A coating material suitable for quartz products and its preparation method

Abstract

This invention provides a coating material suitable for quartz products and its preparation method. The aqueous coating material includes a room-temperature film-forming medium, a high-temperature film-forming medium, ceramic functional additives, and deionized water. The room-temperature film-forming medium includes a thickener / binder, a dispersant, a defoamer, and a leveling agent. The high-temperature film-forming medium includes low-melting-point glass powder and a high-temperature binder. The ceramic functional additives include silicon nitride, silicon carbide, alumina, and zirconium oxide powders. The low-melting-point glass powder and ceramic functional additives can improve the adhesion, density, and mechanical properties of the coating, and adjust its coefficient of thermal expansion. The room-temperature film-forming medium can adjust the viscosity and fineness of the coating material. After being applied to the quartz product, the coating material is annealed and sintered to ensure the bonding strength and density between the coating material and the quartz product. This coating effectively protects the quartz product, preventing erosion and stress damage from other physical or chemical processes, and extending the service life of the quartz product.

Description

Technical Field

[0001] This invention relates to the field of coating preparation technology, and in particular to a coating material suitable for quartz products and its preparation method. Background Technology

[0002] In the processing of photovoltaic and semiconductor products, LPCVD (Low Pressure Chemical Vapor Deposition) technology is commonly used. It is mainly used for processes such as material deposition, such as depositing thin films of oxides, nitrides, and polycrystalline silicon on photovoltaic or semiconductor products.

[0003] Current LPCVD processes typically use quartz tubes as reactor tubes. During silicon deposition, due to the non-directional nature of LPCVD deposition, a large amount of silicon will be deposited on the inner surface of the reactor tube. This deposited silicon will erode the quartz tube, and the coefficient of thermal expansion of the silicon deposited layer differs greatly from that of quartz glass. Due to the effect of thermal stress, the reactor tube may also crack, reducing the service life of the tube. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by proposing a coating material suitable for quartz products and its preparation method. This coating material has good adhesion and a low coefficient of expansion. When applied to the surface of quartz products, it can effectively prevent the deposition of silicon from eroding the quartz products and alleviate the stress on the quartz and silicon deposition layers.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] According to a first aspect of the present invention, a coating material suitable for quartz products is provided. The coating material for quartz products comprises the following components in weight fractions: a room-temperature film-forming medium: 5.0%–25.0%, a high-temperature film-forming medium: 3.0%–25.0%, a ceramic functional additive: 3.0%–30.0%, and the balance being deionized water; wherein the room-temperature film-forming medium comprises a thickening binder, a dispersant, a defoamer, and a leveling agent; the high-temperature film-forming medium comprises low-melting-point glass powder and a high-temperature binder; and the ceramic functional additive comprises silicon nitride powder, silicon carbide powder, alumina powder, and zirconium oxide powder.

[0007] Preferably, the coating material suitable for quartz products comprises the following components in weight fractions:

[0008] The proportions of the components in the room-temperature film-forming medium are as follows: thickener / binder: 7.0%–20.0%; dispersant: 0.1%–2.0%; defoamer: 0.1%–2.0%; leveling agent: 0.1%–2.0%.

[0009] The proportions of the components in the high-temperature film-forming medium are as follows: low-melting-point glass powder: 2.0%–13.0%; high-temperature binder: 2.0%–12.0%.

[0010] The proportions of each component in the ceramic functional additive are as follows: silicon nitride powder: 0.5%–7.0%; silicon carbide powder: 1.0%–8.0%; alumina powder: 1.0%–8.0%; zirconium oxide powder: 0.5%–7.0%.

[0011] The remainder is deionized water.

[0012] Preferably, the low-melting-point glass powder is a silicon-containing glass powder, comprising the following components: silicon oxide, oxide A, oxide B, oxide C, oxide D, and oxide E; wherein the weight fraction of each component is: silicon oxide: 5.0%–50.0%, oxide A: 1.0%–10.0%, oxide B: 1.0%–20.0%, oxide C: 1.0%–15.0%, oxide D: 5.0%–50.0%, and oxide E: 1.0%–20.0%.

[0013] Preferably, oxide A is at least one of alkali metal oxides, including lithium oxide, sodium oxide, and potassium oxide; oxide B is at least one of alkaline earth metal oxides, including magnesium oxide, calcium oxide, strontium oxide, and barium oxide; oxide C is at least one of transition metal oxides, including titanium oxide, zirconium oxide, zinc oxide, and lanthanum oxide; oxide D is at least one of post-transition metal oxides and / or quasi-metal oxides, including lead oxide, bismuth oxide, tellurium oxide, thallium oxide, tin oxide, antimony oxide, gallium oxide, and indium oxide; and oxide E is one or two oxides of aluminum oxide and boron oxide.

[0014] Preferably, the preparation method of the low melting point glass powder includes: preparing raw materials according to the required proportion, stirring and mixing the raw materials evenly, melting them in a fusing furnace at a high temperature of 1000℃~1600℃, and then subjecting the molten glass liquid to water quenching, drying, coarse grinding, fine grinding, and precision grading to obtain the low melting point glass powder.

[0015] Preferably, the high-temperature binder is any one or a combination of two of silica sols or silicates.

[0016] Preferably, the thickening binder is one or a combination of at least two of methylcellulose, hydroxyethylcellulose, hydroxymethylcellulose, sodium hydroxymethylcellulose, sodium carboxymethylcellulose, or polyacrylic acid thickening binders; the dispersant is any one or a combination of ammonium acrylate or styrene-maleic anhydride modified polymers; the defoamer is any one or a combination of mineral oil defoamers or polyethylene glycol; and the leveling agent is any one or a combination of polyether-modified silicone or acrylic leveling agents.

[0017] According to a second aspect of the present invention, a method for preparing a coating material suitable for quartz products is provided, the method comprising:

[0018] Step S1: Weigh out the room temperature film-forming medium, high temperature film-forming medium, ceramic functional additive and deionized water according to the proportions;

[0019] Step S2: Mix deionized water and room temperature film-forming medium evenly to obtain the first mixture;

[0020] Step S3: Add the high-temperature film-forming medium and ceramic functional additives to the first mixture and disperse it using a disperser for 20 to 40 minutes to obtain the second mixture;

[0021] Step S4: Add deionized water to the second mixture for dilution, then use a bead mill to finely grind the diluted mixture and adjust the viscosity to obtain a coating with the required viscosity and fineness;

[0022] Step S5: Apply the coating of the required viscosity and fineness to the surface of the quartz product, dry it, and then anneal the coated quartz product in an annealing furnace before cooling it to room temperature.

[0023] Preferably, in step S5, the annealing temperature is 800–1100°C and the annealing time is 0.5–3 hours.

[0024] Preferably, in step S5, the quartz product is annealed using a two-stage heating and holding method: the first stage involves heating to 300-600°C and holding for 20-50 minutes, and the second stage involves heating to 800-1100°C and holding for 0.5-3 hours.

[0025] Preferably, in step S5, the quartz product is annealed using a three-stage heating and holding method: the first stage is heated to 180-220°C and held for 20-40 minutes, the second stage is heated to 300-600°C and held for 20-50 minutes, and the third stage is heated to 800-1100°C and held for 0.5-3 hours.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows: In the coating material of the present invention, by adjusting the composition ratio of low-melting-point glass powder, the melting point of low-melting-point glass powder can be adjusted, so that the coating material and quartz products can be well fused and bonded; moreover, by adjusting the composition ratio of low-melting-point glass powder, the expansion coefficient of the coating material can also be adjusted, thereby meeting the application requirements of different quartz products; the combination of low-melting-point glass powder and ceramic functional additives can increase the adhesion between the coating material and the surface of the quartz product, improve the density and mechanical properties of the coating material, and reduce its expansion coefficient; the room temperature film-forming medium can adjust the viscosity, fineness and other properties of the coating material; after the coating material is applied to the quartz product and then annealed and sintered, the bonding force and density between the coating material and the quartz product can be guaranteed, thereby effectively protecting the quartz product and preventing erosion and stress damage to the quartz by other physical or chemical processes, thereby greatly improving the service life of the quartz product. Attached Figure Description

[0027] Figure 1 This is a flowchart illustrating a method for preparing coating materials according to some embodiments of the present invention. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the described embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. It is understood that, without conflict, some technical means of the various embodiments described herein can be substituted for or combined with each other.

[0029] In the description of this invention, the terms "first," "second," etc., are used only to distinguish the described objects and have no sequential or technical meaning. Therefore, objects specified with "first," "second," etc., may explicitly or implicitly include one or more of those objects. Furthermore, the words "one" or "a" do not indicate a quantity limitation, but rather indicate the presence of at least one, while "multiple" indicates at least two.

[0030] In the description of this invention, references to "one embodiment" or "some embodiments," etc., mean that one or more embodiments of the invention include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "one embodiment," "some embodiments," "other embodiments," "and other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized.

[0031] According to a first aspect of the present invention, a coating material suitable for quartz products is provided, which has good adhesion, mechanical strength and low coefficient of expansion, and when applied to the surface of quartz products, can effectively prevent the deposition of silicon from eroding the quartz products and alleviate the stress on the quartz and silicon deposition layers.

[0032] In some embodiments, the coating material suitable for quartz products comprises the following components by weight fraction (percentage of the total weight of the coating material): room temperature film-forming medium: 5.0%–25.0%, high temperature film-forming medium: 3.0%–25.0%, ceramic functional additives: 3.0%–30.0%, and the balance being deionized water. The room temperature film-forming medium includes thickeners, binders, dispersants, defoamers, and leveling agents; the high temperature film-forming medium includes low melting point glass powder and high temperature binders; and the ceramic functional additives include silicon nitride (Si3N4) powder, silicon carbide (SiC) powder, alumina (Al2O3) powder, and zirconium oxide (ZrO2) powder.

[0033] In this coating material, the combination of low-melting-point glass powder and ceramic functional additives increases the adhesion between the coating and the quartz material, improves the density and mechanical properties of the coating, and reduces its coefficient of thermal expansion. A high-temperature binder ensures the coating material maintains good adhesion even at high temperatures, providing antioxidant and thermal insulation effects. A room-temperature film-forming medium can adjust the viscosity and fineness of the coating material. After being applied to the quartz product, the coating material undergoes annealing and sintering, ensuring the adhesion and density between the coating material and the quartz product. It remains stable and does not peel off even at high temperatures, effectively protecting the quartz product from erosion and stress damage caused by other physical or chemical processes, thus significantly extending the service life of the quartz product.

[0034] In some preferred embodiments, the coating material suitable for quartz products comprises the following components by weight fraction (percentage of the total weight of the coating material):

[0035] The proportions of each component in the room temperature film-forming medium are as follows: thickener / binder: 7.0%–20.0%; dispersant: 0.1%–2.0%; defoamer: 0.1%–2.0%; leveling agent: 0.1%–2.0%.

[0036] The proportions of each component in the high-temperature film-forming medium are as follows: low-melting-point glass powder: 2.0%–13.0%; high-temperature binder: 2.0%–12.0%.

[0037] The proportions of each component in the ceramic functional additive are as follows: silicon nitride powder: 0.5%–7.0%; silicon carbide powder: 1.0%–8.0%; alumina powder: 1.0%–8.0%; zirconium oxide powder: 0.5%–7.0%.

[0038] The remainder is deionized water.

[0039] Thickening binders increase the consistency of the coating material while maintaining stable flowability. Dispersants accelerate particle breakage, reduce the free energy at the solid-liquid interface, and ensure uniform and stable dispersion of the coating material. Defoamers suppress and eliminate foam, ensuring the stability of the coating material. Leveling agents improve the leveling and wettability of the coating material, reduce surface defects, and enhance film quality. Low-melting-point glass powder improves the adhesion, toughness, wear resistance, heat resistance, and corrosion resistance of the coating material. High-temperature binders enable the coating material to maintain good adhesion even at high temperatures, providing antioxidant and thermal insulation effects. Silicon nitride powder, silicon carbide powder, alumina powder, and zirconium oxide powder, as ceramic functional additives, increase the hardness, improve adhesion, and enhance corrosion resistance of the coating material.

[0040] Furthermore, the preferred weight fraction (percentage of the total weight of the coating material) of low-melting-point glass powder is set to 2.0% to 13.0% (percentage of the total weight of the coating material). Too little will not achieve the effect of fusion and bonding, while too much will result in an excessively thick glass layer between the coating material and the quartz material, which will reduce the melting point of the quartz material at high temperatures and have an adverse effect on the coating effect.

[0041] The coating material of this invention uses low-melting-point glass powder. During high-temperature annealing, the slightly molten state of the low-melting-point glass powder allows for the fusion and bonding of the quartz and coating material. Its advantage lies in overcoming the shortcoming of only having adhesion but no fusion bonding between the coating material and quartz glass, significantly improving the adhesion of the coating material. Simultaneously, the elements in the low-melting-point glass powder can also enhance the corrosion resistance of the coating. Furthermore, the high-temperature binder also plays an auxiliary bonding role; its melting point is slightly higher than that of the low-melting-point glass powder, which can, to some extent, regulate the problem of excessive melting and flow of the low-melting-point glass powder, maintaining the stability of the coating material at high temperatures. At the same time, the low-melting-point glass powder can also adjust the coefficient of thermal expansion of the coating material; when combined with ceramic functional additives, the coefficient of thermal expansion and the hardness of the coating can be adjusted. The room-temperature film-forming medium mainly controls the viscosity, fineness, and solid content of the coating material. In this invention, the preferred weight ratio of the room-temperature film-forming medium is set to 5.0%–25.0%. Excessive solid content or viscosity increases the difficulty of spraying and results in poor uniformity; excessively low solid content or viscosity leads to easy sagging during spraying.

[0042] In some preferred embodiments, the low-melting-point glass powder is a silicon-containing glass powder, characterized by acid and alkali resistance, chemical inertness, and a low coefficient of thermal expansion. This low-melting-point glass powder comprises the following components: silicon dioxide (SiO2), oxide A, oxide B, oxide C, oxide D, and oxide E. The weight fraction (percentage of each component by weight of the total weight of the low-melting-point glass powder) is as follows: silicon dioxide: 5.0%–50.0%, oxide A: 1.0%–10.0%, oxide B: 1.0%–20.0%, oxide C: 1.0%–15.0%, oxide D: 5.0%–50.0%, and oxide E: 1.0%–20.0%.

[0043] Furthermore, oxide A is an alkali metal oxide, oxide B is an alkaline earth metal oxide, oxide C is a transition metal oxide, oxide D is a post-transition metal oxide and / or a quasi-metal oxide; oxide E is one or both of aluminum oxide (Al2O3) and boron oxide (B2O3).

[0044] Furthermore, oxide A is at least one of alkali metal oxides, namely lithium oxide (Li2O), sodium oxide (Na2O), and potassium oxide (K2O); oxide B is at least one of alkaline earth metal oxides, namely magnesium oxide (MgO), calcium oxide (CaO), strontium oxide (SrO), and barium oxide (BaO); oxide C is at least one of transition metal oxides, namely titanium oxide (TiO2), zirconium oxide (ZrO2), zinc oxide (ZnO), and lanthanum oxide (LaO); and oxide D is at least one of post-transition metal oxides and / or quasi-metal oxides, namely lead oxide (PbO), bismuth oxide (Bi2O3), tellurium oxide (TeO2), thallium oxide (Tl2O3), tin oxide (SnO2), antimony oxide (Sb2O3), gallium oxide (Ga2O3), and indium oxide (In2O3).

[0045] In the aforementioned low-melting-point glass powder, silicon dioxide, post-transition metal oxides, and quasi-metal oxides constitute the glass's network structure. Alkali metal oxides can adjust the glass viscosity at high temperatures, facilitating better integration and adhesion with quartz products at suitable temperatures when combined with ceramic functional additives. Transition metal oxides can improve the glass's mechanical strength and provide excellent thermal stability. Simultaneously, silicon dioxide, some alkali metals, and transition metal oxides can improve the coefficient of thermal expansion of both the glass and the coating. Therefore, low-melting-point glass powder is crucial for the overall performance of coating materials. Coating materials prepared using the low-melting-point glass powder of this invention, combined with a room-temperature film-forming medium and ceramic functional additives, exhibit excellent adhesion and mechanical strength. Furthermore, they are compatible with the long-term stable use of quartz materials at high temperatures, effectively protecting the quartz material and preventing its corrosion and damage.

[0046] Increasing the proportion of silicon dioxide in low-melting-point glass powder within a reasonable range can increase the melting point of the low-melting-point glass powder; conversely, decreasing the proportion of silicon dioxide within a reasonable range can decrease the melting point of the low-melting-point glass powder.

[0047] In some preferred embodiments, the low-melting-point glass powder comprises the following components by weight fraction (percentage of the weight of the low-melting-point glass powder): silicon dioxide: 10.0%–40.0%, oxide A: 1.0%–10.0%, oxide B: 5.0%–20.0%, oxide C: 1.0%–10.0%, oxide D: 10.0%–50.0%, and oxide E: 1.0%–15.0%.

[0048] In some other preferred embodiments, the low-melting-point glass powder comprises the following components by weight fraction (percentage of the low-melting-point glass powder by weight): silicon oxide: 10.0%–40.0%; oxide A (alkali metal oxide): 1.0%–10.0%; oxide B (alkaline earth metal oxide): 5.0%–20.0%; zinc oxide: 1.0%–10.0%; tellurium oxide: 5.0%–25.0%; bismuth oxide: 5.0%–25.0%; and aluminum oxide: 1.0%–15.0%.

[0049] In some embodiments, the preparation method of the above-mentioned low melting point glass powder includes: preparing raw materials according to the required proportion, stirring and mixing the raw materials evenly, melting them in a fusing furnace at a high temperature of 1000℃~1600℃, and then subjecting the molten glass liquid to water quenching, drying, coarse grinding, fine grinding, and precision grading to obtain low melting point glass powder.

[0050] In some preferred embodiments, the high-temperature adhesive can be any one or a combination of two of silica sols or silicates. The high-temperature adhesive enables the coating material to maintain good adhesion at high temperatures, providing antioxidant and thermal insulation properties.

[0051] In some preferred embodiments, the thickening binder may be one or a combination of at least two of methylcellulose, hydroxyethylcellulose, hydroxymethylcellulose, sodium hydroxymethylcellulose, sodium carboxymethylcellulose, or polyacrylic acid thickening binders. The dispersant may be any one or a combination of two of ammonium acrylate or styrene-maleic anhydride modified polymers. The defoamer may be any one or a combination of two of mineral oil defoamers or polyethylene glycol. The leveling agent may be any one or a combination of two of polyether-modified silicone or acrylic leveling agents.

[0052] Thickening agents increase the consistency of coating materials while maintaining stable flowability. Dispersants accelerate particle breakage, reduce the free energy at the solid-liquid interface, and ensure uniform and stable dispersion of the coating material. Defoamers suppress and eliminate foam, ensuring the stability of the coating material. Leveling agents improve the leveling and wetting properties of the coating material, reduce surface defects, and enhance coating quality.

[0053] According to a second aspect of the present invention, a method for preparing a coating material suitable for quartz products is provided. (See also...) Figure 1 As shown, in some embodiments, the method for preparing the coating material suitable for quartz products includes:

[0054] Step S1: Weigh out the room temperature film-forming medium, high temperature film-forming medium, ceramic functional additive and deionized water according to the proportion.

[0055] Step S2: Mix deionized water and room temperature film-forming medium evenly to obtain the first mixture.

[0056] Step S3: Add the high-temperature film-forming medium and ceramic functional additives to the first mixture and disperse it using a disperser for 20 to 40 minutes to obtain the second mixture.

[0057] Step S4: Add deionized water to the second mixture for dilution, then use a bead mill to finely grind the diluted mixture and adjust the viscosity to obtain a coating with the required viscosity and fineness.

[0058] Step S5: Apply the coating of the required viscosity and fineness to the surface of the quartz product, dry it, and then anneal the coated quartz product in an annealing furnace before cooling it to room temperature.

[0059] In some preferred embodiments, the viscosity of the diluted mixture in step S4 can be tested using the existing four-cup method, and the viscosity of the mixture can be 15s to 55s ("s" represents seconds, referring to the time required for a specific volume of paint to flow out). The fineness (particle size) of the paint after fine grinding is <15μm.

[0060] In some preferred embodiments, in step S5, the annealing temperature is 800–1100°C and the annealing time is 0.5–3 hours.

[0061] In some other preferred embodiments, in step S5, the quartz product is annealed using a two-stage heating and holding method: the first stage is heated to 300-600°C and held for 20-50 minutes, and the second stage is heated to 800-1100°C and held for 0.5-3 hours.

[0062] In some preferred embodiments, step S5 involves a three-stage heating and holding process to anneal the quartz product: the first stage involves heating to 180–220°C and holding for 20–40 minutes; the second stage involves heating to 300–600°C and holding for 20–50 minutes; and the third stage involves heating to 800–1100°C and holding for 0.5–3 hours. This three-stage heating and holding process allows for sufficient solvent evaporation and binder removal at the medium-low temperature stages, resulting in a good annealing effect, enhanced bonding strength and density between the coating material and the quartz product, and improved overall performance of the coating material.

[0063] In the above-mentioned coating materials, low-melting-point glass powder and ceramic functional additives can improve the mechanical properties of the coating and reduce its coefficient of expansion. Organic functional phases and surfactants can adjust the viscosity and fineness of the coating material. After the coating material is applied to the quartz product and then annealed and sintered, it can ensure the bonding force and density between the coating material and the quartz product, thereby effectively protecting the quartz product and preventing erosion and stress damage to the quartz by other physical or chemical processes, thus greatly improving the service life of the quartz product.

[0064] Seven specific embodiments and one comparative example of the present invention are given below. In each embodiment, a coating was prepared using a predetermined component ratio and preparation method. The coating was then applied to the inner wall of 10 quartz tubes of the same batch and model, followed by annealing to form a coating on the inner wall of the quartz tubes. The average service life of the 10 quartz tubes was then tested and statistically analyzed. In each embodiment, the coating thickness was consistent; the average service life of the quartz tubes can be used to characterize the protective ability of the coating material on the quartz tube. In the comparative example, none of the 10 quartz tubes were coated.

[0065] Table 1 shows the weight ratios of the components in the coating materials of Examples 1, 2A, 3, and 4:

[0066] Table 1

[0067]

[0068] Table 2 shows the weight ratios of the components in the coating materials of Examples 5, 6, and 2B:

[0069] Table 2

[0070]

[0071]

[0072] Table 3 shows the performance test results of the coating materials applied to the quartz tube products in the seven embodiments, as well as the performance test results of the uncoated quartz tube product in Comparative Example 1:

[0073] Table 3

[0074] variable Average lifespan of a quartz tube (days) Example 1 Low melting point glass powder 1 111 Example 2A Low melting point glass powder 2 276 Example 3 Low melting point glass powder 2-low content 134 Example 4 Low melting point glass powder 2-high content 137 Example 5 High-temperature adhesive - low content 201 Example 6 High-temperature adhesive - high content 206 Example 2B One-stage heating process 218 Comparative Example 1 Uncoated 101

[0075] Example 1:

[0076] The weight fractions of each component in the coating material are as follows: thickener / binder: 15.00%, dispersant: 0.50%, leveling agent: 0.50%, defoamer: 0.50%, low melting point glass powder: 5.00%, high temperature binder: 4.00%, silicon nitride: 2.00%, silicon carbide: 3.00%, alumina: 3.00%, zirconium oxide: 1.00%, deionized water: 65.50%.

[0077] The low-melting-point glass powder 1 contains the following components by weight: silicon dioxide: 38.0%; oxide A: 4.0%; oxide B: 12.0%; oxide C: 5.0%; oxide D: 31.0%; and oxide E: 10.0%. The proportion of silicon dioxide in the low-melting-point glass powder 1 is slightly higher, and the melting point of this low-melting-point glass powder 1 is 200–900℃.

[0078] Methods for preparing coating materials include:

[0079] Step S1: Weigh the room temperature film-forming medium, high temperature film-forming medium, ceramic functional additive and deionized water according to the proportions in Example 1 in Table 1.

[0080] Step S2: Mix deionized water and room temperature film-forming medium evenly to obtain the first mixture.

[0081] Step S3: Add the high-temperature film-forming medium and ceramic functional additives to the first mixture and disperse it using a disperser for 20 to 40 minutes to obtain the second mixture.

[0082] Step S4: Add deionized water to the second mixture for dilution, then use a bead mill to finely grind the diluted mixture and adjust the viscosity to obtain a coating with a fineness of 10μm and a viscosity of 40s.

[0083] Step S5: Apply the coating to the surface of the quartz product, dry it, and then anneal the coated quartz product in an annealing furnace, followed by cooling to room temperature. The annealing process involves three stages of heating and holding: the first stage involves heating to 200℃ and holding for 30 minutes; the second stage involves heating to 400℃ and holding for 30 minutes; and the third stage involves heating to 1000℃ and holding for 0.5–3 hours.

[0084] Testing revealed that the coefficient of thermal expansion of the coating prepared using the component ratio and preparation method of Example 1 was 1.56 × 10⁻⁶. - 6 K-1 The average lifespan of a quartz tube is 111 days.

[0085] Example 2A:

[0086] The weight fractions of each component in the coating material are as follows: thickening binder: 15.00%, dispersant: 0.50%, leveling agent: 0.50%, defoamer: 0.50%, low melting point glass powder 2: 5.00%, high temperature binder: 4.00%, silicon nitride: 2.00%, silicon carbide: 3.00%, alumina: 3.00%, zirconium oxide: 1.00%, deionized water: 65.50%.

[0087] The weight ratio of the components in low-melting-point glass powder 2 is as follows: silicon dioxide: 28.0%; oxide A: 5.0%; oxide B: 15.0%; oxide C: 6.0%; oxide D: 35.0%; oxide E: 11.0%. Compared with low-melting-point glass powder 1, the proportion of silicon dioxide in low-melting-point glass powder 2 is slightly lower. The melting point of low-melting-point glass powder 2 is 200-800℃, which is slightly lower than the melting point of low-melting-point glass powder 1.

[0088] Methods for preparing coating materials include:

[0089] Step S1: Weigh the room temperature film-forming medium, high temperature film-forming medium, ceramic functional additive and deionized water according to the proportions in Example 2A in Table 1.

[0090] Step S2: Mix deionized water and room temperature film-forming medium evenly to obtain the first mixture.

[0091] Step S3: Add the high-temperature film-forming medium and ceramic functional additives to the first mixture and disperse it using a disperser for 20 to 40 minutes to obtain the second mixture.

[0092] Step S4: Add deionized water to the second mixture for dilution, then use a bead mill to finely grind the diluted mixture and adjust the viscosity to obtain a coating with a fineness of 10μm and a viscosity of 40s.

[0093] Step S5: Apply the coating to the surface of the quartz product, dry it, and then anneal the coated quartz product in an annealing furnace, followed by cooling to room temperature. The annealing process involves three stages of heating and holding: the first stage involves heating to 200℃ and holding for 30 minutes; the second stage involves heating to 400℃ and holding for 30 minutes; and the third stage involves heating to 1000℃ and holding for 0.5–3 hours.

[0094] Testing revealed that the coefficient of thermal expansion of the coating prepared using the component ratio and preparation method of Example 2A was 1.65 × 10⁻⁶. -6 K -1The average lifespan of a quartz tube is 276 days.

[0095] Example 3:

[0096] The weight fractions of each component in the coating material are as follows: thickening binder: 15.00%, dispersant: 0.50%, leveling agent: 0.50%, defoamer: 0.50%, low melting point glass powder 2: 3.00%, high temperature binder: 4.00%, silicon nitride: 2.44%, silicon carbide: 3.67%, alumina: 3.67%, zirconium oxide: 1.22%, and deionized water: 65.50%.

[0097] The low-melting-point glass powder 2 contains the following components in the following weight ratios: silicon dioxide: 28.0%; oxide A: 5.0%; oxide B: 15.0%; oxide C: 6.0%; oxide D: 35.0%; oxide E: 11.0%. The melting point of this low-melting-point glass powder 2 is 200–800℃.

[0098] Methods for preparing coating materials include:

[0099] Step S1: Weigh the room temperature film-forming medium, high temperature film-forming medium, ceramic functional additive and deionized water according to the proportions in Example 3 in Table 1.

[0100] Step S2: Mix deionized water and room temperature film-forming medium evenly to obtain the first mixture.

[0101] Step S3: Add the high-temperature film-forming medium and ceramic functional additives to the first mixture and disperse it using a disperser for 20 to 40 minutes to obtain the second mixture.

[0102] Step S4: Add deionized water to the second mixture for dilution, then use a bead mill to finely grind the diluted mixture and adjust the viscosity to obtain a coating with a fineness of 10μm and a viscosity of 40s.

[0103] Step S5: Apply the coating to the surface of the quartz product, dry it, and then anneal the coated quartz product in an annealing furnace, followed by cooling to room temperature. The annealing process involves three stages of heating and holding: the first stage involves heating to 200℃ and holding for 30 minutes; the second stage involves heating to 400℃ and holding for 30 minutes; and the third stage involves heating to 1000℃ and holding for 0.5–3 hours.

[0104] Testing revealed that the coefficient of thermal expansion of the coating prepared using the component ratio and preparation method of Example 3 was 2.37 × 10⁻⁶. - 6 K -1 The average lifespan of a quartz tube is 134 days.

[0105] Example 4:

[0106] The weight fractions of each component in the coating material are as follows: thickening binder: 15.00%, dispersant: 0.50%, leveling agent: 0.50%, defoamer: 0.50%, low melting point glass powder 2: 7.00%, high temperature binder: 4.00%, silicon nitride: 1.56%, silicon carbide: 2.33%, alumina: 2.33%, zirconium oxide: 0.78%, and deionized water: 65.50%.

[0107] The low-melting-point glass powder 2 contains the following components in the following weight ratios: silicon dioxide: 28.0%; oxide A: 5.0%; oxide B: 15.0%; oxide C: 6.0%; oxide D: 35.0%; oxide E: 11.0%. The melting point of this low-melting-point glass powder 2 is 200–800℃.

[0108] Methods for preparing coating materials include:

[0109] Step S1: Weigh the room temperature film-forming medium, high temperature film-forming medium, ceramic functional additive and deionized water according to the proportions in Example 4 in Table 1.

[0110] Step S2: Mix deionized water and room temperature film-forming medium evenly to obtain the first mixture.

[0111] Step S3: Add the high-temperature film-forming medium and ceramic functional additives to the first mixture and disperse it using a disperser for 20 to 40 minutes to obtain the second mixture.

[0112] Step S4: Add deionized water to the second mixture for dilution, then use a bead mill to finely grind the diluted mixture and adjust the viscosity to obtain a coating with a fineness of 10μm and a viscosity of 39s.

[0113] Step S5: Apply the coating to the surface of the quartz product, dry it, and then anneal the coated quartz product in an annealing furnace, followed by cooling to room temperature. The annealing process involves three stages of heating and holding: the first stage involves heating to 200℃ and holding for 30 minutes; the second stage involves heating to 400℃ and holding for 30 minutes; and the third stage involves heating to 1000℃ and holding for 0.5–3 hours.

[0114] Testing revealed that the coefficient of thermal expansion of the coating prepared using the component ratio and preparation method of Example 4 was 2.81 × 10⁻⁶. - 6 K -1 The average lifespan of a quartz tube is 137 days.

[0115] Example 5:

[0116] The weight fractions of each component in the coating material are as follows: thickening binder: 15.00%, dispersant: 0.50%, leveling agent: 0.50%, defoamer: 0.50%, low melting point glass powder 2: 5.00%, high temperature binder: 2.50%, silicon nitride: 2.33%, silicon carbide: 3.50%, alumina: 3.50%, zirconium oxide: 1.17%, and deionized water: 65.50%.

[0117] The low-melting-point glass powder 2 contains the following components in the following weight ratios: silicon dioxide: 28.0%; oxide A: 5.0%; oxide B: 15.0%; oxide C: 6.0%; oxide D: 35.0%; oxide E: 11.0%. The melting point of this low-melting-point glass powder 2 is 200–800℃.

[0118] Methods for preparing coating materials include:

[0119] Step S1: Weigh the room temperature film-forming medium, high temperature film-forming medium, ceramic functional additive and deionized water according to the proportions in Example 5 in Table 2.

[0120] Step S2: Mix deionized water and room temperature film-forming medium evenly to obtain the first mixture.

[0121] Step S3: Add the high-temperature film-forming medium and ceramic functional additives to the first mixture and disperse it using a disperser for 20 to 40 minutes to obtain the second mixture.

[0122] Step S4: Add deionized water to the second mixture for dilution, then use a bead mill to finely grind the diluted mixture and adjust the viscosity to obtain a coating with a fineness of 10μm and a viscosity of 39s.

[0123] Step S5: Apply the coating to the surface of the quartz product, dry it, and then anneal the coated quartz product in an annealing furnace, followed by cooling to room temperature. The annealing process involves three stages of heating and holding: the first stage involves heating to 200℃ and holding for 30 minutes; the second stage involves heating to 400℃ and holding for 30 minutes; and the third stage involves heating to 1000℃ and holding for 0.5–3 hours.

[0124] Testing revealed that the coefficient of thermal expansion of the coating prepared using the component ratio and preparation method of Example 5 was 2.28 × 10⁻⁶. - 6 K -1 The average lifespan of a quartz tube is 201 days.

[0125] Example 6:

[0126] The weight fractions of each component in the coating material are as follows: thickener / binder: 15.00%, dispersant: 0.50%, leveling agent: 0.50%, defoamer: 0.50%, low melting point glass powder 2: 5.00%, high temperature binder: 5.50%, silicon nitride: 1.67%, silicon carbide: 2.50%, alumina: 2.50%, zirconium oxide: 0.83%, deionized water: 65.50%.

[0127] The low-melting-point glass powder 2 contains the following components in the following weight ratios: silicon dioxide: 28.0%; oxide A: 5.0%; oxide B: 15.0%; oxide C: 6.0%; oxide D: 35.0%; oxide E: 11.0%. The melting point of this low-melting-point glass powder 2 is 200–800℃.

[0128] Methods for preparing coating materials include:

[0129] Step S1: Weigh the room temperature film-forming medium, high temperature film-forming medium, ceramic functional additive and deionized water according to the proportions in Example 6 in Table 2.

[0130] Step S2: Mix deionized water and room temperature film-forming medium evenly to obtain the first mixture.

[0131] Step S3: Add the high-temperature film-forming medium and ceramic functional additives to the first mixture and disperse it using a disperser for 20 to 40 minutes to obtain the second mixture.

[0132] Step S4: Add deionized water to the second mixture for dilution, then use a bead mill to finely grind the diluted mixture and adjust the viscosity to obtain a coating with a fineness of 10μm and a viscosity of 40s.

[0133] Step S5: Apply the coating to the surface of the quartz product, dry it, and then anneal the coated quartz product in an annealing furnace, followed by cooling to room temperature. The annealing process involves three stages of heating and holding: the first stage involves heating to 200℃ and holding for 30 minutes; the second stage involves heating to 400℃ and holding for 30 minutes; and the third stage involves heating to 1000℃ and holding for 0.5–3 hours.

[0134] Testing revealed that the coefficient of thermal expansion of the coating prepared using the component ratio and preparation method of Example 6 was 2.13 × 10⁻⁶. - 6 K -1 The average lifespan of a quartz tube is 206 days.

[0135] Example 2B:

[0136] The weight fractions of each component in the coating material are the same as in Example 2A: thickening binder: 15.00%, dispersant: 0.50%, leveling agent: 0.50%, defoamer: 0.50%, low melting point glass powder 2: 5.00%, high temperature binder: 4.00%, silicon nitride: 2.00%, silicon carbide: 3.00%, alumina: 3.00%, zirconium oxide: 1.00%, deionized water: 65.50%.

[0137] The low-melting-point glass powder 2 contains the following components in the following weight ratios: silicon dioxide: 28.0%; oxide A: 5.0%; oxide B: 15.0%; oxide C: 6.0%; oxide D: 35.0%; oxide E: 11.0%. The melting point of this low-melting-point glass powder 2 is 200–800℃.

[0138] Methods for preparing coating materials include:

[0139] Step S1: Weigh the room temperature film-forming medium, high temperature film-forming medium, ceramic functional additive and deionized water according to the proportions in Example 2B in Table 2.

[0140] Step S2: Mix deionized water and room temperature film-forming medium evenly to obtain the first mixture.

[0141] Step S3: Add the high-temperature film-forming medium and ceramic functional additives to the first mixture and disperse it using a disperser for 20 to 40 minutes to obtain the second mixture.

[0142] Step S4: Add deionized water to the second mixture for dilution, then use a bead mill to finely grind the diluted mixture and adjust the viscosity to obtain a coating with a fineness of 10μm and a viscosity of 40s.

[0143] Step S5: Apply the coating to the surface of the quartz product, dry it, and then anneal the coated quartz product in an annealing furnace, followed by cooling to room temperature. The annealing temperature is 1000℃, and the annealing time is 0.5 to 3 hours.

[0144] Testing revealed that the coefficient of thermal expansion of the coating prepared using the component ratio and preparation method of Example 2B was 1.70 × 10⁻⁶. -6 K -1 The average lifespan of a quartz tube is 218 days.

[0145] Comparative Example 1: 10 quartz tubes were used directly without any coating material, and the average service life of the quartz tubes was measured to be 101 days.

[0146] Comparing Example 2A with Comparative Example 1, it can be seen that when the coating material and preparation method of the present invention are applied to quartz products, they can effectively protect quartz products and prevent erosion and stress damage to quartz products by other physical or chemical processes, thereby greatly improving the service life of quartz products.

[0147] Comparing Example 1 with Example 2A, it can be seen that when the weight of other components in the low-melting-point glass powder remains unchanged, increasing the proportion of silicon oxide within a reasonable range can increase the melting point of the low-melting-point glass powder. With the proportions of other components and the preparation method remaining unchanged in the coating material, the overall performance (average product lifespan) of the coating material prepared using low-melting-point glass powder 2 (which has a lower melting point) is higher than that of the coating material prepared using low-melting-point glass powder 1.

[0148] Examples 2A to 6 all used low-melting-point glass powder 2 with the same composition.

[0149] Compared to Example 2A, Example 3 reduced the proportion of low-melting-point glass powder 2, while Example 4 increased the proportion of low-melting-point glass powder 2. However, the overall performance of the coatings in Examples 3 and 4 was lower than that of the coating in Example 2A. Therefore, the proportion of low-melting-point glass powder in the coating material needs to be controlled within a suitable range to ensure that the coating has better overall performance.

[0150] Compared to Example 2A, Example 5 reduced the proportion of high-temperature adhesive, resulting in a shorter product lifespan; Example 6 increased the proportion of high-temperature adhesive, also resulting in a shorter product lifespan.

[0151] Example 2B uses the same component ratios and steps S1-S4 as Example 2A. The difference is that in step S5 of Example 2A, a three-stage heating and holding method is used for annealing; while in step S5 of Example 2B, a single-stage annealing method is used. Comparing the test results of the two examples, it can be seen that using a multi-stage heating and holding method to anneal quartz products can achieve a good annealing effect and improve the overall performance of the coating material.

[0152] Therefore, in practical applications, the proportions of different components can be adjusted within a reasonable range according to different application scenarios to meet requirements such as melting point and coating expansion coefficient.

[0153] In the coating material of this invention, the melting point of the low-melting-point glass powder can be adjusted by changing the component ratio, allowing the coating material to bond well with the quartz product. Furthermore, adjusting the component ratio of the low-melting-point glass powder can also adjust the adhesion and coefficient of thermal expansion of the coating material, thereby meeting the application requirements of different quartz products. The combination of low-melting-point glass powder and ceramic functional additives can increase the adhesion between the coating material and the surface of the quartz product, improve the density and mechanical properties of the coating material, and reduce its coefficient of thermal expansion. The room-temperature film-forming medium can adjust the viscosity, fineness, and other properties of the coating material. After the coating material is applied to the quartz product and then annealed and sintered, the bonding strength and density between the coating material and the quartz product can be guaranteed, thus effectively protecting the quartz product and preventing erosion and stress damage from other physical or chemical processes, thereby greatly extending the service life of the quartz product.

[0154] The present invention has been described in the above-described embodiments; however, these embodiments are merely examples for implementing the present invention. It must be noted that the disclosed embodiments do not limit the scope of the present invention. Conversely, any modifications and refinements made without departing from the spirit and scope of the present invention are within the scope of patent protection of the present invention.

Claims

1. A coating material suitable for quartz products, characterized in that: The coating material suitable for quartz products comprises the following components by weight fraction: room temperature film-forming medium: 5.0%–25.0%, high temperature film-forming medium: 9.0%, ceramic functional additives: 3.0%–30.0%, with the balance being deionized water; wherein, the room temperature film-forming medium includes thickening binder, dispersant, defoamer, and leveling agent; the high temperature film-forming medium includes low melting point glass powder: 5.0%, high temperature binder: 4.0%; the ceramic functional additives include silicon nitride powder, silicon carbide powder, alumina powder, and zirconium oxide powder; the low melting point glass powder... The melting point glass powder is used to adjust the coefficient of thermal expansion of the coating material. The low melting point glass powder comprises the following components by weight fraction: silicon dioxide: 28.0%, oxide A: 5.0%, oxide B: 15.0%, oxide C: 6.0%, oxide D: 35.0%, oxide E: 11.0%. Oxide A is an alkali metal oxide, oxide B is an alkaline earth metal oxide, oxide C is a transition metal oxide, oxide D is a post-transition metal oxide and / or quasi-metal oxide, and oxide E is one or two oxides of aluminum oxide and boron oxide.

2. The coating material for quartz products as described in claim 1, characterized in that: The coating material suitable for quartz products comprises the following components by weight fraction: The proportions of each component in the room-temperature film-forming medium are as follows: Thickening binder: 15.00%; Dispersant: 0.50%; Defoamer: 0.50%; Leveling agent: 0.50%; The proportions of each component in the high-temperature film-forming medium are as follows: Low melting point glass powder: 5.00%; High-temperature adhesive: 4.00%; The proportions of each component in the ceramic functional additive are as follows: Silicon nitride powder: 2.00%; Silicon carbide powder: 3.00%; Alumina powder: 3.00%; Zirconia powder: 1.00%; The remainder is deionized water.

3. The coating material for quartz products as described in claim 1, characterized in that: The oxide A is at least one of alkali metal oxides, namely lithium oxide, sodium oxide, and potassium oxide; the oxide B is at least one of alkaline earth metal oxides, namely magnesium oxide, calcium oxide, strontium oxide, and barium oxide; the oxide C is at least one of transition metal oxides, namely titanium oxide, zirconium oxide, zinc oxide, and lanthanum oxide; the oxide D is at least one of post-transition metal oxides and / or quasi-metal oxides, namely lead oxide, bismuth oxide, tellurium oxide, thallium oxide, tin oxide, antimony oxide, gallium oxide, and indium oxide; and the oxide E is one or two oxides of aluminum oxide and boron oxide.

4. The coating material for quartz products as described in claim 1, characterized in that: The preparation method of the low melting point glass powder includes: preparing raw materials according to the required proportion, stirring and mixing the raw materials evenly, melting them in a fusing furnace at a high temperature of 1000℃~1600℃, and then subjecting the molten glass liquid to water quenching, drying, coarse grinding, fine grinding, and precision grading to obtain the low melting point glass powder.

5. The coating material for quartz products as described in claim 1, characterized in that: The high-temperature binder is any one or a combination of two of silica sols or silicates.

6. The coating material for quartz products as described in claim 1, characterized in that: The thickening binder is one or a combination of at least two of methylcellulose, hydroxyethylcellulose, hydroxymethylcellulose, sodium hydroxymethylcellulose, sodium carboxymethylcellulose, or polyacrylic acid thickening binders; the dispersant is any one or a combination of ammonium acrylate or styrene-maleic anhydride modified polymers; the defoamer is any one or a combination of mineral oil defoamers or polyethylene glycol; and the leveling agent is any one or a combination of polyether-modified silicone or acrylic leveling agents.

7. A method for preparing a coating material suitable for quartz products as described in any one of claims 1-6, characterized in that: The method for preparing the coating material suitable for quartz products includes: Step S1: Weigh out the room temperature film-forming medium, high temperature film-forming medium, ceramic functional additive and deionized water according to the proportions; Step S2: Mix deionized water and room temperature film-forming medium evenly to obtain the first mixture; Step S3: Add the high-temperature film-forming medium and ceramic functional additives to the first mixture and disperse it using a disperser for 20 to 40 minutes to obtain the second mixture; Step S4: Add deionized water to the second mixture for dilution, then use a bead mill to finely grind the diluted mixture and adjust the viscosity to obtain a coating with the required viscosity and fineness; Step S5: Apply the coating of the required viscosity and fineness to the surface of the quartz product, dry it, and then anneal the coated quartz product in an annealing furnace before cooling it to room temperature.

8. The method for preparing a coating material suitable for quartz products as described in claim 7, characterized in that: In step S5, the quartz product is annealed using a three-stage heating and holding method: the first stage is to heat to 180-220℃ and hold for 20-40 minutes, the second stage is to heat to 300-600℃ and hold for 20-50 minutes, and the third stage is to heat to 800-1100℃ and hold for 0.5-3 hours.

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