Low-temperature-resistant porcelain insulator and preparation method thereof

Abstract

The application discloses a low-temperature-resistant porcelain insulator and a preparation method thereof, and relates to the field of insulators. The porcelain insulator is prepared by the following steps: first, a porcelain body is prepared; then, a negative-expansion film is attached to the surface of the porcelain body; and finally, a hydrophobic coating is applied to the surface of the negative-expansion film. The negative-expansion film is prepared by the following steps: zirconium nitrate and ammonium tungstate are reacted, acid is added to obtain a precursor, and then citric acid is added to obtain a sol, which is coated on the surface of the porcelain body and then subjected to heat treatment. The negative-expansion film is arranged between the porcelain body and the hydrophobic film, which can avoid cracks or peeling caused by different expansion coefficients due to temperature changes and increase the bonding strength of the two.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of insulators, in particular to a low-temperature-resistant porcelain insulator and a preparation method thereof. BACKGROUND

[0002] Porcelain insulators provide support and insulation for power transmission lines, so the requirements for mechanical strength and insulation strength are relatively high, and the natural environment in China is relatively complex, so porcelain insulators are mostly used in outdoor or even wild environments, so the porcelain insulator products also need to be able to adapt to complex environmental conditions. With the development of the power industry in China, the demand for porcelain insulators in extremely cold regions is also increasing. Ceramic insulators used in extremely cold regions need to withstand harsh working environments such as low temperature freezing, and must have good freeze-thaw resistance to avoid problems such as freeze cracking, aging, and strength reduction. In addition to the freeze-thaw resistance of the porcelain body. Therefore, a low-temperature-resistant porcelain insulator needs to be developed. SUMMARY

[0003] The present application relates to the field of insulators, in particular to a low-temperature-resistant porcelain insulator and a preparation method thereof.

[0004] The technical solution of the present application is as follows:

[0005] A preparation method of a low-temperature-resistant porcelain insulator, first preparing a porcelain body, then attaching a layer of negative expansion film to the surface of the porcelain body, and finally coating a hydrophobic coating on the surface of the negative expansion film.

[0006] The preparation method of the negative expansion film is as follows:

[0007] Zirconium nitrate and ammonium tungstate are reacted, acid is added to obtain a precursor, then citric acid is added to obtain a sol, which is coated on the surface of the porcelain body and subjected to heat treatment.

[0008] As a preferred scheme of the present application, the heat treatment temperature is 500-700 DEG C, and the heat treatment time is 2-4h.

[0009] As a preferred scheme of the present application, the sol further dopes vermiculite / nano calcium carbonate composite material.

[0010] As a preferred scheme of the present application, the preparation method of the vermiculite / nano calcium carbonate composite material is as follows:

[0011] The quicklime, ammonium carbonate and vermiculite mixture are subjected to a hydrothermal reaction at 160-200 DEG C, and then calcined at 100-300 DEG C to obtain the product.

[0012] As a preferred scheme of the present application, the vermiculite mixture includes vermiculite calcined at 300-500 DEG C, 500-700 DEG C and 700-900 DEG C.

[0013] As a preferred scheme of the present application, the hydrophobic coating comprises: 60-80 parts by weight of nano-silica sol, 5-10 parts by weight of acicular wollastonite and 1-8 parts by weight of polyisoprene fiber.

[0014] As a preferred scheme of the present application, the porcelain body with the negative expansion film is put into the silane coupling agent for 20-30 min before the hydrophobic coating is applied.

[0015] The present application also discloses a low-temperature-resistant porcelain insulator prepared by the preparation method.

[0016] The present application has the advantages that: the present application adds a layer of negative expansion film between the porcelain body and the hydrophobic film, which avoids the cracks or peeling caused by the different expansion coefficients due to the temperature change, and increases the bonding strength of the two; meanwhile, the polyisoprene fiber is added to the hydrophobic coating, which also has the characteristics of thermal shrinkage and cold expansion, solves the situation that the cracks are caused by the stress change of the hydrophobic layer due to the temperature change, and forms a network structure on the hydrophobic surface, greatly improves the toughness, and thus ensures the low-temperature-resistant performance of the porcelain insulator. DETAILED DESCRIPTION

[0017] The embodiments of the present application are described in detail below. The embodiments described below are exemplary and are only used to explain the present application, and cannot be understood as a limitation of the present application. The specific techniques or conditions not mentioned in the embodiments are carried out according to the techniques or conditions described in the literature in the field or according to the product instructions. The reagents or instruments not mentioned by the manufacturer are all conventional products that can be obtained on the market.

[0018] The porcelain body used in the following embodiments is a high-alumina porcelain insulator, and the preparation method is as follows:

[0019] According to the weight parts, 80 parts of flint clay, 13 parts of industrial alumina powder, 4 parts of potassium feldspar and 3 parts of polyvinyl alcohol are mixed to form raw materials, and then an appropriate amount of water is added to the above raw materials, and then grinding is carried out to obtain a uniformly mixed slurry; the above slurry is dried at 80℃, and then the dried slurry is extruded to obtain a mud, which is loaded into a mold to form a green body, which is dried at 110℃ to obtain a green body for sintering, then coated with a glaze layer, and then sintered in a kiln at 1150℃.

[0020] Embodiment 1

[0021] A preparation method of a low-temperature-resistant porcelain insulator, first, a porcelain body is prepared, then a layer of negative expansion film is attached to the surface of the porcelain body, and finally a hydrophobic coating is applied to the surface of the negative expansion film.

[0022] The preparation method of the negative expansion film is as follows:

[0023] Zirconium nitrate and ammonium tungstate are uniformly mixed in a mass ratio of 1:2, hydrochloric acid with a concentration of 7 mol / L is added, stirring is conducted at 170°C for 4h to obtain a precursor, then citric acid is added, stirring is conducted to obtain a sol, the sol is coated on the surface of the porcelain body, and heat treatment is conducted. The heat treatment temperature is 550°C, and the heat treatment time is 4h.

[0024] The sol is further doped with 1wt% of vermiculite / nano calcium carbonate composite material. The preparation method of the vermiculite / nano calcium carbonate composite material is as follows:

[0025] The mass ratio of the mixture of quicklime, ammonium carbonate and vermiculite is 1:1:0.3, hydrothermal reaction is conducted at 180°C, then calcination is conducted at 250°C for 30min to obtain the vermiculite / nano calcium carbonate composite material.

[0026] The vermiculite mixture includes vermiculite calcined at 350°C, 650°C and 850°C.

[0027] The hydrophobic coating includes 80 parts by weight of nano silicon dioxide sol, 8 parts by weight of acicular wollastonite and 3 parts by weight of polyisoprene fiber.

[0028] Before the hydrophobic coating is coated, the porcelain body with the negative expansion film is placed in silane coupling agent KH792 for treatment for 25min.

[0029] Example 2

[0030] A preparation method of a low-temperature-resistant porcelain insulator includes the following steps: first, a porcelain body is prepared; then, a layer of negative expansion film is attached to the surface of the porcelain body; finally, a hydrophobic coating is coated on the surface of the negative expansion film.

[0031] The preparation method of the negative expansion film is as follows:

[0032] Zirconium nitrate and ammonium tungstate are uniformly mixed in a mass ratio of 1:2, hydrochloric acid with a concentration of 7 mol / L is added, stirring is conducted at 170°C for 4h to obtain a precursor, then citric acid is added, stirring is conducted to obtain a sol, the sol is coated on the surface of the porcelain body, and heat treatment is conducted. The heat treatment temperature is 600°C, and the heat treatment time is 3h.

[0033] The sol is further doped with 2wt% of vermiculite / nano calcium carbonate composite material. The preparation method of the vermiculite / nano calcium carbonate composite material is as follows:

[0034] The mass ratio of the mixture of quicklime, ammonium carbonate and vermiculite is 1:1:0.3, hydrothermal reaction is conducted at 180°C, then calcination is conducted at 250°C for 30min to obtain the vermiculite / nano calcium carbonate composite material.

[0035] The vermiculite mixture includes vermiculite calcined at 400°C, 600°C and 900°C.

[0036] The hydrophobic coating comprises 70 parts by weight of nanometer silica sol, 10 parts by weight of acicular wollastonite and 6 parts by weight of polyisoprene fiber.

[0037] Before coating the hydrophobic coating, the porcelain body with the negative expansion film is put into silane coupling agent KH792 for treatment for 30 min.

[0038] Example 3

[0039] A preparation method of the low-temperature-resistant porcelain insulator comprises the following steps: first, preparing a porcelain body; then, attaching a negative expansion film on the surface of the porcelain body; and finally, coating a hydrophobic coating on the surface of the negative expansion film.

[0040] The preparation method of the negative expansion film is as follows:

[0041] Zirconium nitrate and ammonium tungstate are uniformly mixed at a molar ratio of 1:2, and hydrochloric acid with a concentration of 7 mol / L is added, and stirring is performed at 170℃ for 4h to obtain a precursor, and then citric acid is added and stirred to obtain a sol, which is coated on the surface of the porcelain body and subjected to heat treatment. The heat treatment temperature is 650℃, and the heat treatment time is 2.5h.

[0042] The sol is further doped with 3wt% of vermiculite / nano calcium carbonate composite material. The preparation method of the vermiculite / nano calcium carbonate composite material is as follows:

[0043] The mixture of quicklime, ammonium carbonate and vermiculite is subjected to hydrothermal reaction at 180℃, and then calcination at 250℃ for 30 min to obtain the vermiculite / nano calcium carbonate composite material.

[0044] The vermiculite mixture comprises vermiculite calcined at 400℃, 600℃ and 900℃.

[0045] The hydrophobic coating comprises 70 parts by weight of nanometer silica sol, 10 parts by weight of acicular wollastonite and 6 parts by weight of polyisoprene fiber.

[0046] Before coating the hydrophobic coating, the porcelain body with the negative expansion film is put into silane coupling agent KH792 for treatment for 25 min.

[0047] Example 4

[0048] A preparation method of the low-temperature-resistant porcelain insulator comprises the following steps: first, preparing a porcelain body; then, attaching a negative expansion film on the surface of the porcelain body; and finally, coating a hydrophobic coating on the surface of the negative expansion film.

[0049] The preparation method of the negative expansion film is as follows:

[0050] Zirconium nitrate and ammonium tungstate are mixed uniformly at a molar ratio of 1:2, hydrochloric acid with a concentration of 7 mol / L is added, stirring is carried out at 170℃ for 4h to obtain a precursor, then citric acid is added, stirring is carried out to obtain a sol, the sol is coated on the surface of a porcelain body, and heat treatment is carried out. The heat treatment temperature is 550℃, and the heat treatment time is 2-4h.

[0051] The sol is further doped with 4wt% vermiculite / nano calcium carbonate composite material. The vermiculite / nano calcium carbonate composite material is prepared by the following method:

[0052] The vermiculite mixture includes vermiculite calcined at 400℃, 600℃ and 800℃.

[0053] The vermiculite mixture includes vermiculite calcined at 400℃, 600℃ and 800℃.

[0054] The hydrophobic coating includes 80 parts by weight of nano silicon dioxide sol, 5 parts by weight of acicular wollastonite and 7 parts by weight of polyisoprene fiber.

[0055] Before the hydrophobic coating is coated, the porcelain body with the negative expansion film is placed in silane coupling agent KH792 for treatment for 25min.

[0056] Embodiment 5

[0057] A preparation method of a low-temperature-resistant porcelain insulator includes the following steps: first, a porcelain body is prepared; then, a negative expansion film is attached to the surface of the porcelain body; finally, a hydrophobic coating is coated on the surface of the negative expansion film.

[0058] The preparation method of the negative expansion film is as follows:

[0059] Zirconium nitrate and ammonium tungstate are mixed uniformly at a molar ratio of 1:2, hydrochloric acid with a concentration of 7 mol / L is added, stirring is carried out at 170℃ for 4h to obtain a precursor, then citric acid is added, stirring is carried out to obtain a sol, the sol is coated on the surface of a porcelain body, and heat treatment is carried out. The heat treatment temperature is 550℃, and the heat treatment time is 2-4h.

[0060] The sol is further doped with 5wt% vermiculite / nano calcium carbonate composite material. The vermiculite / nano calcium carbonate composite material is prepared by the following method:

[0061] The vermiculite mixture includes vermiculite calcined at 400℃, 600℃ and 700℃.

[0062] The vermiculite mixture includes vermiculite calcined at 400℃, 600℃ and 700℃.

[0063] The hydrophobic coating comprises 70 parts by weight of nanometer silica sol, 7 parts by weight of acicular wollastonite and 3 parts by weight of polyisoprene fiber.

[0064] Before coating the hydrophobic coating, the porcelain body with the negative expansion film is treated in silane coupling agent KH792 for 25 min.

[0065] Comparative Example 1 (without negative expansion film)

[0066] A preparation method of a low-temperature-resistant porcelain insulator comprises the following steps: preparing a porcelain body, and coating a hydrophobic coating on the surface of the porcelain body.

[0067] The hydrophobic coating comprises 70 parts by weight of nanometer silica sol, 9 parts by weight of acicular wollastonite and 5 parts by weight of polyisoprene fiber.

[0068] Before coating the hydrophobic coating, the porcelain body with the negative expansion film is treated in silane coupling agent KH792 for 25 min.

[0069] Comparative Example 2 (hydrophobic coating without polyisoprene fiber)

[0070] A preparation method of a low-temperature-resistant porcelain insulator comprises the following steps: preparing a porcelain body, coating a negative expansion film on the surface of the porcelain body, and coating a hydrophobic coating on the surface of the negative expansion film.

[0071] The preparation method of the negative expansion film is as follows:

[0072] Zirconium nitrate and ammonium tungstate are uniformly mixed in a molar ratio of 1:2, hydrochloric acid with a concentration of 7 mol / L is added, and stirring is carried out at 170℃ for 4h to obtain a precursor, then citric acid is added and stirring is carried out to obtain a sol, which is coated on the surface of the porcelain body and subjected to heat treatment. The heat treatment temperature is 650℃, and the heat treatment time is 2.5h.

[0073] The sol is further doped with 3wt% of vermiculite / nano calcium carbonate composite material. The preparation method of the vermiculite / nano calcium carbonate composite material is as follows:

[0074] The mixture of quicklime, ammonium carbonate and vermiculite in a mass ratio of 1:1:0.3 is subjected to hydrothermal reaction at 180℃, and then calcination at 250℃ for 30 min to obtain the vermiculite / nano calcium carbonate composite material.

[0075] The vermiculite mixture comprises vermiculite calcined at 400℃, 600℃ and 900℃.

[0076] The hydrophobic coating comprises 70 parts by weight of nanometer silica sol, 9 parts by weight of acicular wollastonite.

[0077] Before coating the hydrophobic coating, the porcelain body with the negative expansion film is treated in silane coupling agent KH792 for 25 min.

[0078] Comparative Example 3 (vermiculite / nano-calcium carbonate composite without pretreatment)

[0079] A preparation method of a low-temperature-resistant porcelain insulator includes preparing a porcelain body, attaching a negative expansion film to a surface of the porcelain body, and coating a hydrophobic coating on the negative expansion film.

[0080] The negative expansion film is prepared by the following method:

[0081] Zirconium nitrate and ammonium tungstate are mixed uniformly at a molar ratio of 1:2, hydrochloric acid with a concentration of 7 mol / L is added, and stirring is performed at 170 DEG C for 4 h to obtain a precursor, then citric acid is added, and stirring is performed to obtain a sol, which is coated on a surface of a porcelain body and subjected to heat treatment.

[0082] The hydrophobic coating includes 70 parts by weight of nano-silica sol, 9 parts by weight of acicular wollastonite, and 5 parts by weight of polyisoprene fiber.

[0083] Before the hydrophobic coating is coated, the porcelain body with the negative expansion film is placed in silane coupling agent KH792 for 25 min.

[0084] Comparative Example 4 (vermiculite without pretreatment)

[0085] A preparation method of a low-temperature-resistant porcelain insulator includes preparing a porcelain body, attaching a negative expansion film to a surface of the porcelain body, and coating a hydrophobic coating on the negative expansion film.

[0086] The negative expansion film is prepared by the following method:

[0087] Zirconium nitrate and ammonium tungstate are mixed uniformly at a molar ratio of 1:2, hydrochloric acid with a concentration of 7 mol / L is added, and stirring is performed at 170 DEG C for 4 h to obtain a precursor, then citric acid is added, and stirring is performed to obtain a sol, which is coated on a surface of a porcelain body and subjected to heat treatment.

[0088] The sol is further doped with 3 wt% of a vermiculite / nano-calcium carbonate composite. The vermiculite / nano-calcium carbonate composite is prepared by the following method:

[0089] A mixture of quicklime, ammonium carbonate, and vermiculite is subjected to hydrothermal reaction at 180 DEG C, and then is calcined at 250 DEG C for 30 min to obtain the vermiculite / nano-calcium carbonate composite.

[0090] The vermiculite mixture includes vermiculite calcined at 600 DEG C.

[0091] The hydrophobic coating comprises 70 parts by weight of nanometer silica sol, 9 parts by weight of acicular wollastonite and 5 parts by weight of polyisoprene fiber.

[0092] Before the hydrophobic coating is applied, the porcelain body with the negative expansion film is treated in silane coupling agent KH792 for 25 min.

[0093] The above examples 1-5 and comparative examples 1-4 are subjected to performance testing, and the test results are shown in Table 1.

[0094] The contact angle test is that 4 μL of deionized water droplets are placed on the surface of the hydrophobic coating, and the contact angle measurement instrument is used to test before freezing and thawing and after freezing and thawing 30 times at -40℃ to 40℃, respectively.

[0095] Table 1 Performance test results of examples and comparative examples

[0096] Sample Contact angle (°) Contact angle after freeze-thaw 30 times (°) Example 1 128 126 Example 2 125 124 Example 3 130 129 Example 4 127 126 Example 5 126 125 Comparative Example 1 122 108 Comparative Example 2 120 105 Comparative Example 3 121 104 Comparative Example 4 119 100

[0097] As can be seen from the above table, the hydrophobic performance of the examples is better than that of the comparative examples, and the main reasons can be as follows: from the analysis of comparative example 1, the example adds a layer of negative expansion film between the porcelain body and the hydrophobic film, which avoids the cracks or peeling phenomenon caused by the different expansion coefficients due to temperature changes, thereby improving the low-temperature hydrophobic performance of the porcelain insulator; from the analysis of comparative example 2, the example adds polyisoprene fiber with cold expansion and thermal contraction, which reduces the stress change caused by the temperature change of the hydrophobic film; from the analysis of comparative example 3, the example adds vermiculite / nano calcium carbonate composite material in the negative expansion film, which has a certain adsorption of the adjacent two layers of binding material, improves the bonding force of the two sides, and also has certain heat preservation performance, thereby minimizing the large temperature change. From the analysis of comparative example 4, vermiculite is calcined at different temperatures, which has different pore structures, thereby having different heat preservation performance and adsorption performance, thereby affecting the low-temperature performance of the porcelain insulator.

[0098] The above-described examples only express the preferred embodiments of the present application, which are described in detail and specifically, but should not be understood as limiting the scope of the patent of the present application. It should be noted that for those skilled in the art, other various corresponding changes and deformations can be made according to the above-described technical solutions and concepts, and all these changes and deformations should belong to the protection scope of the claims of the present application.

Claims

1. A method for preparing a low-temperature-resistant porcelain insulator, characterized in that a ceramic body is prepared first, then a negative-expansion film is attached to the surface of the ceramic body, and finally a hydrophobic coating is applied to the surface of the negative-expansion film. The negative-expansion film is prepared by the following method: zirconium nitrate and ammonium tungstate are reacted, acid is added to obtain a precursor, then citric acid is added to obtain a sol, which is applied to the surface of the ceramic body and subjected to heat treatment. The sol is further doped with a vermiculite / nano calcium carbonate composite material. The vermiculite / nano calcium carbonate composite material is prepared by the following method: a mixture of quicklime, ammonium carbonate and vermiculite is subjected to hydrothermal reaction at 160-200 DEG C, and then calcination at 100-300 DEG C to obtain the composite material. The hydrophobic coating comprises 60-80 parts by weight of nano silicon dioxide sol, 5-10 parts by weight of acicular wollastonite and 1-8 parts by weight of polyisoprene fiber. The heat treatment temperature is 500-700 DEG C, and the heat treatment time is 2-4 h. The vermiculite mixture comprises vermiculite calcined at 300-500 DEG C, 500-700 DEG C and 700-900 DEG C. Before the hydrophobic coating is applied, the ceramic body with the negative-expansion film is treated in a silane coupling agent for 20-30 min.

2. The method for preparing a low-temperature resistant ceramic insulator according to claim 1, characterized in that, The method is prepared by any one of claims 1-4.

3. The method for preparing a low-temperature resistant ceramic insulator according to claim 1, characterized in that, ​ 4. The method for preparing a low-temperature resistant ceramic insulator according to claim 1, characterized in that, ​ 5. A low temperature resistant porcelain insulator, characterized by ​