CN115572152A - High-voltage hollow porcelain bushing and preparation process thereof - Google Patents

Abstract

The invention discloses a high-voltage hollow porcelain bushing and a preparation process thereof, and relates to the technical field of ceramic materials. The invention discloses a high-voltage hollow porcelain bushing, which comprises a hollow porcelain bushing blank body and a glaze layer, wherein the hollow porcelain bushing blank body is prepared from the following raw materials in parts by weight: 40 to 60 parts of calcined bauxite, 15 to 22 parts of kaolin, 5 to 8 parts of spherical silicon micro powder, 10 to 15 parts of Faku mud, 10 to 15 parts of bentonite, 0.8 to 1.2 parts of light magnesium oxide, 0.02 to 0.04 part of boric acid powder, 10 to 15 parts of barium-titanium gel, 3 to 5 parts of yttrium oxide and 5 to 8 parts of zirconium oxide; also discloses a preparation process of the high-voltage hollow porcelain bushing. The high-voltage hollow porcelain bushing provided by the invention has the advantages of easily available raw materials, low cost, high mechanical strength, high and low temperature resistance, insulativity, weather resistance, high breakdown voltage, excellent toughness and low possibility of brittle failure, and the working stability and the service life of a hollow porcelain bushing product are improved.

Description

High-voltage hollow porcelain bushing and preparation process thereof

Technical Field

The invention belongs to the technical field of ceramic materials, and particularly relates to a high-voltage hollow porcelain bushing and a preparation process thereof.

Background

With the continuous improvement of voltage grades, the power and electrical industry requires more and more high-voltage-grade stain-resistant large porcelain bushings. The higher the voltage level, the larger the geometrical size of the porcelain bushing and the more complex the structural shape. For the porcelain bushing products with higher voltage level (more than 500 kV), if the porcelain bushing products are integrally manufactured according to the conventional method, the forming process is complex, the difficulty is high, a tall factory building, forming equipment and a professional firing kiln are required, in addition, the electric porcelain belongs to brittle porcelain, the strength of the blank of the porcelain insulator in the firing process is not high, the blank can be damaged due to the fact that the blank cannot bear the dead weight when the required products reach the height of more than 3000mm, and therefore the porcelain insulator cannot be formed at one time and fired into products with the thickness of more than 3000 mm.

The hollow porcelain bushing (or hollow porcelain insulator) is largely used for external insulation equipment of high-voltage and ultrahigh-voltage transmission lines and related electrical equipment, so that extremely high requirements are imposed on the external insulation electrical property and mechanical property. Through the research and development of the technology and the introduction of foreign key technologies and equipment, the gap between the whole level of the domestic electric porcelain manufacturing technology and the foreign technology is continuously reduced. The research on the formula of the high-grade voltage porcelain bushing and the reasonable application of the new material ensure the online quality and the final product quality of the high-tonnage porcelain bushing. However, the higher the transmission voltage of the domestic 1000KV porcelain insulator, the higher the requirements for the bending resistance, the breakdown resistance, the mechanical damage resistance, and the like. However, the bending failure load of the porcelain bushing of domestic manufacturers can only be made to be 60-100 kN.m, while the bending failure load of the porcelain bushing abroad can reach 360 kN.m, and the qualification rate of the porcelain bushing reaches more than 92%. Under most conditions when the hollow porcelain bushing works, parallel insulation of air and an insulating part is formed, when the interelectrode voltage of the hollow porcelain bushing in use exceeds a certain value, discharge or penetrating air breakdown can occur on the interface of the porcelain insulator and the air, therefore, the larger the working voltage borne by the hollow porcelain bushing is, the larger the breakdown strength which can be borne by the hollow porcelain bushing is required to be, so that flashover does not occur, and further the high-voltage-level porcelain bushing is required to have higher breakdown-resistant strength and low dielectric loss, so that the working stability and the service life of the existing high-voltage-level porcelain bushing are improved (the maintenance and replacement cost of the large porcelain bushing is too high).

With the increasing global atmospheric environmental problem, the content of dirt particles in the air is increased, and the high-voltage transmission voltage level is high, which easily causes the dirt accumulation on the surface of the hollow porcelain bushing to cause the pollution flashover accident, therefore, a layer of functional glaze is usually covered on the surface of the dried porcelain blank, which can ensure that the porcelain bushing has better mechanical strength and electrical performance, and can also ensure that the porcelain bushing has excellent acid-base resistance, wear resistance, aging resistance, weather resistance and the like. At present, inorganic glaze is commonly used, has excellent temperature resistance, oil resistance, better aging resistance, high bonding strength and good electrical performance, but the inorganic glaze can generate bubbles in the sintering process and is difficult to discharge, so that poor bonding quality is easily caused, and the bonding strength of a bonded porcelain bushing is influenced; because the raw material composition of porcelain bushing and inorganic glaze is different, and the coefficient of expansion of bonding glaze is less than the coefficient of expansion of porcelain bushing, then easily lead to bonding porcelain bushing's associativity poor, the thermal stability is poor, and mechanical strength is lower, and the later stage is chapped easily, influences the life of later stage product, and leads to the incident. In addition, at present, the researches on the inorganic glaze by domestic researchers mainly focus on the bonding force and the bonding strength, so that the glaze color at the bonding part of the porcelain bushing is dull and not bright, and the appearance of a final product is influenced.

Disclosure of Invention

The invention aims to provide a high-voltage hollow porcelain bushing which is easy to obtain raw materials, low in cost, high in mechanical strength, high and low temperature resistance, insulativity and weather resistance, high in breakdown voltage, excellent in toughness and not easy to break, and improves the working stability and the service life of a hollow porcelain bushing product.

In order to realize the aim of the invention, the invention provides a high-voltage hollow porcelain bushing, which comprises a hollow porcelain bushing blank body and a glaze layer, wherein the hollow porcelain bushing blank body is prepared from the following raw materials in parts by weight: 40 to 60 parts of calcined bauxite, 15 to 22 parts of kaolin, 5 to 8 parts of spherical silicon micro powder, 10 to 15 parts of Faku mud, 10 to 15 parts of bentonite, 0.8 to 1.2 parts of light magnesium oxide, 0.02 to 0.04 part of boric acid powder, 10 to 15 parts of barium-titanium gel, 3 to 5 parts of yttrium oxide and 5 to 8 parts of zirconium oxide.

Further, the content of active magnesium oxide in the light magnesium oxide is not less than 60%.

Further, the preparation method of the barium titanium gel comprises the following steps: adding barium hydroxide into a proper amount of glacial acetic acid, and uniformly stirring to form a barium hydroxide solution; adding tetrabutyl titanate into a proper amount of absolute ethyl alcohol, and uniformly stirring to form tetrabutyl titanate solution; and (3) uniformly mixing the barium hydroxide solution and the tetrabutyl titanate solution, continuously stirring until sol is formed, adding a proper amount of water, and continuously stirring for 10-20 min to obtain the barium-titanium gel.

Further, the molar ratio of the barium hydroxide to the tetrabutyl titanate is 1:2, the ratio of the barium hydroxide to the glacial acetic acid is 0.8-1.0 mol/L, the ratio of the tetrabutyl titanate to the absolute ethyl alcohol is 0.8-1.0 mol/L, and the mass of the water is 1/4 of the total mass of the barium hydroxide and the tetrabutyl titanate.

The invention also provides a preparation process of the high-voltage hollow porcelain bushing, which comprises the following steps:

(1) Weighing the raw materials of the hollow porcelain bushing blank in parts by weight, adding calcined bauxite, kaolin, french mud and bentonite into a ball mill, and carrying out ball milling for 24-36 h to obtain a premix;

(2) Adding spherical micro silicon powder into the premix, mixing uniformly, then adding the premixed light magnesium oxide and boric acid powder, mixing for 20-40 min, adding yttrium oxide and zirconium oxide, mixing uniformly, and adding titanium barium gel to obtain a mixture;

(3) Mixing the mixture, the ball stones and the water according to the mass ratio of 1:3:2, ball-milling for 40 hours in a ball mill, and sieving to remove iron to obtain slurry;

(4) Removing water in the slurry to 10-15% by using a filter press, ageing for 48h, and then carrying out extrusion forming to obtain a blank; naturally drying in the shade for 48h, then placing in a sintering furnace for presintering, heating to 600-700 ℃ at the speed of 10 ℃/min at normal temperature, and preserving heat for 3-4 h to obtain a hollow porcelain sleeve blank;

(5) Coating the glaze layer slurry on the surface of the hollow porcelain bushing blank, then loading the blank into a kiln, heating the blank from room temperature to 300-400 ℃ at the speed of 5 ℃/min, and keeping the temperature for 2 hours; heating to 700-800 ℃ at the speed of 0.5 ℃/min, and keeping the temperature for 2-3 h; heating to 1150-1250 ℃ at the speed of 10 ℃/min, keeping the temperature for 6-8 h, and naturally cooling to room temperature.

Further, the glaze layer slurry in the step (5) is composed of a base glaze, a modifier and a pigment, wherein the base glaze is composed of the following raw materials in percentage by weight: 15 to 20 percent of potassium feldspar powder, 15 to 20 percent of quartz powder, 10 to 25 percent of kaolin, 3 to 5 percent of micro aluminum powder, 4 to 6 percent of calcined talcum powder, 10 to 15 percent of kazhou soil, 10 to 20 percent of plateau field washing mud and 10 to 20 percent of wollastonite;

the addition amount of the modifier is 2.0-2.5% of the total mass of the basic glaze, and the modifier is ZrSiO₄ -TiO₂ -GeO₂ A complex;

the colorant is a high temperature colorant oxide.

Further, the ZrSiO₄ -TiO₂ -GeO₂ The compound is prepared by adopting a sol-gel method, and the preparation method comprises the following steps:

p1, adding a certain amount of tetraethoxysilane into 40wt% ethanol solution, then adding 2mol/L hydrochloric acid, stirring for 0.5h, then adding zirconium n-butoxide and lithium chloride, stirring for 1h, then heating to 60-70 ℃, stirring for reaction for 10-20 min to form transparent sol, cooling to room temperature, and then continuing stirring for 1h to form zirconium silicate precursor gel;

p2, adding 3-trichlorogermanium propionic acid and tetrabutyl orthotitanate into 30wt% ethanol solution, uniformly stirring, then adding the mixture into the zirconium silicate precursor gel, adding polyvinylpyrrolidone, uniformly mixing, and stirring for 1-2 hours at 80-90 ℃ to obtain a gel mixture;

p3, stirring the gel mixture at the temperature of 130-140 ℃ for reaction for 4-6 h, cooling to room temperature, then washing with absolute ethyl alcohol, and then preserving heat at 700 ℃ for 4h to obtain ZrSiO₄ -TiO₂ -GeO₂ And (c) a complex.

Further, in the step P1, the molar ratio of Si to Zr in the ethyl orthosilicate and the n-butyl alcohol zirconium is 1.6:1, the molar ratio of Li to Zr in the lithium chloride and the n-zirconium butanol is 0.06: 1.

further, in the step P2, a molar ratio of Ge in the 3-trichlorogermanopropionic acid to Zr in the zirconium silicate precursor gel is 0.32:1; the molar ratio of Ti in the tetrabutyl orthotitanate to Zr in the zirconium silicate precursor gel is 0.25:1; the addition amount of the 30wt% ethanol solution is 2 times of the total mass of the 3-trichlorogermanium propionic acid and tetrabutyl orthotitanate; the addition amount of the polyvinylpyrrolidone is 10% of the total mass of the 3-trichlorogermanium propionic acid and the tetrabutyl orthotitanate.

Further, the preparation process of the high-voltage hollow porcelain bushing is characterized in that the preparation method of the glaze layer slurry comprises the following steps:

s1, weighing basic glaze according to requirements, uniformly mixing, placing in a smelting furnace, heating to 1300-1350 ℃, preserving heat for 2-3h, and then performing water quenching to prepare basic fritted glaze;

s2, weighing the modifier and the pigment according to the requirement, adding the modifier and the pigment into the basic fritted glaze, uniformly mixing to obtain a glaze mixture, and mixing the glaze mixture, the spherulites and water according to a mass ratio of 1:1:0.8, putting into a ball mill, and carrying out ball milling for 30-35h;

s3, removing iron from the glaze slurry discharged from the ball mill by using an iron remover, sieving the glaze slurry with a 250-mesh sieve, ageing the glaze slurry for 72 hours, adjusting the water content (25 +/-0.5)% of the glaze slurry, and measuring the fluidity by using a viscosity meter for 58 +/-2 seconds to obtain the glaze layer slurry.

The invention achieves the following beneficial effects:

1. the spherical silicon micropowder adopted by the invention is of a spherical structure, has good surface fluidity and sintering activity, can be fully filled among the raw materials of the hollow porcelain bushing, further improves the dispersibility among the components, and can also reduce the stress concentration of each interface in the porcelain bushing product, thereby improving the mechanical strength and the shock resistance of the hollow porcelain bushing; the spherical silicon micro powder has excellent insulativity, and is added into the hollow porcelain bushing, so that the breakdown voltage of a porcelain bushing product is remarkably improved, and the electrical insulativity of the hollow porcelain bushing is improved.

2. According to the invention, the light magnesium oxide and the boric acid with a specific proportion are added, and the solid solution amount of magnesium in the glass phase is increased through the action of boron and magnesium on the glass phase in the porcelain bushing, namely, the boron increases the solid solution amount of magnesium in the glass phase in the sintering process, and reduces the glass forming tendency of a high-temperature liquid phase in the cooling process, so that the content of the glass phase in a hollow porcelain bushing product is reduced, and the mechanical strength and the insulation resistance of the hollow porcelain bushing can be improved; meanwhile, the glass structure containing boron and magnesium is a three-dimensional frame structure, the network structure of the glass is strengthened, the strength of the glass phase is improved, and the strength of the hollow porcelain bushing is further improved.

3. The barium titanium gel is added, and the barium titanate is formed in the sintering process, so that the barium titanate can be better dispersed and applied to the hollow porcelain sleeve blank, and the breakdown voltage of the hollow porcelain sleeve can be further improved. The yttrium oxide is easy to form a liquid phase with silicon oxide in the high-temperature sintering process, so that the density of the porcelain sleeve can be improved, the mechanical strength of the porcelain sleeve is improved, and the binding force between the yttrium oxide and a glaze layer is improved; in the sintering process of the zirconia, the ceramic sleeve is promoted to be crystallized, so that the strength of the ceramic sleeve is improved; the bentonite and the normal clay are added, so that the bonding force between the porcelain bushing and the glaze is improved, the porcelain bushing is easy to combine in the bonding process, and the subsequent high-temperature sintering is facilitated.

4. The modifier in the glaze layer is ZrSiO formed by compounding ethyl orthosilicate, zirconium n-butyl alcohol, 3-trichlorogermanium propionic acid and tetrabutyl orthotitanate by adopting a sol-gel method₄ -TiO₂ -GeO₂ The compound reduces the sintering temperature of the glaze layer slurry, ensures that the glaze layer slurry has good high-temperature fluidity, precipitates crystals in the bonding and sintering process, and improves the strength of the glaze layer, thereby improving the bonding strength between the hollow porcelain bushing and the glaze layer, ensuring that the surface color of the glaze layer is uniform, has no color difference, has bright color and improves the weather resistance of the invention; the invention adopts a sol-gel method to prepare ZrSiO₄ 、TiO₂ And GeO₂ The cost is reduced by compounding, and the particle size of the modifier is smaller and can reach below micron level while the uniform compounding of the three substances is controlled by adding the surfactant polyvinylpyrrolidone; chlorineThe addition of lithium oxide greatly reduces the crystallization temperature of zirconium silicate, so that ZrSiO₄ -TiO₂ -GeO₂ The compound can obtain a crystalline phase compound at a lower sintering temperature; in the invention, zrSiO₄ 、TiO₂ And GeO₂ The three substances are synthesized together by a sol-gel method in the form of organic matters, so that the three substances can be simultaneously added into the glaze layer slurry, the three substances can be more conveniently and uniformly dispersed in the glaze layer slurry, bubbles are prevented from being generated at high temperature, the porosity is reduced, and the strength and the toughness of the glaze layer are further improved.

5. The glaze layer slurry and the modifier are matched for use, so that the expansion coefficient of the glaze layer is close to that of the porcelain sleeve blank, and the residual stress is avoided, so that the glaze layer slurry is bonded with a high-strength porcelain sleeve in high-temperature sintering, the glaze layer slurry and the high-strength porcelain sleeve are more completely mutually permeated and are more firmly bonded, the formation of a porcelain glaze intermediate layer is facilitated, and the glaze layer slurry has stronger bonding strength and breaking strength.

6. Due to the addition of the micro-aluminum powder, the micro-aluminum powder is melted into liquid in the high-temperature sintering process, namely about 600 ℃, and fills pores in the slurry, and the glaze layer slurry is oxidized in the sintering process by bonding a dispersed crystalline phase, so that the glaze layer is more densified, and the strength of the glaze layer is enhanced; because the particle size of the micro aluminum powder is small and the melting point is low, the micro aluminum powder is easy to permeate into the porcelain bushing blank in the sintering process, and the bonding strength between the glaze layer and the porcelain bushing is further improved.

7. The invention adds the Chinese clay with little impurity, soft quality and good plasticity, the glaze layer can be fired at a lower temperature without influencing the whiteness of the glaze layer, the Chinese clay is added into the glaze layer slurry according to a proper proportion, so that the glaze layer can better present different colors, the whiteness after the glaze layer slurry is sintered is enhanced, the density is uniform, the color is bright, the surface is not easy to crack, and the glaze layer has better bonding strength and bonding power. The addition of wollastonite reduces the sintering temperature of glaze layer slurry, reduces cracks and warping of a glaze layer, increases the glossiness of the glaze layer, improves the strength of the glaze layer, and enables the glaze layer to have excellent stain resistance and weather resistance.

8. The hollow porcelain bushing is aluminum porcelain, can be used under the high-voltage grade condition (more than 500 kV), and has excellent mechanical strength, toughness, insulativity, high and low temperature resistance, high breakdown voltage and the like; the glaze layer coated on the surface of the hollow porcelain bushing is prepared from potassium feldspar powder, quartz powder, kaolin, micro aluminum powder, calcined talcum powder, ulzhou clay, terrace mud, wollastonite and other raw materials, has excellent mechanical strength, toughness and self-lubricating property, and has excellent weather resistance and hydrophobicity, and the glaze layer is coated on the surface of the hollow porcelain bushing, so that the hollow porcelain bushing is ensured to have high voltage grade, excellent mechanical strength and electrical insulation property, good adhesion between the hollow porcelain bushing and the porcelain bushing, difficult cracking, no influence on the service life of later-stage products, and the aging resistance, weather resistance, wear resistance, waterproofness and the like of the invention are improved.

Detailed Description

The technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The content of active magnesium oxide in the light magnesium oxide is not less than 60%, the light magnesium oxide used in the embodiment is model number CM-85 of Zhengxing magnesite material factory, the content of magnesium oxide is more than 85%, and the content of active magnesium oxide is more than 65%.

The spherical silicon micropowder used in the embodiment of the invention is provided for the Huimai powder.

The micro-aluminum powder is prepared from JT-5 (1-2 mu m) of micro spherical aluminum powder provided by high-tech. aluminum industry, inc. in Jintian aluminum of Hunan province.

Modifier ZrSiO in the embodiment of the invention₄ -TiO₂ -GeO₂ The preparation method of the compound comprises the following steps:

p1, adding 33.3g of tetraethoxysilane into 200mL of 40wt% ethanol solution, then adding 67mL of 2mol/L hydrochloric acid, stirring for 0.5h, then adding 38.4g of zirconium n-butyl alcohol and 0.3g of lithium chloride, stirring for 1h, then heating to 70 ℃, stirring for reaction for 15min to form transparent sol, cooling to room temperature, and continuing stirring for 1h to form zirconium silicate precursor gel.

P2, adding 6.9g3-trichlorogermanium propionic acid and 8.5g tetrabutyl orthotitanate into 30.8g of 30wt% ethanol solution, uniformly stirring, then adding the mixture into the zirconium silicate precursor gel, then adding 1.5g of polyvinylpyrrolidone, uniformly mixing, and stirring for 2 hours at 85 ℃ to obtain a gel mixture.

P3, stirring the gel mixture at the temperature of 135 ℃ for reaction for 5 hours, cooling to room temperature, then washing with absolute ethyl alcohol, and then preserving heat at 700 ℃ for 4 hours to obtain ZrSiO₄ -TiO₂ -GeO₂ And (c) a complex.

The high voltage hollow insulator of the present invention will be described with reference to the following embodiments.

Example 1

The preparation process of the high-voltage hollow porcelain bushing specifically comprises the following steps:

(1) Firstly, 40 parts of calcined bauxite, 22 parts of kaolin, 15 parts of normal mud and 15 parts of bentonite are added into a ball mill, and ball milling is carried out for 24 hours at a ball milling speed of 280r/mim, so as to obtain the premix.

(2) Adding 8 parts of spherical micro silicon powder into the premix, uniformly mixing, then adding 0.8 part of light magnesium oxide and 0.02 part of boric acid powder which are mixed in advance, mixing for 20-40 min, then adding 3 parts of yttrium oxide and 8 parts of zirconium oxide, uniformly mixing, and then adding 15 parts of barium titanium gel to obtain a mixture.

(3) Mixing the mixture, the ball stone and water in a mass ratio of 1:3:2, ball-milling for 40 hours at a ball-milling speed of 360r/mim, and sieving to remove iron to obtain the slurry.

(4) Removing water in the slurry to 10-15% by using a filter press, ageing for 48h, and then carrying out extrusion forming to obtain a blank; naturally drying in the shade for 48h, then placing in a sintering furnace for presintering, heating to 600 ℃ at the normal temperature at the speed of 10 ℃/min, and preserving heat for 4h to obtain the hollow porcelain bushing blank.

(5) Coating the glaze layer slurry on the surface of the hollow porcelain bushing blank, wherein the coating thickness is 0.1mm, then putting the blank into a kiln, heating the blank from room temperature to 400 ℃ at the speed of 5 ℃/min, and keeping the temperature for 2 hours; heating to 700 ℃ at the speed of 0.5 ℃/min, and keeping the temperature for 2h; heating to 1200 ℃ at the speed of 10 ℃/min, keeping the temperature for 7h, and naturally cooling to room temperature.

The preparation method of the barium-titanium gel comprises the following steps: 17.1g of Ba (OH)₂ Adding the mixture into 100mL of glacial acetic acid, and uniformly stirring to form a barium hydroxide solution; adding 68g of tetrabutyl titanate into 100mL of absolute ethyl alcohol, and uniformly stirring to form tetrabutyl titanate solution; and (3) uniformly mixing the barium hydroxide solution and the tetrabutyl titanate solution, continuously stirring until sol is formed, adding 21g of the sol, and continuously stirring for 20min to obtain the barium-titanium gel.

The preparation method of the glaze layer slurry comprises the following steps:

s1, weighing 18% of potassium feldspar powder, 17% of quartz powder, 20% of kaolin, 4% of micro aluminum powder, 5% of calcined talcum powder, 5% of Mizhou soil, 15% of plateau field mud and 16% of wollastonite in percentage by weight as basic glaze materials, uniformly mixing, placing in a smelting furnace, heating to 1350 ℃, preserving heat for 3 hours, and then performing water quenching to obtain the basic frit glaze.

S2, weighing 2.5 parts of modifier ZrSiO based on 100 parts of the total mass of the basic glaze₄ -TiO₂ -GeO₂ And adding the compound and 2.5 parts of pigment into the basic fritted glaze, uniformly mixing to obtain a glaze mixture, and mixing the glaze mixture, the ball stone and water according to a mass ratio of 1:1:0.8 is put into a ball mill for ball milling for 30 to 35 hours. The pigment is prepared from the following components in percentage by mass of 1:1.5 lead oxide and cobalt oxide.

S3, removing iron from the glaze slurry discharged from the ball mill by using an iron remover, sieving the glaze slurry with a 250-mesh sieve, ageing the glaze slurry for 72 hours, adjusting the moisture content of the glaze slurry to be 25 +/-0.5 percent, and measuring the fluidity of the glaze slurry by using a viscosity meter for 58 +/-2 seconds to obtain the glaze layer slurry.

Example 2

The preparation process of the high voltage hollow porcelain bushing in this example 2 is the same as that in example 1, and specifically, reference is made to example 1.

The difference is that the hollow porcelain bushing blank of the high-voltage hollow porcelain bushing in the embodiment 2 comprises the following raw materials in percentage by weight: the hollow porcelain bushing blank consists of the following raw materials in parts by weight: 60 parts of calcined bauxite, 15 parts of kaolin, 5 parts of spherical silicon micro powder, 10 parts of Faku mud, 10 parts of bentonite, 1.2 parts of light magnesium oxide, 0.04 part of boric acid powder, 10 parts of barium-titanium gel, 4 parts of yttrium oxide and 6 parts of zirconium oxide.

The preparation method and the component ratio of the barium-titanium gel are the same as those in the embodiment 1, and the embodiment 1 is specifically referred.

The preparation method and the component ratio of the glaze layer slurry are the same as those in the embodiment 1, and the embodiment 1 is specifically referred to.

Example 3

The preparation process of the high-voltage hollow porcelain bushing in the embodiment 3 is the same as that in the embodiment 1, and the embodiment 1 is specifically referred to.

The difference is that the hollow porcelain bushing blank of the high-voltage hollow porcelain bushing in the embodiment 3 comprises the following raw materials in percentage by weight: the hollow porcelain bushing blank consists of the following raw materials in parts by weight: 50 parts of calcined bauxite, 20 parts of kaolin, 6 parts of spherical silicon micro powder, 12 parts of Faku mud, 12 parts of bentonite, 1.0 part of light magnesium oxide, 0.02 part of boric acid powder, 11 parts of barium-titanium gel, 5 parts of yttrium oxide and 5 parts of zirconium oxide.

The preparation method and the component ratio of the barium-titanium gel are the same as those in the embodiment 1, and the embodiment 1 is specifically referred.

The preparation method and the component ratio of the glaze layer slurry are the same as those in the embodiment 1, and the embodiment 1 is specifically referred to.

Example 4

The preparation process of the high-voltage hollow porcelain bushing in the embodiment 4 is the same as that in the embodiment 1, and the embodiment 1 is specifically referred to.

The difference is that the hollow porcelain bushing blank of the high-voltage hollow porcelain bushing in the embodiment 4 comprises the following raw materials in percentage by weight: the hollow porcelain bushing blank consists of the following raw materials in parts by weight: 55 parts of calcined bauxite, 18 parts of kaolin, 5 parts of spherical silicon micro powder, 12 parts of Faku mud, 10 parts of bentonite, 1.0 part of light magnesium oxide, 0.03 part of boric acid powder, 13 parts of barium-titanium gel, 4 parts of yttrium oxide and 6 parts of zirconium oxide.

The preparation method and the component ratio of the barium-titanium gel are the same as those in the embodiment 1, and the embodiment 1 is specifically referred.

The preparation method and the component ratio of the glaze layer slurry are the same as those in the embodiment 1, and the embodiment 1 is specifically referred to.

Example 5

The preparation process and the components of the high-voltage hollow porcelain bushing in the embodiment 5 are the same as those in the embodiment 1, and the embodiment 1 is specifically referred to.

Except that the hollow porcelain bushing blank in the embodiment 5 is not coated with the glaze slurry, that is, the step (5) is modified as follows: putting the hollow porcelain bushing blank prepared in the step (4) into a kiln, heating from room temperature to 400 ℃ at the speed of 5 ℃/min, and keeping the temperature for 2 hours; heating to 700 ℃ at the speed of 0.5 ℃/min, and keeping the temperature for 2h; heating to 1200 ℃ at the speed of 10 ℃/min, keeping the temperature for 7h, and naturally cooling to room temperature.

Comparative example 1

The raw material components and the preparation process of the comparative example 1 are the same as those in the example 5, namely, the surface of the hollow porcelain bushing is not coated with the glaze layer, and the specific preparation process specifically refers to the example 5. Except that no spherical silica fume was added in this comparative example 1, and the amount of kaolin added was modified to 23 parts.

Comparative example 2

The raw material components and the preparation process of the comparative example 2 are the same as those in the example 5, namely, the surface of the hollow porcelain bushing is not coated with the glaze layer, and the specific preparation process specifically refers to the example 5. Except that in comparative example 2, boric acid powder was not added.

Comparative example 3

The raw material components and the preparation process of the comparative example 3 are the same as those in the example 5, namely, the surface of the hollow porcelain bushing is not coated with the glaze layer, and the specific preparation process specifically refers to the example 5. Except that no barium titanium gel was added in this comparative example 3.

Comparative example 4

The raw material components and the preparation process of the comparative example 4 are the same as those in the example 4, namely, the surface of the hollow porcelain bushing is coated with the glaze layer, and the specific preparation process specifically refers to the example 4. In contrast, in the process for preparing barium-titanium gel in comparative example 4, the molar ratio of barium hydroxide to tetrabutyl titanate is 1:1, i.e. tetrabutyltitanate, was added in an amount of 34g.

Comparative example 5

The raw material components and the preparation process of the comparative example 5 are the same as those in the example 4, namely, the surface of the hollow porcelain bushing is coated with the glaze layer, and the specific preparation process specifically refers to the example 4. Except that in comparative example 5 the modifier is ZrSiO₄ 、TiO₂ And GeO₂ The molar ratio of Zr, ti and Ge in the modifier is 1:0.25:0.32, the modifier mixture being added in an amount of 2.5% of the total mass of the base enamel.

Comparative example 6

The raw material components and the preparation process of the comparative example 6 are the same as those in the example 4, namely, the surface of the hollow porcelain bushing is coated with the glaze layer, and the specific preparation process specifically refers to the example 4. Except that the base glaze of the present comparative example 6 does not contain the aluminum micropowder, that is, the base glaze is composed of the following raw materials by weight: 18% of potassium feldspar powder, 17% of quartz powder, 24% of kaolin, 5% of calcined talcum powder, 5% of kazhou soil, 15% of plateau field washing mud and 16% of wollastonite.

The high voltage hollow porcelain bushings of the above examples 1 to 5 and comparative examples 1 to 6 were tested for mechanical and electrical properties with a glaze layer of 0.1mm in thickness, and the performance of the porcelain bushings with and without glaze coating was tested as shown in table 1 below.

TABLE 1 detection results of the properties of hollow porcelain bushing

As can be seen from the results in table 1, the hollow porcelain bushing of the present invention has excellent mechanical strength and fracture toughness, higher impact and weather resistance voltage, and excellent electrical insulation; after the glaze layer is coated on the surface of the hollow porcelain sleeve, the glaze layer is full in appearance glaze, bright in luster and uniform in color, and the hollow porcelain sleeve with the glaze layer is better in breaking strength, so that the combination of the glaze layer and a porcelain sleeve substrate has excellent mechanical strength and bonding effect.

The technical features of the embodiments described above can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention.

Claims (10)

1. The high-voltage hollow porcelain bushing comprises a hollow porcelain bushing blank and a glaze layer, and is characterized in that the hollow porcelain bushing blank is prepared from the following raw materials in parts by weight: 40 to 60 parts of calcined bauxite, 15 to 22 parts of kaolin, 5 to 8 parts of spherical silicon micro powder, 10 to 15 parts of Faku mud, 10 to 15 parts of bentonite, 0.8 to 1.2 parts of light magnesium oxide, 0.02 to 0.04 part of boric acid powder, 10 to 15 parts of barium-titanium gel, 3 to 5 parts of yttrium oxide and 5 to 8 parts of zirconium oxide.

2. The high-voltage hollow insulator according to claim 1, wherein the light magnesium oxide has an active magnesium oxide content of not less than 60%.

3. The high-voltage hollow porcelain bushing according to claim 1, wherein the barium titanium gel is prepared by the following steps: adding barium hydroxide into a proper amount of glacial acetic acid, and uniformly stirring to form a barium hydroxide solution; adding tetrabutyl titanate into a proper amount of absolute ethyl alcohol, and uniformly stirring to form tetrabutyl titanate solution; and (3) uniformly mixing the barium hydroxide solution and the tetrabutyl titanate solution, continuously stirring until sol is formed, adding a proper amount of water, and continuously stirring for 10-20 min to obtain the barium-titanium gel.

4. The high-voltage hollow porcelain bushing according to claim 3, wherein the molar ratio of the barium hydroxide to the tetrabutyl titanate is 1:2, the ratio of the barium hydroxide to the glacial acetic acid is 0.8-1.0 mol/L, the ratio of the tetrabutyl titanate to the absolute ethyl alcohol is 0.8-1.0 mol/L, and the mass of the water is 1/4 of the total mass of the barium hydroxide and the tetrabutyl titanate.

5. The process for preparing the high-voltage hollow porcelain bushing according to any one of claims 1 to 4, which comprises the following steps:

(1) Weighing the raw materials of the hollow porcelain bushing blank in parts by weight, adding calcined bauxite, kaolin, french mud and bentonite into a ball mill, and carrying out ball milling for 24-36 h to obtain a premix;

(2) Adding spherical micro silicon powder into the premix, mixing uniformly, then adding the premixed light magnesium oxide and boric acid powder, mixing for 20-40 min, adding yttrium oxide and zirconium oxide, mixing uniformly, and adding titanium barium gel to obtain a mixture;

(3) Mixing the mixture, the ball stones and the water according to the mass ratio of 1:3:2, ball-milling for 40 hours in a ball mill, and sieving to remove iron to obtain slurry;

(4) Removing water in the slurry to 10-15% by using a filter press, ageing for 48h, and then carrying out extrusion forming to obtain a blank; naturally drying in the shade for 48h, then placing in a sintering furnace for presintering, heating to 600-700 ℃ at the speed of 10 ℃/min at normal temperature, and preserving heat for 3-4 h to obtain a hollow porcelain sleeve blank;

(5) Coating the glaze layer slurry on the surface of the hollow porcelain bushing blank, then loading the blank into a kiln, heating the blank from room temperature to 300-400 ℃ at the speed of 5 ℃/min, and keeping the temperature for 2 hours; heating to 700-800 ℃ at the speed of 0.5 ℃/min, and keeping the temperature for 2-3 h; heating to 1150-1250 ℃ at the speed of 10 ℃/min, keeping the temperature for 6-8 h, and naturally cooling to room temperature.

6. The process for preparing a high-voltage hollow porcelain bushing according to claim 5, wherein the glaze slurry in step (5) is composed of a base glaze, a modifier and a pigment, and the base glaze is composed of the following raw materials in percentage by weight: 15 to 20 percent of potassium feldspar powder, 15 to 20 percent of quartz powder, 10 to 25 percent of kaolin, 3 to 5 percent of micro aluminum powder, 4 to 6 percent of calcined talcum powder, 10 to 15 percent of kahizhou soil, 10 to 20 percent of plateau field washing mud and 10 to 20 percent of wollastonite;

the addition amount of the modifier is 2.0-2.5% of the total mass of the basic glaze, and the modifier is ZrSiO₄ -TiO₂ -GeO₂ A complex;

the colorant is a high temperature colorant oxide.

7. The process for preparing a high-voltage hollow porcelain bushing according to claim 6, wherein the ZrSiO is₄ -TiO₂ -GeO₂ The compound is prepared by adopting a sol-gel method, and the preparation method comprises the following steps:

p1, adding a certain amount of tetraethoxysilane into 40wt% ethanol solution, then adding 2mol/L hydrochloric acid, stirring for 0.5h, then adding zirconium n-butoxide and lithium chloride, stirring for 1h, then heating to 60-70 ℃, stirring for reaction for 10-20 min to form transparent sol, cooling to room temperature, and then continuing stirring for 1h to form zirconium silicate precursor gel;

p2, adding 3-trichlorogermanium propionic acid and tetrabutyl orthotitanate into 30wt% ethanol solution, uniformly stirring, then adding the mixture into the zirconium silicate precursor gel, adding polyvinylpyrrolidone, uniformly mixing, and stirring for 1-2 hours at 80-90 ℃ to obtain a gel mixture;

p3, stirring the gel mixture at the temperature of 130-140 ℃ for reaction for 4-6 h, cooling to room temperature, then washing with absolute ethyl alcohol, and then preserving heat at 700 ℃ for 4h to obtain ZrSiO₄ -TiO₂ -GeO₂ And (3) a compound.

8. The process for preparing a high-voltage hollow porcelain bushing according to claim 7, wherein in the step P1, the molar ratio of Si to Zr in the ethyl orthosilicate and the zirconium n-butoxide is 1.6:1, the molar ratio of Li to Zr in the lithium chloride and the n-zirconium butanol is 0.06: 1.

9. the process for preparing a high-voltage hollow porcelain bushing according to claim 7, wherein in the step P2, the molar ratio of Ge in the 3-trichlorogermanopropionic acid to Zr in the zirconium silicate precursor gel is 0.32:1; the molar ratio of Ti in the tetrabutyl orthotitanate to Zr in the zirconium silicate precursor gel is 0.25:1; the addition amount of the 30wt% ethanol solution is 2 times of the total mass of the 3-trichlorogermanium propionic acid and the tetrabutyl orthotitanate; the addition amount of the polyvinylpyrrolidone is 10% of the total mass of the 3-trichlorogermanium propionic acid and the tetrabutyl orthotitanate.

10. The process for preparing a high-voltage hollow porcelain bushing according to any one of claims 6 to 9, wherein the method for preparing the glaze slip comprises the steps of:

s1, weighing basic glaze according to requirements, uniformly mixing, placing in a smelting furnace, heating to 1300-1350 ℃, preserving heat for 2-3h, and then performing water quenching to prepare basic fritted glaze;

s2, weighing the modifier and the pigment according to the requirement, adding the modifier and the pigment into the basic fritted glaze, uniformly mixing to obtain a glaze mixture, and mixing the glaze mixture, the spherulites and water according to a mass ratio of 1:1:0.8, putting into a ball mill, and carrying out ball milling for 30-35h;

s3, removing iron from the glaze slurry discharged from the ball mill by using an iron remover, sieving the glaze slurry with a 250-mesh sieve, ageing the glaze slurry for 72 hours, adjusting the water content (25 +/-0.5)% of the glaze slurry, and measuring the fluidity by using a viscosity meter for 58 +/-2 seconds to obtain the glaze layer slurry.