the most attractive and promising candidate material for hydrogen storage. Therefore, numerous researchers both domestically and internationally have conducted systematic studies on their hydrogen absorption performance.
[0004] To date, existing TiFe hydrogen storage alloys generally suffer from problems such as high activation requirements (i.e., difficulty in activation at room temperature), long activation cycles, and poor hydrogen absorption and desorption performance. Summary of the Invention
[0005] In view of the above analysis, the present invention aims to provide an easily activated Ti-Fe-Ce-Mn-Zr-Al-Co based hydrogen storage alloy and its preparation method, so as to solve at least one of the problems of existing TiFe hydrogen storage alloys, such as high activation conditions (i.e., difficult to activate at room temperature), long activation cycle, and poor hydrogen absorption and desorption performance.
[0006] This invention discloses a Ti-Fe-Ce-Mn-Zr-Al-Co based hydrogen storage alloy, wherein the alloy is specifically composed of Ti 1.05 Ce 0.05 Fe 1.15-x-y-z-m Mn x Zr y Al z Co m, where x, y, z, and m are atomic ratios, and 0.1≤x≤0.25, 0.05≤y≤0.2, 0.02≤z≤0.1, and 0.02≤m≤0.1.
[0007] Preferably, the ratio of x, y, z, m is x:y:z:m = 0.15:0.1:0.05:0.05.
[0008] Specifically, the hydrogen storage alloy has a nanocrystalline structure with an average grain size of 50–200 nm and contains grain boundary and phase boundary defects.
[0009] Specifically, the hydrogen storage alloy has a multiphase structure containing TiFe phase, ZrMn2 phase, CeCo2 phase and Al4Mn phase.
[0010] The present invention also provides a method for preparing the hydrogen storage alloy, specifically comprising the following steps:
[0011] S1: The dosage is calculated according to the chemical formula composition and the ingredients are prepared, with appropriate amounts of Mn and Ce added for loss on ignition.
[0012] S2: Place the prepared raw materials in a zirconia crucible, cover the furnace, heat the raw materials to a molten state and keep them at that temperature for a period of time, then pour the liquid alloy into a copper casting mold to obtain a master alloy ingot.
[0013] S3: The master alloy ingot is mechanically crushed and sieved. The sieved alloy powder is then ball-milled to obtain the finished hydrogen storage alloy powder.
[0014] Furthermore, in step S1, the amount of Mn and Ce added is 8% to 10% of the calculated dosage.
[0015] Furthermore, the order and specific operation of placing each raw material in step S2 are as follows: the pure iron rod is placed vertically along the crucible wall, and the order of adding other metal raw materials is as follows: blocky rare earth Ce is placed at the bottom of the crucible, sponge Ti and Zr are placed above rare earth Ce, metal Co is placed on sponge Ti and Zr, electrolytic Mn is placed on metal Co, and electrolytic Al is placed on top.
[0016] Furthermore, the specific operation of raw material melting in step S2 is as follows: vacuuming to 1×10 -2 ~5×10 -5 After Pa, pure argon gas at a pressure of 0.01–0.1 MPa is introduced as a protective gas, and the melting temperature is 1550–1650℃ and held for 3–5 minutes.
[0017] Furthermore, the sieving operation in step S3 involves passing the mechanically crushed alloy fragments through a 200-mesh sieve to obtain alloy powder with a diameter ≤75μm, followed by ball milling.
[0018] Furthermore, the ball milling operation in step S3 is as follows: the alloy powder and stainless steel grinding balls are loaded into a stainless steel ball milling jar, vacuumed and then filled with high-purity argon gas, and ball milled in an all-round planetary high-energy ball mill for 0.5 to 2 hours, with a ball-to-material ratio of 1:18 to 22 and a rotation speed of 300 to 400 rpm.
[0019] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:
[0020] 1. The Ti-Fe-Ce-Mn-Zr-Al-Co based hydrogen storage alloy provided by this invention has low activation conditions, short activation cycle, and good hydrogen absorption and desorption performance.
[0021] This invention combines chemical modification (formula optimization) and microstructure improvement (smelting + short-time ball milling). First, transition elements Ce, Mn, Zr, Al, and Co are added to the TiFe alloy, with an excess of Ti. This causes the formation of α-Ti or β-Ti phases alongside the TiFe phase, significantly reducing the fracture toughness of the TiFe alloy and generating numerous grain boundaries and phase boundaries, providing a rapid pathway for hydrogen diffusion. Multi-element alloying significantly improves the activation performance of the TiFe alloy. In particular, the addition of a small amount of rare earth Ce can significantly improve the alloy's activation performance while maintaining hydrogen absorption capacity, and significantly shorten the incubation time during alloy activation. This is because rare earth elements readily form rare earth hydrides CeH with hydrogen atoms. 2.73 Ti and Mn substitution of Fe leads to an increase in the TiFe phase cell volume, improving the alloy's hysteresis, reducing plateau pressure, and enhancing activation performance. The addition of Zr significantly improves the activation performance and plateau characteristics of the TiFe alloy. The addition of Al introduces more defects into the lattice. Room-temperature activation performance is influenced by the reactivity between hydrogen molecules and the surface oxide layer, and hydrogen reactivity varies depending on the composition of the oxide layer. Co substitution of Fe alters the composition of the surface oxide layer, which is beneficial for alloy activation at room temperature.
[0022] Then, the as-cast sample was ball-milled for a short time to improve its microstructure, overcome the drawbacks of Ti-Fe based hydrogen storage alloys, and retain its advantages, resulting in a significant improvement in the overall performance of the novel hydrogen storage alloy. Mechanical ball milling significantly reduced the grain size of the alloy and formed a large number of crystal defects, increasing the nucleation sites and diffusion channels for hydrogen, further reducing the thermal stability of the hydride and improving the hydrogen absorption and desorption kinetics of the alloy.
[0023] The Ti-Fe-Ce-Mn-Zr-Al-Co based hydrogen storage alloy provided by this invention exhibits excellent activation and hydrogen absorption / desorption performance, with a hydrogen storage capacity ≥1.70 wt.%, a hydrogen absorption plateau pressure ≥0.41 MPa, and a hydrogen desorption plateau pressure ≥0.31 MPa. Activation can be completed in a single step at 30°C and 3 MPa.
[0024] 2. The hydrogen storage alloy provided by this invention has a multiphase structure, including not only the main TiFe phase, but also intermetallic compounds such as ZrMn2 phase, CeCo2 phase, and Al4Mn phase (see...). Figure 1 and Figure 3 In this alloy, Zr and Mn can form the ZrMn2 phase, Ce and Co can form the CeCo2 phase, and Al and Mn can form the Al4Mn phase. These intermetallic compounds significantly improve the activation ability and hydrogen storage capacity of the alloy. The ratio of each phase is TiFe:ZrMn2:CeCo2:Al4Mn = 0.75~0.85:0.06~0.08:0.02~0.03:0.01~0.015. The ZrMn2 phase can combine with hydrogen to form ZrMn2H3, increasing the hydrogen storage capacity of the alloy; the CeCo2 phase can inhibit the formation of Ti2Fe and TiFe2 phases; and the Al4Mn phase can generate more defects, providing channels for hydrogen entry.
[0025] In addition, thanks to the unique composition design of the alloy, the polycrystalline structure formed by multiple elements results in a high defect density in the alloy, providing a fast channel for hydrogen diffusion and reducing the conditions for hydrogen absorption and desorption reactions.
[0026] 3. The hydrogen storage alloy preparation method provided by this invention has a simple process flow, readily available raw materials and equipment, relatively mild process conditions, and low operational difficulty, making it suitable for large-scale production and widespread application. Furthermore, the preparation method provided by this invention, through optimization of process parameters and specific operations, can better introduce crystal defects into the hydrogen storage alloy, increasing hydrogen nucleation sites and diffusion channels; and significantly improve the surface state of the alloy, further reducing the alloy's thermal stability and improving its hydrogen absorption and desorption kinetics.
[0027] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description
[0028] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.
[0029] Figure 1 The XRD diffraction patterns of the as-cast alloys in Examples 1-6 are shown below.
[0030] Figure 2 The images show the SEM morphology of the ball-milled alloy powders in Examples 1-6.
[0031] Figure 3 The XRD patterns of the ball-milled alloy powders in Examples 1-6 are shown below.
[0032] Figure 4 The images show the HRTEM morphology of the ball-milled alloys in Examples 1-6 (red lines indicate the locations of lattice defects). Detailed Implementation
[0033] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.
[0034] This invention discloses a Ti-Fe-Ce-Mn-Zr-Al-Co based hydrogen storage alloy, wherein the alloy is specifically composed of Ti 1.05 Ce 0.05 Fe 1.15-x-y-z-m Mn x Zr y Al z Co m , where x, y, z, and m are atomic ratios, and 0.1≤x≤0.25, 0.05≤y≤0.2, 0.02≤z≤0.1, and 0.02≤m≤0.1.
[0035] The roles, contents, and atomic ratios of each component / element are determined based on the following:
[0036] Ti, Fe: In TiFe alloys, the mass ratio of Ti to Fe significantly affects the hydrogen storage performance. When the Ti content is less than 49.5%, an iron-rich TiFe2 phase forms simultaneously with the TiFe phase. The TiFe2 phase does not absorb hydrogen, resulting in a significantly lower hydrogen storage capacity for iron-rich TiFe-based hydrogen storage alloys. When the Ti content is between 49.5% and 52.5%, a uniform TiFe phase forms. When the Ti content is greater than 52.5%, an α-Ti or β-Ti phase forms simultaneously with the TiFe phase. α-Ti or β-Ti reacts with hydrogen to form titanium hydrides such as TiH and TiH2. Therefore, Ti-rich alloys exhibit significantly higher hydrogen storage capacity during initial activation. However, titanium hydrides are difficult to decompose at low temperatures, resulting in a significantly lower stable hydrogen absorption capacity during cyclic hydrogen absorption and desorption at room temperature compared to the initial activation. Furthermore, the presence of the α-Ti or β-Ti phase significantly reduces the fracture toughness of the TiFe alloy, causing the sample to crack more quickly in a hydrogen atmosphere. These cracks provide an interface for the nucleation and growth of hydrides, thus significantly improving the activation properties of TiFe alloys.
[0037] Ce: Multi-element alloying can significantly improve the activation performance of TiFe alloys. In particular, the addition of a small amount of rare earth Ce can significantly improve the activation performance of the alloy while maintaining the hydrogen absorption capacity, and significantly shorten the incubation time during alloy activation. This is because rare earth elements readily form rare earth hydrides CeH with hydrogen atoms. 2.73 , thus becoming the catalytic active center of the alloy;
[0038] Mn: The substitution of Fe by Ti and Mn leads to an increase in the cell volume of the TiFe phase. This improves the hysteresis of the alloy, reduces the plateau pressure, and enhances activation performance;
[0039] Zr: The addition of Zr significantly improved the activation performance and plateau characteristics of TiFe alloys;
[0040] Al: The addition of Al can generate more defects in the lattice; the room temperature activation performance is affected by the reactivity between hydrogen molecules and the surface oxide layer, and the hydrogen reactivity varies depending on the composition of the oxide layer;
[0041] Co: Co substitution for Fe alters the composition of the surface oxide layer, which is beneficial for the activation of the alloy at room temperature.
[0042] This invention combines chemical modification (formula optimization) and microstructure improvement (melting + short-time ball milling). First, transition elements Ce, Mn, Zr, Al, and Co are added to the TiFe alloy, along with an excess of Ti. This causes the formation of α-Ti or β-Ti phases along with the TiFe phase, significantly reducing the fracture toughness of the TiFe alloy and generating numerous grain boundaries, phase boundaries, and other defects, thus providing a rapid pathway for hydrogen diffusion.
[0043] After comparing the activation performance and kinetic properties of alloy materials with a series of parameters, the optimal ratio of x, y, z, m was determined to be x:y:z:m = 0.15:0.1:0.05:0.05.
[0044] Specifically, the hydrogen storage alloy has a nanocrystalline structure with an average grain size of 50–200 nm, and exhibits grain boundary and phase boundary defects. Figure 4 (The red dashed lines in the middle indicate the locations of lattice defects). The presence of a large number of nanocrystals and crystal defects can effectively suppress grain growth during hydrogen absorption and desorption, provide a fast channel for hydrogen diffusion, and provide nucleation sites for hydrogen absorption and desorption reactions, thereby improving the activation performance and hydrogen absorption and desorption kinetics of the alloy.
[0045] The hydrogen storage alloy provided by this invention has a multiphase structure, including not only the main TiFe phase, but also intermetallic compounds such as ZrMn2 phase, CeCo2 phase, and Al4Mn phase (see [link to related documentation]). Figure 1 and Figure 3 In this alloy, Zr and Mn can form the ZrMn2 phase, Ce and Co can form the CeCo2 phase, and Al and Mn can form the Al4Mn phase. These intermetallic compounds significantly improve the activation ability and hydrogen storage capacity of the alloy. The ratio of each phase is TiFe:ZrMn2:CeCo2:Al4Mn = 0.75~0.85:0.06~0.08:0.02~0.03:0.01~0.015. The ZrMn2 phase can combine with hydrogen to form ZrMn2H3, increasing the hydrogen storage capacity of the alloy; the CeCo2 phase can inhibit the formation of Ti2Fe and TiFe2 phases; and the Al4Mn phase can generate more defects, providing channels for hydrogen entry.
[0046] Specifically, the Ti-Fe-Ce-Mn-Zr-Al-Co based hydrogen storage alloy provided by this invention has good activation performance and hydrogen absorption and desorption performance, with a hydrogen storage capacity ≥1.70wt.%, a hydrogen absorption plateau pressure ≥0.41MPa, and a hydrogen desorption plateau pressure ≥0.31MPa. It can be activated in one step at 30℃ and 3MPa, and can be widely used as a solid hydrogen storage material in hydrogen fuel cells and other scenarios.
[0047] The present invention also provides a method for preparing the hydrogen storage alloy, specifically comprising the following steps:
[0048] S1: The dosage is calculated according to the chemical formula composition and the ingredients are prepared, with appropriate amounts of Mn and Ce added for loss on ignition.
[0049] S2: Place the prepared raw materials in a zirconia crucible, cover the furnace, heat the raw materials to a molten state and keep them at that temperature for a period of time, then pour the liquid alloy into a copper casting mold to obtain a master alloy ingot.
[0050] S3: The master alloy ingot is mechanically crushed and sieved. The sieved alloy powder is then ball-milled to obtain the finished hydrogen storage alloy powder.
[0051] The Ti-Fe-Ce-Mn-Zr-Al-Co based hydrogen storage alloy and its preparation method provided by this invention achieve the corresponding technical effects through a combination of "composition design + mechanical ball milling". Scientific composition design combined with an appropriate ball milling process can obtain alloy powder with a special structure, enabling the alloy to maintain excellent activation performance in air for a long time. Mechanical ball milling significantly reduces the grain size of the alloy while greatly increasing the density of grain boundaries and defects. This provides diffusion channels for the rapid diffusion of hydrogen atoms within the alloy, thus significantly improving the hydrogen absorption / desorption kinetics of the alloy while improving activation performance.
[0052] Furthermore, in step S1, the burn-off amount of Mn and Ce is 8% to 10% of the calculated addition amount. Since elements such as Mn and Ce are volatile, an appropriate burn-off amount needs to be added to ensure that the final alloy composition reaches the preset value. According to experimental verification, it is advisable for the burn-off amount to be 8% to 10% of the calculated addition amount. Too little burn-off amount will result in insufficient content of this component in the alloy; too much will result in material waste and excessive content.
[0053] Furthermore, the order and specific operation of placing each raw material in step S2 are as follows: the pure iron rod is placed vertically along the crucible wall, and the other metal raw materials are added in the following order: blocky rare earth Ce is placed at the bottom of the crucible, sponge Ti and Zr are placed above rare earth Ce, metallic Co is placed on top of sponge Ti and Zr, electrolytic Mn is placed on top of metallic Co, and electrolytic Al is placed on top. This placement order is determined according to the melting point and solid solubility of the metals, which allows the metals to melt sequentially in the order of Fe, Ce, Ti, Zr, Co, Mn, and Al, effectively reducing the burn-off of elements such as Mn and Ce, making the alloy composition more stable and the element distribution more uniform.
[0054] Furthermore, the specific operation of raw material melting in step S2 is as follows: vacuuming to 1×10 -2 ~5×10 -5 After Pa, pure argon gas at a pressure of 0.01–0.1 MPa is introduced as a protective gas, and the melting temperature is 1550–1650℃, held for 3–5 minutes. The vacuum degree, protective gas, and pressure are commonly used technical parameters. The melting temperature and holding time are determined based on the phase diagram. At these melting temperatures and holding times, the alloy can be kept in a molten state with minimal volatilization, thus saving costs and improving the stability of the alloy composition.
[0055] Furthermore, the sieving operation in step S3 involves passing the mechanically crushed alloy fragments through a 200-mesh sieve to obtain alloy powder with a diameter ≤75μm, which is then ball-milled. Choosing this particle size ensures effective ball milling while reducing the cost of mechanical crushing.
[0056] Furthermore, the ball milling operation in step S3 specifically involves: loading the alloy powder and stainless steel grinding balls into a stainless steel ball mill jar, evacuating it, and then filling it with high-purity argon gas. The mixture is then ball-milled in an omnidirectional planetary high-energy ball mill for 0.5–2 hours at a ball-to-material ratio of 1:18–22 and a rotation speed of 300–400 rpm. These ball milling parameters ensure effective milling while shortening the milling time and reducing costs. Extending the milling time, increasing the ball-to-material ratio, or increasing the milling speed will lead to an excessive amount of amorphous phase in the alloy, reducing its hydrogen storage capacity and kinetics. Conversely, shortening the milling time, reducing the ball-to-material ratio, or decreasing the milling speed will increase the grain size and decrease the defect density in the alloy, impairing its hydrogen storage kinetics.
[0057] Based on the above component design and preparation method, the specific components of the embodiments and comparative examples of this invention are as follows:
[0058] Example 1: Ti 1.05 Ce 0.05 Fe 0.8 Mn 0.15 Zr 0.1 Al 0.05 Co 0.05
[0059] Example 2: Ti 1.05 Ce 0.05 Fe 0.85 Mn 0.1 Zr 0.1 Al 0.05 Co 0.05
[0060] Example 3: Ti 1.05 Ce 0.05 Fe 0.7 Mn 0.25 Zr 0.1 Al 0.05 Co 0.05
[0061] Example 4: Ti 1.05 Ce 0.05 Fe 0.7 Mn 0.15 Zr 0.2 Al 0.05 Co 0.05
[0062] Example 5: Ti 1.05 Ce0.05 Fe 0.75 Mn 0.15 Zr 0.1 Al 0.1 Co 0.05
[0063] Example 6: Ti 1.05 Ce 0.05 Fe 0.75 Mn 0.15 Zr 0.1 Al 0.05 Co 0.1
[0064] Comparative Example 1: Ti 1.1 Fe 0.8 Mn 0.2 (As-cast state)
[0065] According to the chemical composition of each embodiment, rare earth metal Ce, sponge Ti and Zr, high-purity Fe, metallic Co, electrolytic Mn, and metallic Al were selected. The high-purity iron rod was polished with sandpaper to remove the surface oxide layer. The rare earth metal Ce and electrolytic Mn were added with an 8-10 wt.% burn-off rate during the batching process. The technical parameters for each stage were as follows: the vacuum induction melting furnace was evacuated to 1×10⁻⁶ ppm before heating. -2 ~5×10 -5 Pa; then, 0.01-0.1 MPa of inert argon gas is introduced into the furnace as a protective gas; the temperature during induction heating is 1550-1650℃; the liquid alloy is held at the molten state for 3-5 minutes; the ingot alloy is mechanically crushed and passed through a 200-mesh sieve, with a particle size of approximately 75 μm. The alloy powder is loaded into a stainless steel ball mill jar along with stainless steel grinding balls and ball-milled for 0.5-2 hours using an omnidirectional planetary ball mill, with a ball-to-material ratio of 1:18-22 and a rotation speed of 300-400 rpm.
[0066] It is worth emphasizing that all process parameters can be appropriately selected within the above range to prepare the hydrogen storage alloy powder described in the patent. Therefore, although only one typical embodiment has been given in this invention, this embodiment is applicable to preparation methods with different parameters.
[0067] Process parameters for Example 1:
[0068] According to the chemical formula Ti 1.05 Ce 0.05 Fe 0.8 Mn 0.15 Zr 0.1 Al 0.05 Co 0.05Bulk rare earth metal Ce, sponge Ti and Zr, pure Fe, electrolytic Mn, metallic Co, and Al were selected. These metals had a purity of 99.5% and were weighed according to their stoichiometric proportions: sponge Ti 406.6 g, sponge Zr 73.8 g, pure Fe 361.5 g, rare earth Ce 59.5 g, metallic Co 23.8 g, electrolytic Mn 70.0 g, and metallic Al 10.9 g. The weighed bulk metals were placed in a zirconia crucible within a medium-frequency induction furnace according to the designed process. A pure iron rod was placed vertically along the crucible wall. Bulk rare earth Ce was placed at the bottom of the crucible, sponge Ti and Zr were placed above rare earth Ce, metallic Co was placed on top of sponge Ti and Zr, electrolytic Mn was placed on top of metallic Co, and electrolytic Al was placed on top of the rest. The furnace lid was then closed, and a vacuum was evacuated for approximately 30 minutes until a vacuum degree of 5 × 10⁻⁶ was reached. -2 Above Pa, high-purity argon protective gas is then introduced until the pressure reaches -0.04 MPa. The heating temperature is adjusted to about 1650℃ to melt all the raw material metals. The molten liquid metal is kept at a constant temperature for 5 minutes to make it uniform. Then, the uniformly mixed liquid metal is poured into a cylindrical copper mold with a diameter of 30 mm and a depth of 80 mm. After cooling to room temperature in the furnace, it is taken out to obtain the master alloy ingot.
[0069] Ti alloy 1.05 Ce 0.05 Fe 0.8 Mn 0.15 Zr 0.1 Al 0.05 Co 0.05 After the ingot is mechanically crushed and sieved through a 200-mesh sieve, 20 grams of the sieved alloy powder and 400 grams of stainless steel grinding balls are weighed and placed together in a 250 ml stainless steel ball mill jar. The jar is then evacuated, filled with high-purity argon gas, and sealed. The jar is then ball-milled for 45 minutes in an all-around planetary high-energy ball mill.
[0070] The raw materials for Examples 2-6 and the comparative examples were weighed according to their chemical formulas, and other preparation process parameters were the same as those for Example 1.
[0071] The phase structure of the cast and ball-milled powders was tested by XRD. The morphology and microstructure of the ball-milled alloy particles were observed by high-resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM). The crystal state of the alloy was determined by selected area electron diffraction (SAED).
[0072] Figure 1The XRD patterns of the as-cast alloys in Examples 1-6 show that alloying with rare earth element Ce and metallic elements Mn, Zr, Co, and Al results in a multiphase structure. Besides the main phase TiFe, the alloys also contain intermetallic compounds such as ZrMn2, CeCo2, and Al4Mn. The ratio of each phase is TiFe:ZrMn2:CeCo2:Al4Mn = 0.8:0.06875:0.025:0.0125.
[0073] Figure 2 The SEM images of the ball-milled alloys in Examples 1-6 show that the particle dispersion of the alloys after ball milling is very good, and no obvious agglomeration is formed.
[0074] Figure 3 The XRD patterns of the ball-milled alloys in Examples 1-6 show that ball milling significantly broadens the diffraction peaks of the alloys. Analysis indicates that this phenomenon is caused by lattice stress and grain refinement generated after ball milling.
[0075] Figure 4 The HRTEM morphology of the ball-milled alloys in Examples 1-6 shows that the alloys have a nanocrystalline structure with a grain size of 50-200 nm.
[0076] The hydrogen absorption activation performance, hydrogen storage capacity, and hydrogen absorption / desorption kinetics of the alloy powder were tested using a fully automated Sieverts system. The hydrogen absorption temperature was 30°C, and the initial hydrogen pressure was 3 MPa; the hydrogen desorption temperature was 30°C, and the hydrogen desorption rate was 1 × 10⁻⁶ MPa. -4 The test was conducted at a pressure of MPa.
[0077] Table 1 Solid-state hydrogen storage performance of alloys from different embodiments
[0078]
[0079] The Ti-Fe-Ce-Mn-Zr-Al-Co based hydrogen storage alloy provided by this invention has good activation performance and hydrogen absorption and desorption performance, with a hydrogen storage capacity ≥1.70wt.%, a hydrogen absorption plateau pressure ≥0.41MPa, and a hydrogen desorption plateau pressure ≥0.31MPa; it can be activated in one step under the conditions of 30℃ and initial hydrogen pressure of 3MPa.
[0080] The above results demonstrate that the ball-milled alloy powder possesses excellent activation properties and high hydrogen absorption capacity. Clearly, the alloy preparation process of this invention is simple and easy to operate, fully suitable for large-scale production, and its performance meets the requirements of various applications for hydrogen storage materials. Compared with similar alloys at home and abroad, the hydrogen storage performance of the alloy of this invention is significantly improved, exhibiting obvious advantages.
[0081] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.
Claims
1. A Ti-Fe-Ce-Mn-Zr-Al-Co based hydrogen storage alloy, characterized in that: The alloy is specifically composed of Ti. 1.05 Ce 0.05 Fe 1.15-x-y-z-m Mn x Zr y Al z Co m , where x, y, z, and m are atomic ratios, and 0.1≤x≤0.25, 0.05≤y≤0.2, 0.02≤z≤0.1, and 0.02≤m≤0.
1.
2. The hydrogen storage alloy according to claim 1, characterized in that: The ratio of x, y, z, m is x:y:z:m = 0.15:0.1:0.05:0.
05.
3. The hydrogen storage alloy according to claim 1, characterized in that: The hydrogen storage alloy has a nanocrystalline structure with an average grain size of 50–200 nm and contains grain boundary and phase boundary defects.
4. The hydrogen storage alloy according to claim 1, characterized in that: The hydrogen storage alloy has a multiphase structure containing TiFe phase, ZrMn2 phase, CeCo2 phase and Al4Mn phase.
5. A method for preparing the hydrogen storage alloy according to any one of claims 1 to 4, characterized in that, Specifically, the following steps are included: S1: The dosage is calculated according to the chemical formula composition and the ingredients are prepared, with appropriate amounts of Mn and Ce added for loss on ignition. S2: Place the prepared raw materials in a zirconia crucible, cover the furnace, heat the raw materials to a molten state and keep them at that temperature for a period of time, then pour the liquid alloy into a copper casting mold to obtain a master alloy ingot. S3: The master alloy ingot is mechanically crushed and sieved. The sieved alloy powder is then ball-milled to obtain the finished hydrogen storage alloy powder.
6. The preparation method according to claim 5, characterized in that: In step S1, the amount of Mn and Ce added is 8% to 10% of the calculated dosage.
7. The preparation method according to claim 5, characterized in that: The order and specific operation of placing each raw material in step S2 are as follows: the pure iron rod is placed vertically along the crucible wall, and the order of adding other metal raw materials is as follows: blocky rare earth Ce is placed at the bottom of the crucible, sponge Ti and Zr are placed above rare earth Ce, metal Co is placed on sponge Ti and Zr, electrolytic Mn is placed on metal Co, and electrolytic Al is placed on top.
8. The preparation method according to claim 5, characterized in that: The specific operation for melting the raw materials in step S2 is as follows: evacuate to 1×10⁻⁶. -2 ~5×10 -5 After Pa, pure argon gas at a pressure of 0.01–0.1 MPa is introduced as a protective gas, and the melting temperature is 1550–1650℃ and held for 3–5 minutes.
9. The preparation method according to claim 5, characterized in that: The sieving operation in step S3 involves passing the mechanically crushed alloy fragments through a 200-mesh sieve to obtain alloy powder with a diameter ≤75μm, followed by ball milling.
10. The preparation method according to claim 5, characterized in that: The ball milling operation in step S3 is as follows: the alloy powder and stainless steel grinding balls are loaded into a stainless steel ball mill jar, vacuumed and then filled with high-purity argon gas, and ball milled in an all-round planetary high-energy ball mill for 0.5 to 2 hours, with a ball-to-material ratio of 1:18 to 22 and a rotation speed of 300 to 400 rpm.