Nickel-manganese-based alloy porous material and simple preparation method and application thereof

Abstract

The application relates to a kind of nickel-manganese-based alloy porous materials and simple preparation method and application thereof.The application belongs to the field of solid refrigeration.The application aims at the technical problems that the method for preparing nickel-manganese-based porous material by alloy powder sintering is easy to cause carbon and oxygen pollution due to the introduction of binder, phase transition temperature change is easy to be caused by using abrasive state powder as raw material, and the process of element powder sintering is complex and cannot guarantee the composition uniformity.The method of the application comprises the following steps: weighing, smelting, then carrying out gas atomization powdering, and finally sintering.By composition design and process adjustment, a porous structure sample with controllable composition, specific porosity range, phase transition temperature interval near room temperature and excellent magnetocaloric performance is obtained in a low-pressure sintering mode, so that the practical application of nickel-manganese-based alloy becomes possible.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of solid refrigeration, and particularly relates to a nickel-manganese-based alloy porous material and a simple preparation method and application thereof. BACKGROUND

[0002] Traditional refrigeration technology mainly relies on gas compression refrigeration technology based on Carnot cycle, but this method has problems of slow start, loud noise, low efficiency and difficulty in miniaturization, in addition, some commonly used gas refrigerants also bring greenhouse effect, and it is particularly necessary to explore a technology capable of replacing traditional gas compression refrigeration. One direction is to use solid phase change materials to produce temperature change under the action of external field (including magnetic field, electric field, force field, etc.), and then design various prototypes such as magnetic refrigerators.

[0003] In mainstream magnetic refrigerators, magnetic materials can be used as active magnetic regenerators, which act as refrigeration working fluids that produce cold and heat transfer materials that exchange heat with the heat transfer fluid during the cycle. Therefore, in order to meet the requirements of refrigeration and heat transfer, on the one hand, materials with giant magnetocaloric effect near room temperature are required to achieve large magnetic entropy change (ΔS m ) or adiabatic temperature change (ΔT ad ). Among them, nickel-manganese-based alloys (nickel-manganese-gallium, nickel-manganese-indium, nickel-manganese-tin, nickel-manganese-antimony, etc.) have magnetic shape memory effect, magnetic superelasticity, magnetoresistance effect and other multi-functional properties, and can also adjust the phase transition temperature by adjusting the chemical composition of elements, doping interstitial atoms and heat treatment, so it has become one of the magnetic heat materials that have attracted much attention.

[0004] Another important goal is to design magnetic materials into porous materials with connected pores to facilitate fluid penetration, thereby achieving efficient and stable heat exchange and improving the refrigeration efficiency of the refrigeration mechanism. Currently, the main preparation methods of porous metal materials include powder sintering method, foaming of molten metal method, infiltration casting method, investment casting method, gas / electrodeposition, and laser rapid prototyping. Among them, the powder sintering method can use loose or vibrated powder, slurry, etc. as raw materials for sintering, and is a simple and easy-to-use method for preparing porous materials.

[0005] However, the current research on sintering of nickel-manganese-based alloy powder is also limited to using the nickel-manganese-gallium powder in a ground state as raw material, bonding by a binder, and assisting in sintering at 1000-1100 DEG C to obtain samples with a density of 45% to 99%. Since the method uses the powder in a ground state, the stress introduced in the grinding process will cause the phase transition temperature of the nickel-manganese-based material to change, adversely affecting the performance of the product. At the same time, the use of the binder will also cause carbon and oxygen pollution to the material, affecting the performance of the material. Another path is to mix the element powder with the binder into a slurry with high viscosity, and then extrude and shape into a certain shape by equipment, and then assist in debinding at 300 DEG C for 1 hour, preliminary sintering at 600 DEG C for 2 hours, and final sintering at 1000 DEG C for 2-12 hours, and then ordering heat treatment at 700 DEG C for 10 hours to obtain a nickel-manganese-gallium alloy with a porosity of 73-76%. However, the workpiece prepared by the above method has low composition uniformity, and the preparation process is complex and the production cost is high. SUMMARY

[0006] The present application aims at the technical problems in the prior art that the alloy powder sintering method for preparing nickel-manganese-based porous materials easily causes carbon and oxygen pollution due to the introduction of a binder, easily causes the phase transition temperature to change due to the use of the powder in a ground state, and the element powder sintering method is complex and cannot guarantee the composition uniformity, and provides a porous structure sample with controllable composition, specific porosity range, phase transition temperature interval near room temperature, and excellent magnetocaloric performance, making the practical application of nickel-manganese-based alloys possible.

[0007] The technical scheme of the present application is as follows:

[0008] One of the objects of the present application is to provide a simple preparation method of a nickel-manganese-based alloy porous material, which is carried out according to the following steps:

[0009] S1: raw materials are weighed according to the atomic stoichiometric ratio of Ni 41 Mn 43 Sn 10 Co6, and an excess of manganese tablets is additionally weighed, the alloy raw materials are melted by high-frequency induction, and an alloy liquid is obtained;

[0010] S2: the alloy liquid is atomized at 3-4 MPa to obtain alloy powder with a diameter of 15-53 μm;

[0011] S3: the alloy powder is loaded into a cleaned quartz tube and vibrated, vacuumized and sealed, and then transferred into a muffle furnace and sintered at 900-1000 DEG C for 2-24 hours, and then the quartz tube is removed after cooling to obtain a nickel-manganese-based alloy porous material.

[0012] It is further limited that the mass of the excess manganese tablets additionally weighed in S1 is 5wt.% of the total mass of the metal materials.

[0013] Further limit, the smelting temperature in S1 is 1500-1700℃, and the smelting time is 40-60 minutes.

[0014] Further limit, the atomizing gas in S2 is 99.999% high-purity argon.

[0015] Further limit, the out furnace temperature in S2 is 70-90℃.

[0016] Further limit, in S3, after the alloy powder is loaded into the quartz tube, high-purity titanium sheet cleaned by anhydrous ethanol is added into the quartz tube.

[0017] Further limit, the specific process of vacuumizing in S3 is: ① first vacuumize to 10 -1 Pa below; ② refill 0.5-1 bar argon, continue vacuumizing, repeat 2-3 times; ③ add liquid nitrogen in the vacuum pump, vacuumize to 10 -4 Pa below, and refill 0.1-0.2 bar argon.

[0018] Further limit, air cooling is used in S3.

[0019] The second purpose of the present application is to provide a nickel-manganese-based alloy porous material prepared by the above method.

[0020] Further limit, the compactness of the nickel-manganese-based alloy porous material is 60.3-80.1%.

[0021] The third purpose of the present application is to provide an application of the nickel-manganese-based alloy porous material prepared by the above method as a solid refrigeration material.

[0022] Compared with the prior art, the present application has the following advantages:

[0023] The present application uses loose or vibrated alloy powder with reasonable designed composition as raw material, at the same time, cooperates with the adjustment of process, and obtains a porous structure sample with controllable composition, specific porosity range, phase transition temperature interval near room temperature and excellent magneto-caloric performance in a low-pressure sintering way, so that the practical application of nickel-manganese-based alloy becomes possible. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The figure is the characteristic graph of the alloy powder obtained in Example 1 of the present application; wherein (a) is macroscopic morphology, (b) is particle size distribution graph, (c) is DSC curve, and (d) is X-ray diffraction pattern;

[0025] Figure 2Fig. 1 is a morphology diagram of the porous structure of the nickel-manganese-based alloy obtained in Example 1-5; wherein (a) represents the outer surface of Example 1; (b) represents the outer surface of Example 2; (c) represents the outer surface of Example 3; (d) represents the outer surface of Example 4; (e) represents the outer surface of Example 5; (f) represents the cross section of Example 5;

[0026] Fig. 3(a) is a magnetization-temperature curve of the nickel-manganese-based alloy porous material obtained in Example 1 of the present application under different magnetic fields;

[0027] Fig. 3(b) is a magnetization-magnetic field curve of the nickel-manganese-based alloy porous material obtained in Example 1 of the present application under different temperatures;

[0028] Fig. 3(c) is a magnetic entropy change-temperature curve of the nickel-manganese-based alloy porous material obtained in Example 1 of the present application under different magnetic fields. DETAILED DESCRIPTION

[0029] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the examples. It should be understood that the specific examples described herein are only used to explain the present application, and are not used to limit the present application.

[0030] The experimental methods used in the following examples are all conventional methods unless otherwise specified. The materials, reagents, methods and instruments used are all conventional materials, reagents, methods and instruments in the art unless otherwise specified, and can be obtained by commercial channels by those skilled in the art.

[0031] The terms "comprise", "include", "have", "contain", or any other variant thereof, as used in the following examples, are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that comprises a listed element does not necessarily limit only those elements, but can include other elements not expressly listed or inherent to such composition, step, method, article, or apparatus.

[0032] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1 to 5” is disclosed, the described range should be interpreted as including ranges “1 to 4”, “1 to 3”, “1 to 2”, “1 to 2 and 4 to 5”, “1 to 3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range. In this specification and claims, range definitions may be combined and / or interchanged, unless otherwise stated, these ranges include all subranges contained therein.

[0033] The indefinite articles “a” and “an” preceding an element or component of this invention do not impose any limitation on the quantity (i.e., number of times) of the element or component. Therefore, “an” or “a” should be interpreted as including one or at least one, and the singular form of an element or component also includes the plural form, unless the quantity clearly refers only to the singular form.

[0034] Example 1: This example provides a simple method for preparing a nickel-manganese-based alloy porous material, which is carried out according to the following steps:

[0035] 1) Clean the raw materials.

[0036] Soak the nickel sheet in aqua regia (a mixture of concentrated hydrochloric acid and concentrated nitric acid in a volume ratio of 3:1) for 5 minutes until the surface of the nickel sheet shows a metallic luster. Then soak it in distilled water for 5 minutes. Repeat the washing process 3 times. Finally, dry it with a hair dryer for later use.

[0037] Soak the manganese flakes in a 10% dilute nitric acid solution for 10 minutes, then sonicate them in distilled water for 2 minutes, and then sonicate them in a 5% dilute nitric acid solution for 10 minutes until the surface of the manganese flakes shows a metallic luster. Then quickly transfer them to distilled water for 5 minutes and repeat the washing process 3 times. Finally, sonicate them in anhydrous ethanol for 2 minutes and use a hair dryer to quickly dry the raw manganese flakes for later use.

[0038] Soak the tin block in a 10% sodium hydroxide solution for 10 minutes until the surface of the tin block has a metallic luster. Then soak it in distilled water for 5 minutes. Repeat this process 3 times. Finally, dry it with a hair dryer for later use.

[0039] Soak the cobalt block in a 30% nitric acid solution for 10 minutes until the surface of the cobalt block shows a metallic luster. Then soak it in distilled water for 5 minutes. Repeat this process 3 times. Finally, dry it with a hair dryer for later use.

[0040] 2) Preparation of nickel-manganese-tin-cobalt alloy powder.

[0041] Weighing: according to the atomic stoichiometric ratio of Ni 41 Mn 43 Sn 10 Co6, 15.25 kg of 99.98% high-purity nickel sheet, 14.98 kg of 99.93% high-purity manganese sheet, 7.53 kg of 99.90% high-purity tin block and 2.24 kg of 99.95% high-purity cobalt block are weighed, and on this basis, in order to offset the loss of manganese element in the atomization process, 5% (i.e. 2 kg) of high-purity manganese is additionally added to the total mass of the metal material.

[0042] Melting: the alloy raw materials are placed in a ceramic crucible and melted by high-frequency induction method, vacuum melting at 1600°C for 40 minutes to obtain an alloy liquid.

[0043] Gas atomization: the alloy liquid is atomized by using 99.999% high-purity argon gas, the atomization pressure is 3.5 MPa, and the tapping temperature is 80°C. After the atomization is completed, the alloy powder of different particle sizes is obtained, and the 270 mesh (53 μm) and 800 mesh (15 μm) sieves are used to screen the alloy powder, and the powder with a diameter of 15-53 μm is sealed in a nylon bag.

[0044] 3) Preparation of nickel-manganese-based alloy porous material.

[0045] Quartz tube cleaning: a quartz tube with an outer diameter of 6 mm and an inner diameter of 4 mm is used as the forming tube material, one end of the quartz tube is open, the middle part is necked, and the other end is sealed. First, immerse the selected quartz tube in 3% mass fraction hydrofluoric acid for 24 hours; then, take out the quartz tube and rinse it with running water for 3 minutes; then, immerse it in distilled water and ultrasonic clean it for 10 minutes, repeat 2 times; finally, seal the open end of the cleaned quartz tube with clean filter paper and put it in a vacuum drying oven for 6 hours.

[0046] Powder loading: put the powder into the cleaned and dried quartz tube and shake it well; then, add high-purity titanium sheet cleaned with anhydrous ethanol for 15 minutes as an oxygen scavenger to the quartz tube to ensure that the titanium sheet does not come into contact with the alloy powder.

[0047] Vacuum pumping: ① Connect the open end of the quartz tube to the vacuum pump for vacuum pumping. In order to reduce the oxygen partial pressure in the quartz tube, first, use the vacuum pump to pump for 10 minutes to make the vacuum degree in the quartz tube reach 10 -1 Pa; ② Backfill 1 bar of 99.999% high-purity argon and continue to pump, repeat 2 times; ③ Add liquid nitrogen in the vacuum pump and pump for 10 minutes to make the vacuum degree in the quartz tube reach 10 -4Pa, then, backfill 0.1 bar of 99.999% high purity argon, and finally, using an oxyacetylene flame, soften and seal the open end of the quartz tube.

[0048] Sintering: The foregoing sample was sintered in a muffle furnace at 900°C for 24 hours, and air-cooled to room temperature to obtain a nickel-manganese-based alloy porous material.

[0049] Example 2: This example differs from Example 1 in that the sintering temperature is 950°C. The other steps and parameters are the same as in Example 1.

[0050] Example 3: This example differs from Example 1 in that the sintering temperature is 1000°C. The other steps and parameters are the same as in Example 1.

[0051] Example 4: This example differs from Example 3 in that the sintering time is 12 hours. The other steps and parameters are the same as in Example 3.

[0052] Example 5: This example differs from Example 3 in that the sintering time is 2 hours. The other steps and parameters are the same as in Example 3.

[0053] Test Experiment

[0054] (I) Figure 1 Characteristics of the gas-atomized powder obtained in Step 2) of Example 1. Among them, Figure 1 (a) is a morphology diagram of the powder, from which it can be seen that the size of the powder is randomly distributed, and the sphericity is good, but there are also some irregularly shaped powders and a small amount of hollow powders and satellite powders. Particle size analysis of the powder was performed, and the particle size distribution diagram shown in Figure 1 (b) was obtained. It can be seen that the d 10 = 22.93 μm, d 50 = 35.34 μm, and d 90 = 53.76 μm. In order to determine the sintering temperature of the powder, high-temperature DSC was performed on the powder, and the heat flow-temperature curve shown in Figure 1 (c) was obtained. From the graph, it can be seen that the melting point of the powder is 1016°C. At the same time, phase identification was performed on the powder, and the X-ray diffraction pattern shown in Figure 1 (d) was obtained. It can be found that the powder is austenitic at room temperature. In addition, the apparent density of the powder was measured to be 4.4 g / cm 3 , and the true density was 7.6740 g / cm 3 .

[0055] (II) Figure 2 is a morphology diagram of the nickel-manganese-based alloy porous structure obtained in Examples 1-5. From Figure 2As can be seen from (a), 2(b) and 2(c), the same sintering time, different sintering temperatures will have different effects on the density of the structure. The higher the sintering temperature, the more obvious the sintering neck of the structure, and the greater the density; while the sintering time has little effect on the density, as shown in (c), 2(d) and 2(e). Figure 2 The density of Examples 1-5 measured by Archimedes method is shown in Table 1. Figure 2 (f) is the cross section of Example 5, from which it can be seen that the structure is sintered more densely, further confirming the reliability of the density measured by Archimedes method.

[0056] (Three) EDS composition analysis was performed on the nickel-manganese-based alloy porous structure obtained in Examples 1-5, and the composition table is shown in Table 1. After t-test, it was found that there was no significant difference in the loss of manganese element under different sintering temperatures and sintering times. Overall, the sintering process caused the loss of about 1 at.% of manganese element in the structure, which provided a basis for subsequent composition control, i.e. by adding excess manganese element in the alloying powder preparation process to compensate for the loss of manganese element during sintering. At the same time, it can be known that different sintering times will affect the uniformity of the composition, which can be proved by the lower composition standard deviation in Table 1.

[0057] Table 1 Composition table (average value ± standard deviation) and density of the structure under different sintering processes

[0058]

[0059] (Four) Temperature-magnetization intensity measurement was performed on the nickel-manganese-based alloy porous structure obtained in Examples 1-5, and the tangent method was used to obtain the start (M s ) and end (M f ) temperatures of the martensitic phase transition of the material, as well as the start (A s ) and end (A f ) temperatures of the reverse martensitic phase transition. Table 2 shows the characteristic temperatures of the martensitic phase transition of the material under the action of a 0.02T magnetic field, as well as the temperature interval and thermal hysteresis. It can be seen that the phase transition temperature of the material is near room temperature, the phase transition temperature interval is 9-18K, and the phase transition thermal hysteresis is 12.5-18K, which is suitable for solid refrigeration applications.

[0060] Table 2 Martensitic phase transition characteristic temperatures of the structure under different sintering processes, temperature interval and thermal hysteresis (K)

[0061]

[0062]

[0063] (Five) Fig. 3 is the magnetic heat performance structure of the porous structure of the nickel-manganese-based alloy obtained in Example 1. As shown in Fig. 3(a), the material can reach 99.0 emu / g (warming curve) and 99.9 emu / g (cooling curve) in the difference of saturation magnetization under the action of a 5T magnetic field, and shows strong magnetic-structure coupling characteristics. The magnetization-field curve obtained in the temperature range of 265-315K is shown in Fig. 3(b). According to this result, the magnetic field-induced entropy change of the sample can be calculated using the Maxwell relation as shown in Fig. 3(c), which is as high as 24.7 J·kg -1 ·K -1 under the change of a 5T magnetic field, the working temperature interval reaches 17.6K, the refrigeration capacity RC value reaches 354.4 J·kg -1 , and the net RC value is 195.7 J·kg -1 . More importantly, the method in the present application is simple and easy to operate, and the phase transition temperature of the prepared structure is at room temperature, which provides unlimited imagination space for the practical application of the nickel-manganese-based material.

[0064] The above description is only the preferred specific implementation of the present application, these specific implementations are different implementations based on the overall concept of the present application, and the protection scope of the present application is not limited to this, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A simplified method for preparing a nickel-manganese-based alloy porous material, characterized in that, Follow these steps: S1: Press Ni 41 Mn 43 Sn 10 Weigh the raw materials according to the atomic stoichiometry of Co6, and then weigh an excess of manganese flakes. Melt the alloy raw materials using a high-frequency induction method to obtain an alloy liquid. S2: The alloy liquid is atomized into powder at 3~4 MPa and then sieved to obtain alloy powder with a diameter of 15~53 μm; S3: The alloy powder is loaded into a cleaned quartz tube and vibrated to compact it. After vacuuming, it is sealed and then transferred to a muffle furnace for sintering at 900~1000℃ for 2~24 hours. After cooling, the quartz tube is removed to obtain a nickel-manganese-based porous alloy material. The specific vacuuming process is as follows: ① First, vacuum to 10℃. -1 ① Below 10 bar; ② Backfill with 0.5~1 bar argon gas, continue evacuation, repeat 2~3 times; ③ Add liquid nitrogen to the vacuum pump, evacuate to 10 bar. -4 Below 0.2 bar, backfill with 0.1~0.2 bar of argon gas.

2. The method according to claim 1, characterized in that, The extra amount of manganese flakes weighed in S1 is 5 wt.% of the total mass of the metal material.

3. The method according to claim 1, characterized in that, The melting temperature in S1 is 1500~1700 ℃, and the melting time is 40~60 minutes.

4. The method according to claim 1, characterized in that, The atomizing gas in S2 is 99.999% high-purity argon, and the furnace exit temperature is 70~90℃.

5. The method according to claim 1, characterized in that, After the alloy powder in S3 is loaded into the quartz tube, a high-purity titanium sheet that has been cleaned with anhydrous ethanol is added into the quartz tube.

6. The method according to claim 1, characterized in that, The S3 uses air cooling.

7. The nickel-manganese-based alloy porous material prepared by the method according to any one of claims 1-6.

8. The nickel-manganese-based alloy porous material according to claim 7, characterized in that, Its density is 60.3% to 80.1%.

9. The application of the nickel-manganese-based alloy porous material prepared by the method according to any one of claims 1-6 as a solid refrigeration material.

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