Y2O3-coated Al2O3 aerogel-containing oxygen barrier coating for steel claw and preparation method of Y2O3-coated Al2O3 aerogel-containing oxygen barrier coating

Abstract

The invention discloses a steel claw oxygen barrier coating containing Y2O3 and Al2O3 aerogel and a preparation method of the steel claw oxygen barrier coating, and belongs to the technical field of coatings. The coating comprises the following components in parts by weight: 100 parts of an organic-inorganic compound adhesive, 5 to 15 parts of Y2O3 and Al2O3 aerogel, 30 to 55 parts of gas-phase nano aluminum oxide, 12 to 15 parts of superfine mullite fiber and an auxiliary agent. The compound adhesive is prepared from silicon-aluminum sol, aluminum sol and modified organic silicon emulsion through a hydrothermal reaction. The Y2O3-coated Al2O3 aerogel is prepared by combining a sol-gel method with CO2 supercritical drying, and the thermal stability of the aerogel is improved by inhibiting high-temperature diffusion of aluminum ions and alpha-phase transformation by utilizing Y < 3 + >. According to the coating, heat transfer is blocked through aerogel nanopores, a compact oxygen barrier layer is formed through high-temperature ceramization of a compound adhesive, low-heat-conduction and corrosion-resistant protection of the surface of the steel claw in the environment of 350-900 DEG C is achieved, the service life of the anode steel claw is effectively prolonged, and iron impurity pollution in electrolytic aluminum is reduced. And the preparation process is simple, is suitable for spray coating or brush coating, and has industrial application value.

Description

Technical Field

[0001] The present invention belongs to the technical field of coatings, and specifically relates to a steel claw oxygen barrier coating containing Y2O3@Al2O3 aerogel and a preparation method thereof. Background Art

[0002] The aluminum industry is one of the foundations of economic development. Aluminum boasts excellent properties, including lightweight, corrosion-resistant, and excellent electrical conductivity, making it widely used in various sectors, including industry, aerospace, power generation, and construction. China's annual electrolytic aluminum production capacity has reached 40 million tons, and the country boasts a large number of aluminum smelters. Currently, corrosion of the anode steel claws is a common problem facing these smelters. At high temperatures of 350-900°C, anode steel claws are susceptible to erosion from the electrolyte, anode feed, air, and electrolytic flue gases. Furthermore, they are subject to damage from thermal stress, electromagnetic forces, and collisions, making them susceptible to oxidative corrosion.

[0003] Corrosion causes the claws to become thinner, reducing their current carrying capacity. This not only increases power loss but also generates more Joule heat, potentially damaging the claws in severe cases. Corrosion not only shortens the claw's service life but also reduces the purity of the molten aluminum. Corrosion on the anode claw surface causes the corrosion layer to detach, allowing large amounts of iron-containing materials to enter the electrolytic electrode coating and residual anodes. This leads to high iron content in the anode carbon block and coating, ultimately resulting in high iron content in the molten aluminum, affecting the quality of the raw aluminum. However, applying a heat-resistant, corrosion-resistant, and oxygen-barrier coating to the anode claws can significantly reduce the severity of the corrosion.

[0004] Alumina aerogel is a nanoporous material with high porosity, low density, high specific surface area, high temperature resistance, and low thermal conductivity. Through in-situ doping modification, adding a small amount of yttrium oxide not only increases the α-phase transition temperature of the alumina aerogel, but the yttrium, evenly distributed within the alumina aerogel network, inhibits the surface diffusion of aluminum ions at high temperatures, thereby suppressing particle sintering and α-phase transition. The alumina aerogel modified in this way exhibits excellent low thermal conductivity, temperature resistance, and mechanical properties.

[0005] Therefore, combined with the aerogel's ultra-low thermal conductivity, strong thermal stability and mechanical properties, adding a large amount of modified alumina aerogel to the coating can greatly improve the coating's thermal insulation, temperature resistance and mechanical properties. Summary of the Invention

[0006] The purpose of the present invention is to develop an oxygen-barrier coating for steel claws containing Y2O3@Al2O3 aerogel. By combining yttria-doped alumina aerogel with an organic-inorganic composite adhesive, the coating solves the corrosion problem of electrolytic aluminum anode steel claws caused by oxidation and thermal stress at high temperatures of 350 to 900°C. By utilizing the thermal insulation properties of the aerogel nanopores and the dense oxygen-barrier layer formed by high-temperature ceramicization of the adhesive, the coating significantly extends the life of the steel claws and reduces contamination by impurities in the molten aluminum and iron.

[0007] In order to achieve the above-mentioned purpose, the present invention adopts the following technical means:

[0008] The present invention provides a Y2O3@Al2O3 aerogel-containing steel claw oxygen barrier coating, which comprises, by mass fraction, 100 parts of an organic-inorganic composite adhesive, 5-15 parts of Y2O3@Al2O3 aerogel, 30-55 parts of fumed nano-alumina powder, 12-15 parts of ultrafine mullite fiber powder, 0.5-1.5 parts of a leveling agent, 1.5-3 parts of a quick-drying agent, 0.5-1.5 parts of a thickener, and 0.5-1.5 parts of a wetting agent.

[0009] In the above scheme, the organic-inorganic composite adhesive includes, by mass fraction, 10-25 parts of silica-alumina sol, 60-75 parts of aluminum sol, 5-10 parts of modified silicone emulsion, and 2-5 parts of silane coupling agent. The organic-inorganic composite adhesive affects the anti-cracking performance and maximum temperature resistance of the coating. According to product requirements, the coating dries naturally without cracking, and the maximum temperature resistance is ≥1000°C.

[0010] In the above scheme, the Y2O3@Al2O3 aerogel includes, by mass fraction:

[0011] 10-15 parts of AlCl3·6H2O, 20-25 parts of EtOH, 15-20 parts of water, 3-5 parts of Y(NO3), 0.1-0.2 parts of hydroxyethyl cellulose, 0.4-0.8 parts of chitosan, and 3-5 parts of propylene oxide.

[0012] The present invention also provides a preparation method of a Y2O3@Al2O3 aerogel steel claw oxygen-barrier coating. The method comprises the following steps: adding, by mass, 100 parts of an organic-inorganic composite adhesive, 5 to 15 parts of Y2O3@Al2O3 aerogel, 30 to 55 parts of fumed nano-alumina powder, 12 to 15 parts of ultrafine mullite fiber powder, 0.5 to 1.5 parts of a leveling agent, 1.5 to 3 parts of a quick-drying agent, 0.5 to 1.5 parts of a thickener, and 0.5 to 1.5 parts of a wetting agent. The mixture is dispersed and stirred at high speed for 1 to 3 hours. Deionized water is added according to the requirements of brushing to adjust the viscosity of the coating, thereby obtaining a gray, viscous Y2O3@Al2O3 aerogel steel claw oxygen-barrier coating.

[0013] In the above scheme, the preparation of the organic-inorganic composite adhesive includes the following steps:

[0014] By mass fraction, 10-25 parts of silica-alumina sol, 60-75 parts of aluminum sol, 5-10 parts of modified silicone emulsion, and 2-5 parts of silane coupling agent were slowly added to the modified silicone emulsion at 50°C under magnetic stirring to prepare reaction solution A, and the reaction was carried out for 30 minutes.

[0015] Slowly add silica-alumina sol into reaction solution A to prepare reaction solution B, and react for 30 minutes;

[0016] Then, the aluminum sol was slowly added to the reaction solution B to prepare the reaction solution C, and the reaction was continued for 60 minutes;

[0017] Finally, the reaction liquid C was added into a hydrothermal reactor and reacted continuously for 6 hours at 120°C and a pressure of 1 MPa to obtain an organic-inorganic composite adhesive.

[0018] In the above scheme, the Y2O3@Al2O3 aerogel is prepared by the following method:

[0019] S1: Add 10-15 parts of AlCl3·6H2O to 15-20 parts of water, add 3-5 parts of Y(NO3)3 solution, ultrasonically disperse for 10 minutes, and add 20-25 parts of ethanol solvent (EtOH) to prepare aluminum precursor solution 1;

[0020] S2: 0.1-0.2 parts of hydroxyethyl cellulose and 0.4-0.8 parts of chitosan are added to the aluminum precursor solution 1, and after stirring for 3 hours, a light yellow suspension 2 with a certain viscosity is formed;

[0021] S3: 3-5 parts of propylene oxide were added dropwise to suspension 2 at a uniform rate and stirred for 10 minutes to obtain Y2O3@Al2O3 sol 3;

[0022] S4: The Y2O3@Al2O3 sol 3 was allowed to stand at room temperature for 2 h to obtain a Y2O3@Al2O3 gel, which was then immersed in EtOH. The EtOH liquid level was required to be about 2 cm higher than the upper surface of the Y2O3@Al2O3 gel and was replaced every 24 h. This step was repeated 3 to 4 times to fully replace the residual water and organic matter in the gel to obtain a Y2O3@Al2O3 wet gel.

[0023] S5: The Y2O3@Al2O3 wet gel is placed in a drying kettle of a multi-purpose supercritical test device, and an appropriate amount of anhydrous ethanol is added to completely submerge it, and CO2 supercritical drying is performed to obtain Y2O3@Al2O3 aerogel.

[0024] In the above scheme, the CO2 supercritical drying pressure is 10-13 MPa, the drying temperature is 35-45°C, and the drying time is 4-6 hours.

[0025] Because the present invention adopts the above technical means, it has the following beneficial effects:

[0026] (1) The present invention adds Al2O3 aerogel and dopes it with nano Y2O3 powder. Combining the high temperature resistance and optical performance advantages of Y2O3@Al2O3 powder, it can reflect back infrared wavelengths with obvious thermal effects; it has the high porosity and temperature resistance of nano powder and aerogel, and the nano pores are smaller than the free path of air molecules, achieving high-performance thermal insulation; the aerogel powder is wrapped with a composite organic-inorganic adhesive, so that the nano pores of the aerogel are converted into blind holes, the particles are bonded to form a coating, and high-temperature ceramicization forms a dense thermal insulation and oxygen barrier coating; the coating is mainly composed of aluminum and oxygen elements, and impurities (such as silicon and sodium) entering the aluminum electrolyte are minimized to ensure the purity of the original aluminum.

[0027] (2) The present invention adopts a composite organic-inorganic adhesive rather than a simple mixture. The silane coupling agent is fully hydrolyzed, and the hydrolysis product is silanol, which bonds with the modified organic silicon; the nano-aluminum silicate sol is positively charged and presents a feather-like dispersed solution. The aluminum sol is acidic and positively charged, and is further combined through electrostatic force and the formation of hydrogen bonds. Under high temperature and high pressure, the bonding force, adhesion and heat resistance of the adhesive are enhanced through coupling and anchoring. During the use of the coating, the high temperature causes the adhesive to ceramicize and sinter, and the lattice condenses to form a dense oxygen barrier layer.

[0028] (3) The oxygen barrier coating is prepared by using Y2O3@Al2O3 aerogel. The construction conditions are simple, it dries naturally, and it can be sprayed or brushed. It has excellent heat insulation and oxygen barrier properties and can greatly extend the service life of the steel claws. Figure 2 The lifespan of a steel claw is 30 to 35 days. As the lifespan increases, the diameter of the steel claw decreases and becomes scrapped when the diameter reaches the scrapping requirement. By measuring the diameter of the steel claw after the last use and the diameter of the steel claw after the current use, the service life of the steel claw can be calculated.

[0029] (4) High-temperature phase change suppression and improved thermal stability

[0030] The traditional Al2O3 aerogel will collapse due to phase change and sintering at high temperature, and the thermal insulation performance will drop sharply. However, the aerogel structure of the present invention is stable, and the Y2O3-doped Al2O3 aerogel can significantly inhibit the Al2O3 aerogel from sintering at high temperature (350-1300℃). 3+ Surface diffusion and α phase transformation delay grain sintering and maintain high specific surface area, among which Y 3+ It is evenly distributed in the aerogel network to form Y-A1 composite oxide, which reduces the contact between grain necks and inhibits grain boundary migration. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is the SEM image of Y2O3@A12O3 aerogel;

[0032] Figure 2 Here are the pictures of the steel claws before use (left) and after multiple uses (right);

[0033] Figure 3 This is the construction drawing of oxygen-barrier coating for steel claws containing Y2O3@Al2O3 aerogel.

[0034] Figure 4 is the thermal conductivity of Example 1;

[0035] Figure 5 is the thermal conductivity of Example 2;

[0036] Figure 6 is the thermal conductivity of Example 3;

[0037] Figure 7 is the proportional thermal conductivity;

[0038] Figure 8 It is a coating formula comparison table;

[0039] Figure 9 It is a comparison table of organic-inorganic compound adhesive formulas;

[0040] Figure 10 This is a comparison table of Y2O3@Al2O3 aerogel preparation. DETAILED DESCRIPTION

[0041] The following is a detailed description of the embodiments of the present invention. Although the present invention will be described and illustrated in conjunction with certain specific embodiments, it should be noted that the present invention is not limited to these embodiments. On the contrary, modifications or equivalent substitutions of the present invention are intended to fall within the scope of the claims of the present invention.

[0042] In addition, in order to better illustrate the present invention, numerous specific details are given in the following detailed description. It will be understood by those skilled in the art that the present invention can also be implemented without these specific details.

[0043] Example 1

[0044] This embodiment provides a method for preparing an oxygen-barrier coating for steel claws containing Y2O3@Al2O3 aerogel, which comprises using Y2O3@Al2O3 aerogel, an organic-inorganic composite adhesive, a fumed nano-alumina powder, ultrafine mullite fiber powder, a leveling agent, a quick-drying agent, a thickener, a wetting agent, and deionized water, and performing high-speed dispersion and stirring to prepare the coating. The method comprises the following steps:

[0045] (1) The organic-inorganic composite adhesive comprises silica-alumina sol, aluminum sol, modified silicone emulsion, and silane coupling agent, which are calculated by mass fraction as follows: 23 parts of silica-alumina sol, 65 parts of aluminum sol, 9 parts of modified silicone emulsion, and 3 parts of silane coupling agent. At 50° C. and under magnetic stirring, a silane coupling agent dilution (15%) is slowly added to the modified silicone emulsion to prepare reaction solution A, and the reaction is carried out for 30 minutes; the silica-alumina sol is slowly added to the reaction solution A to prepare reaction solution B, and the reaction is carried out for 30 minutes; the aluminum sol is then slowly added to the reaction solution B to prepare reaction solution C, and the reaction is carried out for 60 minutes; finally, the reaction solution C is added to a hydrothermal reactor, and the reaction is continuously carried out at 120° C. and a pressure of 1 MPa for 6 hours to obtain an organic-inorganic composite adhesive;

[0046] (2) The Y2O3@Al2O3 aerogel is prepared by the following method:

[0047] S1: Add 15 parts of AlCl3·6H2O to 20 parts of water, add 3 parts of Y(NO3)3, ultrasonically disperse for 10 minutes, and add 25 parts of ethanol solvent (EtOH) to prepare aluminum precursor solution 1;

[0048] S2: 0.1 parts of hydroxyethyl cellulose and 0.4 parts of chitosan were added to the aluminum precursor solution 1, and after stirring for 3 hours, a light yellow suspension 2 with a certain viscosity was formed;

[0049] S3: 5 parts of propylene oxide were added dropwise to suspension 2 at a constant speed (1-2 mL / min) and stirred for 10 min to obtain Y2O3@Al2O3 sol 3;

[0050] S4: The Y2O3@Al2O3 sol 3 was allowed to stand at room temperature for 2 hours to gel and obtain Y2O3@Al2O3 gel. The Y2O3@Al2O3 gel was then immersed in EtOH. The EtOH liquid level should be about 2 cm higher than the upper surface of the Y2O3@Al2O3 gel and the solution was replaced every 24 hours. This step was repeated 3 to 4 times to fully displace the residual water and organic matter in the gel to obtain Y2O3@Al2O3 wet gel.

[0051] S5: The Y2O3@Al2O3 wet gel was placed in a drying vessel of a multi-purpose supercritical test device, and an appropriate amount of anhydrous ethanol was added to completely submerge it. The Y2O3@Al2O3 aerogel was obtained by supercritical CO2 drying at a pressure of 10 MPa, a drying temperature of 40°C, and a drying time of 5 h.

[0052] Calculated by mass fraction: 100 parts of organic-inorganic composite adhesive, 5 parts of Y2O3@Al2O3 aerogel, 54 parts of fumed nano-alumina powder, 12 parts of ultrafine mullite fiber powder, 1 part of leveling agent, 1.5 parts of quick-drying agent, 1 part of thickener, and 0.5 part of wetting agent. Add the above components in sequence and stir at high speed for 1 to 3 hours. Add deionized water to adjust the viscosity of the coating according to the requirements of brushing to obtain a gray viscous Y2O3@Al2O3 aerogel steel claw oxygen barrier coating.

[0053] The Y2O3@Al2O3 aerogel steel claw oxygen barrier coating has a thermal conductivity (25°C) of 0.075W / (m·K), dries naturally at room temperature without cracks, has a maximum temperature resistance of 1065°C, and extends the life of the steel claw to 787 days (converted).

[0054] Example 2

[0055] This embodiment provides a method for preparing an oxygen-barrier coating for steel claws containing Y2O3@Al2O3 aerogel, which comprises using Y2O3@Al2O3 aerogel, an organic-inorganic composite adhesive, a fumed nano-alumina powder, ultrafine mullite fiber powder, a leveling agent, a quick-drying agent, a thickener, a wetting agent, and deionized water, and performing high-speed dispersion and stirring to prepare the coating. The method comprises the following steps:

[0056] (1) The organic-inorganic composite adhesive comprises silica-alumina sol, aluminum sol, modified silicone emulsion, and silane coupling agent, which are calculated by mass fraction as follows: 15 parts of silica-alumina sol, 75 parts of aluminum sol, 5 parts of modified silicone emulsion, and 5 parts of silane coupling agent. At 50° C. and under magnetic stirring, a silane coupling agent dilution (15%) is slowly added to the modified silicone emulsion to prepare reaction solution A, and the reaction is carried out for 30 minutes; the silica-alumina sol is slowly added to the reaction solution A to prepare reaction solution B, and the reaction is carried out for 30 minutes; the aluminum sol is then slowly added to the reaction solution B to prepare reaction solution C, and the reaction is carried out for 60 minutes. n Finally, the reaction solution C was added to a hydrothermal reactor and reacted continuously at 120°C and a pressure of 1 MPa for 6 hours to obtain an organic-inorganic composite adhesive;

[0057] (2) The Y2O3@Al2O3 aerogel is prepared by the following method:

[0058] S1: Add 13 parts of AlCl3·6H2O to 18 parts of water, add 5 parts of Y(NO3)3, ultrasonically disperse for 10 minutes, and add 22 parts of ethanol solvent (EtOH) to prepare aluminum precursor solution 1;

[0059] S2: 0.2 parts of hydroxyethyl cellulose and 0.8 parts of chitosan were added to the aluminum precursor solution 1, and after stirring for 3 hours, a light yellow suspension 2 with a certain viscosity was formed;

[0060] S3: 4 parts of propylene oxide were added dropwise to suspension 2 at a constant speed (1-2 mL / min) and stirred for 10 min to obtain Y2O3@Al2O3 sol 3;

[0061] S4: The Y2O3@Al2O3 sol 3 was allowed to stand at room temperature for 2 hours to gel and obtain Y2O3@Al2O3 gel. The Y2O3@Al2O3 gel was then immersed in EtOH. The EtOH liquid level should be about 2 cm higher than the upper surface of the Y2O3@Al2O3 gel and the solution was replaced every 24 hours. This step was repeated 3 to 4 times to fully displace the residual water and organic matter in the gel to obtain Y2O3@Al2O3 wet gel.

[0062] S5: The Y2O3@Al2O3 wet gel was placed in a drying vessel of a multi-purpose supercritical test device, and an appropriate amount of anhydrous ethanol was added to completely submerge it. The Y2O3@Al2O3 aerogel was obtained by supercritical CO2 drying at a pressure of 12 MPa, a drying temperature of 40°C, and a drying time of 4 h.

[0063] Calculated by mass fraction: 100 parts of organic-inorganic composite adhesive, 13 parts of Y2O3@Al2O3 aerogel, 37 parts of fumed nano-alumina powder, 13 parts of ultrafine mullite fiber powder, 1 part of leveling agent, 2 parts of quick-drying agent, 0.5 parts of thickener, and 1 part of wetting agent. Add the above components in sequence and stir at high speed for 1 to 3 hours. Add deionized water to adjust the viscosity of the coating according to the requirements of brushing to obtain a gray viscous Y2O3@Al2O3 aerogel steel claw oxygen barrier coating.

[0064] The Y2O3@Al2O3 aerogel steel claw oxygen barrier coating has a thermal conductivity (25°C) of 0.064W / (m·K), dries naturally at room temperature without cracks, has a maximum temperature resistance of 1130°C, and extends the life of the steel claw to 931 days (converted).

[0065] Example 3

[0066] This embodiment provides a method for preparing a steel claw oxygen barrier coating containing Y2O3@Al2O3 aerogel, which comprises using Y2O3@Al2O3 aerogel, an organic-inorganic composite adhesive, a fumed nano-alumina powder, ultrafine mullite fiber powder, a leveling agent, a quick-drying agent, a thickener, a wetting agent, and deionized water, and performing high-speed dispersion and stirring to prepare the coating. The method comprises the following steps:

[0067] (1) The organic-inorganic composite adhesive comprises silica-alumina sol, aluminum sol, modified silicone emulsion, and silane coupling agent, which are calculated by mass fraction as follows: 17 parts of silica-alumina sol, 70 parts of aluminum sol, 8 parts of modified silicone emulsion, and 5 parts of silane coupling agent. At 50° C. and under magnetic stirring, a silane coupling agent dilution (15%) is slowly added to the modified silicone emulsion to prepare reaction solution A, and the reaction is carried out for 30 minutes; the silica-alumina sol is slowly added to the reaction solution A to prepare reaction solution B, and the reaction is carried out for 30 minutes; the aluminum sol is then slowly added to the reaction solution B to prepare reaction solution C, and the reaction is carried out for 60 minutes; finally, the reaction solution C is added to a hydrothermal reactor, and the reaction is continuously carried out at 120° C. and a pressure of 1 MPa for 6 hours to obtain an organic-inorganic composite adhesive;

[0068] (2) The Y2O3@Al2O3 aerogel is prepared by the following method:

[0069] S1: Add 12 parts of AlCl3·6H2O to 16 parts of water, add 4 parts of Y(NO3)3, ultrasonically disperse for 10 minutes, and add 22 parts of ethanol solvent (EtOH) to prepare aluminum precursor solution 1;

[0070] S2: 0.2 parts of hydroxyethyl cellulose and 0.6 parts of chitosan were added to the aluminum precursor solution 1, and after stirring for 3 hours, a light yellow suspension 2 with a certain viscosity was formed;

[0071] S3: 3 parts of propylene oxide were added dropwise to suspension 2 at a constant speed (1-2 mL / min) and stirred for 10 min to obtain Y2O3@Al2O3 sol 3;

[0072] S4: The Y2O3@Al2O3 sol 3 was allowed to stand at room temperature for 2 hours to gel and obtain Y2O3@Al2O3 gel. The Y2O3@Al2O3 gel was then immersed in EtOH. The EtOH liquid level should be about 2 cm higher than the upper surface of the Y2O3@Al2O3 gel and the solution was replaced every 24 hours. This step was repeated 3 to 4 times to fully displace the residual water and organic matter in the gel to obtain Y2O3@Al2O3 wet gel.

[0073] S5: The Y2O3@Al2O3 wet gel was placed in a drying vessel of a multi-purpose supercritical test device, and an appropriate amount of anhydrous ethanol was added to completely submerge it. The Y2O3@Al2O3 aerogel was obtained by supercritical CO2 drying at a pressure of 11 MPa, a drying temperature of 45°C, and a drying time of 4.5 h.

[0074] Calculated by mass fraction: 100 parts of organic-inorganic composite adhesive, 8 parts of Y2O3@Al2O3 aerogel, 49 parts of fumed nano-alumina powder, 15 parts of ultrafine mullite fiber powder, 0.5 parts of leveling agent, 3 parts of quick-drying agent, 1.5 parts of thickener, and 1.5 parts of wetting agent. Add the above components in sequence and stir at high speed for 1 to 3 hours. Add deionized water to adjust the viscosity of the coating according to the requirements of brushing to obtain a gray viscous Y2O3@Al2O3 aerogel steel claw oxygen barrier coating.

[0075] The Y2O3@Al2O3 aerogel steel claw oxygen barrier coating has a thermal conductivity (25°C) of 0.069W / (m·K), dries naturally at room temperature without cracks, has a maximum temperature resistance of 1105°C, and extends the life of the steel claw to 848 days (converted).

[0076] Example 4

[0077] Compared with Example 1, the preparation process of the organic-inorganic composite adhesive and Y2O3@Al2O3 aerogel is the same, except that the coating formula of Example 1 is replaced with the coating formula of Example 2.

[0078] The Y2O3@Al2O3 aerogel steel claw oxygen barrier coating has a thermal conductivity (25°C) of 0.068W / (m·K), dries naturally at room temperature without cracks, has a maximum temperature resistance of 1065°C, and extends the life of the steel claw to 873 days (converted).

[0079] Example 5

[0080] Compared with Example 3, the preparation process of the organic-inorganic composite adhesive and Y2O3@Al2O3 aerogel is the same, except that the coating formula of Example 3 is replaced by the coating formula of Example 2.

[0081] The Y2O3@Al2O3 aerogel steel claw oxygen barrier coating has a thermal conductivity (at 25°C) of 0.066W / (m·K), dries naturally at room temperature without cracks, has a maximum temperature resistance of 1105°C, and extends the life of the steel claw to 901 days (converted).

[0082] Example 6

[0083] Compared with Example 3, the preparation process of the organic-inorganic composite adhesive and Y2O3@Al2O3 aerogel is the same, except that the coating formula of Example 3 is replaced with the coating formula of Example 2, and the amount of the organic-inorganic composite adhesive in the coating formula is changed to 85 parts.

[0084] The Y2O3@Al2O3 aerogel oxygen-barrier coating for steel claws has a thermal conductivity of 0.061 W / (m·K) at 25°C, dries naturally at room temperature without cracking, and has a maximum temperature resistance of 1090°C, extending the life of the steel claws to 846 days (converted). Due to the reduced amount of organic-inorganic composite adhesive, while the coating did not crack, the life of the steel claws was significantly shortened compared to Example 2. The composite adhesive failed to completely encapsulate the porous filler, allowing a small amount of gas to enter the steel claws through the pores, causing the claws to oxidize more rapidly during use.

[0085] Comparative Example

[0086] This comparative example provides a method for preparing a steel claw oxygen barrier coating, which comprises using an organic-inorganic composite adhesive, fumed nano-alumina powder, ultrafine mullite fiber powder, a leveling agent, a quick-drying agent, a thickener, a wetting agent, and deionized water, and performing high-speed dispersion and stirring steps, and comprises the following steps:

[0087] (1) The organic-inorganic composite adhesive is the same as that in Example 2;

[0088] (2) Calculated by mass fraction: 100 parts of organic-inorganic composite adhesive, 50 parts of fumed nano-alumina powder, 13 parts of ultrafine mullite fiber powder, 1 part of leveling agent, 2 parts of quick-drying agent, 0.5 parts of thickener, and 1 part of wetting agent. Add the above components in sequence and stir at high speed for 1 to 3 hours. Add deionized water to adjust the viscosity of the coating according to the requirements of brushing to obtain a gray viscous steel claw oxygen barrier coating.

[0089] The thermal conductivity coefficient of the thermal insulation coating (25°C) is 0.116W / (m·K), it dries naturally at room temperature without cracks, has a maximum temperature resistance of 1130°C, and extends the life of the steel claws to 554 days (converted).

Claims

1. A Y2O3@Al2O3 aerogel steel claw oxygen barrier coating, characterized in that: Calculated by mass, it includes: 100 parts of organic-inorganic composite adhesive, 5-15 parts of Y2O3@Al2O3 aerogel, 30-55 parts of gas-phase nano-alumina powder, 12-15 parts of ultrafine mullite fiber powder, 0.5-1.5 parts of leveling agent, 1.5-3 parts of quick-drying agent, 0.5-1.5 parts of thickener, and 0.5-1.5 parts of wetting agent.

2. The Y2O3@Al2O3 aerogel steel claw oxygen barrier coating according to claim 1, characterized in that: The organic-inorganic composite adhesive comprises, by mass fraction, 10 to 25 parts of silica-alumina sol, 60 to 75 parts of aluminum sol, 5 to 10 parts of modified silicone emulsion, and 2 to 5 parts of silane coupling agent.

3. The Y2O3@Al2O3 aerogel steel claw oxygen barrier coating according to claim 1, characterized in that: Y2O3@Al2O3 aerogel by mass fraction include: 10-15 parts of AlCl3·6H2O, 20-25 parts of EtOH, 15-20 parts of water, 3-5 parts of Y(NO3), 0.1-0.2 parts of hydroxyethyl cellulose, 0.4-0.8 parts of chitosan, and 3-5 parts of propylene oxide.

4. A method for preparing an oxygen-barrier coating for steel claws containing Y2O3@Al2O3 aerogel, characterized in that: Calculated by mass fraction, 100 parts of organic-inorganic composite adhesive, 5-15 parts of Y2O3@Al2O3 aerogel, 30-55 parts of fumed nano-alumina powder, 12-15 parts of ultrafine mullite fiber powder, 0.5-1.5 parts of leveling agent, 1.5-3 parts of quick-drying agent, 0.5-1.5 parts of thickener, and 0.5-1.5 parts of wetting agent are added in sequence and stirred at high speed for 1-3 hours. Deionized water is added to adjust the viscosity of the coating according to the requirements of brushing to obtain a gray viscous Y2O3@Al2O3 aerogel steel claw oxygen barrier coating.

5. The preparation method according to claim 4, characterized in that The preparation of the organic-inorganic composite adhesive comprises the following steps: By mass fraction, 10-25 parts of silica-alumina sol, 60-75 parts of aluminum sol, 5-10 parts of modified silicone emulsion, and 2-5 parts of silane coupling agent were slowly added to the modified silicone emulsion at 50°C under magnetic stirring to prepare reaction solution A, and the mixture was reacted for 30 minutes. Slowly add silica-alumina sol into reaction solution A to prepare reaction solution B, and react for 30 minutes; Then, the aluminum sol was slowly added to the reaction solution B to prepare the reaction solution C, and the reaction was continued for 60 minutes; Finally, the reaction liquid C was added into a hydrothermal reactor and reacted continuously for 6 hours at 120°C and a pressure of 1 MPa to obtain an organic-inorganic composite adhesive.

6. The preparation method according to claim 4, characterized in that The Y2O3@Al2O3 aerogel is prepared by the following method: S1: Add 10-15 parts of AlCl3·6H2O to 15-20 parts of water, add 3-5 parts of Y(NO3)3 solution, ultrasonically disperse for 10 minutes, and add 20-25 parts of ethanol solvent (EtOH) to prepare aluminum precursor solution 1; S2: 0.1-0.2 parts of hydroxyethyl cellulose and 0.4-0.8 parts of chitosan are added to the aluminum precursor solution 1, and after stirring for 3 hours, a light yellow suspension 2 with a certain viscosity is formed; S3: 3-5 parts of propylene oxide were added dropwise to suspension 2 at a uniform rate and stirred for 10 minutes to obtain Y2O3@Al2O3 sol 3; S4: The Y2O3@Al2O3 sol 3 was allowed to stand at room temperature for 2 h to obtain a Y2O3@Al2O3 gel, which was then immersed in EtOH. The EtOH liquid level should be about 2 cm higher than the upper surface of the Y2O3@Al2O3 gel and replaced every 24 h. This step was repeated 3 to 4 times to fully replace the residual water and organic matter in the gel to obtain a Y2O3@Al2O3 wet gel. S5: The Y2O3@Al2O3 wet gel is placed in a drying kettle of a multi-purpose supercritical test device, and an appropriate amount of anhydrous ethanol is added to completely submerge it, and CO2 supercritical drying is performed to obtain Y2O3@Al2O3 aerogel.

7. The preparation method according to claim 6, characterized in that: CO2 supercritical drying pressure is 10~13MPa, drying temperature is 35~45℃, and drying time is 4~6h.

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