Radiation-resistant thermal control filler and antistatic thermal control coating and preparation method thereof

Abstract

The present application relates to a radiation-resistant thermal control filler and a preparation method thereof, as well as an antistatic thermal control coating and a preparation method thereof, wherein the filler preparation method includes: (1) reacting a mixed salt solution of aluminum salt and zinc salt with an alkaline solution to obtain a precursor; (2) drying and calcining the precursor to obtain an aluminum-doped zinc oxide powder; and (3) purifying the aluminum-doped zinc oxide powder in an oxygen atmosphere to obtain a radiation-resistant thermal control filler, wherein the purification temperature is higher than the calcination temperature. The above-mentioned filler preparation method adopts oxygen atmosphere purification treatment, utilizes the principles of lattice defect regulation and crystal internal vacancy design, reduces the concentration of oxygen vacancy defects in powder pigments, achieves inhibition of proton irradiation damage to fillers, improves the stability of fillers and coatings containing the fillers in a vacuum-proton irradiation environment, ensures space proton irradiation stability while meeting antistatic requirements, and extends the service life of the material.

Description

Technical Field

[0001] The present application relates to the field of surface engineering technology, and in particular to a radiation-resistant thermal control filler and a preparation method thereof, and an antistatic thermal control coating and a preparation method thereof. Background Art

[0002] Thermal control coating is an important part of the spacecraft thermal control system. It regulates the solar absorption rate (α s ) and hemispherical emissivity (ε h ) to control the thermal balance of the spacecraft to ensure that the spacecraft itself and its payload are always at normal operating temperature.

[0003] When a spacecraft is flying in a high orbit or deep space exploration, the solar wind and charged particles in space will charge the outer surface materials of the spacecraft, causing a large amount of static electricity to accumulate on the local surface of the spacecraft, posing the risk of static electricity accumulation and discharge, interference with the operation of electronic equipment on the spacecraft, and system failure. In order to avoid the static electricity accumulation effect of spacecraft in the space environment, anti-static performance requirements are put forward for thermal control coatings in the space environment. At the same time, when a spacecraft is flying in a high orbit or deep space exploration for a long time, the space radiation characteristics it is subjected to are different from those of low-Earth orbit spacecraft, among which high-energy and high-dose proton radiation characteristics are the most prominent. Therefore, thermal control coating materials used in high-orbit or deep space exploration environments should have anti-static and proton radiation resistance characteristics in addition to the common thermal control coating material characteristics.

[0004] Thermal control coatings are mainly composed of functional filler components and adhesive components. The adhesive component usually adopts a material system of silicone resin and silicate, which can well resist the effects of ultraviolet radiation and atomic oxygen. Functional fillers are the most important components in thermal control coatings, responsible for realizing the thermal control, antistatic and anti-radiation properties of the coating. At present, zinc oxide is usually doped with metal elements as a filler for antistatic thermal control coatings with high reflectivity. However, zinc oxide has poor tolerance to proton irradiation. This is because high-energy protons in space (50Kev) can ionize common thermal control coating fillers such as zinc oxide and zinc titanate, constantly causing the formation of free oxygen and oxygen vacancies in their lattices, and gradually forming defects, which will cause the solar absorption ratio of the thermal control coating to continue to increase, seriously affecting the heat dissipation capacity of the coating, and cannot meet the service life requirements of the spacecraft. Therefore, for thermal control coatings in long-term high orbit or deep space environments, how to ensure the stability of space proton irradiation while meeting the antistatic requirements is an urgent problem to be solved.

[0005] Application Contents

[0006] The present application provides a radiation-resistant thermal control filler and a preparation method thereof, as well as an antistatic thermal control coating and a preparation method thereof, to solve the technical problem of how to ensure the stability of the thermal control coating under proton irradiation in space while meeting the antistatic requirements when the thermal control coating is used in a high-orbit or deep-space environment for a long time.

[0007] The present application provides a method for preparing a radiation-resistant thermal control filler, comprising:

[0008] (1) reacting a mixed salt solution of aluminum salt and zinc salt with an alkaline solution to prepare a precursor;

[0009] (2) drying and calcining the precursor to obtain aluminum-doped zinc oxide powder; and

[0010] (3) Purifying the aluminum-doped zinc oxide powder in an oxygen atmosphere to obtain a radiation-resistant thermal control filler, wherein the purification temperature is higher than the calcination temperature.

[0011] The present application also provides a radiation-resistant thermal control filler, which is prepared by the above-mentioned preparation method of the radiation-resistant thermal control filler; wherein, the aluminum doping ratio of the radiation-resistant thermal control filler is 1% to 5%, and the filler has a microscopic rod-like structure, and the length of the rod-like structure is 100 nanometers to 1 micron.

[0012] The present application provides a method for preparing an antistatic thermal control coating, comprising: adding the above-mentioned radiation-resistant thermal control filler into a base resin, mixing and dispersing the mixture evenly to obtain a coating; and spraying the coating onto a substrate to form an antistatic thermal control coating.

[0013] The present application also provides an antistatic thermal control coating, which is prepared by the above-mentioned preparation method of the antistatic thermal control coating. In the preparation method of the radiation-resistant thermal control filler of the present application, aluminum is selected as the doping element of zinc oxide. At this time, the high-valent aluminum ions replace the zinc ions in zinc oxide, generate oxygen vacancies, increase the carrier concentration, and thus increase the conductivity of the filler to obtain an antistatic filler. For example, the solar absorption ratio of the filler prepared in a specific example of the present application is 0.19±0.02, the hemispherical emissivity is 0.91±0.02, and the resistivity of the filler powder is as low as 10 6 Ω·m.

[0014] Considering that the melting point (1975°C) and boiling point (2360°C) of aluminum-doped zinc oxide powder are relatively high, the oxygen atmosphere purification process in step (3) is equivalent to a recrystallization process. The purification temperature higher than the calcination temperature causes many recrystallization nuclei to exist on the surface when the temperature rises. When the purification process is carried out in an oxygen environment, a lot of adsorbed oxygen will participate in it to fill the oxygen vacancy defects in the crystal.

[0015] At present, the main technical paths for enhancing the radiation resistance of structural materials are fine grain strengthening to increase grain boundaries and second phase strengthening to increase phase interfaces. Oxygen vacancy defects are the main radiation-induced defects that degrade the optical properties of powder pigments. In order to improve the stability of fillers against proton radiation, this application purifies the fillers in an oxygen atmosphere, uses the principle of lattice defect regulation of phase interfaces and vacancy design inside the crystal, reduces the concentration of oxygen vacancy defects in powder pigments, suppresses proton radiation damage to fillers, improves the stability of fillers in a vacuum-proton radiation environment, and ensures the stability of space proton radiation while meeting anti-static requirements, thereby extending the service life of the material. For example, in one example of this application, the filler is subjected to 50kev3.5×10 16 p / cm 2 After injection of vacuum-proton irradiation, the degradation of the solar absorption ratio is less than 0.05, and the degradation of the hemispherical emissivity is less than 0.03, which is lower than the existing highly reflective anti-static fillers. It can meet the application requirements of subsequent high-orbit, deep space exploration and other models for low-absorption, high-emission and high-stability anti-static thermal control coatings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0017] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0018] Figure 1 shows the X-ray diffraction pattern of the radiation-resistant thermal control filler in Example 1;

[0019] Figure 2 Shows Figure 1 Energy spectrum analysis diagram of the filler in;

[0020] Figure 3 Shows Figure 1 Volume resistivity test diagram of filler in;

[0021] Figure 4 The microstructure of the radiation-resistant thermal control filler of Example 2 after SEM testing is shown;

[0022] Figure 5 The microstructure of the radiation-resistant thermal control filler of Example 3 after SEM testing is shown. DETAILED DESCRIPTION

[0023] The present application discloses a radiation-resistant thermal control filler and a preparation method thereof, an antistatic thermal control coating and a preparation method thereof. Those skilled in the art can refer to the content of this article and appropriately improve the process parameters to achieve it. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art, and they are all deemed to be included in the scope of protection covered by this application. The products, processes and applications described in this application have been described through preferred embodiments. Relevant personnel can obviously modify or appropriately change and combine the products, processes and applications described in this article without departing from the content, spirit and scope of this application to realize and apply the technology of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0024] It should be noted that, in this document, relational terms such as "first" and "second", "step 1" and "step 2", and "(1)" and "(2)" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0025] The present application provides a method for preparing a radiation-resistant thermal control filler, comprising:

[0026] (1) reacting a mixed salt solution of aluminum salt and zinc salt with an alkaline solution to prepare a precursor;

[0027] (2) drying and calcining the precursor to obtain aluminum-doped zinc oxide powder; and

[0028] (3) Purifying the aluminum-doped zinc oxide powder in an oxygen atmosphere to obtain a radiation-resistant thermal control filler, wherein the purification temperature is higher than the calcination temperature.

[0029] In the above preparation method, aluminum is selected as the doping element of zinc oxide. At this time, the high-valent aluminum ions replace the zinc ions in zinc oxide, generate oxygen vacancies, increase the carrier concentration, and thus improve the conductivity of the filler to obtain an antistatic filler. For example, in a specific example of the present application, the solar absorption ratio of the filler prepared is 0.19±0.02, the hemispherical emissivity is 0.91±0.02, and the resistivity of the filler powder is as low as 10 6 Ω·m.

[0030] Considering that the melting point (1975°C) and boiling point (2360°C) of aluminum-doped zinc oxide powder are relatively high, the oxygen atmosphere purification process in step (3) is equivalent to a recrystallization process. The purification temperature higher than the calcination temperature causes many recrystallization nuclei to exist on the surface when the temperature rises. When the purification process is carried out in an oxygen environment, a lot of adsorbed oxygen will participate in it to fill the oxygen vacancy defects in the crystal.

[0031] At present, the main technical paths for enhancing the radiation resistance of structural materials are fine grain strengthening to increase grain boundaries and second phase strengthening to increase phase interfaces. Oxygen vacancy defects are the main radiation-induced defects that degrade the optical properties of powder pigments. In order to improve the stability of fillers against proton radiation, this application purifies the fillers in an oxygen atmosphere, and uses the principles of lattice defect regulation and internal vacancy design of the crystal to reduce the concentration of oxygen vacancy defects in powder pigments, thereby inhibiting the proton radiation damage of the fillers, improving the stability of the fillers in a vacuum-proton radiation environment, and ensuring the stability of space proton radiation while meeting the anti-static requirements, thereby extending the service life of the material. For example, in one example of this application, the filler is subjected to 50kev3.5×10 16 p / cm 2 After injection of vacuum-proton irradiation, the degradation of the solar absorption ratio is less than 0.05, and the degradation of the hemispherical emissivity is less than 0.03, which is lower than the existing highly reflective anti-static fillers. It can meet the application requirements of subsequent high-orbit, deep space exploration and other models for low-absorption, high-emission and high-stability anti-static thermal control coatings.

[0032] Specifically, in step (1), the molar ratio of zinc to aluminum in the mixed salt solution is 1:(0.01-0.05); the alkaline solution is at least one of sodium hydroxide, urea and ammonia solution; the molar ratio of the mixed salt solution to the alkaline solution is 3:(4-7). For example, the aluminum salt and the zinc salt can be aluminum nitrate and zinc acetate, respectively, or can be zinc nitrate and aluminum nitrate, which are not listed here one by one.

[0033] Aluminum is selected as the doping element, and when the aluminum doping ratio is between 1% and 5%, aluminum ions can completely enter the filler powder of the zinc oxide lattice. At this time, the high-valent aluminum ions replace the zinc ions in the zinc oxide, generate oxygen vacancies, increase the carrier concentration, and thus improve the conductivity of the filler to obtain an antistatic filler.

[0034] At least one of sodium hydroxide, urea and ammonia solution is selected as the alkaline solution. The different ion activities caused by the different adsorption points of hexagonal polar zinc oxide ions under anionic conditions can change the growth rate of each crystal face, forming an anisotropic growth rate mechanism, and realizing the preparation of rod-shaped nano-scale aluminum-doped zinc oxide, that is, the filler has a microscopic rod-shaped structure, and the length of the rod-shaped structure is 100nm~1μm.

[0035] In step (1), a mixed salt solution and an alkaline solution are reacted by a coprecipitation method to obtain a precursor; wherein, during the reaction, the alkaline solution is heated in a water bath to 70 to 90°C, the mixed salt solution is added dropwise to the alkaline solution at a rate of 20 to 50 ml / min, and stirred at a rate of 100 to 500 r / min. After the mixed salt solution is added dropwise, the pH value of the mixed reaction solution is tested to maintain the pH value of the mixed reaction solution at 8 to 10, and the water bath is kept heated while stirring for 10 to 60 minutes, and then the mixture is allowed to stand at room temperature for 8 to 16 hours for aging to terminate the coprecipitation reaction. The present application adopts the above-mentioned zinc source and uses a coprecipitation method to react, and the aluminum-doped zinc oxide powder obtained thereby has high whiteness, uniform composition, high purity, and a controllable stoichiometric ratio.

[0036] After the coprecipitation reaction is completed, pure water, ethanol, and pure water may be added to the reaction system to alternately filter and clean the precipitate to obtain the above-mentioned precursor. For example, a suction filtration funnel may be used to alternately filter and clean the obtained precipitate with pure water and ethanol until the pH of the filtrate is the same as that of pure water, and the precipitate may be drained to obtain a clean precursor.

[0037] In step (2), the precursor prepared in step (1) is dried, for example, the precursor can be dried at a temperature of 100 to 120° C. for 4 to 8 hours.

[0038] The calcination may be performed once or multiple times, and the calcination atmosphere may be an atmospheric environment. For example, the calcination may include a first stage calcination and a second stage calcination in sequence; wherein the temperature of the first stage calcination is 200 to 300°C, the calcination time is 12 to 24 hours, and a dried powder is obtained after calcination, and the powder is crushed using a mortar; the crushed powder is subjected to a second stage calcination, the calcination temperature is 300 to 700°C, the calcination time is 3 to 7 hours, and finally an aluminum-doped zinc oxide powder is obtained.

[0039] In step (3), during the oxygen atmosphere purification process, an oxygen atmosphere can be formed by injecting an oxygen flow rate of 20 to 30 ml / min, the purification temperature is 750 to 900° C., and the purification time is 1 to 2 hours. The oxygen atmosphere purification process is equivalent to a recrystallization process, and the purification temperature higher than the calcination temperature causes many recrystallization nuclei to exist on the surface when the temperature rises, and when the purification process is carried out under an oxygen environment, there will be a lot of adsorbed oxygen involved, and the oxygen vacancy defects in the crystal are filled, thereby suppressing the proton irradiation damage of the filler, improving the stability of the filler in a vacuum-proton irradiation environment, ensuring the stability of the space proton irradiation while meeting the antistatic requirements, and extending the service life of the material.

[0040] The present application also provides a radiation-resistant thermal control filler, which is prepared by any of the above-mentioned preparation methods of radiation-resistant thermal control fillers. The aluminum doping ratio of the prepared radiation-resistant thermal control filler is 1% to 5%, and the filler has a microscopic rod-like structure with a length of 100 nanometers to 1 micron.

[0041] The present application also provides a method for preparing an antistatic thermal control coating, comprising: adding the above-mentioned radiation-resistant thermal control filler to the base resin, mixing and dispersing uniformly to obtain a coating; spraying the coating on the substrate to form an antistatic thermal control coating. Wherein, the base resin can be a silicone resin, and the silicone resin is mixed with butyl acetate before adding the radiation-resistant thermal control filler; and the radiation-resistant thermal control filler accounts for 65-80wt% of the solid content of the coating. For example, 10g of space-grade methyl silicone resin and 100g of butyl acetate can be added to a beaker, mixed evenly, and then 40g of the above-mentioned radiation-resistant thermal control filler and 70g of glass beads are added, and a high-speed dispersing device is used for sand milling dispersion, with a rotation speed of 800r / min, and dispersion for 40 minutes. The obtained coating is evenly dispersed without precipitation.

[0042] The present application also provides an antistatic thermal control coating, which is prepared by any of the above-mentioned methods for preparing the antistatic thermal control coating. In the preparation method of the antistatic thermal control coating, the above-mentioned radiation-resistant thermal control filler is used, so the coating meets the antistatic requirements while ensuring the stability of space proton irradiation.

[0043] Embodiment 1:

[0044] The preparation method of the radiation-resistant thermal control filler comprises:

[0045] (1) Weigh 645.4g of zinc acetate and 22.6g of aluminum nitrate and dissolve them in pure water. The solution is diluted to 3000ml as a mixed salt solution; weigh 300g of sodium hydroxide and dissolve them in pure water. The solution is diluted to 750ml as an alkaline solution. Heat the alkaline solution to 80°C in a water bath and stir at a rate of 200r / min. At the same time, add the mixed salt solution to the alkaline solution with a constant pressure burette and keep stirring. After the mixed salt solution is added, the pH value of the titrated mixed solution is tested to be 8, and the water bath is kept heated and stirred for 30 minutes. The titrated mixed solution is placed at room temperature and allowed to stand for 12 hours to obtain a reaction solution. Filter the reaction solution and wash it alternately with pure water and anhydrous ethanol until the pH of the filtrate is the same as that of pure water to obtain a precursor.

[0046] (2) The precursor was placed in an oven and dried at 100°C for 4 hours. After drying, it was calcined at 300°C for 20 hours to complete the first stage of calcination. The powder calcined in the first stage was crushed and placed in a muffle furnace for the second stage of calcination, i.e., calcined at 450°C for 5 hours to obtain aluminum-doped zinc oxide powder, with an aluminum doping ratio of 2%.

[0047] (3) placing the aluminum-doped zinc oxide powder in a tubular furnace, introducing an oxygen atmosphere, and purifying it at a temperature of 800° C. for 1 hour. The purification temperature is higher than the calcination temperature, thereby obtaining a radiation-resistant thermal control filler.

[0048] The preparation method of the antistatic thermal control coating includes: adding 10g of space-grade methyl silicone resin and 100g of butyl acetate into a beaker, mixing evenly, adding 40g of the above-mentioned radiation-resistant thermal control filler and 70g of glass beads, using a high-speed dispersing device for sand grinding dispersion, with a rotation speed of 800r / min, dispersing for 40 minutes, and the obtained coating is evenly dispersed without precipitation; spraying the coating on a substrate to form an antistatic thermal control coating.

[0049] like Figure 1 and Figure 2 As shown, from the energy spectrum analysis data of the filler prepared in this example, it can be seen that the filler composition contains aluminum and zinc elements, and the X-ray diffraction crystal phase of the filler is well consistent with the standard zinc oxide powder crystal phase, and no other impurity phases are seen, indicating that the aluminum element in the filler enters the zinc oxide lattice through the reaction to form an aluminum-doped modified zinc oxide filler.

[0050] like Figure 3 As shown, the volume resistivity of the prepared filler powder was tested, and the volume resistivity of the powder was 3.4×10 5 Ω·m, meeting the anti-static requirements of powders. Compared with general aluminum-doped zinc oxide powder fillers, the highly reflective anti-static thermal control filler has higher whiteness and is more suitable for use as a filler in thermal control coatings.

[0051] The antistatic performance test and vacuum proton irradiation resistance test of the prepared antistatic thermal control coating were carried out. The volume resistivity of the coating was 5.7×10 6 Ω·m; after 50kev3.5×10 16 p / cm 2 After the vacuum-proton irradiation with a certain amount of injection, its thermal radiation performance after vacuum proton irradiation is slightly degraded, and its antistatic performance is basically unchanged. The specific test results are shown in Table 1.

[0052] Table 1 Comparison of volume resistivity and thermal radiation performance of the coatings in Examples 1 to 3 before and after proton irradiation

[0053]

[0054] Embodiment 2:

[0055] The preparation method of the radiation-resistant thermal control filler comprises:

[0056] (1) Weigh 987.5g of zinc acetate and 16.95g of aluminum nitrate and dissolve them in pure water. The solution is diluted to 4500ml as a mixed salt solution; weigh 420g of sodium hydroxide and dissolve it in pure water. The solution is diluted to 1050ml as an alkaline solution. Heat the alkaline solution to 80°C in a water bath and stir at a rate of 300r / min. At the same time, use a constant pressure burette to drop the mixed salt solution into the alkaline solution and keep stirring. After the mixed salt solution is added, the pH value of the titrated mixed solution is tested to be 8, and the water bath is kept heated and stirred for 30 minutes. The titrated mixed solution is placed at room temperature and allowed to stand for 12 hours to obtain a reaction solution. Filter the reaction solution and wash it alternately with pure water and anhydrous ethanol until the pH of the filtrate is the same as that of pure water to obtain a precursor.

[0057] (2) The precursor was placed in an oven and dried at 100°C for 4 hours. After drying, it was calcined at 300°C for 20 hours to complete the first stage of calcination. The powder calcined in the first stage was crushed and placed in a muffle furnace for the second stage of calcination, i.e., calcined at 450°C for 5 hours to obtain aluminum-doped zinc oxide powder with an aluminum doping ratio of 1%.

[0058] (3) placing the aluminum-doped zinc oxide powder in a tubular furnace, introducing an oxygen atmosphere, and purifying it at a temperature of 800° C. for 1 hour. The purification temperature is higher than the calcination temperature, thereby obtaining a radiation-resistant thermal control filler.

[0059] The preparation method of the antistatic thermal control coating includes: adding 10g of space-grade methyl silicone resin and 100g of butyl acetate into a beaker, mixing evenly, adding 40g of the above-mentioned radiation-resistant thermal control filler and 70g of glass beads, using a high-speed dispersing device for sand grinding dispersion, with a rotation speed of 800r / min, dispersing for 40 minutes, and the obtained coating is evenly dispersed without precipitation; spraying the coating on a substrate to form an antistatic thermal control coating.

[0060] like Figure 4 As shown in the figure, the filler powder obtained in this example has a particle size of about 100 to 600 nm, a regular and complete shape, and a rod-like microstructure. The volume resistivity of the powder is 1.8×10 5 Ω·m, meeting the anti-static requirements of powders. Compared with general aluminum-doped zinc oxide powder fillers, the prepared highly reflective anti-static thermal control filler has higher whiteness and is more suitable as a filler for heat dissipation anti-static thermal control coatings.

[0061] The antistatic performance and vacuum proton irradiation resistance tests of the prepared coating were carried out, and the volume resistivity of the coating was 2.8×10 6 Ω·m, after vacuum proton irradiation, the thermal radiation performance is slightly degraded, and the antistatic performance is basically unchanged. 16 p / cm 2 The specific test results after vacuum-proton irradiation with a certain amount of injection are shown in Table 1.

[0062] Embodiment 3:

[0063] The preparation method of the radiation-resistant thermal control filler comprises:

[0064] (1) Weigh 645.4g of zinc acetate and 11.26g of aluminum nitrate and dissolve them in pure water. The solution is diluted to 3000ml as a mixed salt solution; weigh 600.1g of urea and dissolve it in pure water. The solution is diluted to 1000ml as an alkaline solution. Heat the alkaline solution to 80°C in a water bath and stir at a rate of 300r / min. At the same time, add the mixed salt solution to the alkaline solution with a constant pressure burette and keep stirring. After the mixed salt solution is added, the pH value of the titrated mixed solution is tested to be 8, and the water bath is kept heated and stirred for 30 minutes. The titrated mixed solution is placed at room temperature and allowed to stand for 12 hours to obtain a reaction solution. Filter the reaction solution and wash it alternately with pure water and anhydrous ethanol until the pH of the filtrate is the same as that of pure water to obtain a precursor.

[0065] (2) The precursor was placed in an oven and dried at 100°C for 4 hours. After drying, it was calcined at 300°C for 20 hours to complete the first stage of calcination. The powder calcined in the first stage was crushed and placed in a muffle furnace for the second stage of calcination, i.e., calcined at 450°C for 5 hours to obtain aluminum-doped zinc oxide powder with an aluminum doping ratio of 1%.

[0066] (3) placing the aluminum-doped zinc oxide powder in a tubular furnace, introducing an oxygen atmosphere, and purifying it at a temperature of 800° C. for 1 hour. The purification temperature is higher than the calcination temperature, thereby obtaining a radiation-resistant thermal control filler.

[0067] The preparation method of the antistatic thermal control coating includes: adding 10g of space-grade methyl silicone resin and 100g of butyl acetate into a beaker, mixing evenly, adding 40g of the above-mentioned radiation-resistant thermal control filler and 70g of glass beads, using a high-speed dispersing device for sand grinding dispersion, with a rotation speed of 800r / min, dispersing for 40 minutes, and the obtained coating is evenly dispersed without precipitation; spraying the coating on a substrate to form an antistatic thermal control coating.

[0068] like Figure 5 As shown in the figure, the filler powder prepared in this example has a particle size of about 50 to 200 nm, a regular and complete shape, and a round microstructure. The volume resistivity of the powder is 4.7×10 5 Ω·m, meeting the anti-static requirements of powders. Compared with general aluminum-doped zinc oxide powder fillers, the prepared highly reflective anti-static thermal control filler has higher whiteness and is more suitable as a filler for heat dissipation anti-static thermal control coatings.

[0069] The antistatic performance and vacuum proton irradiation resistance tests of the prepared coating were carried out. The volume resistivity of the coating was 6.9×10 6 Ω·m, after vacuum proton irradiation, the thermal radiation performance is slightly degraded, and the antistatic performance is basically unchanged. 16 p / cm 2 The specific test results after vacuum-proton irradiation with a certain amount of injection are shown in Table 1.

[0070] Comparative Example 1:

[0071] The preparation method of the thermal control filler comprises:

[0072] (1) Weigh 645.4g of zinc acetate and 22.6g of aluminum nitrate and dissolve them in pure water. The solution is diluted to 3000ml as a mixed salt solution; weigh 300g of sodium hydroxide and dissolve them in pure water. The solution is diluted to 750ml as an alkaline solution. Heat the alkaline solution to 80°C in a water bath and stir at a rate of 200r / min. At the same time, add the mixed salt solution to the alkaline solution with a constant pressure burette and keep stirring. After the mixed salt solution is added, the pH value of the titrated mixed solution is tested to be 8, and the water bath is kept heated and stirred for 30 minutes. The titrated mixed solution is placed at room temperature and allowed to stand for 12 hours to obtain a reaction solution. Filter the reaction solution and wash it alternately with pure water and anhydrous ethanol until the pH of the filtrate is the same as that of pure water to obtain a precursor.

[0073] (2) The precursor was placed in an oven and dried at 100°C for 4 hours. After drying, it was calcined at 300°C for 20 hours to complete the first stage of calcination. The powder calcined in the first stage was crushed and placed in a muffle furnace for the second stage of calcination, i.e., calcined at 450°C for 5 hours to obtain aluminum-doped zinc oxide powder as a thermal control filler, with an aluminum doping ratio of 2%.

[0074] The preparation method of the antistatic thermal control coating includes: adding 10g of space-grade methyl silicone resin and 100g of butyl acetate into a beaker, mixing evenly, adding 40g of the above-mentioned radiation-resistant thermal control filler and 70g of glass beads, using a high-speed dispersing device for sand grinding dispersion, with a rotation speed of 800r / min, dispersing for 40 minutes, and the obtained coating is evenly dispersed without precipitation; spraying the coating on a substrate to form an antistatic thermal control coating.

[0075] Compared with Example 1, the preparation method of the thermal control filler in Comparative Example 1 does not include an oxygen atmosphere purification step. The volume resistivity of the prepared filler powder was tested, and the volume resistivity of the powder was 3.9×10 5 Ω·m, which meets the antistatic requirements of powders. The antistatic performance test and vacuum proton irradiation resistance test of the prepared coating were carried out. The hemispherical emissivity did not change significantly before and after irradiation, but the volume resistivity of the coating increased from 3.3×10 6 Ω·m increased to 7.6×10 6 Ω·m, the solar absorption ratio increased from 0.18 before irradiation to 0.48. It can be seen that after vacuum proton irradiation, the thermal radiation performance of the powder deteriorated seriously, and the coating appearance showed obvious yellowing, and the antistatic performance changed little, indicating that the oxygen atmosphere purification step can achieve antistatic performance while ensuring proton irradiation resistance. 16 p / cm 2 The specific test results after vacuum-proton irradiation with a certain amount of injection are shown in Table 2.

[0076] Table 2 Comparison of volume resistivity and thermal radiation performance of the coatings in Comparative Examples 1 to 3 before and after proton irradiation

[0077]

[0078] Comparative Example 2:

[0079] The preparation method of the thermal control filler comprises:

[0080] (1) Weigh 645.4g of zinc acetate and 22.6g of aluminum nitrate and dissolve them in pure water. The solution is diluted to 3000ml as a mixed salt solution; weigh 300g of sodium hydroxide and dissolve them in pure water. The solution is diluted to 750ml as an alkaline solution. Heat the alkaline solution to 80°C in a water bath and stir at a rate of 200r / min. At the same time, add the mixed salt solution to the alkaline solution with a constant pressure burette and keep stirring. After the mixed salt solution is added, the pH value of the titrated mixed solution is tested to be 8, and the water bath is kept heated and stirred for 30 minutes. The titrated mixed solution is placed at room temperature and allowed to stand for 12 hours to obtain a reaction solution. Filter the reaction solution and wash it alternately with pure water and anhydrous ethanol until the pH of the filtrate is the same as that of pure water to obtain a precursor.

[0081] (2) The precursor was placed in an oven and dried at 100°C for 4 hours. After drying, it was calcined at 300°C for 20 hours to complete the first stage of calcination. The powder calcined in the first stage was crushed and placed in a muffle furnace for the second stage of calcination, i.e., calcined at 450°C for 5 hours to obtain aluminum-doped zinc oxide powder, with an aluminum doping ratio of 2%.

[0082] (3) The aluminum-doped zinc oxide powder is placed in a tubular furnace, introduced into a hydrogen atmosphere, and purified at a temperature of 800° C. for 1 hour. The purification temperature is higher than the calcination temperature, thereby obtaining a thermal control filler.

[0083] The preparation method of the antistatic thermal control coating includes: adding 10g of space-grade methyl silicone resin and 100g of butyl acetate into a beaker, mixing evenly, adding 40g of the above-mentioned radiation-resistant thermal control filler and 70g of glass beads, using a high-speed dispersing device for sand grinding dispersion, with a rotation speed of 800r / min, dispersing for 40 minutes, and the obtained coating is evenly dispersed without precipitation; spraying the coating on a substrate to form an antistatic thermal control coating.

[0084] Compared with Example 1, the preparation method of the thermal control filler in Comparative Example 2 adopts hydrogen atmosphere purification, and the purification temperature remains unchanged. The volume resistivity of the prepared filler powder is tested, and the volume resistivity of the powder is 8.8×10 5 Ω·m, which meets the antistatic requirements of powders. The antistatic performance test and vacuum proton irradiation resistance test of the prepared coating showed that the hemispherical emissivity did not change significantly before and after irradiation, but the volume resistivity of the coating increased from 5.3×10 6 Ω·m increased to 8.3×10 6Ω·m, the solar absorption ratio increased from 0.2 before irradiation to 0.5. It can be seen that after vacuum proton irradiation, the thermal radiation performance of the powder deteriorated seriously, and the coating appearance showed obvious yellowing, and the antistatic performance changed little, indicating that the oxygen atmosphere purification step can achieve antistatic performance while ensuring proton irradiation resistance, and changing the atmosphere conditions will not improve the radiation resistance. 16 p / cm 2 The specific test results after vacuum-proton irradiation with a certain amount of injection are shown in Table 2.

[0085] Comparative Example 3:

[0086] The preparation method of the thermal control filler comprises:

[0087] (1) Weigh 645.4g of zinc acetate and 22.6g of aluminum nitrate and dissolve them in pure water. The solution is diluted to 3000ml as a mixed salt solution; weigh 300g of sodium hydroxide and dissolve them in pure water. The solution is diluted to 750ml as an alkaline solution. Heat the alkaline solution to 80°C in a water bath and stir at a rate of 200r / min. At the same time, add the mixed salt solution to the alkaline solution with a constant pressure burette and keep stirring. After the mixed salt solution is added, the pH value of the titrated mixed solution is tested to be 8, and the water bath is kept heated and stirred for 30 minutes. The titrated mixed solution is placed at room temperature and allowed to stand for 12 hours to obtain a reaction solution. Filter the reaction solution and wash it alternately with pure water and anhydrous ethanol until the pH of the filtrate is the same as that of pure water to obtain a precursor.

[0088] (2) The precursor was placed in an oven and dried at 100°C for 4 hours. After drying, it was calcined at 300°C for 20 hours to complete the first stage of calcination. The powder calcined in the first stage was crushed and placed in a muffle furnace for the second stage of calcination, i.e., calcined at 450°C for 5 hours to obtain aluminum-doped zinc oxide powder, with an aluminum doping ratio of 2%.

[0089] (3) placing the aluminum-doped zinc oxide powder in a tubular furnace, introducing an oxygen atmosphere, and purifying it at a temperature of 400° C. for 1 hour. The purification temperature is lower than the calcination temperature, thereby obtaining a radiation-resistant thermal control filler.

[0090] The preparation method of the antistatic thermal control coating includes: adding 10g of space-grade methyl silicone resin and 100g of butyl acetate into a beaker, mixing evenly, adding 40g of the above-mentioned radiation-resistant thermal control filler and 70g of glass beads, using a high-speed dispersing device for sand grinding dispersion, with a rotation speed of 800r / min, dispersing for 40 minutes, and the obtained coating is evenly dispersed without precipitation; spraying the coating on a substrate to form an antistatic thermal control coating.

[0091] Compared with Example 1, the temperature of oxygen atmosphere purification in the preparation method of the thermal control filler in Comparative Example 3 is lower than the maximum calcination temperature. The volume resistivity of the prepared filler powder was tested, and the volume resistivity of the powder was 2.8×10 5 Ω·m, which meets the antistatic requirements of powders. The antistatic performance test and vacuum proton irradiation resistance test of the prepared coating were carried out. The hemispherical emissivity did not change significantly before and after irradiation, but the volume resistivity of the coating increased from 3.3×10 6 Ω·m increased to 6.6×10 6 Ω·m, the solar absorption ratio increased from 0.18 before irradiation to 0.48. It can be seen that after vacuum proton irradiation, the thermal radiation performance of the powder deteriorated seriously, and the coating appearance showed obvious yellowing, and the antistatic performance changed little, indicating that the atmosphere conditions and purification temperature in the oxygen atmosphere purification step must meet the requirements at the same time to achieve antistatic performance and ensure proton irradiation resistance. Changing the temperature conditions will not improve the radiation resistance. 16 p / cm 2 The specific test results after vacuum-proton irradiation with a certain amount of injection are shown in Table 2.

[0092] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A method for preparing a radiation-resistant thermal control filler, characterized in that: include: (1) reacting a mixed salt solution of aluminum salt and zinc salt with an alkaline solution to prepare a precursor; (2) drying and calcining the precursor to obtain aluminum-doped zinc oxide powder; as well as (3) Recrystallizing the aluminum-doped zinc oxide powder in an oxygen atmosphere to obtain the radiation-resistant thermal control filler, wherein the oxygen atmosphere is formed by injecting an oxygen flow rate of 20 to 30 ml / min, the recrystallization temperature is higher than the calcination temperature, the recrystallization temperature is 750 to 900° C., and the time is 1 to 2 hours.

2. The method for preparing the radiation-resistant thermal control filler according to claim 1, characterized in that: In the step (1), the molar ratio of zinc to aluminum in the mixed salt solution is 1:(0.01-0.05); the alkaline solution is at least one of sodium hydroxide, urea and ammonia solution; and the molar ratio of the mixed salt solution to the alkaline solution is 3:(4-7).

3. The method for preparing the radiation-resistant thermal control filler according to claim 2, characterized in that: In the step (1), the mixed salt solution and the alkaline solution are reacted by a coprecipitation method to obtain the precursor; wherein, in the reaction, the alkaline solution is heated in a water bath to 70-90° C., the mixed salt solution is added dropwise to the alkaline solution at a rate of 20-50 ml / min, and stirred at a rate of 100-500 r / min. After the mixed salt solution is added dropwise, the pH value of the mixed reaction solution is tested to maintain the pH value of the mixed reaction solution at 8-10, the water bath is kept heated while stirring for 10-60 minutes, and then the solution is allowed to stand at room temperature for 8-16 hours for aging to terminate the coprecipitation reaction.

4. The method for preparing the radiation-resistant thermal control filler according to claim 1, characterized in that: In the step (2), the calcination includes a first stage calcination and a second stage calcination in sequence; wherein the temperature of the first stage calcination is 200-300°C, and the calcination time is 12-24 hours; the temperature of the second stage calcination is 300-700°C, and the calcination time is 3-7 hours.

5. A radiation-resistant thermal control filler, characterized in that: The radiation-resistant thermal control filler is prepared by the preparation method of the radiation-resistant thermal control filler according to any one of claims 1 to 4; wherein the aluminum doping ratio of the radiation-resistant thermal control filler is 1% to 5%, and the filler has a microscopic rod-like structure, and the length of the rod-like structure is 100 nanometers to 1 micron.

6. A method for preparing an antistatic thermal control coating, characterized in that: include: The radiation-resistant thermal control filler according to claim 5 is added to the base resin, mixed and dispersed evenly to prepare a coating; the coating is sprayed on a substrate to form the antistatic thermal control coating.

7. The method for preparing the antistatic thermal control coating according to claim 6, characterized in that: The base resin is an organic silicon resin, and the organic silicon resin is mixed with butyl acetate before adding the radiation-resistant heat control filler; and the radiation-resistant heat control filler accounts for 65-80wt% of the solid content of the coating.

8. An antistatic thermal control coating, characterized in that: The antistatic thermal control coating is prepared by the preparation method of the antistatic thermal control coating according to claim 6 or 7.

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