Anti-pollution flashover porcelain insulator and preparation method thereof

Abstract

The present invention relates to the field of insulator technology, and a kind of anti-pollution flashover porcelain insulator and preparation method thereof is provided.The porcelain insulator of the present invention includes porcelain insulator matrix, filling layer and super-hydrophobic coating from the inside out, and the coating used for the filling layer includes the raw material of following weight parts: SiO2‑Al2O3‑ZrO2 composite sol 20~30 parts, bauxite 5~10 parts, sodium tripolyphosphate 0.5~3 parts, sodium dihydrogen phosphate 0.5~3 parts, silane coupling agent 5~10 parts;The super-hydrophobic coating is dried after being coated on porcelain insulator matrix by fluorinated sol solution, and the fluorinated sol solution includes SiO2‑La2O3 sol, hydrophobic gas-phase nano-silica, fluorinating agent and silane coupling agent.The super-hydrophobic coating of the present invention has good hydrophobicity and self-cleaning ability, and water droplets can adsorb the pollutants such as dust, bacteria adhering to the insulator surface, so that the insulator surface remains clean, greatly improves the anti-pollution flashover performance of the insulator.

Description

Technical Field

[0001] The present invention relates to the technical field of insulators, and in particular to an anti-pollution flashover porcelain insulator and a preparation method thereof. Background Art

[0002] Insulators are devices installed between conductors at different potentials, or between a conductor and a ground potential component, capable of withstanding voltage and mechanical stress. They are specialized insulating components designed to increase creepage distances and play a vital role in overhead transmission lines. They are typically made of glass or ceramic. Insulators made of ceramic are called porcelain insulators.

[0003] Porcelain insulators have the advantages of high mechanical strength, stable chemical properties, good insulation performance, and excellent corrosion resistance, making them the most widely used in the insulator industry, and their use in railway traction network power systems is increasing. However, my country's natural environment is relatively complex, and porcelain insulators are mostly used outdoors or even in the wild, so porcelain insulator products are also required to be able to adapt to complex environmental conditions. However, the glaze of existing ceramic insulators is prone to bubbles and uneven glazing during use, which leads to a small number of pores on the surface of the porcelain insulator. It is not smooth and flat, easily contaminated, and difficult to clean, resulting in poor anti-pollution flashover effect. Once the porcelain insulator is damaged, accidents will occur frequently. Due to the increasingly serious air pollution, pollution flashover accidents occur frequently, which greatly shortens the service life of ceramic insulators. At the same time, it also increases the maintenance cost of the insulator, affects the normal operation of the railway power grid, and reduces economic benefits. Summary of the Invention

[0004] The present invention aims to overcome at least one of the above-mentioned shortcomings and deficiencies of the prior art and provide an anti-pollution flashover porcelain insulator and a method for manufacturing the same. The purpose of the present invention is achieved based on the following technical solutions:

[0005] In one aspect, the present invention provides an anti-pollution flashover porcelain insulator, which comprises, from the inside out, a porcelain insulator base, a filling layer, and a super-hydrophobic coating;

[0006] The coating used for the filling layer includes the following raw materials in parts by weight: 20-30 parts of SiO2-Al2O3-ZrO2 composite sol, 5-10 parts of bauxite, 0.5-3 parts of sodium tripolyphosphate, 0.5-3 parts of sodium dihydrogen phosphate, and 5-10 parts of silane coupling agent;

[0007] The super hydrophobic coating is formed by coating a fluorinated sol solution on a porcelain insulator substrate and then drying the solution. The fluorinated sol solution comprises SiO2-La2O3 sol, hydrophobic gas-phase nano-silica, a fluorinating agent and a silane coupling agent.

[0008] After porcelain insulators are fired and formed, a small amount of pores appear on their surface. The vast majority of bauxite is aluminum oxide, and during the firing process, most of it exists in the filling layer in the form of corundum microcrystals, directly increasing the hardness of the filling layer. A small portion melts into the porcelain insulator matrix, strengthening the glass network inside the insulator and further increasing the hardness. The SiO2-Al2O3-ZrO2 composite sol can effectively fill the pores, effectively improving the smoothness of the insulator surface and preventing water from penetrating into the matrix. The filling layer has a dense structure, and the glass phase therein fills the pores on the matrix surface, effectively hindering the penetration of surface-adsorbed water into the matrix, greatly reducing the destructive effect of water volume expansion caused by freezing on the material. Furthermore, the filling layer has a high hardness and bonds well with the matrix. Coating it on the matrix material increases the mechanical strength of the material, which is beneficial for improving the material's freeze-thaw resistance. Sodium tripolyphosphate improves the coating's suspension properties and ensures uniformity. Sodium dihydrogen phosphate offers advantages such as excellent water resistance, low curing shrinkage, high high-temperature strength, and the ability to achieve high-strength bonding at relatively low temperatures. It begins sintering at 1000-1300°C, decomposing and volatilizing P2O5, which bonds to the insulator substrate. It does not form low-melting products at high temperatures, making it an excellent coating binder. Silane coupling agents, combined with SiO2-Al2O3-ZrO2 composite sols, enhance the hydrophobicity of the filler layer while preventing cracking during heat treatment, maintaining the integrity and strength of the filler layer. This function is similar to that of silane coupling agents in coatings.

[0009] Super-hydrophobic coating is mainly composed of C, F, O, La and Si elements, and after sol is modified by fluorinating agent, low surface energy of coating is given, and coating shows super-hydrophobicity. Add hydrophobic fumed nano-silica and SiO2-La2O3 sol to form micro-nano double-layer structure and form larger protrusion on coating surface, and be covered with small protrusion again on protrusion, and particle arrangement produces a lot of spaces, produces the effect of surface structure similar to lotus leaf. This surface microstructure can make the contact surface of water droplet and solid trap a large amount of air, form " air film ", make contact area reduce, contact angle increase. Not only super-hydrophobicity is further improved in the coating after adding silane coupling agent, and coating avoids cracking and keeps integrity and firm of coating in thermal treatment process simultaneously, and silane coupling agent organically combines SiO2-La2O3 sol and fumed nano-silica two kinds of particles to form micro-nano double-layer structure, is similar to Cassie model. The invention imparts super-hydrophobicity to the coating through the combined action of low-surface-energy substances and micro-nano structures with smaller roughness and higher air interception area.

[0010] The super-hydrophobic coating of the present invention also has an excellent self-cleaning function. Water droplets can easily roll on the super-hydrophobic surface with a small rolling angle. During the rolling process, they can absorb pollutants such as dust and bacteria adhering to the surface of the insulator, so that the surface of the insulator always remains clean, just like the surface of a lotus leaf, greatly improving the anti-pollution flashover performance of the insulator.

[0011] Preferably, the mass ratio of SiO2-La2O3 sol, hydrophobic fumed nano-silica, fluorinating agent and silane coupling agent in the fluorinated sol solution is 10:1-3:1-2:1-2.

[0012] Another aspect of the present invention provides a method for preparing a pollution flashover-resistant porcelain insulator, comprising the following steps:

[0013] S1. Preparation of super-hydrophobic coating:

[0014] S11. Preparation of SiO2-La2O3 sol: dissolving lanthanum oxide in nitric acid to prepare a lanthanum nitrate solution, then adding aqueous ammonia to adjust the solution to a pH of 8.5-9.5, filtering to obtain a precipitate, washing, and dispersing in distilled water to obtain a La(OH)3 suspension; mixing TEOS, water, and ethanol, then adding nitric acid to the mixture until the pH is 2-3, stirring for 15-60 minutes, then adding the La(OH)3 suspension, adding nitric acid to adjust the mixture to a pH of 3-4, stirring at 60-90°C for 2-4 hours, and cooling;

[0015] S12, fluorination of the sol: adding a fluorinating agent to the SiO2-La2O3 sol obtained in step S11, stirring for 0.5 to 2 hours to obtain a fluorinated sol;

[0016] S13, preparing a fluorinated sol solution: mixing TEOS and hydrochloric acid and stirring, adding the fluorinated sol obtained in step S12, hydrophobic fumed nano-silica and a silane coupling agent thereto, and ultrasonically dispersing for 1 to 3 hours to obtain a fluorinated sol solution;

[0017] S2. Add water to the raw materials of the coating used for the filling layer and ball-grind them to prepare a coating, then immerse the porcelain insulator substrate in the prepared coating, cover the surface of the porcelain insulator substrate with the coating by spin coating, remove the substrate, dry it, and then calcine it at 1000-1150° C. for 1-3 hours, and cool it to below 80° C. to obtain a porcelain insulator substrate covered with the filling layer;

[0018] S3, pretreatment of the porcelain insulator substrate: cleaning and drying the surface of the porcelain insulator substrate obtained in step S2;

[0019] S4. Applying a super-hydrophobic coating: coating a fluorinated SiO2-ZrO2 sol solution on the surface of the porcelain insulator substrate and drying.

[0020] Preferably, in step S11, the TEOS and ethanol are mixed and stirred at a speed of 1000-2000 r / min and a temperature of 20-40°C.

[0021] Preferably, the stirring speed in step S12 is 300-1000 r / min, and the temperature is 20-40°C.

[0022] Preferably, the fluorinating agent in step S12 is any one or more of 1H,1H,2H,2H-perfluorodecyltriethoxysilane, 1H,1H,2H,2H-perfluorooctyltriethoxysilane, heptadecafluorodecyltrimethoxysilane, perfluorooctyltrimethoxysilane, perfluoropolyether silane, and hydroxyfluorosilicone oil.

[0023] Preferably, the silane coupling agent in step S13 is a hydrolyzed silane coupling agent, and the silane coupling agent includes one or more of γ-(methoxyacryloxy)propyltrimethoxysilane, γ-glycidyloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, and 3-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0024] Preferably, the hydrolysis of the silane coupling agent is performed by mixing the silane coupling agent with ethanol and water in a volume ratio of 1:1:2, and stirring the mixture at 50-60° C. for 30 minutes.

[0025] Preferably, the thickness of the filling layer in step S2 is 2 to 5 mm, and / or the thickness of the super-hydrophobic coating in step S3 is 3 to 6 mm.

[0026] Preferably, the spin coating method in step S2 is to first spin coat at a rotation speed of 300-500 r / min for 15-30 s, and then spin coat at a rotation speed of 2000-2500 r / min for 60-90 s.

[0027] Preferably, the pretreatment of the porcelain insulator substrate in step S3 specifically includes: washing with water 2 to 4 times, then washing with ethanol 1 to 2 times, and drying at 60 to 100° C. The spin coating method can improve the coating efficiency on the substrate, make it easier to bond with the substrate, and provide a more uniform coating with high bonding strength.

[0028] Preferably, the coating method in step S4 includes dipping, spin coating or spray coating.

[0029] Preferably, the spin coating method is to first spin coat at a speed of 300-800 r / min for 10-20 seconds, and then spin coat at a speed of 2000-2500 r / min for 60-120 seconds. The spin coating method can improve the coating efficiency on the substrate, make it easier to bond with the substrate, and provide a more uniform coating with high bonding strength.

[0030] Preferably, the drying in step S4 includes placing the coated porcelain insulator at room temperature to evaporate water, and then drying it at 100-150°C.

[0031] The present invention can achieve at least one of the following beneficial effects:

[0032] 1. The present invention is by arranging packed layer and super-hydrophobic layer on porcelain insulator matrix, and packed layer effectively fills pore and has higher hardness, is well combined with matrix, effectively improves the flatness and the mechanical property of insulator surface, for super-hydrophobic coating provides good coating surface, improves bonding strength, while packed layer also has certain hydrophobicity;Super-hydrophobic layer adopts fluorinated sol solution, with low surface free energy, and shaped micro-nano double-layer structure, particle arrangement produces a lot of spaces, with less roughness and higher air trapped area, produces the effect of the surface structure similar to lotus leaf, with excellent super-hydrophobic effect.Super-hydrophobic coating of the present invention also has good self-cleaning ability, and water droplet can adsorb the pollutants such as dust, bacteria that stick to insulator surface, makes insulator surface remain clean all the time, greatly improves the anti-pollution flashover performance of insulator.

[0033] 2. The porcelain insulator of the present invention has good super-hydrophobicity, self-cleaning properties, mechanical stability, chemical stability and time stability. The salt density on the surface of the insulator is significantly lower than that of ordinary insulators, and its surface salt density is only about 1 / 5 of that of ordinary insulators. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only a portion of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0035] Preparation method of SiO2-Al2O3-ZrO2 composite sol: dissolve zirconium oxychloride in water (ratio 1 mol zirconium oxychloride: 2L water), stir for 30 minutes to obtain zirconium oxychloride hydrolyzate; dissolve aluminum nitrate in appropriate amount of water, adjust the pH to about 8.5 with 1 mol / L ammonia water, and stir for 30 minutes to obtain Al(OH)3 suspension; mix TEOS, ethanol and water in a mass ratio of 1:2:4, and then add 1 mol / L nitric acid dropwise to the pH to 2, stir for 30 minutes to obtain TEOS hydrolyzate; then add Al(OH)3 suspension and zirconium oxychloride hydrolyzate to TEOS hydrolyzate, add 1 mol / L nitric acid dropwise to adjust the pH of the mixture to 3, stir the reaction at 80°C for 3 hours, and cool.

[0036] In the following examples, the preparation of SiO2-La2O3 sol: TEOS, ethanol and water were mixed in a mass ratio of 1:2:4, and the concentration of nitric acid was 1 mol / L; the specific gravity of the coating used in the filling layer was 1.8-1.85 g / cm 3 .

[0037] Example 1

[0038] A pollution-flashover-proof porcelain insulator comprises, from the inside out, a porcelain insulator substrate, a filling layer and a super-hydrophobic coating; wherein the coating used for the filling layer comprises the following raw materials in parts by weight: 20 parts of SiO2-Al2O3-ZrO2 composite sol, 10 parts of bauxite, 0.5 parts of sodium tripolyphosphate, 0.5 parts of sodium dihydrogen phosphate, and 5 parts of a silane coupling agent; the super-hydrophobic coating is formed by coating a fluorinated sol solution on the porcelain insulator substrate and then drying it; the fluorinated sol solution comprises SiO2-La2O3 sol, hydrophobic vapor-phase nano-silica, a fluorinating agent, and a silane coupling agent, with a mass ratio of 10:1:1:1.

[0039] The method for preparing the anti-pollution flashover porcelain insulator of this embodiment comprises the following steps:

[0040] S1. Preparation of super-hydrophobic coating:

[0041] S11. Preparation of SiO2-La2O3 sol: dissolving lanthanum oxide in nitric acid to prepare a 0.1 mol / L lanthanum nitrate solution, then adding ammonia water dropwise thereto to adjust the solution to pH 8.5, filtering to obtain a precipitate, washing, and dispersing in distilled water to obtain a La(OH)3 suspension; mixing TEOS, water, and ethanol, then adding nitric acid dropwise thereto to a pH of 2, and stirring at 1000 r / min at 20°C for 60 min; then adding La(OH)3 suspension (molar ratio La:Si=1:1), adding nitric acid dropwise to adjust the mixture to pH 3, stirring at 60°C at 1000 r / min for 4 h, and cooling;

[0042] S12, fluorination of the sol: adding a fluorinating agent 1H,1H,2H,2H-perfluorodecyltriethoxysilane to the SiO2-La2O3 sol obtained in step S11, and stirring at 300 r / min at 20°C for 2 h to obtain a fluorinated sol;

[0043] S13, preparing a fluorinated sol solution: TEOS and hydrochloric acid (volume ratio of 5:1, total volume of the two: total mass of the added substances is 1:1) are mixed and stirred, and the fluorinated sol obtained in step S12, hydrophobic fumed nano-silica and a silane coupling agent are added thereto, and ultrasonic dispersion is performed for 1 hour to obtain; the silane coupling agent is a hydrolyzed silane coupling agent, specifically, γ-(methoxyacryloyloxy)propyltrimethoxysilane, ethanol and water are mixed in a volume ratio of 1:1:2, and stirred at 50°C for 30 minutes;

[0044] S2. The raw materials of the coating for the filling layer are added with water and ball-milled to prepare a coating, and then the porcelain insulator substrate is immersed in the prepared coating. The coating is covered on the surface of the porcelain insulator substrate by spin coating, first at a speed of 300 r / min for 15 seconds, then at a speed of 2000 r / min for 60 seconds, removed, dried, and then calcined at 1000° C. for 3 hours, and cooled to below 80° C. to obtain a porcelain insulator substrate covered with a filling layer, wherein the thickness of the filling layer is 2 mm;

[0045] S3, pretreatment of the porcelain insulator substrate: the surface of the porcelain insulator substrate obtained in step S2 was washed twice with water, then once with ethanol, and dried at 60°C;

[0046] S4. Apply super-hydrophobic coating: while hot, apply fluorinated SiO2-ZrO2 sol solution on the surface of the porcelain insulator substrate by dipping, immerse twice, each time for 1 min, let it stand at room temperature to evaporate the water, and then dry it at 100°C to obtain a super-hydrophobic coating with a thickness of 3 mm.

[0047] Example 2

[0048] A pollution-flashover-proof porcelain insulator comprises, from the inside out, a porcelain insulator base, a filling layer and a super-hydrophobic coating; wherein the coating used for the filling layer comprises the following raw materials in parts by weight: 30 parts of SiO2-Al2O3-ZrO2 composite sol, 5 parts of bauxite, 3 parts of sodium tripolyphosphate, 3 parts of sodium dihydrogen phosphate, and 10 parts of a silane coupling agent; the super-hydrophobic coating is formed by coating a fluorinated sol solution on the porcelain insulator base and then drying it; the fluorinated sol solution comprises SiO2-La2O3 sol, hydrophobic vapor-phase nano-silica, a fluorinating agent, and a silane coupling agent, with a mass ratio of 10:3:2:2.

[0049] The method for preparing the anti-pollution flashover porcelain insulator of this embodiment comprises the following steps:

[0050] S1. Preparation of super-hydrophobic coating:

[0051] S11. Preparation of SiO2-La2O3 sol: dissolving lanthanum oxide in nitric acid to prepare a 0.1 mol / L lanthanum nitrate solution, then adding ammonia water dropwise thereto to adjust the solution to a pH of 9.5, filtering to obtain a precipitate, washing, and dispersing in distilled water to obtain a La(OH)3 suspension; mixing TEOS and ethanol, then adding nitric acid dropwise thereto to a pH of 3 (molar ratio of La:Si=1:1), and stirring at 40°C at a speed of 2000 r / min for 15 minutes; then adding the La(OH)3 suspension, and adding nitric acid dropwise to adjust the pH of the mixture to 4, stirring at 90°C at a speed of 2000 r / min for 2 hours, and cooling;

[0052] S12, fluorination of the sol: adding a fluorinating agent of heptadecafluorodecyltrimethoxysilane and perfluorooctyltrimethoxysilane (volume ratio 2:1) to the SiO2-La2O3 sol obtained in step S11, and stirring at 40°C and 1000 r / min for 0.5 h to obtain a fluorinated sol;

[0053] S13, preparing a fluorinated sol solution: TEOS and hydrochloric acid (volume ratio of 5:1, total volume of the two: total mass of the added substances is 1:1) are mixed and stirred, and the fluorinated sol obtained in step S12, hydrophobic fumed nano-silica and a silane coupling agent are added thereto, and ultrasonic dispersion is performed for 3 hours to obtain; the silane coupling agent is a hydrolyzed silane coupling agent, specifically, γ-glycidyloxypropyltrimethoxysilane and 3-aminopropyltrimethoxysilane (volume ratio of 1:1) are mixed with ethanol and water in a volume ratio of 1:1:2, and stirred at 60°C for 30 minutes;

[0054] S2. The raw materials of the coating for the filling layer are added with water and ball-milled to prepare a coating, and then the porcelain insulator substrate is immersed in the prepared coating. The coating is covered on the surface of the porcelain insulator substrate by spin coating, first at a speed of 400 r / min for 20 seconds and then at a speed of 2000 r / min for 60 seconds. The substrate is taken out and dried, and then calcined at 1150° C. for 1 hour and cooled to below 50° C. to obtain a porcelain insulator substrate covered with a filling layer, wherein the thickness of the filling layer is 5 mm;

[0055] S3, pretreatment of the porcelain insulator substrate: washing the surface of the porcelain insulator substrate obtained in step S2 twice with water, then twice with ethanol, and drying at 100°C;

[0056] S4. Apply a super-hydrophobic coating: Spin-coat the surface of the porcelain insulator substrate with a fluorinated SiO2-ZrO2 sol solution while it is still hot. First, spin-coat at a speed of 500 r / min for 10 seconds and then at a speed of 2500 r / min for 120 seconds. Let it stand at room temperature to evaporate the water, and then dry it at 150°C to obtain a super-hydrophobic coating with a thickness of 6 mm.

[0057] Example 3

[0058] A pollution-flashover-proof porcelain insulator comprises, from the inside out, a porcelain insulator base, a filling layer and a super-hydrophobic coating; wherein the coating used for the filling layer comprises the following raw materials in parts by weight: 27 parts of SiO2-Al2O3-ZrO2 composite sol, 8 parts of bauxite, 2 parts of sodium tripolyphosphate, 2 parts of sodium dihydrogen phosphate, and 7 parts of a silane coupling agent; the super-hydrophobic coating is formed by coating a fluorinated sol solution on the porcelain insulator base and then drying it; the fluorinated sol solution comprises SiO2-La2O3 sol, hydrophobic vapor-phase nano-silica, a fluorinating agent and a silane coupling agent, with a mass ratio of 10:2:1.5:1.5.

[0059] The method for preparing the anti-pollution flashover porcelain insulator of this embodiment comprises the following steps:

[0060] S1. Preparation of super-hydrophobic coating:

[0061] S11. Preparation of SiO2-La2O3 sol: dissolving lanthanum oxide in nitric acid to prepare a 0.1 mol / L lanthanum nitrate solution, then adding aqueous ammonia to adjust the solution to pH 9, filtering to obtain a precipitate, washing, and dispersing in distilled water to obtain a La(OH)3 suspension; mixing TEOS and ethanol, then adding nitric acid to the mixture until the pH is 2-3, and stirring at 30°C at a speed of 1500 r / min for 40 minutes; then adding La(OH)3 suspension (molar ratio of La:Si=1:1), adding nitric acid to adjust the mixture to pH 3.5, stirring at 70°C at a speed of 15 r / min for 3 hours, and cooling;

[0062] S12, fluorination of the sol: adding a fluorinating agent, perfluoropolyether silane, to the SiO2-La2O3 sol obtained in step S11, and stirring at 600 rpm for 1 h at 30°C to obtain a fluorinated sol;

[0063] S13, preparing a fluorinated sol solution: TEOS and hydrochloric acid (volume ratio of 5:1, total volume of the two: total mass of the added substances is 1:1) are mixed and stirred, and the fluorinated sol obtained in step S12, hydrophobic fumed nano-silica and a silane coupling agent are added thereto, and ultrasonic dispersion is performed for 2 hours to obtain; the silane coupling agent is a hydrolyzed silane coupling agent, specifically, γ-glycidyloxypropyltrimethoxysilane is mixed with ethanol and water in a volume ratio of 1:1:2, and stirred at 55°C for 30 minutes;

[0064] S2. The raw materials of the coating for the filling layer are ball-milled with water to prepare a coating, and then the porcelain insulator substrate is immersed in the prepared coating. The coating is covered on the surface of the porcelain insulator substrate by spin coating, first at a speed of 500 r / min for 15 seconds and then at a speed of 2500 r / min for 60 seconds. The substrate is taken out and dried, and then calcined at 1050° C. for 2 hours and cooled to below 60° C. to obtain a porcelain insulator substrate covered with a filling layer. The thickness of the filling layer is 3 mm.

[0065] S3, pretreatment of the porcelain insulator substrate: the surface of the porcelain insulator substrate obtained in step S2 was washed with water 3 times, then washed with ethanol 13 times, and dried at 80°C;

[0066] S4. Apply a super-hydrophobic coating: While hot, apply a fluorinated SiO2-ZrO2 sol solution on the surface of the porcelain insulator substrate by dipping, spin coating, or spraying. First, spin coat at a speed of 800 r / min for 10 seconds, then spin coat at a speed of 2500 r / min for 60 seconds. Let it stand at room temperature to evaporate the water, and then dry it at 130°C to obtain a super-hydrophobic coating with a thickness of 4 mm.

[0067] Example 4

[0068] A pollution-flashover-proof porcelain insulator comprises, from the inside out, a porcelain insulator base, a filling layer and a super-hydrophobic coating; wherein the coating used for the filling layer comprises the following raw materials in parts by weight: 22 parts of SiO2-Al2O3-ZrO2 composite sol, 6 parts of bauxite, 1 part of sodium tripolyphosphate, 2.5 parts of sodium dihydrogen phosphate, and 8 parts of a silane coupling agent; the super-hydrophobic coating is formed by coating a fluorinated sol solution on the porcelain insulator base and then drying it; the fluorinated sol solution comprises SiO2-La2O3 sol, hydrophobic vapor-phase nano-silica, a fluorinating agent and a silane coupling agent, with a mass ratio of 10:1.5:2:2.

[0069] The method for preparing the anti-pollution flashover porcelain insulator of this embodiment comprises the following steps:

[0070] S1. Preparation of super-hydrophobic coating:

[0071] S11. Preparation of SiO2-La2O3 sol: dissolving lanthanum oxide in nitric acid to prepare a 0.1 mol / L lanthanum nitrate solution, then adding ammonia water dropwise thereto to adjust the solution to pH 9, filtering to obtain a precipitate, washing, and dispersing in distilled water to obtain a La(OH)3 suspension; mixing TEOS and ethanol, then adding nitric acid dropwise thereto to a pH of 2.5, and stirring at room temperature at a speed of 1200 r / min for 30 min; then adding the La(OH)3 suspension, adding nitric acid dropwise thereto to adjust the mixture to pH 3, stirring at 80°C at a speed of 1200 r / min for 3 h, and cooling;

[0072] S12, fluorination of the sol: adding a fluorinating agent 1H,1H,2H,2H-perfluorooctyltriethoxysilane and hydroxyfluorosilicone oil (volume ratio 1:1) to the SiO2-La2O3 sol obtained in step S11, and stirring at a speed of 800 r / min at room temperature for 1 h to obtain a fluorinated sol;

[0073] S13, prepare a fluorinated sol solution: TEOS and hydrochloric acid (volume ratio of 5:1, total volume of the two: total mass of the added substances is 1:1) are mixed and stirred, the fluorinated sol obtained in step S12, hydrophobic fumed nano-silica and silane coupling agent are added thereto, and ultrasonic dispersion is performed for 2.5 hours to obtain; the silane coupling agent is a hydrolyzed silane coupling agent, specifically, the silane coupling agent γ-glycidyloxypropyltrimethoxysilane and 3-(2,3-epoxypropoxy)propyltrimethoxysilane (volume ratio of 1:1) are mixed with ethanol and water in a volume ratio of 1:1:2, and stirred at 60°C for 30 minutes;

[0074] S2. The raw materials of the coating for the filling layer are ball-milled with water to prepare a coating, and then the porcelain insulator substrate is immersed in the prepared coating. The coating is covered on the surface of the porcelain insulator substrate by spin coating, first at a speed of 500 r / min for 30 seconds and then at a speed of 2000 r / min for 60 seconds. The substrate is removed and dried, and then calcined at 1100° C. for 2 hours and cooled to below 80° C. to obtain a porcelain insulator substrate covered with a filling layer, wherein the thickness of the filling layer is 4 mm;

[0075] S3, pretreatment of the porcelain insulator substrate: the surface of the porcelain insulator substrate obtained in step S2 was washed twice with water, then washed twice with ethanol, and dried at 70°C;

[0076] S4. Apply a super-hydrophobic coating: While hot, apply a fluorinated SiO2-ZrO2 sol solution on the surface of the porcelain insulator substrate by dipping, spin coating, or spraying. First, spin coat at a speed of 500 r / min for 15 seconds, then spin coat at a speed of 2500 r / min for 100 seconds. Let it stand at room temperature to evaporate the water, and then dry it at 110°C to obtain a super-hydrophobic coating with a thickness of 5 mm.

[0077] Example 5

[0078] A pollution-flashover-proof porcelain insulator comprises, from the inside out, a porcelain insulator base, a filling layer and a super-hydrophobic coating; wherein the coating used for the filling layer comprises the following raw materials in parts by weight: 25 parts of SiO2-Al2O3-ZrO2 composite sol, 7 parts of bauxite, 1.5 parts of sodium tripolyphosphate, 1.5 parts of sodium dihydrogen phosphate, and 8 parts of a silane coupling agent; the super-hydrophobic coating is formed by coating a fluorinated sol solution on the porcelain insulator base and then drying it; the fluorinated sol solution comprises SiO2-La2O3 sol, hydrophobic vapor-phase nano-silica, a fluorinating agent, and a silane coupling agent, with a mass ratio of 10:2.5:1.5:2.

[0079] The method for preparing the anti-pollution flashover porcelain insulator of this embodiment comprises the following steps:

[0080] S1. Preparation of super-hydrophobic coating:

[0081] S11. Preparation of SiO2-La2O3 sol: dissolving lanthanum oxide in nitric acid to prepare a 0.1 mol / L lanthanum nitrate solution, then adding ammonia water dropwise thereto to adjust the solution to a pH of 9, filtering to obtain a precipitate, washing, and dispersing in distilled water to obtain a La(OH)3 suspension; mixing TEOS and ethanol, then adding nitric acid dropwise thereto to a pH of 2, and stirring at room temperature (25°C) at a speed of 1500 r / min for 30 minutes; then adding La(OH)3 suspension (molar ratio La:Si=1:1), adding nitric acid dropwise to adjust the mixture to a pH of 4, stirring at 80°C at a speed of 1500 r / min for 3 hours, and cooling;

[0082] S12, fluorination of the sol: adding a fluorinating agent 1H,1H,2H,2H-perfluorooctyltriethoxysilane and heptadecafluorodecyltrimethoxysilane (volume ratio 1:1) to the SiO2-La2O3 sol obtained in step S11, and stirring at room temperature (25°C) at a speed of 500 r / min for 1 hour to obtain a fluorinated sol;

[0083] S13, preparing a fluorinated sol solution: TEOS and hydrochloric acid (volume ratio of 5:1, total volume of the two: total mass of the added substances is 1:1) are mixed and stirred, and the fluorinated sol obtained in step S12, hydrophobic fumed nano-silica and a silane coupling agent are added thereto, and ultrasonic dispersion is performed for 2 hours to obtain; the silane coupling agent is a hydrolyzed silane coupling agent, specifically, the silane coupling agent γ-(methoxyacryloxy)propyltrimethoxysilane and γ-glycidyloxypropyltrimethoxysilane (volume ratio of 1:1) are mixed with ethanol and water in a volume ratio of 1:1:2, and stirred at 55°C for 30 minutes;

[0084] S2. The raw materials of the coating for the filling layer are added with water and ball-milled to prepare a coating, and then the porcelain insulator substrate is immersed in the prepared coating. The coating is covered on the surface of the porcelain insulator substrate by spin coating, first at a speed of 500 r / min for 20 seconds and then at a speed of 2000 r / min for 90 seconds. The coating is removed and dried, and then calcined at 1100° C. for 2 hours and cooled to below 80° C. to obtain a porcelain insulator substrate covered with a filling layer, wherein the thickness of the filling layer is 3 mm;

[0085] S3, pretreatment of the porcelain insulator substrate: the surface of the porcelain insulator substrate obtained in step S2 was washed with water three times, then washed once with ethanol, and dried at 85°C;

[0086] S4. Apply a super-hydrophobic coating: While hot, apply a fluorinated SiO2-ZrO2 sol solution on the surface of the porcelain insulator substrate by dipping, spin coating, or spraying. First, spin coat at a speed of 300 r / min for 20 seconds, then spin coat at a speed of 2000 r / min for 120 seconds. Let it stand at room temperature to evaporate the water, and then dry it at 120°C to obtain a super-hydrophobic coating with a thickness of 4.5 mm.

[0087] Comparative Example 1

[0088] The filling layer was removed, and the super-hydrophobic coating was directly coated on the porcelain insulator substrate, with the rest being the same as in Example 1. At this point, the bonding strength between the super-hydrophobic coating and the porcelain insulator substrate was not high enough, and cracks could be seen inside the coating in the microscopic image.

[0089] Comparative Example 2

[0090] The super-hydrophobic coating is removed, and only the filling layer is covered on the porcelain insulator substrate. The rest is the same as in Example 1.

[0091] Comparative Example 3

[0092] Step S12 is removed, i.e. the sol is not fluorinated, and the rest is the same as in Example 1.

[0093] Comparative Example 4

[0094] The fumed nano-silica in the super-hydrophobic coating was removed, and the rest was the same as in Example 1.

[0095] Comparative Example 5

[0096] The silane coupling agent in the super-hydrophobic coating was removed, and the rest was the same as in Example 1.

[0097] The products obtained in Examples 1-5 and Comparative Examples 1-5 (7 cm x 3 cm samples) were subjected to water contact angle and surface free energy measurements. The water contact angle measurement includes measuring the static contact angle and the sliding angle of a water droplet on the surface. The measurement results are listed in Table 1.

[0098] Table 1

[0099]

[0100]

[0101] It can be seen from the data in Table 1 that the super-hydrophobic coating has a great influence on the hydrophobic properties of the insulator surface. The sol fluorination, gas-phase nano-silica and silane coupling agent in the coating all have an impact on the hydrophobic properties of the coating, indicating that the three work together to achieve a super-hydrophobic effect; removing the filling layer will affect the bonding strength between the super-hydrophobic coating and the porcelain insulator substrate, so it also has a certain impact on the hydrophobicity.

[0102] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A pollution-proof flashover porcelain insulator, characterized in that: From the inside out, it includes a porcelain insulator base, a filling layer, and a super-hydrophobic coating; The coating used for the filling layer includes the following raw materials in parts by weight: 20-30 parts of SiO2-Al2O3-ZrO2 composite sol, 5-10 parts of bauxite, 0.5-3 parts of sodium tripolyphosphate, 0.5-3 parts of sodium dihydrogen phosphate, and 5-10 parts of silane coupling agent; The super hydrophobic coating is formed by coating a fluorinated sol solution on a porcelain insulator substrate and then drying it, wherein the fluorinated sol solution includes SiO2-La2O3 sol, hydrophobic fumed nano-silica, a fluorinating agent, and a silane coupling agent; A method for preparing an anti-pollution flashover porcelain insulator comprises the following steps: S1. Preparation of super-hydrophobic coating: S11. Preparation of SiO2-La2O3 sol: dissolving lanthanum oxide in nitric acid to prepare a lanthanum nitrate solution, then adding aqueous ammonia to adjust the solution to a pH of 8.5-9.5, filtering to obtain a precipitate, washing, and dispersing in distilled water to obtain a La(OH)3 suspension; mixing TEOS, water, and ethanol, then adding nitric acid to the mixture until the pH is 2-3, stirring for 15-60 minutes, then adding the La(OH)3 suspension, adding nitric acid to adjust the mixture to a pH of 3-4, stirring at 60-90°C for 2-4 hours, and cooling; S12, fluorination of the sol: adding a fluorinating agent to the SiO2-La2O3 sol obtained in step S11, stirring for 0.5 to 2 hours to obtain a fluorinated sol; S13, preparing a fluorinated sol solution: mixing TEOS and hydrochloric acid and stirring, adding the fluorinated sol obtained in step S12, hydrophobic fumed nano-silica and a silane coupling agent thereto, and ultrasonically dispersing for 1 to 3 hours to obtain a fluorinated sol solution; S2. Add water to the raw materials of the coating used for the filling layer and ball-grind them to prepare a coating, then immerse the porcelain insulator substrate in the prepared coating, cover the surface of the porcelain insulator substrate with the coating by spin coating, remove the substrate, dry it, and then calcine it at 1000-1150° C. for 1-3 hours, and cool it to below 80° C. to obtain a porcelain insulator substrate covered with the filling layer; S3, pretreatment of the porcelain insulator substrate: cleaning and drying the surface of the porcelain insulator substrate obtained in step S2; S4. Applying a super-hydrophobic coating: coating a fluorinated SiO2-La2O3 sol solution on the surface of the porcelain insulator substrate and drying.

2. The anti-pollution flashover porcelain insulator according to claim 1, characterized in that: In step S11, the TEOS and ethanol are mixed and stirred at a speed of 1000-2000 r / min and a temperature of 20-40°C.

3. The anti-pollution flashover porcelain insulator according to claim 1, characterized in that: In step S12, the stirring speed is 300-1000 r / min and the temperature is 20-40°C.

4. The anti-pollution flashover porcelain insulator according to claim 1, characterized in that: The fluorinating agent in step S12 is any one or more of 1H,1H,2H,2H-perfluorodecyltriethoxysilane, 1H,1H,2H,2H-perfluorooctyltriethoxysilane, heptadecafluorodecyltrimethoxysilane, perfluorooctyltrimethoxysilane, perfluoropolyether silane, and hydroxyfluorosilicone oil.

5. The anti-pollution flashover porcelain insulator according to claim 1, characterized in that: The silane coupling agent in step S13 is a hydrolyzed silane coupling agent, and the silane coupling agent includes one or more of γ-(methoxyacryloxy)propyltrimethoxysilane, γ-glycidyloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, and 3-(2,3-epoxypropoxy)propyltrimethoxysilane.

6. The anti-pollution flashover porcelain insulator according to claim 1, characterized in that: The thickness of the filling layer in step S2 is 2 to 5 mm, and / or the thickness of the super-hydrophobic coating in step S4 is 3 to 6 mm.

7. The anti-pollution flashover porcelain insulator according to claim 1, characterized in that: The pretreatment of the porcelain insulator substrate in step S3 specifically includes: washing with water 2 to 4 times, then washing with ethanol 1 to 2 times, and drying at 60 to 100°C.

8. The anti-pollution flashover porcelain insulator according to claim 1, characterized in that: The coating method in step S4 includes dipping, spin coating or spray coating.

9. The anti-pollution flashover porcelain insulator according to claim 1, characterized in that: The drying in step S4 includes placing the coated porcelain insulator at room temperature to evaporate the water, and then drying it at 100-150°C.

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