A kind of infrared low emissivity material and preparation method thereof

Abstract

The present invention provides an infrared low emissivity material and a preparation method thereof, the preparation method comprising: (1) mixing barium carbonate, strontium carbonate, aluminum oxide and silicon dioxide and sintering the mixture to obtain Ba x Sr 1‑x Al2Si2O8 ceramic powder; (2) the Ba x Sr 1‑ x The Al2Si2O8 ceramic powder is ball-milled to obtain the infrared low emissivity material. x Sr 1‑x Al2Si2O8 ceramic powder, and prepare Ba by doping barium carbonate and strontium carbonate x Sr 1‑x Al2Si2O8 ceramic powder can increase the mobility of carriers in ceramic powder, thereby increasing the conductivity of the material; in addition, the Ba x Sr 1‑x The ball milling treatment of Al2Si2O8 ceramic powder can, on the one hand, control the morphology and size of the powder. On the other hand, the ball milling process will cause the molecules and atoms in the ceramic powder to vibrate and rotate, thereby enhancing the powder's absorption in the infrared band. In this way, under the synergistic effect of conductivity and crystal vibration, the infrared emissivity of the material in a high-temperature environment can be significantly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of infrared stealth materials, and in particular to a low infrared emissivity material and a preparation method thereof. Background Art

[0002] Infrared detectors are a passive detection technology that detects, identifies, and tracks targets by analyzing and comparing the radiation differences between the target and the background environment. They offer high mobility, high accuracy, and strong anti-interference capabilities. Kirchhoff's law states that lowering the target's surface temperature and using low-emissivity materials can reduce the intensity of the target's infrared radiation. Therefore, low-emissivity infrared materials and cooling materials have become the main research areas for counter-infrared detection technology.

[0003] In related technologies, lowering the target's surface temperature is difficult, so low-emissivity materials are often used to reduce the target's infrared radiation intensity. However, due to temperature limitations, infrared radiation suppression materials cannot achieve their low infrared emissivity in high-temperature environments. This results in a greater difference in radiation intensity between the target and the background environment, increasing the probability of detection and identification by infrared detectors.

[0004] Therefore, based on the above problems, there is an urgent need to provide an infrared low-emissivity material and a preparation method thereof. Summary of the Invention

[0005] The embodiments of the present invention provide a low-emissivity infrared material and a preparation method thereof, which can solve the problem of high infrared emissivity of infrared radiation suppression materials in high-temperature environments in related technologies.

[0006] In a first aspect, an embodiment of the present invention provides a method for preparing an infrared low-emissivity material, the preparation method comprising:

[0007] (1) Mix barium carbonate, strontium carbonate, aluminum oxide and silicon dioxide and sinter them to obtain Ba x Sr 1-x Al2Si2O8 ceramic powder;

[0008] (2) the Ba x Sr 1-x The Al2Si2O8 ceramic powder is ball-milled to obtain the infrared low-emissivity material.

[0009] Preferably, in step (1), the molar ratio of barium carbonate, strontium carbonate, aluminum oxide and silicon dioxide is (0.2-0.3):(0.7-0.8):1:2.

[0010] Preferably, in step (1), the sintering temperature is 1400-1600° C., and the sintering time is 2-4 hours.

[0011] Preferably, in step (1), the temperature is increased in stages during the sintering process; wherein the heating rate in the first stage is 10-15°C / min, and the heating rate in the second stage is 4-8°C / min.

[0012] Preferably, in step (2), the rotation speed of the ball mill is 350-450 r / min, the time is 5-7 h, and the ball-to-material ratio is (4-5):1.

[0013] Preferably, the particle size of the infrared low emissivity material is 4 to 6 μm.

[0014] In a second aspect, the present invention provides an infrared low-emissivity material prepared using any of the preparation methods described in the first aspect above.

[0015] Preferably, the infrared emissivity of the low infrared emissivity material is lower than 0.35 at a high temperature of 800°C.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects:

[0017] In the present invention, firstly, high temperature resistant Ba x Sr 1-x Al2Si2O8 ceramic powder, and prepare Ba by doping barium carbonate and strontium carbonate x Sr 1-x Al2Si2O8 ceramic powder can increase the mobility of carriers in ceramic powder, thereby increasing the conductivity of the material; in addition, the Ba x Sr 1-x The ball milling treatment of Al2Si2O8 ceramic powder can, on the one hand, control the morphology and size of the powder. On the other hand, the ball milling process will cause the molecules and atoms in the ceramic powder to vibrate and rotate, thereby enhancing the powder's absorption in the infrared band. In this way, under the synergistic effect of conductivity and crystal vibration, the infrared emissivity of the material in a high-temperature environment can be significantly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 This is a scanning electron microscope image of the BaAl2Si2O8 ceramic powder provided in Comparative Example 1 of the present invention after sintering;

[0020] Figure 2 Ba provided in Example 1 of the present invention x Sr 1-x Scanning electron microscope image of Al2Si2O8 ceramic powder after sintering;

[0021] Figure 3 is Ba provided in Example 1 of the present invention x Sr 1-x Synchronous thermal analyzer analysis curve of Al2Si2O8 ceramic powder;

[0022] Figure 4 This is a reflectivity test result diagram of an infrared low-emissivity material provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0024] In order to solve the above problems, an embodiment of the present invention provides a method for preparing an infrared low-emissivity material, which comprises:

[0025] (1) Mix barium carbonate, strontium carbonate, aluminum oxide and silicon dioxide and sinter them to obtain Ba x Sr 1-x Al2Si2O8 ceramic powder;

[0026] (2) the Ba x Sr 1-x The Al2Si2O8 ceramic powder is ball-milled to obtain the infrared low-emissivity material.

[0027] In the embodiment of the present invention, starting from the high temperature resistance, the inventors found that among many high temperature resistant materials, the melting point of barium feldspar is as high as 1760℃, and it has the advantages of excellent high temperature resistance (greater than 1590℃), small thermal expansion coefficient, good oxidation resistance, and strong acid and alkali corrosion resistance. Through research, it was found that strontium feldspar and barium feldspar have the same lattice structure, and the two can form Ba by solid solution after doping. x Sr 1-x Al2Si2O8 composite ceramics.

[0028] Therefore, in this embodiment, firstly, high temperature resistant Ba x Sr 1-xAl2Si2O8 ceramic powder, and prepare Ba by doping barium carbonate and strontium carbonate x Sr 1-x Al2Si2O8 ceramic powder, the doping of strontium elements can make the crystal structure of the ceramic powder undergo phase change, reduce the lattice constant, make the migration of carriers in the powder easier, and then increase the mobility of carriers in the ceramic powder, so that the conductivity of the powder material increases; in addition, the addition of Ba x Sr 1- x Ball milling of Al2Si2O8 ceramic powder not only controls the powder's morphology and size, increasing the material's infrared emissivity, but also causes the molecules and atoms within the powder to vibrate and rotate. This vibrational process resonates with infrared light, enhancing the powder's absorption in the infrared band. Therefore, the synergistic effects of conductivity and crystal vibration in the powder of this embodiment significantly reduce the material's infrared emissivity in high-temperature environments.

[0029] According to some preferred embodiments, in step (1), the molar ratio of barium carbonate, strontium carbonate, aluminum oxide and silicon dioxide is (0.2-0.3):(0.7-0.8):1:2 (for example, it can be 0.2:0.8:1:2, 0.25:0.75:1:2 or 0.3:0.7:1:2).

[0030] Through experimental research of the present invention, it is found that if the strontium carbonate doped in barium carbonate, aluminum oxide and silicon dioxide is too low, the lattice in the powder will be distorted, thereby increasing the dipole moment and reducing the conductivity of the ceramic powder, thereby increasing the infrared emissivity of the ceramic powder material. When the doping amount of strontium carbonate is within the above range, the crystal structure in the ceramic powder will undergo a phase change, the lattice constant will decrease, and the crystal structure will be denser. In this way, when the carriers in the ceramic powder migrate, only less energy is required to cross the energy barrier of the grain boundary, thereby increasing the mobility of the carriers in the ceramic powder, thereby effectively reducing the infrared emissivity of the ceramic powder. Therefore, in this embodiment, the doping ratio of barium carbonate and strontium carbonate during the sintering process is controlled, which is beneficial to ensure that Ba x Sr 1-x On the basis of the good temperature resistance of Al2Si2O8 ceramic powder, it is further ensured that the ceramic powder has a higher electrical conductivity, which is beneficial to reduce its infrared emissivity.

[0031] It should be noted that, in this embodiment, before sintering, barium carbonate, strontium carbonate, aluminum oxide and silicon dioxide are added to a nylon tank with polyacrylate ammonium dispersant and polyacrylamide for more uniform mixing of the powders, and the ball milling is performed at a rotation speed of 350 to 450 r / min, a time of 5 to 7 h, and a ball-to-material ratio of (4 to 5):1.

[0032] According to some preferred embodiments, in step (1), the sintering temperature is 1400-1600°C (for example, 1400°C, 1450°C, 1500°C, 1550°C or 1600°C), and the sintering time is 2-4h (for example, 2h, 3h or 4h).

[0033] In this embodiment, the sintering temperature and time of the powder are controlled within the above-mentioned range, which is conducive to the formation of better crystallinity of the ceramic powder, and further conducive to ensuring better high-temperature resistance and lower infrared emissivity of the ceramic powder; if the sintering temperature is too low, it is not conducive to ensuring better crystallinity of the ceramic powder, and thus is not conducive to ensuring better comprehensive performance of the ceramic powder. Generally speaking, increasing the temperature is conducive to further increasing the crystallinity of the material in the ceramic powder, but the increase in temperature has little effect on the crystallinity of the material, which will cause a large waste of energy.

[0034] According to some preferred embodiments, in step (1), the temperature is increased in stages during the sintering process; wherein the heating rate in the first stage is 10 to 15°C / min (for example, 10°C / min, 11°C / min, 12°C / min, 13°C / min, 14°C / min or 15°C / min), and the heating rate in the second stage is 4 to 8°C / min (for example, 4°C / min, 5°C / min, 6°C / min, 7°C / min or 84°C / min).

[0035] In this embodiment, the temperature is increased in stages during the sintering process, and the heating rate of each stage is controlled. This facilitates sufficient reaction between the powders during the sintering process, thereby ensuring good high-temperature resistance and low infrared emissivity of the ceramic powder. Specifically, during the sintering process in this embodiment, the temperature is first increased from room temperature to 200°C at a rate of 10-15°C / min. After reaching 200°C, the temperature is then increased to the sintering temperature at a rate of 4-8°C / min.

[0036] According to some preferred embodiments, in step (2), the ball milling speed is 350-450 r / min (for example, 350 r / min, 380 r / min, 400 r / min, 420 r / min or 450 r / min), the time is 5-7 h (for example, 5 h, 6 h or 7 h), and the ball-to-material ratio is (4-5):1 (for example, 4:1, 4.5:1 or 5:1).

[0037] In this embodiment, the inventors, after extensive research, discovered that ball milling the sintered ceramic powder can improve the morphology and size of the ceramic powder while ensuring its high-temperature resistance and further reducing its infrared emissivity. By controlling the milling parameters during the milling process, the revolution of the milling jar can generate centripetal acceleration several times, or even dozens of times, the same as the acceleration of gravity. Under the strong centrifugal force, the grinding balls and powder tumble at high speed in the milling jar. The mutual friction between them generates a strong shear force on the powder. Mechanical ball milling changes the powder's microscopic morphology from spherical to flaky, thereby reducing the specific surface area of ​​the powder particles and, in turn, the infrared emissivity of the powder. On the other hand, during the ball milling process of powder, the molecules and atoms in the crystal will produce lattice vibrations. The influence of lattice vibrations on the infrared emissivity of the powder can be regarded as the interaction or even strong coupling between photons and phonons. When photons and phonons have the same frequency and wave vector, they can resonate, interact and exchange energy, and their resonant frequency just includes the infrared window band of 3 to 5 μm. Therefore, the lattice vibration will produce resonant absorption of infrared light, thereby further reducing the infrared emissivity of the powder.

[0038] It should be noted that the grinding balls used in the ball milling in this embodiment are corundum balls.

[0039] According to some preferred embodiments, the particle size of the infrared low emissivity material is 4 to 6 μm (for example, 4 μm, 5 μm or 6 μm).

[0040] In this embodiment, the ceramic powder is ground from a spherical shape to a flake shape by controlling the ball milling parameters during the ball milling process, and the particle size of the flake powder is preferably within the above range, which is conducive to ensuring the ceramic powder has good high temperature resistance and low infrared emissivity.

[0041] An embodiment of the present invention further provides a low infrared emissivity material, which is prepared using any of the above-mentioned preparation methods.

[0042] According to some preferred embodiments, the infrared emissivity of the low infrared emissivity material is lower than 0.35 at a high temperature of 800°C.

[0043] In summary, in this embodiment, first, by doping strontium elements during the sintering process and controlling the sintering temperature and heating rate during the sintering process, it is beneficial to the phase change of the crystal structure in the ceramic powder, so that the carriers in the ceramic powder only need less energy to cross the energy barrier of the grain boundary when migrating, which increases the mobility of the carriers in the ceramic powder, thereby effectively reducing the infrared emissivity of the ceramic powder. In addition, the ceramic powder is ball-milled. On the one hand, the morphology and size of the powder can be controlled. On the other hand, the ball-milling process will cause the molecules and atoms in the ceramic powder to vibrate and rotate, thereby enhancing the powder's absorption in the infrared band. In this way, under the synergistic effect of conductivity and lattice vibration, the infrared emissivity of the material in a high-temperature environment can be significantly reduced.

[0044] An embodiment of the present invention further provides an infrared low-emissivity coating, which is prepared using the infrared low-emissivity material prepared above; wherein the infrared low-emissivity coating preparation method comprises the following steps:

[0045] (1) Preparation of infrared low emissivity fillers;

[0046] (2) stirring and mixing the inorganic phosphate binder, the infrared low emissivity filler and the surfactant in a certain proportion to obtain an infrared low emissivity coating;

[0047] (3) Scraping the infrared low emissivity coating onto the pre-treated target substrate and curing the coating to obtain the infrared low emissivity coating.

[0048] In this embodiment, by first preparing an infrared low-emissivity filler, the obtained infrared low-emissivity filler has both good high temperature resistance and low infrared emissivity. By combining an inorganic phosphate adhesive and an infrared low-emissivity filler with each other and adding a certain amount of surfactant, it is beneficial to prepare an infrared low-emissivity coating with good adhesion and fluidity, which is beneficial to scrape the coating onto the target substrate surface by scraping, and then obtain an infrared low-emissivity coating with good stability at high temperature, which can meet the requirements of the hot end components for infrared stealth performance under high temperature conditions.

[0049] It should be noted that when applying the infrared low-emissivity coating to the surface of the target substrate, the substrate is first pretreated. The pretreatment method is as follows: for example, the target substrate is a GH3030 high-temperature alloy plate (diameter 4.5 cm, thickness 1.2 mm). First, the substrate is polished with 400-mesh sandpaper. Then, the substrate is subjected to the following surface treatments in sequence: degreasing (immersion in a saturated ethanol solution of potassium hydroxide for 120 hours), water washing, natural air drying, sandpaper polishing, ultrasonic water washing, and oven drying. The above pretreatment operation is conducive to further ensuring good adhesion between the coating and the substrate. At the same time, it should be noted that the thickness of the coating after scraping is preferably 240 to 250 μm.

[0050] According to some preferred embodiments, in step (3), the curing is staged curing; wherein the temperature of the first stage curing is 20-30°C (for example, 20°C, 22°C, 25°C, 28°C or 30°C), and the time is 20-24h (for example, 20h, 21h, 22h, 23h or 24h); the temperature of the second stage curing is 450-550°C (for example, 450°C, 480°C, 500°C, 520°C or 550°C), and the time is 2-3h (for example, 2h, 2.5h or 3h).

[0051] After the paint is scraped on the surface of the substrate, the infrared low-emissivity filler is dispersed in the paint on the surface of the substrate. There are a large number of interfaces between the particles in the coating, which causes the infrared radiation to be repeatedly reflected on the interface, increasing the path of the infrared radiation to pass through the medium, and the infrared radiation is absorbed while passing through the medium. In this embodiment, in order to make the filler particles in the paint tightly connected together on the surface of the substrate, and at the same time make the particles in the paint tightly connected to form a dense coating, after the paint is scraped on the surface of the substrate, the coating is first placed at room temperature for 20 to 24 hours to dry naturally. After drying, the humidity of the coating is 55 to 57%, and then it is cured at a temperature of 450 to 500°C. During the high-temperature curing process, the powder particles in the coating are connected to each other to form a more uniform structure, reducing the area of ​​the grain boundary, and the structure is more complete. The smooth surface makes it easier to reduce the infrared emissivity of the coating surface.

[0052] In order to more clearly illustrate the technical solutions and advantages of the present invention, a low infrared emissivity material and a preparation method thereof are described in detail below through several embodiments.

[0053] Example 1:

[0054] (1) Barium carbonate, strontium carbonate, aluminum oxide, silicon dioxide, polyacrylate dispersant, and polyacrylamide were added to a nylon jar in a molar ratio of 0.25:0.75:1:2 and mixed and ball-milled at a speed of 400 r / min and a ball-to-material ratio of 5:1. After ball milling for 3 h, the mixture was placed in a high-temperature sintering furnace at 1600 ° C for 3 h and naturally cooled to room temperature of 25 ° C to obtain Ba 0.25 Sr 0.75 Al2Si2O8 ceramic powder; wherein, during the sintering process, the heating rate from room temperature (25°C) to 200°C is 15°C / min, and the heating rate from 200°C to 1600°C is 6°C / min;

[0055] (2) Will Ba 0.25 Sr 0.75 Al2Si2O8 ceramic powder was placed in a nylon jar and ball-milled at a speed of 400 r / min for 6 hours to obtain infrared low-emissivity material; wherein, corundum balls were used as grinding balls, and the ball-to-material ratio was 5:1.

[0056] Depend on Figure 1 It can be seen that without adding Sr 2+ When the BaAl2Si2O8 grains are in small granular form, there is also a molten glass phase; Figure 2 For Ba 0.25 Sr 0.75 Micromorphology of Al2Si2O8 ceramic powder, Sr added 2+ After that, the grains grew significantly, from small particles to long strips, indicating that Ba 0.25 Sr 0.75 Al2Si2O8 has been transformed into a monoclinic phase. The particles have become larger, the gaps between the particles have become smaller, the surface has become brighter and smoother, the geometric shape has become more regular, the integrity and periodicity of the lattice have been enhanced, and many large particles have formed and stacked on each other, thus minimizing the energy of the system. This is conducive to improving the density of the powder, reducing the specific surface area of ​​the particles, and thus reducing the infrared emissivity of the powder. At the same time, Figure 2 It can be seen from the figure that an endothermic peak appears at about 100℃. Analysis shows that this is caused by the endothermic dehydration of the powder, which corresponds to the weight loss of the system shown in the TG curve. The decomposition of organic matter in the gel mainly occurs below 500℃. The two small endothermic peaks and weight loss curves between 150 and 500℃ correspond to the decomposition of the polyacrylate ammonium dispersant and the polyacrylamide polymer gel in the system respectively. The endothermic peak near 750℃ is due to the decomposition of carbonates, and the sharp exothermic peak around 1200℃ is due to the decomposition of Ba 0.25 Sr 0.75 The synthesis of Al2Si2O8 ceramic powder, therefore, this example determines Ba 0.25 Sr 0.75The synthesis temperature of Al2Si2O8 powder is 1200℃, and after high-temperature solid-phase sintering at 1580℃, the sample has better structural integrity.

[0057] Example 2:

[0058] (1) Barium carbonate, strontium carbonate, aluminum oxide, silicon dioxide, polyacrylate dispersant, and polyacrylamide were added to a nylon jar in a molar ratio of 0.25:0.75:1:2 and mixed and ball-milled at a speed of 450 r / min and a ball-to-material ratio of 5:1. After ball milling for 3 h, the mixture was placed in a high-temperature sintering furnace at 1500 ° C for 3 h and naturally cooled to room temperature of 25 ° C to obtain Ba 0.25 Sr 0.75 Al2Si2O8 ceramic powder; wherein, during the sintering process, the heating rate from room temperature (25°C) to 200°C is 13°C / min, and the heating rate from 200°C to 1500°C is 5°C / min;

[0059] (2) Will Ba 0.25 Sr 0.75 Al2Si2O8 ceramic powder was placed in a nylon jar and ball-milled at a speed of 450 r / min for 5 hours to obtain infrared low-emissivity material; wherein, corundum balls were used as grinding balls, and the ball-to-material ratio was 5:1.

[0060] Example 3:

[0061] Example 3 is substantially the same as Example 1, except that in step (1), the molar ratio of barium carbonate, strontium carbonate, aluminum oxide, and silicon dioxide is 0.1:0.9:1:2.

[0062] Example 4:

[0063] Example 4 is substantially the same as Example 1, except that in step (1), the molar ratio of barium carbonate, strontium carbonate, aluminum oxide, and silicon dioxide is 0.5:0.5:1:2.

[0064] Comparative Example 1:

[0065] Comparative Example 1 is basically the same as Example 1, except that, in step (1), barium carbonate, aluminum oxide and silicon dioxide, polyacrylate ammonium dispersant and polyacrylamide in a molar ratio of 1:1:2 are added to a nylon jar and mixed and ball-milled at a speed of 400 r / min, and the ball-to-material ratio is set to 5:1. After ball milling for 3 hours, it is placed in a high-temperature sintering furnace and sintered at 1600°C for 3 hours. After naturally cooling to room temperature of 25°C, BaAl2Si2O8 ceramic powder is obtained; wherein, during the sintering process, the heating rate from room temperature (25°C) to 200°C is 13°C / min, and the heating rate from 200°C to 1600°C is 5°C / min.

[0066] Comparative Example 2:

[0067] Comparative Example 2 is basically the same as Example 1, except that, in step (1), strontium carbonate, aluminum oxide and silicon dioxide, polyacrylate dispersant and polyacrylamide in a molar ratio of 1:1:2 are added to a nylon tank and mixed and ball-milled at a speed of 400 r / min, and the ball-to-material ratio is set to 5:1. After ball milling for 3 hours, it is placed in a high-temperature sintering furnace and sintered at 1600°C for 3 hours. After naturally cooling to room temperature of 25°C, SrAl2Si2O8 ceramic powder is obtained; wherein, during the sintering process, the heating rate from room temperature (25°C) to 200°C is 13°C / min, and the heating rate from 200°C to 1600°C is 5°C / min.

[0068] Comparative Example 3:

[0069] Comparative Example 3 is substantially the same as Example 1, except that step (2) is not included, i.e., Ba 0.25 Sr 0.75 The Al2Si2O8 ceramic powder is not subjected to ball milling treatment.

[0070] The materials prepared in the embodiments and comparative examples were subjected to emissivity tests, and the test results are shown in Table 1. The test method is as follows: the average emissivity of the materials in the above embodiments and comparative examples after tableting was measured using an IR-2 dual-band infrared emissivity meter and a BC-1 precision temperature controller. First, the IR-2 dual-band infrared emissivity meter was turned on, and the temperature of the black body was set to 430°C. After the black body was heated to 430°C and stabilized for half an hour, 3-5 μm and 8-14 μm band filters were installed on the lens respectively. After calibrating the instrument, the average emissivity at room temperature (25°C) was first measured. Then, the BC-1 precision temperature controller was turned on, and the target temperatures of the temperature controller were set to room temperature, 100°C, 200°C, 300°C, 400°C, 500°C, 600°C, 700°C and 800°C respectively. After the temperature of the temperature controller and the sample were stable, the corresponding infrared emissivities were recorded respectively.

[0071] Table 1

[0072]

[0073] As can be seen from Table 1, the material prepared in Example 1 of the present invention has a low infrared emissivity at high temperatures. As the test temperature increases, the infrared emissivity of the material in the 3-5 μm band gradually decreases, and the infrared emissivity in the range of room temperature to 800°C is less than 0.35, which means that it can be used as an infrared stealth material for hot-end components.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for preparing an infrared low emissivity material, characterized in that: The preparation method comprises: (1) Mix barium carbonate, strontium carbonate, aluminum oxide and silicon dioxide and sinter them to obtain Ba x Sr 1-x Al2Si2O8 ceramic powder; the molar ratio of barium carbonate, strontium carbonate, aluminum oxide and silicon dioxide is (0.2~0.3): (0.7~0.8): 1:2; (2) The Ba x Sr 1-x Al2Si2O8 ceramic powder is ball-milled, and the microscopic morphology of the powder is changed from spherical to flake by mechanical ball milling to obtain the infrared low-emissivity material; the particle size of the infrared low-emissivity material is 4-6 μm.

2. The preparation method according to claim 1, characterized in that In step (1), the sintering temperature is 1400-1600° C. and the sintering time is 2-4 hours.

3. The preparation method according to claim 1, characterized in that In step (1), the temperature is increased in stages during the sintering process; wherein the heating rate in the first stage is 10-15°C / min, and the heating rate in the second stage is 4-8°C / min.

4. The preparation method according to claim 1, characterized in that In step (2), the rotation speed of the ball mill is 350-450 r / min, the time is 5-7 h, and the ball-to-material ratio is (4-5):

1.

5. An infrared low emissivity material, characterized in that: The preparation method according to any one of claims 1 to 4 is used for preparation.

6. The material according to claim 5, characterized in that The infrared low emissivity material has an infrared emissivity lower than 0.35 at a high temperature of 800°C.

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