A composite coating material for quartz products and a method for producing the same

Abstract

The application provides a composite coating material suitable for quartz products and a preparation method thereof, and the composite coating material comprises a bonding layer arranged on the surface of the quartz product, a transition layer arranged on the bonding layer and a protective layer arranged on the transition layer. The bonding layer, the transition layer and the protective layer respectively play the roles of adhesion, buffering isolation and strength protection, and each coating respectively comprises a thickening binder, a surfactant, a low-melting-point glass powder, a high-temperature binder, a ceramic functional additive and deionized water, and the composite performance of each coating is different by adjusting the component proportion of each coating. The sectional annealing mode is adopted during the preparation of each coating, so that a good annealing effect can be obtained, and the adhesion and mechanical performance of the coating are ensured. The thermal expansion coefficients of each coating are consistent, so that the close combination between each coating is ensured. The composite coatings cooperate with each other, so that the damage of deposited silicon to the quartz product can be effectively prevented, the service life of the quartz product is prolonged, and the process cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of coating preparation, in particular to a composite coating material suitable for quartz products and a preparation method thereof. Background Art

[0002] In the processing of photovoltaic and semiconductor products, LPCVD (Low Pressure Chemical Vapor Deposition) technology is often used. It is mainly used for material deposition processes, such as depositing oxide, nitride, polysilicon and other thin films on photovoltaic or semiconductor products.

[0003] Existing LPCVD processes typically use quartz tubes as reaction furnace tubes. During the silicon deposition process, since the deposition process of the LPCVD process is non-directional, a large amount of silicon will also be deposited on the inner surface of the furnace tube. This deposited silicon will corrode the quartz tube. In addition, the expansion coefficient of the deposited silicon layer is significantly different from that of the quartz glass. Due to the effect of thermal stress, it will also cause the furnace tube to explode, reducing the service life of the tube. Summary of the Invention

[0004] The present invention aims to address the shortcomings of the prior art by proposing a composite coating material suitable for quartz products and a preparation method thereof. An adhesive layer, a transition layer, and a protective layer are sequentially provided on the quartz product to respectively serve the functions of adhesion, buffering isolation, and strength protection. This effectively prevents damage to the quartz product by deposited silicon, thereby extending the service life of the quartz product and reducing process costs.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] According to a first aspect of the present invention, a composite coating material suitable for a quartz product is provided, the composite coating material comprising a bonding layer provided on a surface of the quartz product, a transition layer provided on the bonding layer, and a protective layer provided on the transition layer.

[0007] The coating of the bonding layer includes the following components by weight: thickening binder: 5.0% to 25.0%, surfactant: 0.5% to 5.0%, ceramic functional additive: 3.0% to 25.0%, low melting point glass powder: 2.0% to 10.0%, high temperature binder: 2.0% to 10.0%, and the balance is deionized water.

[0008] The coating of the transition layer includes the following components by weight: thickening binder: 6.0% to 30.0%, surfactant: 0.5% to 6.0%, ceramic functional additive: 3.0% to 25.0%, low melting point glass powder: 2.0% to 10.0%, high temperature binder: 2.0% to 10.0%, and the balance is deionized water.

[0009] The coating of the protective layer includes the following components by weight fraction: thickening binder 5.0% to 25.0%, surfactant 0.5% to 5.0%, ceramic functional additive 3.0% to 25.0%, low melting point glass powder 2.0% to 10.0%, high temperature binder 2.0% to 10.0%, and the balance deionized water.

[0010] Preferably, the ceramic functional additive in the coating of each layer includes one or more of silicon nitride, silicon carbide, aluminum oxide, magnesium oxide, silicon oxide, zirconium oxide, boron nitride, and sodium silicate.

[0011] Further, the ceramic functional additive in the coating of the bonding layer includes silicon carbide, aluminum oxide, zirconium oxide, silicon oxide, and magnesium oxide; the ceramic functional additive in the coating of the transition layer includes silicon carbide, aluminum oxide, zirconium oxide, silicon oxide, magnesium oxide, and silicon nitride; and the ceramic functional additive in the coating of the protective layer includes silicon carbide, aluminum oxide, zirconium oxide, silicon oxide, boron nitride, and sodium silicate.

[0012] Further, the ceramic functional additive in the coating of the bonding layer includes: silicon carbide 2.0% to 15.0%, aluminum oxide 1.0% to 10.0%, zirconium oxide 0.1% to 6.0%, magnesium oxide 0.5% to 8.0%, and silicon nitride 0.5% to 8.0%;

[0013] The ceramic functional additive in the coating of the transition layer includes: silicon carbide 1.0% to 10.0%, aluminum oxide 1.0% to 10.0%, zirconium oxide 0.1% to 6.0%, magnesium oxide 0.5% to 8.0%, and silicon nitride 0.5% to 10.0%;

[0014] The ceramic functional additive in the coating of the protective layer includes: silicon carbide 2.0% to 15.0%, aluminum oxide 1.0% to 10.0%, zirconium oxide 0.1% to 6.0%, boron nitride 0 to 6.0%, and sodium silicate 0.5% to 8.0%.

[0015] Preferably, the thickening binder is one or a combination of at least two of methylcellulose, hydroxyethylcellulose, hydroxymethylcellulose, sodium hydroxymethylcellulose, sodium carboxymethylcellulose, or a polyacrylic thickening binder.

[0016] Preferably, the high temperature binder is any one or a combination of both of a silica sol or a silicate.

[0017] Preferably, the surface active agent comprises a dispersant, a leveling agent and an antifoaming agent; the dispersant is one or more of ammonium salt of acrylic acid or styrene maleic anhydride modified polymer; the antifoaming agent is one or more of mineral oil antifoaming agent or polyethylene glycol; the leveling agent is one or more of polyether modified silicone or acrylate leveling agent.

[0018] Preferably, the low melting point glass powder has a melting point of 200-850℃.

[0019] According to the second aspect of the present application, a preparation method of the composite coating material for quartz products is provided, and the preparation method comprises sequentially preparing a bonding layer, a transition layer and a protective layer. The preparation steps of each layer comprise:

[0020] Step S1: weighing the thickening binder, the surface active agent, the low melting point glass powder, the high temperature binder, the ceramic functional additive and the deionized water according to the proportion;

[0021] Step S2: mixing the deionized water, the thickening binder and the surface active agent uniformly to obtain a first mixture;

[0022] Step S3: adding the low melting point glass powder, the high temperature binder and the ceramic functional additive into the first mixture, and dispersing for 20-40 minutes using a dispersing machine to obtain a second mixture;

[0023] Step S4: diluting the second mixture by adding deionized water, and then finely grinding the diluted mixture using a bead mill, and adjusting the viscosity to obtain a coating with a desired viscosity and fineness;

[0024] Step S5: coating the coating with the desired viscosity and fineness onto the surface of the quartz product or the corresponding coating, drying, and then annealing the coated quartz product using an annealing furnace, and then cooling to room temperature.

[0025] Preferably, the dry film thicknesses of the bonding layer, the transition layer and the protective layer are 0.01-0.5mm respectively. The viscosity of the coating obtained in the preparation step S4 of the bonding layer is greater than the viscosity of the coating obtained in the preparation step S4 of the transition layer, and the viscosity of the coating obtained in the preparation step S4 of the transition layer is greater than the viscosity of the coating obtained in the preparation step S4 of the protective layer.

[0026] Preferably, in step S5, the coated quartz product is annealed in a three-stage temperature rising and holding manner: the first stage is to rise to 180-220℃ and hold for 20-40min, the second stage is to rise to 300-600℃ and hold for 20-50min, and the third stage is to rise to 800-1100℃ and hold for 30-180min.

[0027] Compared with the prior art, the present application has the beneficial effects that the present application sequentially sets the adhesive layer, the transition layer and the protective layer on the quartz product, which respectively play the roles of adhesion, buffering and insulation and strength protection, the composite coating cooperates with each other, can effectively prevent the damage of the deposited silicon to the quartz product, prolong the service life of the quartz product and reduce the process cost. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 Structure diagram of the composite coating material of some embodiments of the present application applied to the quartz product.

[0029] Figure 2 Flow chart of the preparation steps of each coating of some embodiments of the present application.

[0030] In the figure, 10-quartz product, 20-adhesive layer, 30-transition layer, 40-protective layer. DETAILED DESCRIPTION

[0031] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions of the embodiments of the present application will be described clearly and completely below in combination with the drawings of the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, not all the embodiments. Based on the described embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor belong to the scope of protection of the present application. It can be understood that some technical means of the various embodiments described herein can be replaced or combined with each other without conflict.

[0032] In the description of the present application, if there are terms such as "first", "second", etc., they are only used to distinguish the described objects, and do not have any order or technical meaning. Therefore, the objects defined with "first", "second", etc. can be explicitly or implicitly included one or more objects. And "one" or "an" and the like do not represent quantity limitation, but represent the existence of at least one, and "multiple" represents no less than two.

[0033] In the description of the present application, reference to "one embodiment" or "some embodiments" and the like means that the specific features, structures or characteristics described in connection with the embodiment are included in one or more embodiments of the present application. Therefore, the statements "in one embodiment", "in some embodiments", "in other some embodiments", "in other some embodiments" and the like appearing in different places in the specification are not necessarily all referring to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized.

[0034] According to a first aspect of the present application, a composite coating material suitable for quartz products is provided. Referring to Figure 1In some embodiments, the composite coating material includes a bonding layer 20 disposed on the surface of the quartz product 10, a transition layer 30 disposed on the bonding layer 20, and a protective layer 40 disposed on the transition layer 30. The bonding layer 20 is prepared by coating and drying a bonding layer coating and then annealing, the transition layer 30 is prepared by coating and drying a transition layer coating and then annealing, and the protective layer 40 is prepared by coating and drying a protective layer coating and then annealing.

[0035] The bonding layer 20 coating includes the following components in the following weight fractions (percentages of the total weight of the bonding layer coating): thickening binder: 5.0% to 25.0%, surfactant: 0.5% to 5.0%, ceramic functional additive: 3.0% to 25.0%, low-melting-point glass powder: 2.0% to 10.0%, high-temperature binder: 2.0% to 10.0%, and the balance deionized water.

[0036] The transition layer 30 coating includes the following components in the following weight fractions (percentages of the total weight of the transition layer coating): thickening binder: 6.0% to 30.0%, surfactant: 0.5% to 6.0%, ceramic functional additive: 3.0% to 25.0%, low-melting-point glass powder: 2.0% to 10.0%, high-temperature binder: 2.0% to 10.0%, and the balance deionized water.

[0037] The protective layer 40 coating includes the following components in the following weight fractions (percentages of the total weight of the protective layer coating): thickening binder: 5.0% to 25.0%, surfactant: 0.5% to 5.0%, ceramic functional additive: 3.0% to 25.0%, low-melting-point glass powder: 2.0% to 10.0%, high-temperature binder: 2.0% to 10.0%, and the balance deionized water. Further, the ceramic functional additive in the protective layer 40 coating is mainly sodium silicate.

[0038] In each coating, the low-melting-point glass powder and the ceramic functional additive are combined to increase the bonding force between the coating and the quartz product and between the coatings, to improve the density and mechanical properties of the coating, and to reduce the expansion coefficient of the coating. The composite coating material described above is applied to the quartz product 10, the bonding layer 20, the transition layer 30, and the protective layer 40, which respectively play the roles of adhesion, buffering and insulation, and strength protection. The composite coatings cooperate with each other to effectively prevent the deposited silicon from damaging the quartz product, to extend the service life of the quartz product, and to reduce the process cost.

[0039] In some preferred embodiments, the ceramic functional additives in the coating of each layer can include one or more of silicon nitride (Si3N4), silicon carbide (SiC), aluminum oxide (Al2O3), magnesium oxide (MgO), silicon oxide (SiO2), zirconium oxide (ZrO2), boron nitride (BN), and sodium silicate (Na2O-nSiO2).

[0040] The silicon nitride can improve the hardness, strength, and wear resistance of the coating, and increase the durability. The silicon carbide can improve the hardness, wear resistance, chemical corrosion resistance, water resistance, and weather resistance of the coating. The aluminum oxide can enhance the hardness, wear resistance, gloss, and flatness of the coating. The magnesium oxide can significantly improve the hardness of the coating, improve the adhesion and durability of the coating, and also has good flame retardant performance, enabling the coating to remain stable in a high-temperature environment. The silicon oxide can be used as a filler to optimize the film-forming property of the coating, enabling the coating to quickly form a uniform and smooth coating. The zirconium oxide can increase the hardness, wear resistance, chemical resistance, and leveling property of the coating, while also improving the gloss and stability. The boron nitride can enhance the mechanical strength, heat resistance, wear resistance, and corrosion resistance of the coating, and effectively resist thermal expansion in a high-temperature environment. The sodium silicate can be used to adjust the viscosity of the coating, improve the hiding power and flatness of the coating, and also enable the components in the coating to be uniformly dispersed, preventing the occurrence of sedimentation or granular substances.

[0041] In some preferred embodiments, the ceramic functional additives in the coating of the bonding layer 20 include silicon carbide, aluminum oxide, zirconium oxide, silicon oxide, and magnesium oxide; the ceramic functional additives in the coating of the transition layer 30 include silicon carbide, aluminum oxide, zirconium oxide, silicon oxide, magnesium oxide, and silicon nitride; and the ceramic functional additives in the coating of the protective layer 40 include silicon carbide, aluminum oxide, zirconium oxide, silicon oxide, boron nitride, and sodium silicate.

[0042] In some preferred embodiments, the ceramic functional additives in the coating of the bonding layer 20 include 2.0% to 15.0% (percentage of the total weight of the coating of the bonding layer) of silicon carbide, 1.0% to 10.0% of aluminum oxide, 0.1% to 6.0% of zirconium oxide, 0.5% to 8.0% of magnesium oxide, and 0.5% to 8.0% of silicon nitride.

[0043] The ceramic functional additives in the coating of the transition layer 30 include 1.0% to 10.0% (percentage of the total weight of the coating of the transition layer) of silicon carbide, 1.0% to 10.0% of aluminum oxide, 0.1% to 6.0% of zirconium oxide, 0.5% to 8.0% of magnesium oxide, and 0.5% to 10.0% of silicon nitride.

[0044] The ceramic functional additives in the coating of the protective layer 40 include: 2.0% to 15.0% silicon carbide (percentage of the total weight of the coating of the protective layer), 1.0% to 10.0% aluminum oxide, 0.1% to 6.0% zirconium oxide, 0 to 6.0% boron nitride, and 0.5% to 8.0% sodium silicate.

[0045] In some embodiments, the coating of the adhesive layer 20 includes the following components in the following weight fractions: thickening binder: 10.0% to 25.0%, high-temperature binder: 2.0% to 8.0%, ceramic functional additives: 3.0% to 20.0%, low-melting-point glass powder: 3.0% to 10.0%, surfactant: 0.5 to 5.0%, and the balance being deionized water. The ceramic functional additives include: 2.0% to 15.0% silicon carbide (percentage of the total weight of the coating of the adhesive layer), 1.0% to 5.0% aluminum oxide, 0.1% to 6.0% zirconium oxide, 0.5% to 8.0% magnesium oxide, and 0.5% to 8.0% silicon nitride.

[0046] The coating of the transition layer 30 includes the following components in the following weight fractions: thickening binder: 8.0% to 25.0%, high-temperature binder: 2.0% to 10.0%, ceramic functional additives: 3.0% to 22.0%, low-melting-point glass powder: 3.0% to 10.0%, surfactant: 0.5 to 5.0%, and the balance being deionized water. The ceramic functional additives include: 1.0% to 10.0% silicon carbide (percentage of the total weight of the coating of the transition layer), 1.0% to 5.0% aluminum oxide, 0.1% to 6.0% zirconium oxide, 0.5% to 8.0% magnesium oxide, and 0.5% to 10.0% silicon nitride.

[0047] The coating of the protective layer 40 includes the following components in the following weight fractions: thickening binder: 10.0% to 25.0%, high-temperature binder: 2.0% to 8.0%, ceramic functional additives: 3.0% to 20.0%, low-melting-point glass powder: 3.0% to 10.0%, surfactant: 0.5 to 5.0%, and the balance being deionized water. The ceramic functional additives include: 2.0% to 15.0% silicon carbide (percentage of the total weight of the coating of the protective layer), 1.0% to 5.0% aluminum oxide, 0.1% to 6.0% zirconium oxide, 0.1% to 6.0% boron nitride, and 1.0% to 8.0% sodium silicate.

[0048] In some embodiments, the high-temperature binder can be any one or a combination of both of silicon sol or silicate. The high-temperature binder enables the coating material to maintain good bonding performance in a high-temperature environment, and plays an antioxidation and heat insulation role.

[0049] In some embodiments, the thickening binder can employ one or a combination of at least two of methylcellulose, hydroxyethylcellulose, hydroxymethylcellulose, sodium hydroxymethylcellulose, sodium carboxymethylcellulose, or polyacrylic thickening binder.

[0050] In some embodiments, the surface active agent includes a dispersant, a leveling agent, and an antifoaming agent. In application, the dispersant can employ one or more of ammonium salt of acrylic acid or styrene maleic anhydride modified polymer; the antifoaming agent can employ one or more of mineral oil antifoaming agent or polyethylene glycol; and the leveling agent can employ one or more of polyether modified silicone or acrylic leveling agent. The dispersant can make the particle breakage more rapid, reduce the solid-liquid interface free energy, and make the coating material dispersed uniformly and stably. The antifoaming agent can inhibit and eliminate the foam, and ensure the stability of the coating material. The leveling agent can improve the leveling property, wetting property, reduce the surface defects, and improve the coating film quality of the coating material.

[0051] In some embodiments, the low melting point glass powder can employ a commercially available low melting point glass powder product, and the melting point of the low melting point glass powder is 200-850°C. The low melting point glass powder can improve the adhesion, toughness, wear resistance, heat resistance, and corrosion resistance of the coating material.

[0052] In some preferred embodiments, the viscosity of the coating of the bonding layer 20 is greater than the viscosity of the coating of the transition layer 30, and the viscosity of the coating of the transition layer 30 is greater than the viscosity of the coating of the protective layer 40. That is, the viscosity of the bonding layer coating, the transition layer coating, and the protective layer coating decreases in turn. In this way, the bonding layer 20 can be closely combined with the quartz product 10, and can play a buffering and bonding role, thereby enhancing the adhesion and durability of the composite coating material.

[0053] In some embodiments, the viscosity of the coating of each layer can be tested by the four-cup method in the prior art, and the viscosity of the coating can be 15s-55s (s represents seconds, which refers to the time required for the flow of a specific volume of coating). For example, in an embodiment, the viscosity of the coating of the bonding layer is 25s-55s, the viscosity of the coating of the transition layer is 20s-50s, and the viscosity of the coating of the protective layer is 15s-45s.

[0054] According to a second aspect of the present application, a preparation method of the composite coating material is provided, and the preparation method comprises: sequentially preparing the bonding layer 20, the transition layer 30, and the protective layer 40. That is, the bonding layer 20 is first prepared on the quartz product 10, then the transition layer 30 is prepared on the bonding layer 20, and finally the protective layer 40 is prepared on the transition layer 30.

[0055] In some embodiments, the preparation method of the composite coating material comprises the following steps: Figure 2 In some embodiments, the preparation method of the composite coating material comprises the following steps:

[0056] S1: proportionally weigh thickening binder, surfactant, low-melting glass powder, high-temperature binder, ceramic functional additive and deionized water.

[0057] S2: mix the deionized water, thickening binder and surfactant uniformly to obtain a first mixture. In this step, a disperser product in the prior art can be used to mix the deionized water, thickening binder and surfactant, and the mixing time is 10-30 minutes.

[0058] S3: add the low-melting glass powder, high-temperature binder and ceramic functional additive to the first mixture, and use a disperser to disperse for 20-40 minutes to obtain a second mixture. In this step, the disperser can be a disperser product in the prior art.

[0059] S4: add deionized water to the second mixture to dilute it, then use a bead mill to finely grind the diluted mixture, and adjust the viscosity to obtain a coating with the desired viscosity and fineness. In this step, the bead mill can be a bead mill product in the prior art, and the ball-to-material ratio during grinding is (1-3):1. After fine grinding, the fineness (particle size) of the coating is <15 μm. The viscosity of the prepared coating can be tested by the four-cup method in the prior art, and the viscosity of the coating can be 15-55 s (s represents seconds, which refers to the time required for a specific volume of coating to flow out).

[0060] S5: apply the coating with the desired viscosity and fineness to the surface of a quartz product or a corresponding coating, dry it, then use an annealing furnace to anneal the coated quartz product, and then cool it to room temperature to form the desired coating.

[0061] Specifically, the preparation steps of the bonding layer 20 include:

[0062] S1: proportionally weigh thickening binder, surfactant, low-melting glass powder, high-temperature binder, ceramic functional additive and deionized water according to the component proportions of the coating of the bonding layer;

[0063] S2: mix the deionized water, thickening binder and surfactant uniformly to obtain a first mixture;

[0064] S3: add the low-melting glass powder, high-temperature binder and ceramic functional additive to the first mixture, and use a disperser to disperse for 20-40 minutes to obtain a second mixture;

[0065] S4: add deionized water to the second mixture to dilute it; then use a bead mill to finely grind the diluted mixture, and adjust the viscosity to obtain the coating required by the bonding layer;

[0066] S5: The coating is applied to the quartz product 10, and after drying, the coated quartz product is annealed using an annealing furnace, and then cooled to room temperature, thereby forming the bonding layer 20.

[0067] The preparation steps of the transition layer 30 include:

[0068] S1: The thickening binder, surfactant, low-melting glass powder, high-temperature binder, ceramic functional additive, and deionized water are weighed according to the component proportions of the coating for the transition layer;

[0069] S2: The deionized water, thickening binder, and surfactant are mixed uniformly to obtain a first mixture;

[0070] S3: The low-melting glass powder, high-temperature binder, and ceramic functional additive are added to the first mixture, and a dispersing machine is used for dispersion for 20-40 minutes to obtain a second mixture;

[0071] S4: Deionized water is added to the second mixture for dilution; then a bead mill is used for fine grinding of the diluted mixture, and viscosity adjustment is performed to obtain the required coating for the transition layer;

[0072] S5: The coating is applied to the bonding layer 20, and after drying, the coated quartz product is annealed using an annealing furnace, and then cooled to room temperature, thereby forming the transition layer 30.

[0073] The preparation steps of the protective layer 40 include:

[0074] S1: The thickening binder, surfactant, low-melting glass powder, high-temperature binder, ceramic functional additive, and deionized water are weighed according to the component proportions of the coating for the protective layer;

[0075] S2: The deionized water, thickening binder, and surfactant are mixed uniformly to obtain a first mixture;

[0076] S3: The low-melting glass powder, high-temperature binder, and ceramic functional additive are added to the first mixture, and a dispersing machine is used for dispersion for 20-40 minutes to obtain a second mixture;

[0077] S4: Deionized water is added to the second mixture for dilution; then a bead mill is used for fine grinding of the diluted mixture, and viscosity adjustment is performed to obtain the required coating for the protective layer;

[0078] S5: The coating is applied to the transition layer 30, and the coated quartz product is annealed, and then cooled to room temperature, thereby forming the protective layer 40.

[0079] The composite coating material is applied to the quartz product, and the adhesive layer, the transition layer and the protective layer respectively play the roles of adhesion, buffering and insulation and strength protection, that is, the adhesive layer is used to effectively adhere the composite coating material to the surface of the quartz product, to improve the adhesion of the composite coating material, the transition layer in the middle can play the role of buffering and insulation, and the outermost protective layer plays the role of strength protection; the composite coating cooperates with each other to effectively prevent the deposited silicon from damaging the quartz product, to prolong the service life of the quartz product and to reduce the process cost.

[0080] It should be noted that the thickness of each coating layer and the coating process can be reasonably set according to the actual situation. In some preferred embodiments, the dry film thicknesses of the adhesive layer 20, the transition layer 30 and the protective layer 40 are respectively 0.01-0.5 mm. The adhesive layer 20, the transition layer 30 and the protective layer 40 are respectively coated by using the pneumatic spray gun spraying method, so as to ensure the uniformity of the coating thickness.

[0081] Further, the viscosity of the coating obtained in the preparation step S4 of the adhesive layer is greater than the viscosity of the coating obtained in the preparation step S4 of the transition layer, and the viscosity of the coating obtained in the preparation step S4 of the transition layer is greater than the viscosity of the coating obtained in the preparation step S4 of the protective layer. That is, the viscosities of the adhesive layer coating, the transition layer coating and the protective layer coating decrease in turn. In this way, the adhesive layer can be closely combined with the quartz product, and can play the roles of buffering and adhesion, so as to enhance the adhesion and durability of the composite coating.

[0082] In an embodiment, the viscosity of the coating obtained in the preparation step S4 of the adhesive layer is 25-55 s, the viscosity of the coating obtained in the preparation step S4 of the transition layer is 20-50 s, and the viscosity of the coating obtained in the preparation step S4 of the protective layer is 15-45 s.

[0083] In some embodiments, in the step S5, the annealing temperature is 800-1100℃, and the annealing time is 0.5-3 hours. Further, the annealing temperature of the adhesive layer is 1050℃, the annealing time is 60 min; the annealing temperature of the transition layer is 1010℃, the annealing time is 60 min; and the annealing temperature of the protective layer is 950℃, the annealing time is 45 min.

[0084] In other embodiments, in the step S5, the quartz product is annealed by using a two-stage temperature rising and holding method: the first stage is to rise to 300-600℃ and hold for 20-50 minutes, and the second stage is to rise to 800-1100℃ and hold for 0.5-3 hours. The two-stage temperature rising and holding method can make the solvent fully volatilize and the glue fully discharge at the medium and low temperature stage, to obtain a good annealing effect, to enhance the bonding strength and the compactness between the coating material and the quartz product and between the adjacent coating layers, and to improve the comprehensive performance of the coating material.

[0085] In some embodiments, the quartz product after coating is annealed in three stages in each coating step S5: the first stage is to heat to 180-220℃ and keep for 20-40min, the second stage is to heat to 300-600℃ and keep for 20-50min, and the third stage is to heat to 800-1100℃ and keep for 30-180min. The three-stage annealing process can make the solvent fully volatilize and the glue fully discharge at low and medium temperatures, so as to obtain good annealing effect, enhance the bonding strength and compactness between the coating material and the quartz product and between adjacent coating layers, and improve the comprehensive performance of the coating material.

[0086] Three embodiments and three comparative examples of the present application are given below. In each embodiment or comparative example, 10 quartz tube products of the same batch and model are selected as test objects. In embodiments 1-3, the component proportions and preparation method of the composite coating material of the application are used to form three-layer composite coatings on the 10 quartz tubes. In comparative example 1, the component proportions of the adhesive layer in embodiment 1 are used to form a single adhesive layer coating on the 10 quartz tubes. In comparative example 2, the component proportions of the protective layer in embodiment 1 are used to form a single protective layer coating on the 10 quartz tubes. In comparative example 3, the 10 quartz tubes are not coated with any coating material. The average service life of the quartz tubes in each embodiment or comparative example is tested.

[0087] Table 1 shows the weight proportions of the components in the composite coating material in embodiments 1 and 2:

[0088] Table 1

[0089]

[0090] Table 2 shows the weight proportions of the components in the composite coating material in embodiment 3, and the coating component proportions in comparative examples 1-3:

[0091] Table 2

[0092]

[0093] Table 3 shows the average service life test results of the quartz tubes in embodiments 1-3 and comparative examples 1-3:

[0094] Table 3

[0095] Coating situation Quartz tube average service life (days) Example 1 Three-layer composite coating 355 Example 2 Three-layer composite coating 347 Example 3 Three-layer composite coating 322 Comparative Example 1 Single adhesive layer 255 Comparative Example 2 Single protective layer 241 Comparative Example 3 No coating 101

[0096] Embodiment 1:

[0097] The weight fraction of each component in the bonding layer coating is as follows: thickening binder 17.0%, surfactant 1.5%, ceramic functional additive 9.0%, low-melting glass powder 4.0%, high-temperature binder 4.0%, and water 64.5%. The ceramic functional additive includes silicon carbide 2.0%, aluminum oxide 4.0%, zirconium oxide 0.5%, magnesium oxide 1.5%, and silicon nitride 1.0%.

[0098] The preparation steps of the bonding layer are as follows:

[0099] S1: The thickening binder, surfactant, low-melting glass powder, high-temperature binder, ceramic functional additive, and deionized water are weighed according to the component ratio of the bonding layer coating;

[0100] S2: The deionized water, thickening binder, and surfactant are mixed uniformly to obtain a first mixture;

[0101] S3: The low-melting glass powder, high-temperature binder, and ceramic functional additive are added to the first mixture, and a disperser is used for dispersion for 20-40 minutes to obtain a second mixture;

[0102] S4: Deionized water is added to the second mixture for dilution, and a bead mill is used for fine grinding of the diluted mixture, and viscosity adjustment is performed to obtain the required coating for the bonding layer. The viscosity of the coating is 49 s when tested using a four-cup coating machine;

[0103] S5: The coating is applied to the quartz product, and the coated quartz product is subjected to annealing treatment, and then cooled to room temperature to form the bonding layer. During the annealing treatment, the coated quartz product is subjected to three-stage temperature rising and holding: the first stage is to rise to 200°C and hold for 30 minutes, the second stage is to rise to 400°C and hold for 30 minutes, and the third stage is to rise to 1050°C and hold for 100 minutes.

[0104] The weight fraction of each component in the transition layer is as follows: thickening binder 16.0%, surfactant 1.5%, ceramic functional additive 9.0%, low-melting glass powder 4.0%, high-temperature binder 4.0%, and deionized water 65.5%. The ceramic functional additive includes silicon carbide 3.0%, aluminum oxide 3.0%, zirconium oxide 0.5%, magnesium oxide 1.5%, and silicon nitride 1.0%.

[0105] The preparation steps of the transition layer are as follows:

[0106] S1: The thickening binder, surfactant, low-melting glass powder, high-temperature binder, ceramic functional additive, and deionized water are weighed according to the component ratio of the bonding layer coating;

[0107] S2: mix the deionized water, thickening binder and surfactant uniformly to obtain a first mixture;

[0108] S3: add the low-melting point glass powder, high-temperature binder and ceramic functional additive to the first mixture and disperse using a dispersing machine for 20-40 minutes to obtain a second mixture;

[0109] S4: add deionized water to the second mixture to dilute; then finely grind the diluted mixture using a bead mill and adjust the viscosity to obtain the coating required for the transition layer; the viscosity of the coating is 44 s as tested using a four-cup method;

[0110] S5: apply the coating to the bonding layer and anneal the coated quartz product, and then cool to room temperature to form the transition layer; during the annealing process, the coated quartz product is annealed using a three-stage temperature raising and holding method: the first stage is to raise the temperature to 200°C and hold for 30 min, the second stage is to raise the temperature to 400°C and hold for 30 min, and the third stage is to raise the temperature to 1050°C and hold for 100 min.

[0111] The weight fractions of the components in the protective layer are: thickening binder: 15.0%, surfactant: 1.5%, ceramic functional additive: 9.0%, low-melting point glass powder: 4.0%, high-temperature binder: 4.0%, and deionized water: 66.5%. The ceramic functional additive includes: silicon carbide: 4.0%, aluminum oxide: 2.0%, zirconium oxide: 0.5%, magnesium oxide: 1.5%, and sodium silicate: 1.0%.

[0112] The preparation steps of the protective layer are:

[0113] S1: weigh the thickening binder, surfactant, low-melting point glass powder, high-temperature binder, ceramic functional additive and deionized water according to the component proportions of the protective layer coating;

[0114] S2: mix the deionized water, thickening binder and surfactant uniformly to obtain a first mixture;

[0115] S3: add the low-melting point glass powder, high-temperature binder and ceramic functional additive to the first mixture and disperse using a dispersing machine for 20-40 minutes to obtain a second mixture;

[0116] S4: add deionized water to the second mixture to dilute; then finely grind the diluted mixture using a bead mill and adjust the viscosity to obtain the coating required for the protective layer; the viscosity of the coating is 37 s as tested using a four-cup method;

[0117] S5: The coating is applied to the transition layer, and the coated quartz product is annealed and then cooled to room temperature to form a protective layer. During the annealing process, the coated quartz product is annealed in three stages of temperature rise and holding: the first stage is to rise to 200°C and hold for 30 min, the second stage is to rise to 400°C and hold for 30 min, and the third stage is to rise to 1050°C and hold for 100 min.

[0118] It is detected that the thermal expansion coefficient of the adhesive layer prepared in Example 1 is 1.45 x 10 -6 K -1 , the thermal expansion coefficient of the transition layer is 1.56 x 10 -6 K -1 , and the thermal expansion coefficient of the protective layer is 1.51 x 10 -6 K -1 . The average service life of the quartz tube measured in Example 1 is 355 days.

[0119] Example 2:

[0120] The weight fraction of each component in the adhesive layer: thickening binder: 17.0%, surfactant: 1.5%, ceramic functional additive: 9.0%, low-melting-point glass powder: 4.0%, high-temperature binder: 4.0%, and deionized water: 64.5%. Among them, the ceramic functional additive includes: silicon carbide: 2.0%, aluminum oxide: 4.0%, zirconium oxide: 1.0%, magnesium oxide: 1.0%, and silicon nitride: 1.0%.

[0121] The preparation steps of the adhesive layer are as follows:

[0122] S1: The thickening binder, surfactant, low-melting-point glass powder, high-temperature binder, ceramic functional additive, and deionized water are weighed according to the component ratio of the adhesive layer coating;

[0123] S2: Mix the deionized water, thickening binder, and surfactant uniformly to obtain a first mixture;

[0124] S3: Add the low-melting-point glass powder, high-temperature binder, and ceramic functional additive to the first mixture, and use a dispersing machine to disperse for 20-40 minutes to obtain a second mixture;

[0125] S4: Dilute the second mixture with deionized water, then finely grind the diluted mixture using a bead mill, and adjust the viscosity to obtain the required coating for the adhesive layer; the viscosity of the coating is 46 s using a four-cup test.

[0126] S5: The coating is applied to the quartz product, and the coated quartz product is annealed and then cooled to room temperature, thereby forming the bonding layer. During the annealing, the coated quartz product is annealed in three stages of temperature increase and holding: the first stage is to increase the temperature to 200°C and hold for 30 min, the second stage is to increase the temperature to 400°C and hold for 30 min, and the third stage is to increase the temperature to 1050°C and hold for 100 min.

[0127] The weight fractions of the components in the transition layer coating are as follows: thickening binder: 16.0%, surfactant: 1.5%, ceramic functional additive: 9.0%, low-melting glass powder: 4.0%, high-temperature binder: 4.0%, and deionized water: 65.5%. The ceramic functional additive includes: silicon carbide: 3.0%, aluminum oxide: 3.0%, zirconium oxide: 1.0%, magnesium oxide: 1.0%, and silicon nitride: 1.0%.

[0128] The preparation steps of the transition layer are as follows:

[0129] S1: The thickening binder, surfactant, low-melting glass powder, high-temperature binder, ceramic functional additive, and deionized water are weighed according to the component proportions of the transition layer coating;

[0130] S2: The deionized water, thickening binder, and surfactant are mixed uniformly to obtain a first mixture;

[0131] S3: The low-melting glass powder, high-temperature binder, and ceramic functional additive are added to the first mixture, and a disperser is used for dispersion for 20-40 min to obtain a second mixture;

[0132] S4: Deionized water is added to the second mixture for dilution; then a bead mill is used for fine grinding of the diluted mixture, and viscosity adjustment is performed to obtain the required coating for the transition layer; the viscosity of the coating is tested using a four-cup method and is 42 s;

[0133] S5: The coating is applied to the quartz product, and the coated quartz product is annealed and then cooled to room temperature, thereby forming the bonding layer. During the annealing, the coated quartz product is annealed in three stages of temperature increase and holding: the first stage is to increase the temperature to 200°C and hold for 30 min, the second stage is to increase the temperature to 400°C and hold for 30 min, and the third stage is to increase the temperature to 1050°C and hold for 100 min.

[0134] The weight fraction of each component in the protective layer: thickening binder: 15.0%, surfactant: 1.5%, ceramic functional additive: 9.0%, low-melting glass powder: 4.0%, high-temperature binder: 4.0%, deionized water: 66.5%. Among them, the ceramic functional additive includes: silicon carbide: 4.0%, aluminum oxide: 2.0%, zirconium oxide: 1.0%, magnesium oxide: 1.0%, sodium silicate: 1.0%.

[0135] The preparation steps of the protective layer are:

[0136] S1: The thickening binder, surfactant, low-melting glass powder, high-temperature binder, ceramic functional additive and deionized water are weighed according to the component ratio of the protective layer coating;

[0137] S2: Mix the deionized water, thickening binder and surfactant uniformly to obtain a first mixture;

[0138] S3: Add the low-melting glass powder, high-temperature binder and ceramic functional additive to the first mixture, and use a dispersing machine to disperse for 20-40 minutes to obtain a second mixture;

[0139] S4: Dilute the second mixture with deionized water, then finely grind the diluted mixture using a bead mill, and adjust the viscosity to obtain the required coating for the protective layer; the viscosity of the coating is 35s using a four-cup test;

[0140] S5: Apply the coating to the transition layer, and anneal the coated quartz product, then cool it to room temperature to form the protective layer. During annealing, the coated quartz product is annealed in three stages of temperature rise and holding: the first stage is to rise to 200°C and hold for 30 minutes, the second stage is to rise to 400°C and hold for 30 minutes, and the third stage is to rise to 1050°C and hold for 100 minutes.

[0141] It is detected that the thermal expansion coefficient of the bonding layer prepared in Example 2 is 1.42×10 -6 K -1 , the thermal expansion coefficient of the transition layer is 1.53×10 -6 K -1 , and the thermal expansion coefficient of the protective layer is 1.49×10 -6 K -1 . The average service life of the quartz tube measured in Example 2 is 347 days.

[0142] Example 3:

[0143] The weight fraction of each component in the bonding layer coating is as follows: thickening binder 17.0%, surfactant 1.5%, ceramic functional additive 10.0%, low-melting glass powder 4.0%, high-temperature binder 4.0%, and deionized water 63.5%. The ceramic functional additive includes silicon carbide 3.0%, aluminum oxide 4.0%, zirconium oxide 0.5%, magnesium oxide 1.5%, and silicon nitride 1.0%.

[0144] The preparation steps of the bonding layer are as follows:

[0145] S1: The thickening binder, surfactant, low-melting glass powder, high-temperature binder, ceramic functional additive, and deionized water are weighed according to the component ratio of the bonding layer coating;

[0146] S2: The deionized water, thickening binder, and surfactant are mixed uniformly to obtain a first mixture;

[0147] S3: The low-melting glass powder, high-temperature binder, and ceramic functional additive are added to the first mixture, and a disperser is used for dispersion for 20-40 minutes to obtain a second mixture;

[0148] S4: The deionized water is added to the second mixture for dilution, and a bead mill is used for fine grinding of the diluted mixture, and viscosity adjustment is performed to obtain the required coating for the bonding layer. The viscosity of the coating is 52 s when tested using a four-cup coating machine.

[0149] S5: The coating is applied to the quartz product, and the coated quartz product is subjected to annealing treatment, and then cooled to room temperature to form the bonding layer. During the annealing treatment, the coated quartz product is subjected to three-stage temperature rising and holding: the first stage is to rise to 200°C and hold for 30 minutes, the second stage is to rise to 400°C and hold for 30 minutes, and the third stage is to rise to 1050°C and hold for 100 minutes.

[0150] The weight fraction of each component in the transition layer coating is as follows: thickening binder 16.0%, surfactant 1.5%, ceramic functional additive 10.0%, low-melting glass powder 4.0%, high-temperature binder 4.0%, and deionized water 64.5%. The ceramic functional additive includes silicon carbide 4.0%, aluminum oxide 3.0%, zirconium oxide 0.5%, magnesium oxide 1.5%, and silicon nitride 1.0%.

[0151] The preparation steps of the transition layer are as follows:

[0152] S1: The thickening binder, surfactant, low-melting glass powder, high-temperature binder, ceramic functional additive, and deionized water are weighed according to the component ratio of the transition layer coating;

[0153] S2: mix the deionized water, thickening binder and surfactant uniformly to obtain a first mixture;

[0154] S3: add the low-melting point glass powder, high-temperature binder and ceramic functional additive to the first mixture and disperse using a dispersing machine for 20-40 minutes to obtain a second mixture;

[0155] S4: add deionized water to the second mixture to dilute; then finely grind the diluted mixture using a bead mill and adjust the viscosity to obtain the coating required for the transition layer; the viscosity of the coating is 47 s as tested using a four-cup method;

[0156] S5: apply the coating to the bonding layer and anneal the coated quartz product, and then cool to room temperature to form the transition layer. During the annealing process, the coated quartz product is annealed using a three-stage temperature raising and holding method: the first stage is to raise the temperature to 200°C and hold for 30 min, the second stage is to raise the temperature to 400°C and hold for 30 min, and the third stage is to raise the temperature to 1050°C and hold for 100 min.

[0157] The weight fractions of the components in the protective layer are: thickening binder: 15.0%, surfactant: 1.5%, ceramic functional additive: 10.0%, low-melting point glass powder: 4.0%, high-temperature binder: 4.0%, and deionized water: 65.5%. The ceramic functional additive includes: silicon carbide: 5.0%, aluminum oxide: 2.0%, zirconium oxide: 0.5%, magnesium oxide: 1.5%, and sodium silicate: 1.0%.

[0158] The preparation steps of the protective layer are:

[0159] S1: weigh the thickening binder, surfactant, low-melting point glass powder, high-temperature binder, ceramic functional additive and deionized water according to the component proportions of the protective layer coating;

[0160] S2: mix the deionized water, thickening binder and surfactant uniformly to obtain a first mixture;

[0161] S3: add the low-melting point glass powder, high-temperature binder and ceramic functional additive to the first mixture and disperse using a dispersing machine for 20-40 minutes to obtain a second mixture;

[0162] S4: add deionized water to the second mixture to dilute; then finely grind the diluted mixture using a bead mill and adjust the viscosity to obtain the coating required for the protective layer; the viscosity of the coating is 42 s as tested using a four-cup method;

[0163] S5: The coating is applied to the transition layer, and the coated quartz product is annealed and then cooled to room temperature to form a protective layer. During the annealing process, the coated quartz product is annealed in three stages of temperature rise and holding: the first stage is to rise to 200°C and hold for 30 min, the second stage is to rise to 400°C and hold for 30 min, and the third stage is to rise to 1050°C and hold for 100 min.

[0164] The thermal expansion coefficient of the adhesive layer prepared in Example 3 is 1.49 x 10 -6 K -1 The thermal expansion coefficient of the transition layer is 1.63 x 10 -6 K -1 The thermal expansion coefficient of the protective layer is 1.57 x 10 -6 K -1 The average service life of the quartz tube measured in Example 3 is 322 days.

[0165] Comparative Example 1:

[0166] The components of the adhesive layer coating in Example 1 are used to form a single adhesive layer coating on the surface of the quartz tube. The average service life of the quartz tube in Comparative Example 1 is 255 days as tested.

[0167] Comparative Example 2:

[0168] The components of the protective layer coating in Example 1 are used to form a single protective layer coating on the surface of the quartz tube. The average service life of the quartz tube in Comparative Example 2 is 241 days as tested.

[0169] Comparative Example 3:

[0170] 10 quartz tube products have no coating material applied to their surfaces. The average service life of the quartz tube in Comparative Example 3 is 101 days as tested.

[0171] Comparing the test results of the above examples and comparative examples, we can see that:

[0172] Compared with the no-coating condition of Comparative Example 3, Examples 1-3 and Comparative Examples 1-2 all form a coating on the surface of the quartz tube product, and the average service life of the quartz tube with a coating is extended. In addition, compared with the single coating condition of Comparative Examples 1-2, the average service life of the quartz tube with a composite coating in Examples 1-3 is significantly longer.

[0173] The single coating structure is used in the comparative example 1 and the comparative example 2, and it can be seen from the use effect that the single coating can prolong the service life of the quartz tube to a certain extent: compared with the comparative example 3 without coating, the average service life of the quartz tube in the comparative example 1 is prolonged by 154 days, and the average service life of the quartz tube in the comparative example 2 is prolonged by 140 days.

[0174] Compared with the comparative example 3 without coating, the composite coating material is prepared on the surface of the quartz tube in the examples 1-3, and the average service life of the quartz tube is prolonged by more than three times. Specifically, the average service life of the quartz tube in the example 1 is prolonged by 254 days, the average service life of the quartz tube in the example 2 is prolonged by 246 days, and the average service life of the quartz tube in the example 3 is prolonged by 221 days. It can be seen that after the composite coating material and the preparation method of the present application are used, the composite coatings cooperate with each other, can effectively prevent the deposited silicon from damaging the quartz product, greatly prolong the service life of the quartz product, and reduce the process cost.

[0175] Compared with the example 1, the proportion of magnesium oxide (1.5% is adjusted to 1.0%) and zirconium oxide (0.5% is adjusted to 1.0%) is adjusted in the example 2, the coating viscosity changes little, the thermal expansion coefficient slightly decreases, and the average service life of the quartz tube in the example 1 is slightly longer than that in the example 2. Compared with the example 1, the proportion of silicon carbide (2%, 3%, 4% is adjusted to 3%, 4%, 5%) is adjusted in the example 3, the coating viscosity and the thermal expansion coefficient both increase, and the average service life of the quartz tube in the example 1 is longer than that in the example 3.

[0176] Overall, the application effect of the example 1 is the best, and compared with the comparative example 3 without coating, the average service life of the quartz tube in the example 1 is prolonged by 254 days. Therefore, in practical application, the component proportioning and the preparation method in the example 1 can be preferably used.

[0177] In summary, the present application provides a composite coating material suitable for quartz products and a preparation method thereof. The adhesive layer, the transition layer and the protective layer are sequentially arranged on the quartz product, and respectively play the roles of adhesion, buffering and isolation and strength protection. The composite coatings cooperate with each other, can effectively prevent the deposited silicon from damaging the quartz product, prolong the service life of the quartz product, and reduce the process cost.

[0178] The present application has been described by the above-mentioned related examples, however, the above-mentioned examples are only examples for implementing the present application. It must be pointed out that the disclosed examples do not limit the scope of the present application. On the contrary, modifications and improvements made without departing from the spirit and scope of the present application are within the scope of the patent protection of the present application.

Claims

1. A composite coating material suitable for quartz products, characterized by: The composite coating material includes a bonding layer provided on the surface of the quartz product, a transition layer provided on the bonding layer, and a protective layer provided on the transition layer; The coating of the bonding layer includes the following components by weight: thickening binder: 5.0% to 25.0%, surfactant: 0.5% to 5.0%, ceramic functional additive: 3.0% to 25.0%, low melting point glass powder: 2.0% to 10.0%, high temperature binder: 2.0% to 10.0%, and the balance is deionized water; the ceramic functional additives in the coating of the bonding layer include: silicon carbide 2.0% to 15.0%, aluminum oxide 1.0% to 10.0%, zirconium oxide 0.1% to 6.0%, magnesium oxide 0.5% to 8.0%, and silicon nitride 0.5% to 8.0%; The coating of the transition layer includes the following components by weight: thickening binder: 6.0% to 30.0%, surfactant: 0.5% to 6.0%, ceramic functional additive: 3.0% to 25.0%, low melting point glass powder: 2.0% to 10.0%, high temperature binder: 2.0% to 10.0%, and the balance is deionized water; the ceramic functional additives in the coating of the transition layer include: silicon carbide 1.0% to 10.0%, aluminum oxide 1.0% to 10.0%, zirconium oxide 0.1% to 6.0%, magnesium oxide 0.5% to 8.0%, and silicon nitride 0.5% to 10.0%; The coating of the protective layer includes the following components by weight: thickening binder: 5.0% to 25.0%, surfactant: 0.5% to 5.0%, ceramic functional additive: 3.0% to 25.0%, low-melting point glass powder: 2.0% to 10.0%, high-temperature binder: 2.0% to 10.0%, and the balance is deionized water; the ceramic functional additives in the coating of the protective layer include: silicon carbide 2.0% to 15.0%, aluminum oxide 1.0% to 10.0%, zirconium oxide 0.1% to 6.0%, boron nitride 0 to 6.0%, and sodium silicate 0.5% to 8.0%.

2. The composite coating material suitable for quartz products according to claim 1, characterized in that: The high-temperature adhesive is any one of silica sol and silicate or a combination of the two.

3. The composite coating material suitable for quartz products according to claim 1, characterized in that: The thickening binder is one or a combination of at least two of methyl cellulose, hydroxyethyl cellulose, hydroxymethyl cellulose, sodium hydroxymethyl cellulose, sodium carboxymethyl cellulose or polyacrylic acid thickening binders.

4. The composite coating material suitable for quartz products according to claim 1, characterized in that: The surfactant includes a dispersant, a leveling agent and a defoamer; the dispersant is one or more of acrylic acid ammonium salts or styrene maleic anhydride modified polymers; the defoamer is one or more of mineral oil defoamers or polyethylene glycols; and the leveling agent is one or more of polyether modified silicone or acrylic leveling agents.

5. The composite coating material suitable for quartz products according to claim 1, characterized in that: The melting point of the low-melting-point glass powder is 200-850°C.

6. A method for preparing a composite coating material suitable for quartz products according to any one of claims 1 to 5, characterized in that: The bonding layer, transition layer and protective layer are prepared in sequence; wherein the preparation steps of each layer include: Step S1: weighing a thickening binder, a surfactant, a low-melting-point glass powder, a high-temperature binder, a ceramic functional additive, and deionized water in proportion; Step S2: uniformly mixing deionized water, a thickening binder, and a surfactant to obtain a first mixture; Step S3: adding low-melting-point glass powder, high-temperature binder and ceramic functional additive to the first mixture, and dispersing the mixture for 20 to 40 minutes using a disperser to obtain a second mixture; Step S4: adding deionized water to the second mixture to dilute it, then finely grinding the diluted mixture using a bead mill and adjusting the viscosity to obtain a coating with the desired viscosity and fineness; Step S5: Apply a coating of required viscosity and fineness to the surface of the quartz product or the corresponding coating, and after drying, anneal the coated quartz product in an annealing furnace, and then cool to room temperature.

7. The method for preparing a composite coating material suitable for quartz products according to claim 6, characterized in that: The dry film thicknesses of the bonding layer, the transition layer, and the protective layer are respectively 0.01 to 0.5 mm; the viscosity of the coating obtained in the preparation step S4 of the bonding layer is greater than the viscosity of the coating obtained in the preparation step S4 of the transition layer, and the viscosity of the coating obtained in the preparation step S4 of the transition layer is greater than the viscosity of the coating obtained in the preparation step S4 of the protective layer.

8. The method for preparing a composite coating material suitable for quartz products according to claim 6, wherein: In step S5, the coated quartz product is annealed in a three-stage heating and holding method: the first stage is heating to 180-220°C and holding for 20-40 minutes, the second stage is heating to 300-600°C and holding for 20-50 minutes, and the third stage is heating to 800-1100°C and holding for 30-180 minutes.

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