Electric porcelain hollow insulator glaze and preparation process and glazing method thereof

Abstract

The invention discloses electric porcelain hollow insulator glaze and a preparation process and a glazing method thereof, and belongs to the technical field of insulator glaze, the electric porcelain hollow insulator glaze is prepared from the following raw materials in parts by mass: 80 parts of aluminum oxide, 10-16 parts of mullite powder, 1-3 parts of wollastonite, 5-8 parts of kaolin clay, 3-7 parts of zirconium-containing powder, 6-10 parts of feldspar, 1.0-1.7 parts of yttrium oxide and 0.5-1.5 parts of phlogopite; the mullite powder is prepared from 20 to 30 weight percent of polycrystalline mullite fiber and the balance of sintered mullite. The preparation process comprises the following steps: pressing raw material powder, molding, crushing and drying to obtain dry granules; and carrying out flash burning on the dried particles to obtain the electric porcelain hollow insulator glaze. The electric porcelain hollow insulator glaze obtained by the preparation process can improve the insulativity and mechanical strength of an insulator.

Description

Technical Field

[0001] The invention belongs to the technical field of insulator glazes, in particular to an electric porcelain hollow insulator glaze, a preparation process and a glazing method thereof. Background Art

[0002] Hollow insulators are a key insulating component of power systems, mainly used to support and fix conductors, while isolating the electric field between the conductors and the ground or brackets to prevent current leakage and electrical faults. It is usually made of ceramic materials and has excellent insulation properties and mechanical strength. Hollow insulators are widely used in power transmission systems such as transmission lines, substations and power plants, and are important components to ensure the reliability and safety of the power grid. Due to their lightweight design and excellent weather resistance, hollow insulators can also work stably in harsh power environments.

[0003] Since the center space of a hollow insulator is not completely vacuumed, residual air may form a conductive channel under the action of a strong electric field. This phenomenon will gradually worsen over time and may eventually cause the insulator to break down. Although hollow porcelain insulators are light and have good heat dissipation performance, their impact resistance may not be as good as that of solid insulators. In some extreme environments, their mechanical properties may not be sufficient to ensure long-term safe operation. Summary of the invention

[0004] In order to overcome the above technical problems, the present invention provides a hollow insulator glaze material for electric porcelain, a preparation process and a glazing method thereof. The hollow insulator glaze material for electric porcelain of the present invention can improve the insulation and mechanical strength of the insulator.

[0005] The present invention solves the above technical problems through the following technical solutions.

[0006] The invention discloses an electric porcelain hollow insulator glaze, which comprises the following raw materials in parts by weight: 80 parts of aluminum oxide, 10 to 16 parts of mullite powder, 1 to 3 parts of wollastonite, 5 to 8 parts of kaolin clay, 3 to 7 parts of zirconium-containing powder, 6 to 10 parts of feldspar, 1.0 to 1.7 parts of yttrium oxide and 0.5 to 1.5 parts of phlogopite;

[0007] In some preferred embodiments, the glaze for the electrical porcelain hollow insulator comprises the following raw materials in parts by weight: 80 parts of alumina, 12 to 16 parts of mullite powder, 1.3 to 2.8 parts of wollastonite, 6 to 8 parts of kaolin clay, 3.4 to 6.2 parts of zirconium-containing powder, 6.5 to 8 parts of feldspar, 1.2 to 1.6 parts of yttrium oxide and 0.8 to 1.5 parts of phlogopite.

[0008] In some preferred embodiments, the mullite powder consists of 10-20wt% polycrystalline mullite fiber and the balance sintered mullite; preferably, the mullite powder consists of 15-20wt% polycrystalline mullite fiber and the balance sintered mullite.

[0009] In some preferred embodiments, the diameter of the polycrystalline mullite fiber is 3-5 μm.

[0010] In some preferred embodiments, the bulk density of the polycrystalline mullite fiber is 75-85 kg / m 3 .

[0011] In some preferred embodiments, the Al content of the polycrystalline mullite is 2 O 3 The content is 72-75%.

[0012] In some preferred embodiments, the composition of the sintered mullite includes Al 2 O 3 :70~73%、TiO 2 ≤0.5%、Na 2 O≤0.3%、K 2 O≤0.3%,Fe 2 O 3 ≤0.5%.

[0013] In some preferred embodiments, the bulk density of the sintered mullite is ≥2.80 g / cm 3 .

[0014] In some preferred embodiments, the porosity of the sintered mullite is ≤3.0%.

[0015] In the present invention, mullite itself has excellent dielectric properties, the high density of sintered mullite provides excellent hardness and wear resistance, and the grain boundaries of polycrystalline mullite fibers can inhibit crack propagation and improve the toughness of the glaze layer; the high density of sintered mullite and the polycrystalline structure of polycrystalline mullite fibers have different thermal expansion behaviors, and the two adjust the thermal expansion coefficient of the glaze to better match the porcelain body, thereby reducing the risk of glaze cracking.

[0016] In some preferred embodiments, the feldspar is at least one of potassium feldspar, sodium feldspar, oligoclase and andesine.

[0017] In some preferred embodiments, the zirconium-containing powder is zirconium oxide and basic zirconium chloride.

[0018] In some preferred embodiments, the mass ratio of zirconium oxide to basic zirconium chloride in the zirconium-containing powder is 10:2.5-2.8. Among them, zirconium oxide has a high melting point, chemical stability and mechanical strength, and is often used to enhance the wear resistance and thermal shock resistance of glazes. Basic zirconium chloride can be used as a dispersant or sintering aid to help the zirconium oxide particles to be evenly distributed, reduce the sintering temperature, and improve the density and adhesion of the glaze.

[0019] The present invention also discloses a preparation process of a porcelain hollow insulator glaze, comprising the following steps:

[0020] S1. Grind and sieve the raw materials prepared according to the desired ratio, and then add polycrystalline mullite fiber to obtain raw material powder;

[0021] S2. The raw material powder is pressed and formed, and then crushed and dried to obtain dry particles;

[0022] S3. The dried particles are flash-fired to obtain glaze for electrical porcelain hollow insulators.

[0023] In some preferred embodiments, the sieved particle size is 5-8 μm.

[0024] In some preferred embodiments, the compression molding is performed at a pressure of 20 to 50 MPa and the pressure is maintained for 10 to 40 seconds.

[0025] In some preferred embodiments, the particle size of the dry particles is 3 to 8 mm.

[0026] In some preferred embodiments, the maximum temperature of the flash burning is 900-1000°C.

[0027] In some preferred embodiments, the flash burning time is 10 to 25 seconds.

[0028] In some preferred embodiments, the heating rate of the flash burning is 110-120°C / min;

[0029] In some preferred embodiments, the electric field strength of the flash burning is 1500-2500 V / cm.

[0030] The present invention also discloses a glazing method for the above-mentioned hollow insulator glaze or the hollow insulator glaze obtained by the preparation process, the steps of which are to wet-grind the hollow insulator glaze to obtain glaze slurry, spray the glaze slurry onto the surface of the hollow insulator porcelain body, and then fire it.

[0031] In some preferred embodiments, the thickness of the sprayed glaze is 0.1-0.5 mm, preferably 0.2-0.5 mm.

[0032] In some preferred embodiments, the glazing further includes a drying step.

[0033] In some preferred embodiments, the firing temperature is 1100-1300°C.

[0034] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] 1. The mullite powder used in the present invention has high dielectric strength, the sintered mullite of the present invention provides hardness and wear resistance, and the polycrystalline mullite fiber can improve the toughness of the glaze. The thermal expansion coefficients of the two are more matched with the porcelain body, which can reduce the risk of glaze cracking.

[0037] 2. Ordinary sintering methods will make components such as kaolin clay and feldspar easily form a liquid phase at high temperatures, and may also cause segregation. The flash firing process used in the present invention can accurately control the liquid phase generation time, avoid component segregation caused by excessive flow, and thus improve the uniformity of the glaze. The flash firing process can also soften the contact points between wollastonite and phlogopite particles to promote interface bonding. The polycrystalline fibers in mullite powder can maintain structural stability under short-term high temperature flash firing to avoid fiber melting and fracture.

[0038] 3. The glaze of the electric porcelain insulator of the present invention is applied to the surface of the porcelain body of the electric porcelain insulator to improve its insulation performance and mechanical strength. In the embodiment, the breakdown strength of the insulator is ≥31kV / mm; in some preferred embodiments, the breakdown strength of the insulator is 31-33kV / mm. In the embodiment, the tracking resistance index of the insulator is ≥620V; in some preferred embodiments, the tracking resistance index is 620-680V. DETAILED DESCRIPTION

[0039] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and carefully in combination with preferred embodiments below, but the protection scope of the present invention is not limited to the following specific embodiments.

[0040] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0041] The "range" disclosed in the present invention is defined in the form of a lower limit and an upper limit, and a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of a particular range. The range defined in this way can be inclusive or exclusive of end values, and can be combined arbitrarily, that is, any lower limit can be combined with any upper limit to form a range. For example, if a range of 60-120 and 80-110 is listed for a specific parameter, it is understood that the range of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following ranges can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present invention, unless otherwise specified, the numerical range "ab" represents an abbreviation of any real number combination between a and b, wherein a and b are real numbers. For example, the numerical range "0-5" represents that all real numbers between "0-5" have been fully listed herein, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0042] If not otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form a new technical solution.

[0043] Unless otherwise specified, all technical features and optional technical features of the present invention can be combined with each other to form a new technical solution.

[0044] If not otherwise specified, all steps of the present invention may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), which means that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0045] If there is no special explanation, the "include" and "comprising" mentioned in the present invention represent open-ended or closed-ended expressions. For example, the "include" and "comprising" may represent that other components not listed may also be included or only the listed components may be included or only the listed components may be included.

[0046] If not specifically stated, in the present invention, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0047] The raw material information used in the following examples is as follows:

[0048] Alumina has a D50 of 10 μm and was purchased from Beijing Zhongke Yannuo New Materials Co., Ltd.

[0049] The polycrystalline mullite fiber has a diameter of 3-5 μm, a single fiber length of 10-150 mm, and a bulk density of 80 kg / cm 3 , the content of aluminum oxide is 72-75%, and the content of aluminum oxide and silicon oxide is 99.5%;

[0050] Sintered mullite was purchased from Jiangsu Jingxin New Materials Co., Ltd. The composition of sintered mullite includes Al 2 O 3 :71.32%、TiO 2 :0.22%, Na 2 O: 0.23%, K 2 O:0.24% and Fe 2 O 3 :0.32%; the density of sintered mullite is 2.83g / cm 3 , the porosity is 2.5%.

[0051] The alias of basic zirconium chloride is zirconium oxychloride octahydrate, and its CAS number is 13520-92-8;

[0052] Phlogopite was purchased from Lingshou County Huajing Mica Co., Ltd., model G-200, with a breakdown strength of 120 kV / mm.

[0053]

Electric hollow insulator glaze and its preparation process

[0054] Example 1

[0055] The glaze formula of the electric porcelain hollow insulator of the present embodiment is as follows:

[0056] 80 parts of aluminum oxide, 13.2 parts of mullite powder, 2.5 parts of wollastonite, 7.1 parts of kaolin clay, 3.4 parts of zirconium-containing powder, 7.3 parts of feldspar (albite), 1.4 parts of yttrium oxide, and 1.5 parts of phlogopite;

[0057] The mullite powder consists of 15wt% polycrystalline mullite fiber and the remainder sintered mullite;

[0058] The mass ratio of zirconium oxide to basic zirconium chloride in the zirconium-containing powder is 10:2.5.

[0059] The preparation process of the glaze material for the hollow insulator of the electric porcelain of the present embodiment is as follows:

[0060] According to the above formula, the glaze for the electric porcelain hollow insulator is prepared, and the steps are as follows:

[0061] S1. Prepare the raw materials according to the required ratio, grind and sieve the raw materials to a particle size of 5μm, and then add polycrystalline mullite fiber to obtain a raw material powder;

[0062] S2. The raw material powder is pressed at 45 MPa for 15 seconds and then crushed and dried to obtain dry particles, the particle size of the dry particles is 3 to 8 mm;

[0063] S3. The dried particles are heated to 900°C at a heating rate of 110°C / min and sintered for 15s. The flash firing electric field intensity is 1500V / cm. After flash firing, a glaze for electric porcelain hollow insulators is obtained.

[0064] Example 2

[0065] The difference between this embodiment and embodiment 1 is that:

[0066] The glaze formula of the electric porcelain hollow insulator of the present embodiment is as follows:

[0067] 80 parts of alumina, 12 parts of mullite powder, 1.3 parts of wollastonite, 8 parts of kaolin clay, 6.2 parts of zirconium-containing powder, 6.5 parts of feldspar (potash feldspar), 1.2 parts of yttrium oxide, and 1.3 parts of phlogopite.

[0068] Example 3

[0069] The difference between this embodiment and embodiment 1 is that:

[0070] The glaze formula of the electric porcelain hollow insulator of the present embodiment is as follows:

[0071] 80 parts of alumina, 15 parts of mullite powder, 1.6 parts of wollastonite, 6.4 parts of kaolin clay, 5.8 parts of zirconium-containing powder, 8 parts of feldspar (albite), 1.6 parts of yttrium oxide, and 1.0 part of phlogopite.

[0072] The mullite powder consists of 20wt% polycrystalline mullite fiber and the remainder sintered mullite.

[0073] Example 4

[0074] The difference between this embodiment and embodiment 1 is that:

[0075] The glaze formula of the electric porcelain hollow insulator of the present embodiment is as follows:

[0076] 80 parts of alumina, 16 parts of mullite powder, 2.8 parts of wollastonite, 7.5 parts of kaolin clay, 4.8 parts of zirconium-containing powder, 7.2 parts of feldspar (albite), 1.3 parts of yttrium oxide, and 0.8 parts of phlogopite.

[0077] The mass ratio of zirconium oxide to basic zirconium chloride in the zirconium-containing powder is 10:2.8.

[0078] Example 5

[0079] The difference between this embodiment and embodiment 1 is that:

[0080] The mass ratio of zirconium oxide to basic zirconium chloride in the zirconium-containing powder of this embodiment is 10:3.2.

[0081] Comparative Example 1

[0082] The difference between this comparative example and Example 1 is:

[0083] The mullite powder in this comparative example contains only sintered mullite but no polycrystalline mullite fiber.

[0084] Comparative Example 2

[0085] The difference between this comparative example and Example 1 is:

[0086] The mullite powder in this comparative example consists of 23 wt % of polycrystalline mullite fibers and the remainder of sintered mullite.

[0087] Comparative Example 3

[0088] The difference between this comparative example and Example 1 is:

[0089] The maximum flash temperature of this comparative example is 700°C.

[0090] Comparative Example 4

[0091] The difference between this comparative example and Example 1 is:

[0092] 80 parts of alumina, 13.2 parts of mullite powder, 2.5 parts of wollastonite, 7.1 parts of kaolin clay, 3.4 parts of zirconium-containing powder, 7.3 parts of feldspar (albite), 1.4 parts of yttrium oxide and 1.5 parts of muscovite;

[0093] The white mica was purchased from Lingshou County Huajing Mica Co., Ltd. The model is wet white mica W-325, and the breakdown strength is 146.5 kV / mm.

[0094] [Glazing method of glaze for electric porcelain hollow insulator]

[0095] The glazes for the hollow insulators of the above-mentioned embodiments and comparative examples were wet-grinded at a rotation speed of 180 rpm for 3 hours to obtain a glaze slurry with a solid content of 75%. The glaze slurry was sprayed on the surface of the porcelain body of the hollow insulator of the electric porcelain. The thickness of the sprayed glaze was 2.8 mm. The glaze was then fired at 1180° C. for 2.5 hours. The hollow insulator of the electric porcelain was obtained by cooling in the furnace.

[0096]

Test example

[0097] The insulators were glazed and fired to obtain a breakdown strength and a tracking index. The test results are shown in Table 1.

[0098] Breakdown strength (test method refers to GB / T 5593): the highest electric field strength that a material can withstand to avoid being destroyed (broken down) under the action of an electric field;

[0099] Tracking resistance index (test method refers to GB / T 4207): The voltage required for the material surface to form a permanent conductive carbon path after withstanding the action of 50 drops of electrolyte at a rate of one drop per 30 seconds.

[0100] Table 1

[0101]

[0102] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods. The specific embodiments described above further describe the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A glaze for an electrical porcelain hollow insulator, characterized in that: The preparation method comprises the following raw materials in parts by weight: 80 parts of aluminum oxide, 10 to 16 parts of mullite powder, 1 to 3 parts of wollastonite, 5 to 8 parts of kaolin clay, 3 to 7 parts of zirconium-containing powder, 6 to 10 parts of feldspar, 1.0 to 1.7 parts of yttrium oxide and 0.5 to 1.5 parts of phlogopite.

2. The glaze for hollow insulators of electrical porcelain according to claim 1, characterized in that: The mullite powder consists of 10-20wt% of polycrystalline mullite fibers and the remainder of sintered mullite.

3. The glaze for hollow insulator of electric porcelain according to claim 1, characterized in that: The feldspar is at least one of potassium feldspar, albite, oligoclase and andesine; And / or, the zirconium-containing powder is zirconium oxide and basic zirconium chloride.

4. The glaze for hollow insulators of electrical porcelain according to claim 2, characterized in that: Satisfy at least one of the following conditions ① to ⑥: ① The diameter of the polycrystalline mullite fiber is 3 to 5 μm; ② The bulk density of the polycrystalline mullite fiber is 75-85 kg / m 3 ; ③ The Al2O3 content of the polycrystalline mullite is 72-75%; ④ The composition of the sintered mullite includes Al2O3: 70-73%, TiO2≤0.5%, Na2O≤0.3%, K2O≤0.3%, Fe2O3≤0.5%; ⑤ The bulk density of the sintered mullite is ≥2.80 g / cm 3 ; ⑥ The porosity of the sintered mullite is ≤3.0%.

5. The glaze for hollow insulators of electrical porcelain according to claim 3, characterized in that: The mass ratio of zirconium oxide to basic zirconium chloride in the zirconium-containing powder is 10:2.5-2.

8.

6. The process for preparing the glaze for hollow insulators of electrical porcelain according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. Grind and sieve the raw materials prepared according to the desired ratio, and then add polycrystalline mullite fiber to obtain raw material powder; S2. The raw material powder is pressed and formed, and then crushed and dried to obtain dry particles; S3. The dried particles are flash-fired to obtain glaze for electrical porcelain hollow insulators.

7. The process for preparing the glaze for hollow insulators of electrical porcelain according to claim 6, characterized in that: Satisfy at least one of the following conditions ① to ③: ① The particle size of the screening is 5 to 8 μm; ② The compression molding is carried out at a pressure of 20 to 50 MPa and the pressure is maintained for 10 to 40 seconds; ③ The particle size of the dried particles is 3 to 8 mm.

8. The process for preparing the glaze for hollow insulators of electrical porcelain according to claim 6, characterized in that: Satisfy at least one of the following conditions ① to ④: ① The maximum temperature of the flash burning is 900-1000°C; ② The flash burning time is 10 to 25 seconds; ③ The heating rate of the flash burning is 110-120°C / min; ④ The electric field strength of the flash burning is 1500-2500V / cm.

9. A method for glazing an insulator glaze according to any one of claims 1 to 5 or an insulator glaze prepared by the preparation process according to any one of claims 6 to 8, characterized in that: The steps are as follows: wet-grinding the glaze material of the electric porcelain hollow insulator to obtain glaze slurry, spraying the glaze slurry onto the surface of the porcelain body of the electric porcelain hollow insulator, and then firing.

10. The method for applying glaze to hollow insulator glaze according to claim 9, characterized in that: Satisfy at least one of the following conditions ① to ③: ① The thickness of the sprayed glaze is 0.1-0.5 mm; ② After the glaze spraying, a drying step is also included; ③The firing temperature is 1100-1300°C.

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