Glaze for improving bonding strength of glaze blank, and preparation method and application of glaze
Through the glaze and blank washing process of specific formulas, the problems of impact damage and glaze defects before firing of electric ceramic glaze are solved, and the strength of glaze blanks is improved and the glaze quality is improved, meeting the requirements of high quality and high whiteness.
Patent Information
- Application Number
- CN202510434550.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-08
- Publication Date
- 2025-06-20
AI Technical Summary
Existing electric porcelain glazes are prone to damage before firing, and the glaze surface is often affected by defects such as glaze deficiency, glaze jump, pinhole, etc., resulting in the appearance quality not meeting the standards, especially in areas with severe wind and sand, with higher requirements.
The glaze with specific formulas is used, including bentonite, calcium metasilicate powder, calcined talc powder, feldspar, Anyang feldspar, Pingxiang natural quartz powder, Shaanxi kaolin, ultrafine zircon sand powder, alumina powder and industrial-grade barium carbonate. Through ball milling and sieving treatment, glaze slurry with high binding strength is prepared, and the blank is washed on the surface of the blank to ensure smooth surface.
The bonding strength of the glaze blank is significantly improved, the collision loss rate before firing is reduced, from 1% to less than 1%, ensuring the improvement of glaze quality, meeting the requirements of high quality and high whiteness in wind and sand areas, and improving the bending strength after firing.
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of electric porcelain insulators, and particularly relates to a glaze for improving the bonding strength between glaze and blank, a method for preparing the glaze, and an application thereof. Background Art
[0002] In the production of electric porcelain, mechanical strength is a very important performance for judging the quality of electric porcelain. Because when the electric porcelain material has high strength, under the condition of the same voltage level, the utilization rate of the material can be improved and the use cost of the product can be reduced. In the production of electric porcelain, it is necessary to spray glaze on the surface of the prepared blank.
[0003] In the production of existing electric porcelain, the appearance quality is troubled by glaze surface defects such as lack of glaze, skipping glaze, and pinholes. In areas with severe sandstorms, the requirements for the appearance quality of electric porcelain are even higher, far exceeding the national standards, resulting in a low first-pass rate of porcelain parts that meet the high requirements. After a detailed analysis of the production process, it is found that from the perspective of the formula, whether the glaze and the blank match and whether they are well combined after glazing have a certain impact on the glaze surface quality, which is an important influencing factor; from the perspective of the process, from the forming of the blank to the firing, it has a great impact on the glaze surface quality. Among them, the following 3 points have a greater impact on the glaze surface defects and there is no good solution yet. The following 3 points are specifically as follows: First, if the tool used for blank forming is not sharp or the operator does not master the cutting force and speed well, it is easy to make the surface of the blank pitted, which is extremely likely to cause skipping glaze and pinholes on the glaze surface during high-temperature firing, and ultimately lead to unqualified appearance quality of the glaze surface after firing.
[0004] Second, after the blank is made, the blank is placed on a round plate made of wood fiber material. The blank is sent to the subsequent process along with the round plate. However, because this round plate is made of wood fiber material and the density of the wood fiber material is not high, it is easy to get moldy and aged and produce peeling and flaking phenomena. These wood skins and wood chips are very easy to pierce into the lower umbrella of the blank (sometimes up to more than 1 cm deep). After the wood skins and wood chips pierced into the blank are glazed and fired in the kiln, the high temperature of thousands of degrees Celsius will burn out the wood skins and wood chips. If the high-temperature fluidity during the firing process is large, the glaze layer will flow into the holes pierced by the wood skins and wood chips, resulting in pinhole phenomena after forming. If the high-temperature fluidity is small, the glaze material is difficult to flow, and the holes left after burning out cannot be covered, resulting in lack of glaze.
[0005] Third, during the transfer process before firing, it is inevitable that the glaze and the blank will be rubbed against each other. Because the bonding strength between the glaze and the blank still needs to be improved, the collision damage rate before firing is about 5%. Summary of the Invention
[0006] The present invention aims to provide a glaze for improving the bonding strength between glaze and blank, so as to improve the bonding strength between glaze and blank and reduce the collision damage rate before firing.
[0007] To achieve the above object, the present invention adopts the following technical solutions: A glaze for improving the bonding strength between glaze and blank, comprising the following raw materials in parts by mass: 6-10 parts of bentonite, 6-10 parts of calcium metasilicate micropowder, 6-14 parts of calcined talc powder, 18-22 parts of feldspar for sail growth, 8-12 parts of Anyang feldspar, 18-22 parts of Pingxiang natural quartz powder, 12-16 parts of Shaanxi kaolin, 6-10 parts of ultrafine zircon sand micropowder, 1-3 parts of alumina micropowder, 1-3 parts of industrial grade barium carbonate, and 0.04-0.08 parts of sodium carboxymethyl cellulose.
[0008] Preferably, the bentonite is 6-8 parts.
[0009] Preferably, the calcium metasilicate micropowder is 7-8 parts.
[0010] Preferably, the calcined talc powder is 9-10 parts.
[0011] Preferably, the ultrafine zircon sand micropowder is 7-8 parts.
[0012] Preferably, the sodium carboxymethyl cellulose is 0.04-0.06 parts The present invention also provides a preparation method of a glaze for improving the bonding strength between glaze and blank, comprising the following steps: S1. Ball milling: Take each raw material in the glaze for improving the bonding strength between glaze and blank and add water for ball milling to obtain a primary slurry; S2. Screen the primary slurry to obtain a secondary slurry, and age the secondary slurry to obtain a glaze slurry for improving the bonding strength of the glaze.
[0013] The present invention also provides an application of a glaze for improving the bonding strength between glaze and blank, which is used for the application of the glaze for improving the bonding strength between glaze and blank on porcelain insulators.
[0014] Preferably, the following application steps are further included: The first step is to grind the glaze for improving the bonding strength between glaze and blank into a glaze slurry; The second step is to apply the glaze slurry onto the blank to be sintered; The third step is to fire the glazed blank in a kiln.
[0015] Preferably, before the second step, for the blank with pits after forming, the surface of the blank is washed. When washing the blank, place the blank on a rotating fixture, rotate the blank, and use a sponge dipped in clean water to clean the dust and stains on the blank. It is required that the surface of the blank after washing is clean and smooth without any foreign objects; the washed blanks should be neatly placed on the table waiting for glazing and stacking is not allowed. By washing the blank, the dust on the surface of the blank is effectively removed and the surface of the blank is made smooth, which helps to ensure the smoothness of the glaze surface after subsequent glazing, thereby reducing or even avoiding the problems of glaze jumping and pinholes caused by the pits of the blank itself after subsequent firing.
[0016] Preferably, the water for washing the blanks should be changed frequently to ensure the quality of blank washing. Soaking the blanks in water is not allowed. It is required that each part be evenly wiped to prevent water accumulation due to pits on the surface of the blanks. During the blank washing process, if cracks are found on the blanks, they shall be scrapped and returned to the pulp pond for the next time.
[0017] Through the component design of the glaze, the present invention uses Pingxiang natural quartz powder to introduce a large amount of SiO2 into the glaze to play a framework role. The main purpose is to adjust the melting temperature, expansion coefficient and high-temperature viscosity of the glaze, and improve the wear resistance, hardness, whiteness, transparency and chemical stability of the glaze.
[0018] Shaanxi kaolin powder is used to improve the mechanical strength, wear resistance, chemical stability and elasticity of the glaze, increase the high-temperature viscosity and melting temperature of the glaze, and reduce the expansion coefficient of the glaze. In addition, Shaanxi kaolin powder can improve the suspension performance of the glaze slurry and the adhesion performance to the green body.
[0019] Using Fan Cheng feldspar and Anyang feldspar to reduce the melting temperature of the glaze, decrease the high-temperature viscosity of the glaze and increase the brightness of the glaze, while promoting the melting of quartz.
[0020] Using calcium metasilicate micropowder to reduce the high-temperature viscosity of the glaze, promote the diffusion of pigments. When reacting with SiO2, it can form very stable silicates, and endow the glaze with high mechanical strength, good elasticity and luster.
[0021] Using calcined talc powder to reduce the expansion coefficient of the glaze, improve the elasticity of the glaze, promote the formation of the intermediate layer between the body and the glaze, and improve the mechanical strength and thermal stability of the glaze; at the same time, improve the opacification of the glaze, increase the whiteness of the glaze, make the glaze insensitive to the firing atmosphere, and the glaze surface does not turn yellow and is not easily smoked.
[0022] Using alumina micropowder to provide corundum crystals for the glaze, and improve the whiteness, stiffness, high-temperature viscosity, chemical stability and thermal shock resistance of the glaze, and greatly improve the strength and wear resistance of the glaze vitreous body.
[0023] Using ultrafine zircon sand micropowder to improve the covering ability and whiteness of the glaze, and it is not affected by the reducing atmosphere or oxidation atmosphere; ultrafine zircon sand micropowder has great chemical inertness, can improve the chemical stability of the glaze, making the glaze resistant to both acid and alkali; ultrafine zircon sand micropowder can significantly reduce the thermal expansion of the glaze and improve the thermal stability of the glaze; ultrafine zircon sand micropowder can improve the high-temperature mechanical strength and dielectric properties of the glaze.
[0024] Using industrial-grade barium carbonate to increase the gloss, whiteness and dielectric properties of the glaze surface.
[0025] Using CMC to improve the suspension performance and adhesion of the glaze slurry, and when used in combination with bentonite, it can make the glaze firmly adhere to the green body.
[0026] With the combination of Pingxiang natural stone, Shaanxi kaolin, ultrafine zircon sand powder, alumina powder, etc., the quality after firing is better.
[0027] The glaze for improving the bonding strength between glaze and body of the present invention not only realizes the high-strength bonding between glaze and body before firing, ensures the normal quality of the glaze surface, reduces the chipping rate before firing from 5% to less than 1% of the chipping rate before firing, greatly reduces the chipping rate, and helps to reduce costs. In addition, the porcelain glaze surface obtained after firing is smooth and has high whiteness, meeting the high-quality requirements and high whiteness requirements for the glaze surface in sandy areas. In addition, the flexural strength of the fired test strip with ordinary material is more than 134 Mpa, and the flexural strength of the fired test strip with C130 porcelain material is more than 208 Mpa. Specific embodiments
[0028] The following is a further detailed description through specific embodiments: A glaze for improving the bonding strength between glaze and body, comprising raw materials with the mass percentages shown in Table 1 below, Table 1: Raw material formula table of the glaze for improving the bonding strength between glaze and body
[0029] Among them, CMC is sodium carboxymethyl cellulose.
[0030] The specific physical and chemical properties of the above components are as follows: Bentonite: Appearance quality, before firing: gray / greyish-black block, soft, delicate, with a slippery feeling. After firing: gray / grayish-white block, no black spots on the surface and cross-section, not sintered. The analysis of its chemical composition is as follows:
[0031] In addition, bentonite is a clay with a high hydration rate, and its average hydration rate is 90%; it is a highly plastic clay, and its bonding force is about 5.0 MPa on average.
[0032] Calcium metasilicate powder: Appearance quality, before firing: gray powder. After firing: gray powder, not sintered. The analysis of its chemical composition is as follows:
[0033] In addition, calcium metasilicate powder is a processed powder material, and the particles with a size ≥ 0.063 mm are zero; the mechanical iron in calcium metasilicate powder is very low, about 0.002%.
[0034] Calcined talc powder: Appearance quality, before firing: white powder material. After firing: white powder material, not sintered. The analysis of its chemical composition is as follows:
[0035] In addition, calcined talc powder is a processed powder material, with 8% of particles ≥ 0.063 mm; the mechanical iron content is very low, around 0.006%.
[0036] Fan Chengzhang stone: Appearance quality, before firing: It is a yellow or light yellow powder material. After firing: It is a grayish-white molten block, round and smooth, with a relatively smooth cross-section, and a small amount of black dots are evenly distributed. The chemical composition analysis is as follows:
[0037] In addition, Fan Chengzhang stone is a processed material, with about 95% of particles ≤ 0.063 mm; it is the raw material after processing of Fan Chengzhang stone, so the mechanical iron content is around 0.01%.
[0038] Fan Anyang feldspar: Appearance quality, before firing: It is a grayish-white / white powder material. After firing: It is a grayish-white molten block, with a higher degree of melting than washed potassium feldspar, and a small amount of black dots are evenly distributed. The chemical composition analysis is as follows:
[0039] In addition, Anyang feldspar powder is a processed material, with about 12% of particles ≤ 0.063 mm; it is the raw material after processing of Anyang feldspar powder, so the mechanical iron content is around 0.015%.
[0040] Pingxiang natural quartz powder: Appearance quality, before firing: It is a grayish-white or grayish-yellow powder. After firing: It is a white or yellowish-white powder, containing a small amount of black impurities. The chemical composition analysis is as follows:
[0041] In addition, Pingxiang natural quartz powder is a natural ultra-fine powder material, with only about 5% of particles ≥ 0.063 mm; Pingxiang natural quartz powder is a raw material with a fineness that does not require processing, so the mechanical iron content is very low, around 0.001%.
[0042] Shaanxi kaolin powder: Appearance quality, before firing: It is a grayish-black powder. After firing: It is a white powder, not sintered. The chemical composition analysis is as follows:
[0043] In addition, Shaanxi kaolin powder is a processed powder material, with about 12% of particles ≥ 0.063 mm; Shaanxi kaolin powder is a clay with medium to low plasticity, and its bonding force is about 0.5 MPa on average, which plays a very important role in improving the suspension performance of the new formula slurry; the mechanical iron content of Shaanxi kaolin powder is very low, around 0.008%.
[0044] Ultra-fine zircon sand powder: Appearance quality, before firing: It is a white powder. After firing: It is a white powder, not sintered. The chemical composition analysis is as follows:
[0045] In addition, zirconium silicate powder is an ultra-fine powder, with zero particles ≥ 0.045 mm; since zirconium silicate powder is a chemical raw material, its mechanical iron content is extremely low, less than 0.0001%.
[0046] Aluminum oxide fine powder: Appearance quality, before firing: white powder. After firing: white powder. Its chemical composition analysis is as follows:
[0047] In addition, aluminum oxide fine powder is an ultra-fine powder, with particles ≥ 0.045 mm less than 5%; the mechanical iron content of aluminum oxide fine powder is less than 0.001%; the conversion rate of aluminum oxide fine powder: ≥ 95%; the true density of aluminum oxide fine powder: ≥ 3.96 g / cm 3 .
[0048] Industrial-grade barium carbonate: Appearance quality, before firing: white powder. After firing: white molten state, with a light green circle at the edge.
[0049] This formula can make the fired glaze surface smooth and white after being combined with the green body, and there are no problems such as peeling and cracking on the produced electro-ceramic glaze surface, ensuring the qualified glaze surface quality. In addition, the bending strength of the test bar of the C120 porcelain material formula (C120 porcelain material formula in GB / T 8411.1 of the national standard) of the glaze in this embodiment after firing can exceed 134 Mpa, and the bending strength of the test bar of the C130 porcelain material formula (C130 porcelain material formula in GB / T 8411.1 of the national standard) can exceed 208 Mpa.
[0050] The following Table 2 takes specific formulas to form different test examples as an example: Table 2 Specific situation table of different formulas
[0051] All the above formulas adopt a glaze preparation method for improving the glaze-green body bonding strength, including the following steps: S1. Ball milling: Take the raw materials of each above formula and add water for ball milling, test the ball milling fineness, and obtain the primary slurry; S2. Screen and remove iron from the primary slurry to obtain the secondary slurry, and age the secondary slurry to obtain a glaze slurry for improving the glaze bonding strength.
[0052] When the glaze prepared by the above process is used, first, adjust the specific gravity of the glaze slurry for standby, then wash the green body for standby. After that, apply the prepared glaze slurry onto the green body to be sintered, then measure the thickness of the glaze layer. After inspecting the quality of the glazed green body, complete the glazing process. Finally, fire the glazed green body in the kiln. Before glazing the green body, for the green body with pits after forming, wash the surface of the green body. When washing the green body, place the green body on a rotating fixture, rotate the green body, and use a sponge dipped in clean water to clean the dust and stains on the green body. It is required that the surface of the washed green body is clean and smooth without any foreign objects; the washed green bodies should be neatly placed on the table waiting for glazing, and stacking is not allowed. The water for washing the green body should be changed frequently to ensure the quality of washing the green body. It is not allowed to soak the green body in water. It is required that each part is wiped evenly to prevent water accumulation due to pits on the surface of the green body. During the process of washing the green body, if cracks are found on the green body, it shall be scrapped and returned to the pulp tank for disposal.
[0053] The pre-firing test conditions of the above different formulations are shown in Table 3 below, and the post-firing test results are shown in Table 4 below.
[0054] Table 3 Pre-firing test conditions table
[0055] Table 4 Post-firing test conditions table
[0056] From the above test results, it can be seen that Tests 4 to 7 can ensure that the glaze surface is normal before firing without continuous peeling and cracking, etc. At the same time, the pre-firing damage rate is also controlled within 1%. And after firing, the glaze surface is smooth without problems such as glaze shrinkage and pinholes. The surface of the glaze is also white and more beautiful, and the post-firing bending strength is also high; in addition, in Tests 4 to 7, the bending strength has also been greatly improved compared with Tests 1-3.
[0057] In Test Example 1, the content of bentonite is high, and the fluidity of its glaze slurry is only 0.21, with poor fluidity. However, the relative viscosity of the glaze is large, resulting in too thick glazing thickness and very poor bonding quality between the glaze and the green body, and it is extremely easy to have cracks on the glaze surface. In the formula of this Test Example 1, although the use of CMC is lacking and there is an overly thick glaze layer, the pre-firing damage rate can be controlled within 3% from the formulation configuration.
[0058] In Test Example 2, after optimizing the ingredients again, the fluidity of the glaze slurry before firing is improved, but the glaze layer is too thin, and the high-temperature fluidity of the glaze during firing is poor, resulting in a rough and gray glaze surface after firing.
[0059] In Test 3, by readjusting the formula again, it can ensure that all performances are good before firing, and the pre-firing damage rate is also reduced to 2%. The glaze surface after firing is smooth, but the whiteness is insufficient and the appearance color is somewhat lacking, but the bending strength has been greatly improved compared with that.
[0060] For Tests 4 to 7, through the optimization of the formula, the glaze blank before firing has extremely strong bonding force. The surface quality of the glaze blank before firing is very good, without phenomena such as peeling and cracking. Under this extremely strong bonding force, even if inevitable rubbing and bumping occur, the damage rate before firing can be reduced to within 1%.
[0061] For Tests 4 to 7, by controlling the components of each raw material and cleaning the surface of the blank with a sponge dipped in clean water, the dust on the surface of the blank is effectively removed, and at the same time, the surface of the blank with pits is made smooth, ensuring that the glaze surface after glazing is smooth. Under the condition that the temperature in the constant-temperature kiln is uniform, the high-temperature fluidity of the glaze is controlled at 47 - 49 mm, ensuring that there will be no problems of excessive or too small fluidity of the glaze at high temperature. Thus, even if there are tiny pits, wood skins, and wood chips in the glazed blank, the appropriate high-temperature fluidity can be used to make the glaze basically cover the holes left after burning the wood chips and wood skins and the pits on the blank after production, thereby reducing the probability of unqualified products caused by pinholes or lack of glaze on the glaze surface after firing. In addition, compared with the technology not shown in this embodiment, in the glaze for ultra-high voltage porcelain insulators made of common raw materials such as feldspar, highly plastic clay, wollastonite, zirconium silicate, and alumina that have been publicly available, during firing, the high-temperature fluidity at the lower fire position is 48 - 50 mm, and the high-temperature fluidity at the upper fire position is 52 - 56 mm. It is difficult to solve the problems caused by wood skins and wood chips before firing with this kind of high-temperature fluidity control after firing, while Tests 4 to 7 in this experimental example can greatly reduce the glaze surface quality problems caused thereby.
[0062] The above are only the experimental examples of the present invention, and specific technical solutions and / or common knowledge such as characteristics well known in the art are not described in detail herein. It should be noted that for those skilled in the art, without departing from the technical solution of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the implementation effect of the present invention and the practicability of the patent. The protection scope required by this application should be based on the content of its claims, and the specific implementation manners described in the specification can be used to interpret the content of the claims.
Claims
1. A glaze for improving the bonding strength of a glaze blank, characterized in that: The invention comprises the following raw materials in parts by weight: 6-10 parts of bentonite, 6-10 parts of calcium metasilicate powder, 6-14 parts of calcined talc, 18-22 parts of feldspar, 8-12 parts of Anyang feldspar, 18-22 parts of Pingxiang natural quartz powder, 12-16 parts of Shaanxi kaolin, 6-10 parts of ultrafine zircon sand powder, 1-3 parts of alumina powder, 1-3 parts of industrial-grade barium carbonate and 0.04-0.08 parts of sodium carboxymethyl cellulose.
2. The glaze for improving the bonding strength of the glaze blank according to claim 1, characterized in that: The bentonite is 6-8 parts.
3. The glaze for improving the bonding strength of the glaze blank according to claim 1, characterized in that: The calcium metasilicate powder is 7-8 parts.
4. The glaze for improving the bonding strength of the glaze blank according to claim 1, characterized in that: The calcined talc powder is 9-10 parts.
5. The glaze for improving the bonding strength of the glaze blank according to claim 1, characterized in that: The ultrafine zircon sand powder is 7-8 parts.
6. The glaze for improving the bonding strength of the glaze blank according to claim 1, characterized in that: The sodium carboxymethyl cellulose is 0.04-0.06 parts.
7. A method for preparing a glaze for improving the bonding strength of a glaze blank, characterized in that: The steps include: S1. Ball milling: taking each raw material of any one of claims 1 to 6 and adding water to ball mill to obtain a primary slurry; S2. Screening the primary slurry to obtain secondary slurry, aging the secondary slurry to obtain a glaze slurry with improved glaze bonding strength.
8. An application of a glaze for improving the bonding strength of a glaze blank, characterized in that: The glaze for improving the bonding strength of the glaze blank according to any one of claims 1 to 6 is used in the application of electric porcelain insulators.
9. The use of a glaze for improving the bonding strength of a glaze blank according to claim 8, characterized in that: It also includes the following application steps: The first step is to grind the glaze material that improves the bonding strength of the glaze blank into glaze slurry; The second step is to apply the glaze slurry to the green body to be sintered; The third step is to put the glazed body into the kiln for firing.
10. The use of a glaze for improving the bonding strength of a glaze blank according to claim 9, characterized in that: Before the second step, the surface of the blanks with pits after forming is washed. When washing, the blanks are placed on a rotating tooling, rotated, and the dust and stains on the blanks are cleaned with a sponge and clean water. The surface of the blanks after washing is required to be clean and smooth without any foreign matter. The washed blanks should be neatly placed on the table waiting for glazing, and stacking is not allowed.