Method for preparing high-entropy alloy by extracting multi-metal ion solution based on MOF (Metal Organic Framework) and Joule heat technologies

Abstract

The invention discloses a method for preparing a high-entropy alloy by extracting a multi-metal ion solution based on MOF (Metal Organic Framework) and Joule heat technologies. The method comprises the following steps: (1) enabling terephthalic acid and multi-metal ions to form MOF powder in a mixed organic solvent; (2) pre-carbonizing metal organic framework (MOF) powder, quickly heating through flash evaporation Joule heat, and cooling to obtain high-entropy alloy powder; the multi-metal ions are manganese, cobalt, nickel, copper and iron; according to the preparation method, the MOF and two-step Joule thermal combination strategy is adopted, the preparation method has the advantages of being low in cost, high in reaction efficiency, simple in technological process and the like, and meanwhile the prepared high-entropy alloy powder has excellent mechanical performance and shows good application prospects.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of multi-metal alloy material preparation, and particularly relates to a method for preparing high-entropy alloy based on MOFization and Joule heat technology extraction of multi-metal ion solution. BACKGROUND

[0002] As a new type of alloy material composed of five or more main metal elements in near-equiatomic ratio, high-entropy alloy has shown great application potential in the field of material science in recent years. Compared with traditional alloys, high-entropy alloy has a series of excellent performance characteristics, including excellent mechanical performance, such as high strength and high toughness at the same time, outstanding corrosion resistance, excellent high-temperature stability suitable for high-temperature working environment, and good radiation resistance, etc. These characteristics make high-entropy alloy have important application value in the fields of aerospace engine hot end components, nuclear reactor structural materials, marine engineering equipment, high-end mechanical manufacturing tools, and biomedical implants, etc.

[0003] There are mainly two methods for preparing high-entropy alloy at present: traditional arc melting method, under the protection of inert gas (such as argon), the metal raw materials are directly melted by high-temperature arc, and then cooled into ingots in a water-cooled copper crucible; mechanical alloying method, the metal powder is ground in a high-energy ball mill for a long time, the atomic level mixing is realized through repeated cold welding-fracture of powder particles, forming amorphous or nanocrystalline solid solution powder, and then densified by hot pressing / sintering.

[0004] Traditional preparation of high-entropy alloy relies on high-purity metal raw materials, which is high in cost; requires high temperature of 1000-3000℃ for more than 2h; the final formed high-entropy alloy has high melt segregation (composition deviation > 5at%), and can only realize laboratory preparation of kilograms, which is difficult to scale up, therefore, seeking a low-cost high-entropy alloy production process has become an important topic for sustainable development of new energy industry. SUMMARY

[0005] The present application provides a method for preparing high-entropy alloy based on MOFization and Joule heat technology extraction of multi-metal ion solution, which is low in cost, high in reaction efficiency and excellent in mechanical performance.

[0006] Technical scheme: The present application provides a method for preparing high-entropy alloy based on MOFization and Joule heat technology extraction of multi-metal ion solution, comprising the following steps:

[0007] (1) reacting terephthalic acid and multi-metal ions in a mixed organic solvent to form metal organic framework MOF powder;

[0008] (2) the metal organic framework MOF powder is pre-carbonized, then is rapidly heated through flash joule heat, and high-entropy alloy powder is obtained after cooling;

[0009] The multi-metal ions are manganese, cobalt, nickel, copper and iron.

[0010] Preferably, in step (1), the total mole ratio of terephthalic acid to multi-metal ions is 1:1-2:1.

[0011] Preferably, in step (1), the mixed organic solvent is specifically prepared as follows: ethanol and deionized water are added to N,N-dimethylformamide, and after ultrasonic dispersion, the mixed organic solvent is obtained.

[0012] Preferably, the volume ratio of N,N-dimethylformamide, ethanol and deionized water is 14-18:0.8-1.2:0.8-1.2.

[0013] Preferably, in step (1), the specific preparation method of the metal organic framework MOF is as follows: terephthalic acid is first added to the mixed organic solvent and ultrasonic dispersion is performed; then FeCl2·4H2O, CuCl2·2H2O, MnCl2·4H2O, CoCl2·6H2O and NiCl2·6H2O solid particles are added to the obtained mixed organic solvent and stirring is performed; the above mixed solution is placed in an autoclave for heating reaction; finally, the solution obtained by the reaction is washed, centrifuged and vacuum dried to obtain the metal organic framework MOF powder.

[0014] Preferably, the mole ratio of FeCl2·4H2O, CuCl2·2H2O, MnCl2·4H2O, CoCl2·6H2O and NiCl2·6H2O is 1:1:1:1:1.

[0015] Preferably, the heating temperature in the heating reaction is 150-190℃, and the reaction time is 6-18 hours.

[0016] Preferably, the washing frequency is 3-5 times; the centrifugal speed is 9000-12000r / min; and the centrifugal time is 7-10min.

[0017] Preferably, the vacuum drying temperature is 55-75℃.

[0018] Preferably, in step (2), the pre-carbonization temperature is 450-550℃, and the heating time is 15-30s; in the rapid heating, the heating temperature is 2400-2600℃, and the heating time is 0.2-0.6 seconds.

[0019] The application provides a new method for preparing high-entropy alloy by using a multi-metal solution conversion process. 2+ 2+ 2+ 2+ 2+ In the preparation process, a MOF precursor design strategy is adopted. Uniform MOF structures are successfully constructed by using terephthalic acid ligands and multi-metal ions (Fe 2+ 2+ 2+ 2+ 2+ Further, high-entropy alloy is prepared through two-step joule heat treatment. The first step is pre-carbonization treatment, which removes the organic ligand and forms a carbon carrier, effectively preventing oxidation of the metal in the subsequent treatment process. The second step is flash joule heat treatment, which uses instantaneous high temperature to promote the diffusion and fusion of multi-metal atoms, and finally forms a high-entropy alloy phase.

[0020] Advantages: Compared with the prior art, the application has the following advantages:

[0021] The application uses metal solution instead of high-purity metal raw materials, breaking the dependence of traditional processes on expensive elemental metals, and reducing the raw material cost by more than 50%. The MOF and joule heat combination strategy is adopted: first, terephthalic acid ligands and multi-metal ions are used to construct uniform MOFs in a specific solvent, achieving atomic dispersion, and the mass of the obtained MOF powder is 181.1 mg, and the yield is 40.8%; then, two-step joule heat treatment is performed, first pre-carbonization to remove the ligand and form a carbon carrier to prevent oxidation, and then flash joule heat to promote the diffusion and fusion of metal atoms to form a high-entropy alloy phase, and finally the mass of the obtained high-entropy alloy powder is 86.3 mg. Compared with the traditional smelting method, the core alloying process is completed in 0.2-0.6 s, the energy consumption is reduced by 80%, and the reaction efficiency is significantly improved. The prepared high-entropy alloy has a more uniform structure, and the solvus deviation can be controlled within 2at%, which is significantly better than the 5at% of the traditional method. The alloy has excellent strength, good corrosion resistance, excellent high-temperature oxidation resistance and stable mechanical properties, and is suitable for aerospace, chemical industry, energy and other fields, providing a new idea for the industrial production of high-entropy alloy. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The process flowchart of the application is shown in the figure;

[0023] Figure 2 The XRD characterization graph of the high-entropy alloy of the application is shown in the figure;

[0024] Figure 3 The SEM characterization graph of the high-entropy alloy of the application is shown in the figure;

[0025] Figure 4 TEM characterization diagram of the high-entropy alloy of the present application;

[0026] Figure 5 EDS characterization diagram of the high-entropy alloy, a diagram is the energy spectrum diagram of C element; b diagram is the energy spectrum diagram of Mn element; c diagram is the energy spectrum diagram of Co element; d diagram is the energy spectrum diagram of Ni element; e diagram is the energy spectrum diagram of Fe element; f diagram is the energy spectrum diagram of Cu element. DETAILED DESCRIPTION

[0027] The present application will be further illustrated in conjunction with the accompanying drawings and specific embodiments, and it should be understood that the following specific embodiments are only used to illustrate the present application and not to limit the scope of the present application.

[0028] Example 1

[0029] (I) Preparation of metal organic framework MOF

[0030] Into a 100ml polytetrafluoroethylene tube, 28ml of N,N-dimethylformamide (DMF), 1.6ml of ethanol, 1.6ml of deionized water were sequentially added, and an ultrasonic cleaning machine was used for ultrasonic dispersion for 10min to obtain a mixed organic solvent system; 4mmol of terephthalic acid (PTA) was added to the obtained mixed organic solvent system, and ultrasonic dispersion was performed for 15min; 0.4mmol of FeCl2·4H2O, CuCl2·2H2O, MnCl2·4H2O, CoCl2·6H2O and NiCl2·6H2O solid particles were sequentially added to the obtained organic ligand solution, and stirring was performed for 30min; the obtained mixed solution was transferred to a 100ml Teflon-lined autoclave, and solvothermal reaction was performed at a constant temperature of 150℃ for 6h; the solution obtained by reaction was washed and centrifuged with ethanol three times, the centrifugal speed was 9000r / min, the centrifugal time was 7min, and then vacuum drying was performed at 55℃ to obtain metal organic framework MOF powder.

[0031] (II) Joule heat treatment of metal organic framework MOF powder

[0032] The obtained dried metal organic framework MOF powder was placed in carbon paper, and the carbon paper was loaded into a joule heat device, pre-carbonization was performed at 450℃ for 15s, flash joule heat was performed at 2400℃ for 0.2s, and after reaction, natural cooling was performed in an argon atmosphere, and finally high-entropy alloy powder was obtained. See Figure 1 The process flow chart for preparing the high-entropy alloy of the present application.

[0033] Figure 2 As shown in FIG. 6, three obvious diffraction peaks appeared in the high-entropy alloy of the present application, which correspond to the characteristic peaks of face-centered cubic structure, proving that the high-entropy alloy is of face-centered cubic structure; Figure 3For the particle distribution of the high-entropy alloy in the scanning electron micrograph of the application, the overall material morphology is uniform; Figure 4 For the particle distribution of the high-entropy alloy under the perspective electron microscope of the application, the red box in the figure is enlarged to the lower right corner, and the lattice spacing is marked. The particle size is small, the particle dispersion is good, indicating that the particle size crystallinity is high, and the crystal structure is highly ordered; Figure 5 For the EDS characterization diagram of the high-entropy alloy, it can be observed that the particle distribution of various elements is uniform.

[0034] Example 2

[0035] (I) Preparation of metal organic framework MOF

[0036] Into a 100ml polytetrafluoroethylene tube, 36ml N,N-dimethylformamide (DMF), 2.4ml ethanol, 2.4ml deionized water were added in turn, and ultrasonic dispersion was carried out for 10min using an ultrasonic cleaning machine to obtain a mixed organic solvent system; 4mmol of terephthalic acid (PTA) was added to the obtained mixed organic solvent system, and ultrasonic dispersion was carried out for 15min; 0.4mmol of FeCl2·4H2O, CuCl2·2H2O, MnCl2·4H2O, CoCl2·6H2O and NiCl2·6H2O solid particles were added to the obtained organic ligand solution in turn, and fully stirred for 30min; the obtained mixed solution was transferred to a 100ml Teflon-lined autoclave, and solvent thermal reaction was carried out at a constant temperature of 190℃ for 18h; the reaction solution was washed with ethanol and centrifuged three times, the centrifugal speed was 12000r / min, and the centrifugal time was 10min, then vacuum drying was carried out at 75℃, and metal organic framework MOF powder was obtained.

[0037] (II) Joule heat treatment of metal organic framework MOF powder

[0038] The obtained dried metal organic framework MOF powder was placed in carbon paper, and the carbon paper was loaded into a joule heat device, pre-carbonization was carried out at 550℃ for 30s, flash joule heat was carried out at 2600℃ for 0.6s, and after reaction, natural cooling was carried out in an argon atmosphere, and finally high-entropy alloy powder was obtained. See Figure 1 The process flow chart for preparing high-entropy alloy according to the application.

[0039] Example 3

[0040] (I) Preparation of metal organic framework MOF

[0041] Into a 100ml Teflon tube, 32ml of N,N-dimethylformamide (DMF), 2ml of ethanol, 2ml of deionized water were added in sequence, and ultrasonic dispersion was performed for 10min using an ultrasonic cleaning machine to obtain a mixed organic solvent system; 2mmol of terephthalic acid (PTA) was added to the obtained mixed organic solvent system, and ultrasonic dispersion was performed for 15min; 0.4mmol of FeCl2·4H2O, CuCl2·2H2O, MnCl2·4H2O, CoCl2·6H2O and NiCl2·6H2O solid particles were added to the obtained organic ligand solution in sequence, and stirring was performed for 30min; the obtained mixed solution was transferred into a 100ml Teflon-lined autoclave, and solvothermal reaction was performed at a constant temperature of 170℃ for 12h; the solution obtained by reaction was washed with ethanol and centrifuged three times, the centrifugal speed was 10000r / min, the centrifugal time was 8min, and then vacuum drying was performed at 65℃ to obtain metal organic framework MOF powder.

[0042] (II) Joule heat treatment of the metal organic framework MOF powder

[0043] The obtained dried metal organic framework MOF powder was placed in carbon paper, and the carbon paper was loaded into a Joule heat device to perform pre-carbonization at 500℃ for 20s and flash Joule heat at 2500℃ for 0.4s, and then natural cooling was performed in an argon atmosphere to finally obtain high-entropy alloy powder. See Figure 1 The process flow chart for preparing the high-entropy alloy.

[0044] Comparative Example 1

[0045] (I) Preparation of metal organic framework MOF

[0046] Into a 100ml Teflon tube, 32ml of N,N-dimethylformamide (DMF), 2ml of ethanol, 2ml of deionized water were added in sequence, and ultrasonic dispersion was performed for 10min using an ultrasonic cleaning machine to obtain a mixed organic solvent system; 2mmol of terephthalic acid (PTA) was added to the obtained mixed organic solvent system, and ultrasonic dispersion was performed for 15min; 0.4mmol of FeCl2·4H2O, CuCl2·2H2O, MnCl2·4H2O, CoCl2·6H2O and NiCl2·6H2O solid particles were added to the obtained organic ligand solution in sequence, and stirring was performed for 30min; the obtained mixed solution was transferred into a 100ml Teflon-lined autoclave, and solvothermal reaction was performed at a constant temperature of 150℃ for 6h; the solution obtained by reaction was washed with ethanol and centrifuged three times, the centrifugal speed was 9000r / min, the centrifugal time was 7min, and then vacuum drying was performed at 55℃ to obtain metal organic framework MOF powder.

[0047] (II) Joule heat treatment of the metal organic framework MOF powder

[0048] The obtained dry metal organic framework MOF powder was placed in carbon paper, and the carbon paper was loaded into a joule heating device for direct heating at 2500°C for 0.4s of flash joule heating, and after the reaction, natural cooling was performed under an argon atmosphere.

[0049] The sample prepared by MOF and rapid thermal shock in the comparative example had local structural inhomogeneity; the particles appeared to be agglomerated, the material morphology was segregated; and part of the dispersion was uneven.

Claims

1. A method for preparing high-entropy alloys based on MOF formation and Joule heating technology for extracting multi-metal ion solutions, characterized in that: Includes the following steps: (1) Terephthalic acid is reacted with polymetallic ions in a mixed organic solvent to form metal-organic framework (MOF) powder; (2) The metal-organic framework (MOF) powder is first pre-carbonized, then rapidly heated by flash Joule heating, and then cooled to obtain high-entropy alloy powder. The polymetallic ions are manganese, cobalt, nickel, copper, and iron.

2. The method for preparing high-entropy alloys based on MOF formation and Joule heating technology for extracting multi-metal ion solutions according to claim 1, characterized in that: In step (1), the total molar ratio of terephthalic acid to polymetallic ions is 1:1 to 2:

1.

3. The method for preparing high-entropy alloys based on MOF formation and Joule heating technology for extracting multi-metal ion solutions according to claim 1, characterized in that: In step (1), the specific preparation of the mixed organic solvent is as follows: ethanol and deionized water are added to N,N-dimethylformamide, and after ultrasonic dispersion, the mixed organic solvent is obtained.

4. The method for preparing high-entropy alloys based on MOF formation and Joule heating technology for extracting multi-metal ion solutions according to claim 3, characterized in that: The volume ratio of N,N-dimethylformamide, ethanol and deionized water is 14-18:0.8-1.2:0.8-1.

2.

5. The method for preparing high-entropy alloys based on MOF formation and Joule heating technology for extracting multi-metal ion solutions according to claim 1, characterized in that: In step (1), the specific preparation method of the metal-organic framework (MOF) is as follows: First, terephthalic acid is added to a mixed organic solvent and ultrasonically dispersed to obtain an organic ligand solution; then, FeCl2·4H2O, CuCl2·2H2O, MnCl2·4H2O, CoCl2·6H2O, and NiCl2·6H2O solid particles are added to the organic ligand solution and stirred; the above mixed solution is placed in an autoclave for heating and reaction; finally, the solution obtained from the reaction is washed, centrifuged, and vacuum dried to obtain metal-organic framework (MOF) powder.

6. The method for preparing high-entropy alloys based on MOF formation and Joule heating technology for extracting multi-metal ion solutions according to claim 5, characterized in that: The molar ratio of FeCl2·4H2O, CuCl2·2H2O, MnCl2·4H2O, CoCl2·6H2O, and NiCl2·6H2O is 1:1:1:1:

1.

7. The method for preparing high-entropy alloys based on MOF formation and Joule heating technology for extracting multi-metal ion solutions according to claim 5, characterized in that: The heating temperature in the heating reaction is 150–190°C, and the reaction time is 6–18 hours.

8. The method for preparing high-entropy alloys based on MOF formation and Joule heating technology for extracting multi-metal ion solutions according to claim 5, characterized in that: The washing cycle is 3 to 5 times; the centrifugation speed is 9000 to 12000 r / min; and the centrifugation time is 7 to 10 min.

9. The method for preparing high-entropy alloys based on MOF formation and Joule heating technology for extracting multi-metal ion solutions according to claim 5, characterized in that: The vacuum drying temperature is 55–75°C.

10. The method for preparing high-entropy alloys based on MOF formation and Joule heating technology for extracting multi-metal ion solutions according to claim 1, characterized in that: In step (2), the pre-carbonization temperature is 450-550℃ and the heating time is 15-30s; the rapid heating temperature is 2400-2600℃ and the heating time is 0.2-0.6 seconds.

Images