Preparation method of high-entropy boride infrared radiation material

Abstract

The application relates to a preparation method of a high-entropy boride infrared radiation material, which is characterized in that four nitrate or sulfate powders in Co(NO3)3.6H2O, Ni(NO3)2.6H2O, Cr(NO3)3.9H2O, Cu(NO3)2.3H2O and FeSO4.7H2O are used as raw materials, sodium borohydride is used as a boron source, the raw materials and the boron source are respectively stirred and dissolved in deionized water which is pre-swept by nitrogen or argon for 40-80 minutes, the obtained salt solution and the boron source aqueous solution are mixed, and then the high-entropy boride infrared radiation material is prepared through a reduction reaction, filtration and freeze-drying. The application has the characteristics of simple required equipment, easy preparation method, strong repeatability and high production efficiency, and can be used for industrial large-scale production. The prepared high-entropy boride material is not only structurally stable, but also has high infrared emissivity, and can be used as an infrared radiation material.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of high-entropy ceramic materials and the field of infrared radiation materials, and in particular to a preparation method of a high-entropy boride infrared radiation material. BACKGROUND

[0002] Objects at a temperature higher than absolute zero will radiate energy in the form of electromagnetic waves, and the radiation intensity will increase exponentially with the increase of temperature. In the high-temperature field, especially in industrial kilns, when the temperature is below 800 °C, the heat transfer in the furnace mainly relies on thermal convection; when the temperature reaches 800-1000 °C, thermal convection and thermal radiation act together; when the temperature is higher than 1000 °C, thermal conduction mainly relies on thermal radiation. 90% of the heat obtained by the heated object is obtained through the process of thermal radiation heat transfer. Therefore, introducing high infrared radiation materials into the heat transfer scene of high-temperature equipment can enhance the heat radiation, improve the thermal efficiency of the base material, reduce energy consumption, prolong the service life of the base, and improve the utilization rate of energy.

[0003] Transition metal materials are often studied for high infrared radiation materials, but such infrared radiation materials composed of single main element materials have great limitations, and the radiation characteristics are single. The defects in specific wave bands make it difficult to meet the use requirements of the overall radiation performance. Especially as the temperature rises, the peak of blackbody radiation will move towards short wavelengths. This defect makes the coating only exhibit excellent infrared radiation performance at a specific temperature. Reasonable doping can effectively improve the infrared radiation performance of the coating, especially for high-entropy materials with multiple main elements. Due to the different atomic radii of the main elements, the substitution and replacement of atoms will cause strong lattice distortion, which will enhance the lattice vibration frequency and improve the infrared radiation ability. At the same time, different main element materials have different infrared radiation abilities in different wave band ranges, which can produce a complementary effect to obtain a broadband high infrared radiation material.

[0004] The system entropy is improved by multi-principal element design, which inhibits the adverse effects of enthalpy, so that it shows lower Gibbs free energy, which is beneficial to thermal stability. And the atomic size difference between the principal elements causes large lattice distortion, so it shows excellent performance in electricity, optics, magnetism and catalysis, etc. It is one of the major discoveries in the field of high-entropy materials in recent years. The main preparation method of high-entropy borides reported at present is vacuum sintering. The method of discharging sintering under protective gas in CN115196968A obtains high-entropy boride powder. CN115073183A combines sol-gel and vacuum calcination to prepare high-entropy borides. CN115159990A discloses a method of obtaining high-entropy borides by ball milling and vacuum calcination. However, the above methods all have problems such as complex operation, long synthesis period, high energy consumption and serious environmental pollution. Therefore, it has good application value to develop a rapid preparation method of high-entropy borides. At present, there is no research report on the use of high-entropy borides for infrared radiation materials. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a simple and convenient preparation method of high-entropy boride infrared radiation material.

[0006] To solve the above problems, the preparation method of high-entropy boride infrared radiation material according to the present application is characterized in that: the method refers to using four kinds of nitrate or sulfate in Co(NO3)3·6H2O, Ni(NO3)2·6H2O, Cr(NO3)3·9H2O, Cu(NO3)2·3H2O and FeSO4·7H2O powders as raw materials, sodium borohydride as boron source, and the raw materials and boron source are respectively dissolved in deionized water which is pre-blasted with nitrogen or argon for 40-80 minutes, and the obtained salt solution and boron source aqueous solution are mixed, then subjected to reduction reaction, filtration and freeze-drying to obtain high-entropy boride infrared radiation material.

[0007] In the preparation method, the reaction solution is continuously blown with nitrogen or argon, and the reaction container is placed in an ice water bath for cooling during the preparation process.

[0008] The dissolution duration of the nitrate or sulfate is 30-40 min; the mass ratio of the raw material to water is (1.101-1.260):120, and the metal atoms in the raw material are in equimolar ratio.

[0009] The stirring speed is 400-700 r / min.

[0010] The reduction reaction is carried out as follows: the sodium borohydride aqueous solution is slowly injected into the salt solution with a syringe, and the reaction can be completed in 30-40 min; the mass ratio of sodium borohydride to deionized water in the sodium borohydride aqueous solution is 0.605:60.

[0011] The filtration is performed by vacuum filtration, and the filter cake is washed by deionized water and anhydrous ethanol alternately for 3-6 times, each time for 1 minute.

[0012] The freezing drying condition refers to that the freezing temperature is-45 to-63 DEG C, the vacuum degree is 30-40 Pa, and the duration is 8-12 h until the ice crystal disappears completely.

[0013] The high-entropy boride is prepared by the above method.

[0014] The high-entropy boride has the infrared emissivity of 0.8887-0.9033 in the range of 2.5-20 mu m.

[0015] Compared with the prior art, the present application has the following advantages:

[0016] 1. The present application uses four kinds of nitrate or sulfate in Co (NO3) 3.6H2O, Ni (NO3) 2.6H2O, Cr (NO3) 3.9H2O, Cu (NO3) 2.3H2O and FeSO4.7H2O powder as raw materials, sodium borohydride as boron source, and adopts the method of chemical reduction and freeze drying to prepare high-entropy boride infrared radiation material, which has the characteristics of simple required equipment, easy preparation method, strong repeatability and high production efficiency, and can be used for industrial mass production.

[0017] 2. The high-entropy boride infrared radiation material prepared by the present application has enhanced lattice vibration frequency due to lattice distortion caused by multi-principal element design, which improves the infrared radiation capacity of the material; and the infrared radiation capacity of different principal element materials in different waveband ranges is not the same, which can produce complementary effect, so as to obtain broadband high infrared radiation material. At the same time, the high configuration entropy brought by multi-principal element design helps to improve the stability of the system; the slow diffusion effect delays the redistribution of elements at high temperature, and inhibits the formation of new phases, which is beneficial to the phase stability at high temperature. Therefore, the high-entropy boride infrared radiation material prepared by the present application not only has stable structure, but also has high infrared emissivity, and can be used as infrared radiation material.

[0018]

Optical performance

[0019] The absorption spectrum of the high-entropy boride infrared radiation material in the range of 2.5-20 mu m is obtained by using German Bruker Tensor 27 infrared spectrometer (containing integrating sphere), and then the infrared emissivity is obtained according to national standard GB / T 26974-2011. Through calculation, the infrared emissivity of the high-entropy boride infrared radiation material prepared by the present application is 0.8887-0.9033.

[0020]

Thermal stability performance

[0021] The high-entropy boride infrared radiation material is placed in a box furnace in an air atmosphere, and a thermal stability experiment is carried out at 600 DEG C for 100 hours. The results show that the high-entropy boride infrared radiation material prepared by the application has a stable structure, and the infrared emissivity fluctuation is only 0.021~0.043, which can meet the use requirements under high-temperature working conditions. BRIEF DESCRIPTION OF DRAWINGS

[0022] The specific embodiments of the application will be further described in detail below with reference to the accompanying drawings.

[0023] Figure 1 The infrared emission spectrum of (CoNiCuFe)B2 in the embodiment 1 of the application in the 2.5~20 μm wave band.

[0024] Figure 2 The XRD diagram of (CoNiCuFe)B2 in the embodiment 1 of the application.

[0025] Figure 3 The SEM diagram of (CoNiCuFe)B2 in the embodiment 1 of the application.

[0026] Figure 4 The infrared emission spectrum of (CrNiCuFe)B2 in the embodiment 2 of the application in the 2.5~20 μm wave band.

[0027] Figure 5 The infrared emission spectrum of (CrCoNiCu)B2 in the embodiment 3 of the application in the 2.5~20 μm wave band. DETAILED DESCRIPTION

[0028] A preparation method of a high-entropy boride infrared radiation material, the method is that four kinds of nitrate or sulfate in Co(NO3)3.6H2O, Ni(NO3)2.6H2O, Cr(NO3)3.9H2O, Cu(NO3)2.3H2O and FeSO4.7H2O powders are used as raw materials, sodium borohydride is used as a boron source, the raw materials and the boron source are respectively dissolved in deionized water which is pre-blasted by nitrogen or argon for 40-80 minutes, and the stirring speed is 400-700 r / min, the obtained salt solution and the boron source aqueous solution are mixed, then filtered by vacuum filtration after reduction reaction, and the deionized water and anhydrous ethanol are alternately cleaned for 3-6 times during the filtration process. Finally, the high-entropy boride infrared radiation material is obtained by freezing at-24 DEG C for 12 hours, and then freeze-drying under the conditions of-45 DEG C to-63 DEG C, vacuum degree of 30-40 Pa and duration of 8-12 hours until all ice crystals disappear. The infrared emissivity of the high-entropy boride infrared radiation material in the range of 2.5-20 mu m is 0.8887-0.9033.

[0029] The dissolution duration of the nitrate or sulfate is 30-40 min; the mass ratio (g / g) of the raw materials to water is (1.101-1.260):120, and the metal atoms in the raw materials are in equimolar ratio.

[0030] The reduction reaction is performed by the following method: the sodium borohydride aqueous solution is slowly injected into the salt solution by a syringe, and the reaction can be completed in 30-40 min; the mass ratio (g / g) of sodium borohydride to deionized water in the sodium borohydride aqueous solution is 0.605:60.

[0031] In the preparation method, the reaction solution is continuously purged by nitrogen or argon, and the reaction container is placed in an ice water bath for cooling during the preparation process.

[0032] Example 1

[0033] Co(NO3)3.6H2O 0.291 g (1 mmol), Ni(NO3)2.6H2O 0.291 g (1 mmol), Cu(NO3)2.3H2O 0.242 g (1 mmol) and FeSO4.7H2O 0.278 g (1 mmol) powders are weighed respectively. The weighed raw materials are dissolved in 120 g of deionized water which is pre-blasted by nitrogen for 40 min, the dissolution process is stirred by a mechanical stirrer, the stirring speed is set to 400 r / min, and the duration is 30 min, and a salt solution is obtained.

[0034] NaBH4 0.605 g (16 mmol) was dissolved in 60 g of deionized water which was pre-nitrogen purged for 60 min to obtain a sodium borohydride aqueous solution.

[0035] The sodium borohydride aqueous solution was slowly added into the salt solution by a syringe, and the reaction was carried out for 30 min. The solution after the reaction was filtered by vacuum suction filtration, and deionized water and anhydrous ethanol were used to clean the filter alternately for 3 times during the suction filtration process. The sample obtained after the suction filtration was first frozen for 12 h at-24 °C, and then placed in a freeze dryer, with a temperature of-63 °C and a vacuum degree of 40 Pa, for 12 h until all ice crystals disappeared, to obtain a (CoNiCuFe)B2 high-entropy boride infrared radiation material powder.

[0036] Figure 1 In order to obtain the infrared emission spectrum of the (CoNiCuFe)B2 high-entropy boride infrared radiation material powder prepared, it was measured that the infrared emissivity of the powder in the 2.5~20 μm waveband reached 0.9033, indicating that the material has high infrared radiation characteristics.

[0037] Table 1 is the EDS result of the (CoNiCuFe)B2 high-entropy boride infrared radiation material powder prepared, which shows that the molar ratio of each metal element in the high-entropy boride conforms to the original component design, and is a typical high-entropy compound state.

[0038] Table 1 EDS result of (CoNiCuFe)B2 high-entropy boride infrared radiation material powder

[0039]

[0040] Figure 2 For the XRD spectrum of the (CoNiCuFe)B2 high-entropy boride infrared radiation material powder prepared, obvious peaks belonging to high-entropy alloy boride (100), (101), (110), (210) can be observed.

[0041] Figure 3 For the SEM image of the (CoNiCuFe)B2 high-entropy boride infrared radiation material powder prepared, it shows that the material prepared is aggregated by particles.

[0042] Example 2

[0043] Cr(NO3)3·9H2O 0.4 g (1 mmol), Ni(NO3)2·6H2O 0.291 g (1 mmol), Cu(NO3)2·3H2O 0.242 g (1 mmol) and FeSO4·7H2O 0.278 g (1 mmol) were weighed respectively. The weighed raw materials were added to 120 g of deionized water which was previously purged with nitrogen for 80 min to dissolve, and the dissolving process was stirred by a mechanical stirrer at a speed of 700 r / min for 40 min to obtain a salt solution.

[0044] NaBH4 0.605 g (16 mmol) was dissolved in 60 g of deionized water which was previously purged with nitrogen for 60 min to obtain a sodium borohydride aqueous solution.

[0045] The sodium borohydride aqueous solution was slowly added to the salt solution by a syringe, and the reaction was carried out for 30 min. The solution after the reaction was filtered by vacuum suction filtration, and deionized water and anhydrous ethanol were used to clean the filter alternately for 6 times during the suction filtration process. The sample obtained after suction filtration was first frozen at -24 °C for 12 h, and then placed in a freeze dryer, with a temperature of -45 °C and a vacuum degree of 30 Pa, for 12 h until all ice crystals disappeared, to obtain a (CrNiCuFe)B2 high-entropy boride infrared radiation material powder.

[0046] Figure 4 In order to obtain the infrared emission spectrum of the (CrNiCuFe)B2 high-entropy boride infrared radiation material powder, it was measured that the infrared emissivity of the powder in the wavelength range of 2.5-20 μm reached 0.8887, indicating that the material has high infrared radiation characteristics.

[0047] Example 3

[0048] Cr(NO3)3·9H2O 0.4 g (1 mmol), Co(NO3)3·6H2O 0.291 g (1 mmol), Ni(NO3)2·6H2O 0.291 g (1 mmol) and Cu(NO3)2·3H2O 0.242 g (1 mmol) were weighed respectively. The weighed raw materials were added to 120 g of deionized water which was previously purged with nitrogen for 60 min to dissolve, and the dissolving process was stirred by a mechanical stirrer at a speed of 500 r / min for 35 min to obtain a salt solution.

[0049] NaBH4 0.605 g (16 mmol) was dissolved in 60 g of deionized water which was previously purged with nitrogen for 60 min to obtain a sodium borohydride aqueous solution.

[0050] The aqueous solution of sodium borohydride was slowly added into the salt solution by a syringe, and the reaction was carried out for 35 min. The solution after the reaction was filtered by vacuum suction filtration, and deionized water and anhydrous ethanol were used for cleaning 5 times alternately during the suction filtration process. The sample obtained after the suction filtration was first frozen at-24 °C for 12 h, and then placed in a freeze dryer, the temperature was-55 °C, the vacuum degree was 35 Pa, and the process was continued for 12 h until all the ice crystals disappeared, and then the (CrCoNiCu)B2 high-entropy boride infrared radiation material powder was obtained.

[0051] Figure 5 In order to obtain the infrared emission spectrum of the (CrCoNiCu)B2 high-entropy boride infrared radiation material powder, it was measured that the infrared emissivity of the powder in the 2.5~20 μm wave band reached 0.8995, indicating that the material has high infrared radiation characteristics.

Claims

1. A method for preparing a high-entropy boride infrared radiation material, characterized in that: This method involves using four of the following powders as raw materials in a reaction vessel: Co(NO3)3·6H2O, Ni(NO3)2·6H2O, Cr(NO3)3·9H2O, Cu(NO3)2·3H2O, and FeSO4·7H2O. Sodium borohydride is used as the boron source. The raw materials and the boron source are dissolved separately in deionized water that has been purged with nitrogen or argon for 40–80 minutes by stirring. The resulting salt solution is mixed with the aqueous solution of the boron source and then subjected to a reduction reaction, filtration, and freeze-drying to obtain a high-entropy boride infrared radiation material. The dissolution time is 30–40 min. The mass ratio of raw materials to water is (1.101–1.260):120, and the metal atoms in the raw materials are in equimolar proportions.

2. The method for preparing a high-entropy boride infrared radiation material as described in claim 1, characterized in that: In this preparation method, the reaction solution is continuously purged with nitrogen or argon gas, and the reaction vessel is placed in an ice-water bath for cooling during the preparation process.

3. The method for preparing a high-entropy boride infrared radiation material as described in claim 1, characterized in that: The stirring speed is 400–700 r / min.

4. The method for preparing a high-entropy boride infrared radiation material as described in claim 1, characterized in that: The reduction reaction is carried out as follows: sodium borohydride aqueous solution is slowly injected into the salt solution using a syringe, and the reaction is allowed to proceed for 30-40 minutes; the mass ratio of sodium borohydride to deionized water in the sodium borohydride aqueous solution is 0.605:

60.

5. The method for preparing a high-entropy boride infrared radiation material as described in claim 1, characterized in that: The filtration is carried out by vacuum filtration. During the filtration process, the filter cake is washed with deionized water and anhydrous ethanol alternately 3 to 6 times, each time for 1 minute.

6. The method for preparing a high-entropy boride infrared radiation material as described in claim 1, characterized in that: The freeze-drying conditions refer to a freezing temperature of -45 to -63 °C, a vacuum degree of 30 to 40 Pa, and a duration of 8 to 12 hours, until all ice crystals are observed to have disappeared.

7. A high-entropy boride infrared radiation material prepared by any one of claims 1 to 6.

8. The high-entropy boride infrared radiation material as described in claim 7, characterized in that: The infrared emissivity of this high-entropy boride infrared radiation material is 0.8887~0.9033 in the 2.5~20 μm band.

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