White antistatic particles and a method for their production
By growing ITO particles in situ on the surface of ZnO powder, the problem that ZnO powder coatings cannot meet the antistatic requirements is solved, and white antistatic particles are prepared while maintaining the heat dissipation performance of the coating, which is suitable for aerospace and other fields.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-29
- Publication Date
- 2026-04-14
AI Technical Summary
Existing ZnO powder coatings cannot meet the antistatic requirements on high-orbit spacecraft. At the same time, adding conductive agents will increase the solar absorptivity of the coating and reduce its heat dissipation capacity.
ITO particles were grown in situ on the surface of ZnO powder. By controlling the ratio of ITO precursor to powder dilute suspension, white antistatic particles were prepared while maintaining the heat dissipation performance of the coating.
The prepared white antistatic particles have good antistatic properties and do not affect the solar absorptivity of the coating, making them suitable for applications such as aerospace.
Smart Images
Figure CN119552533B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of material preparation, and relates to a white antistatic particle and its preparation method, specifically to a white antistatic particle for use in coatings and its preparation method, and more particularly to a white antistatic particle for use in spacecraft thermal control coatings and its preparation method. Background Technology
[0002] Thermal control coatings are commonly applied to spacecraft surfaces and are essential functional materials for spacecraft thermal control systems, playing a crucial role in controlling the surface temperature of the spacecraft and its individual components. Thermal control coatings work by adjusting the solar absorptivity (α) of the spacecraft surface. S ) and infrared emissivity (ε H Two key photothermal performance parameters are thermal radiation performance and thermal radiation performance. Thermal radiation performance controls the absorption of thermal energy from outer space (the sun, earth, planets, etc.) and the radiated thermal energy from the spacecraft into outer space, and maintains the ratio of these two within a certain range, thereby keeping the spacecraft's structural components and equipment within the required operating temperature range. Simultaneously, thermal control coatings are also commonly used inside spacecraft to enhance heat exchange between internal bulkheads and individual machine surfaces, achieving a more uniform temperature distribution within the spacecraft through radiative heat transfer.
[0003] High-orbit (e.g., geosynchronous orbit) spacecraft experience surface potential accumulation of thousands of volts due to impacts from charged particles. Discharge can severely disrupt the normal operation of electronic equipment; therefore, thermal control coatings used in high-orbit spacecraft must possess antistatic properties. Currently, commonly used ZnO powders have a resistivity exceeding 10 Ω·cm. 5 The surface resistance of the coating prepared from it far exceeds the antistatic requirement of 10 kΩ-cm. 12 Ω / □, lacking antistatic properties. Adding conductive additives such as aluminum powder, ITO powder, and ATO powder to thermal control coatings can reduce the surface resistance of ZnO coatings. However, conductive agents are typically gray or light green, which increases the solar absorptivity of the coating, thus reducing its heat dissipation capacity. Therefore, there is an urgent need to develop antistatic particles that possess both antistatic properties and do not reduce the coating's heat dissipation capacity. Summary of the Invention
[0004] To address the above problems, this invention provides a white antistatic granule and a method for preparing the same.
[0005] In a first aspect, the present invention provides a white antistatic particle, comprising: a powder, and ITO particles grown in situ on the surface of the powder; wherein the powder is at least one selected from ZnO powder, TiO2 powder, MgO powder, and BaSO4 powder; and the ITO particles are composed of In and Sn.
[0006] Preferably, the particle size of the powder is 100-500 nm; the particle size of the ITO particles is 5-20 nm.
[0007] Preferably, based on the total mass of the white antistatic particles being 100%, the powder accounts for 75-99% of the mass, and the ITO particles account for 1-25% of the mass.
[0008] Preferably, the molar ratio of In to Sn in the ITO particles is (6-9):1.
[0009] Preferably, the volume resistivity of the white antistatic particles is ≤2000KΩ-cm.
[0010] Secondly, the present invention provides a method for preparing the above-mentioned white antistatic particles, comprising:
[0011] (1) Dissolve the powder in deionized water and stir it in a water bath at a constant temperature to obtain a dilute suspension of the powder; the solid content of the dilute suspension is 5-20%;
[0012] (2) Weigh crystalline tin chloride (SnCl4·5H2O) and indium chloride tetrahydrate (InCl3·4H2O) according to the stoichiometric ratio, and dissolve them in deionized water to obtain an ITO precursor solution; the concentration of the ITO precursor solution is 0.01-0.5 mol / L.
[0013] (3) The obtained ITO precursor solution was added dropwise to the dilute suspension of the powder, and the pH value of the solution was adjusted to 8-12 for reaction. After the reaction was completed, the product was filtered, washed and dried to obtain composite powder containing ITO.
[0014] (4) The obtained ITO-containing composite powder is calcined to obtain the white antistatic particles.
[0015] Preferably, in step (1), the temperature of the water bath constant temperature stirring is 30-80°C.
[0016] Preferably, in step (2), the stoichiometric ratio of the crystalline tin chloride to indium chloride tetrahydrate is 1:(4-10).
[0017] Preferably, in step (3), ammonia is added to the system to adjust the pH value, wherein the mass fraction of the ammonia is 25-28%.
[0018] Preferably, in step (3), the mass ratio of ITO in the ITO precursor solution to the mass of powder in the dilute suspension is 1:99 to 25:75.
[0019] Preferably, in step (3), the obtained ITO precursor solution is added dropwise to the dilute suspension of the powder for reaction, and the reaction is carried out by heating and stirring at 30-90°C for 1-12 hours; the pH value is adjusted to 8-12, and the reaction is continued by heating and stirring at 30-90°C for 1-12 hours.
[0020] Preferably, in step (3), the solvent used for washing is deionized water or anhydrous ethanol.
[0021] Preferably, in step (4), the calcination temperature is 300-700°C and the time is 4-24 hours.
[0022] Beneficial effects:
[0023] (1) The white antistatic particles prepared by the present invention are white and have good antistatic properties, and can be applied to automobiles, ships, aviation, aerospace and other fields.
[0024] (2) The method for preparing white antistatic particles provided by the present invention is simple to operate, low in cost, short in time, and easy to promote and apply in industrial applications. Attached Figure Description
[0025] Figure 1 SEM image of the white antistatic particles prepared in Example 1;
[0026] Figure 2 Solar reflectance spectra of white antistatic particles prepared in Examples 1 and 2, and solar reflectance spectra of ZnO particles; where S-1 represents Example 1 and S-2 represents Example 2. Detailed Implementation
[0027] To further illustrate the invention's content, features, and practical effects, the invention will be described in detail below with reference to embodiments. It should be noted that the modification methods of the invention are not limited to these specific implementation methods. Equivalent substitutions and modifications made by those skilled in the art based on their reading of the invention's content, without departing from the spirit and essence of the invention, are also within the scope of protection claimed by this invention.
[0028] In this invention, a heterogeneous precipitation method is used. By controlling the mass ratio of the ITO precursor to the powder in a dilute suspension, self-nucleation growth caused by excessively high ITO precursor concentration is avoided, allowing ITO particles to grow in situ on the powder surface in the dilute suspension (from...). Figure 1It can be seen that the ITO particles grow in situ on the powder surface, rather than being generated as ITO powder particles alone. Furthermore, because the proportion of ITO particles in the antistatic particles is low in this invention, the antistatic particles exhibit the color of the powder, meaning that this invention produces white antistatic particles. Therefore, the preparation method of this invention can grow ITO particles in situ on the powder surface, achieving the preparation of white antistatic particles, thus not affecting the solar absorptivity of the coating, and consequently, not affecting the heat dissipation performance of the coating.
[0029] The following is an exemplary description of the method for preparing the white antistatic particles provided by the present invention.
[0030] The powder was dissolved in deionized water and stirred in a water bath at a constant temperature to obtain a dilute suspension of the powder.
[0031] In an optional embodiment, the temperature of the water bath constant temperature stirring is 30-80°C, for example, 50°C.
[0032] In an optional embodiment, the solid content of the dilute suspension of the powder is 5-20%.
[0033] Crystalline tin chloride (SnCl4·5H2O) and indium chloride tetrahydrate (InCl3·4H2O) were weighed according to stoichiometric ratio and dissolved in deionized water to obtain an ITO precursor solution.
[0034] In an optional embodiment, the stoichiometric ratio of crystalline tin chloride to indium chloride tetrahydrate is 1:(4-10); preferably 1:9 or 2:8; more preferably, to improve the antistatic properties of ITO particles, the molar ratio of In to Sn is 1:9.
[0035] The obtained ITO precursor solution was added dropwise to a dilute suspension of the powder for reaction. The mixture was heated and stirred at 30–90°C for 1–12 hours. Then, ammonia (NH3·H2O) was added dropwise to adjust the pH of the solution to 8–14 to facilitate the formation of ITO particles from the ITO precursor. The mixture was then heated and stirred at 30–90°C for another 1–12 hours. After the reaction was complete, the product was filtered and washed with a large amount of deionized water and anhydrous ethanol until no chloride ions were present in the filtrate. The product was then dried in an oven to obtain a composite powder containing ITO. If the pH is <8, ITO cannot precipitate heterogeneously, meaning that ITO particles cannot be prepared from the precursor.
[0036] In an optional embodiment, the mass ratio of ITO in the ITO precursor solution to the mass of powder in the dilute suspension is 1:99 to 25:75. If the mass ratio of ITO in the ITO precursor solution to the mass of powder in the dilute suspension is too large (or the mass of ITO in the ITO precursor solution is too high), the ITO powder will nucleate and precipitate independently, and cannot form ITO particles through heterogeneous precipitation on the ZnO surface. Although the volume resistivity of the powder is low, the solar absorptivity increases, and the heat dissipation performance decreases.
[0037] In an optional embodiment, the ammonia solution has a mass fraction of 25-28%. Preferably, the pH of the solution is adjusted to 10-11.
[0038] The obtained ITO-coated composite powder was calcined and then cooled to room temperature to obtain the white antistatic particles.
[0039] In an optional embodiment, the calcination temperature is 300–700°C, for example, 500°C; the calcination time is 4–24 h, for example, 12 h. If the calcination time is too short or the calcination temperature is too low, the ITO sintering will be incomplete, the ITO particles will not be fully prepared, and the volume resistivity of the powder will increase.
[0040] In this invention, all steps are performed under normal pressure.
[0041] In this invention, the volume resistivity of the white antistatic particles is tested using a powder resistance test method.
[0042] The following examples further illustrate the present invention in detail. It should also be understood that the following examples are only for further explanation of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention are within the scope of protection of the present invention. The specific process parameters, etc., in the following examples are merely examples within a suitable range; that is, those skilled in the art can make appropriate selections within the appropriate range based on the description herein, and are not intended to be limited to the specific values in the examples below.
[0043] Example 1
[0044] (1) Weigh 100g of ZnO powder, dissolve it in 2000ml of deionized water, and stir continuously in a constant temperature water bath at 50℃ to prepare a dilute suspension of the powder.
[0045] (2) Based on the stoichiometric ratio of Sn:In in ITO of 5g powder and SnCl4·5H2O and InCl3·4H2O in tetrahydrate, respectively weigh out the corresponding crystalline tin chloride (SnCl4·5H2O) and indium chloride tetrahydrate (InCl3·4H2O), and dissolve them in deionized water to prepare ITO precursor solution.
[0046] (3) The ITO precursor solution was added dropwise to the dilute suspension of the powder, and the mixture was heated and stirred at 50°C for 2 hours. Then, ammonia water (NH3·H2O) was added dropwise to the system to adjust the pH of the solution to pH 8, and the mixture was stirred at 50°C for another 2 hours. After the reaction was completed, the product was filtered and washed with a large amount of deionized water and anhydrous ethanol until no chloride ions were found in the filtrate. The product was then dried in an oven.
[0047] (4) The dried composite powder material is placed in a high-temperature furnace for calcination, heated to 300°C and kept at that temperature for 12 hours, and then naturally cooled to room temperature to obtain white antistatic particles.
[0048] Example 2
[0049] The preparation process of the white antistatic particles in this Example 2 is the same as that in Example 1, except that the powder is BaSO4 in step (1).
[0050] Example 3
[0051] The preparation process of the white antistatic particles in Example 3 is the same as that in Example 1, except that the powder is TiO2 in step (1).
[0052] Example 4
[0053] The preparation process of the white antistatic particles in Example 4 is the same as that in Example 1, except that the powder is MgO in step (1).
[0054] Example 5
[0055] The preparation process of the white antistatic particles in Example 5 is the same as that in Example 1, except that the mass of ITO powder in step (2) is 10g.
[0056] Example 6
[0057] The preparation process of the white antistatic particles in Example 6 is the same as that in Example 1, except that in step (3), the pH value of the solution is adjusted to 10.
[0058] Example 7
[0059] The preparation process of the white antistatic particles in Example 7 is the same as that in Example 1, except that the calcination temperature in step (4) is 500℃.
[0060] Comparative Example 1
[0061] In this comparative example 1, ZnO powder was used directly.
[0062] Comparative Example 2
[0063] The preparation process of the white antistatic particles in Comparative Example 2 is the same as that in Example 1, except that in step (3), the pH value of the solution is adjusted to 6.
[0064] Comparative Example 3
[0065] The preparation process of the white antistatic particles in Comparative Example 3 is the same as that in Example 1, except that the calcination temperature in step (4) is 200°C.
[0066] Comparative Example 4
[0067] The preparation process of the white antistatic particles in Comparative Example 4 is the same as that in Example 1, except that the mass of ITO powder in step (2) is 30g.
[0068] Table 1 lists the raw material composition, reaction conditions, volume resistivity, and solar absorptivity of Examples 1-7 and Comparative Examples 1-4.
[0069] Table 1:
[0070] powder ITO powder pH temperature Volume resistivity (kΩ-cm) Solar absorptivity Example 1 ZnO 5g 8 300℃ 163.24 0.13 Example 2 <![CDATA[TiO2]]> 5g 8 300℃ 1031.51 0.13 Example 3 MgO 5g 8 300℃ 29.85 0.12 Example 4 <![CDATA[BaSO4]]> 5g 8 300℃ 222.97 0.13 Example 5 ZnO 10g 8 300℃ 568.06 0.12 Example 6 ZnO 5g 10 300℃ 38.61 0.13 Example 7 ZnO 5g 8 500℃ 7.04 0.12 Comparative Example 1 ZnO - - - 23754 0.12 Comparative Example 2 ZnO 5g 6 300℃ 18592 0.12 Comparative Example 3 ZnO 5g 8 200℃ 26915 0.13 Comparative Example 4 ZnO 30g 8 300℃ 49.28 0.26 .
[0071] Table 1 shows that the volume resistivity of the white antistatic particles prepared by this invention is significantly lower than that of the ZnO powder in Comparative Example 1. Specifically, comparing Examples 1 and 7 shows that increasing the sintering temperature significantly reduces the volume resistivity. Comparing Examples 1 and 2 shows that when pH < 8, the powder resistivity is relatively high. Comparing Examples 1 and 3 shows that when the sintering temperature is too low, the powder resistivity is also high. Comparing Examples 1 and 4 shows that when the ITO powder content is too high, although the volume resistivity is low, the solar absorptivity increases, and the heat dissipation performance decreases.
[0072] Figure 1 The image shows a SEM image of the white antistatic particles prepared in Example 1. As can be seen from the image, the ITO particles are uniformly prepared on the powder.
[0073] Figure 2 The solar reflectance spectra of the white antistatic particles prepared in Example 1 and the solar reflectance spectra of ZnO particles are shown in the figures. As can be seen from the figures, the solar reflectance spectra of the antistatic particles and the ZnO particles are basically the same, and do not affect the heat dissipation effect.
Claims
1. A method for preparing white antistatic granules, characterized in that, The white antistatic particles comprise: a powder, and ITO particles grown in situ on the surface of the powder; the powder is at least one of ZnO powder, TiO2 powder, MgO powder, and BaSO4 powder; the ITO particles are composed of In and Sn; the particle size of the powder is 100 nm to 500 nm; the particle size of the ITO particles is 5 to 20 nm. The preparation method of the white antistatic particles includes: (1) Dissolve the powder in deionized water and stir it in a water bath at a constant temperature to obtain a dilute suspension of the powder; (2) Weigh crystalline tin chloride and indium chloride tetrahydrate according to the stoichiometric ratio, and dissolve them in deionized water to obtain an ITO precursor solution; the stoichiometric ratio of crystalline tin chloride to indium chloride tetrahydrate is 1:(4-10). (3) The obtained ITO precursor solution is added dropwise to the dilute suspension of the powder, and the pH value of the solution is adjusted to 8-12 for reaction. After the reaction is completed, the product is filtered, washed and dried to obtain a composite powder containing ITO. The mass ratio of ITO in the ITO precursor solution to the mass of the powder in the dilute suspension is 1:99-1:
10. (4) The obtained ITO-containing composite powder is calcined to obtain the white antistatic particles; the calcination temperature is 300-700℃ and the time is 4-24h.
2. The preparation method according to claim 1, characterized in that, The molar ratio of In to Sn in the ITO particles is (6-9):
1.
3. The preparation method according to claim 1, characterized in that, The solid content of the dilute suspension is 5-20%; The concentration of the ITO precursor solution is 0.01–0.5 mol / L.
4. The preparation method according to claim 1, characterized in that, In step (1), the temperature of the water bath constant temperature stirring is 30-80℃.
5. The preparation method according to claim 1, characterized in that, In step (3), ammonia water is added to the system to adjust the pH value, and the mass fraction of the ammonia water is 25-28%.
6. The preparation method according to claim 1, characterized in that, In step (3), the obtained ITO precursor solution is added dropwise to the dilute suspension of the powder for reaction, and the reaction is carried out by heating and stirring at 30-90°C for 1-12 hours; the pH value is adjusted to 8-12, and the reaction is continued by heating and stirring at 30-90°C for 1-12 hours.