High-temperature-resistant coating slurry, high-temperature-resistant quartz tube and preparation method and application thereof

Abstract

The invention discloses a preparation method and application of high-temperature-resistant coating slurry and a high-temperature-resistant quartz tube, and the slurry is prepared from the following components in parts by mass: 4-10 parts of phosphate, 4-10 parts of lyosol, 0.1-20 parts of silicon carbide, 0.1-20 parts of aluminum oxide, 0.1-10 parts of aluminum nitride and 4-20 parts of inorganic solvent. The coating prepared from the slurry can effectively reduce the deformation rate of the quartz tube at high temperature and prolong the service life of the quartz tube. Compared with the prior art, the slurry can be directly spin-coated on the surface of the quartz tube, the coating is uniform in coating and controllable in thickness, the production cost is greatly reduced, and industrial production is facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of quartz material processing and manufacturing, and in particular to a high temperature resistant coating slurry, a high temperature resistant quartz tube, and a preparation method and application thereof. Background Art

[0002] Quartz tubes, especially large-diameter quartz tubes, are widely used in metal smelting molds, chemical pipelines, semiconductor industry and other fields. Due to the special use environment, quartz tubes must be able to withstand extreme temperature and pressure conditions to ensure the safety of production and operation and experimental personnel. Therefore, quartz tubes are often fast-consuming products in actual production and manufacturing, which increases production costs.

[0003] In order to increase the service life and application range of quartz tubes, a common method is to apply a coating on their outer surface. The coating can improve the surface characteristics of the quartz tube and also improve its high temperature resistance, thermal deformation resistance and other properties.

[0004] Since the surface of the quartz tube is very smooth, ordinary slurry cannot be directly applied. At present, the existing technology for coating the slurry on the surface of the quartz tube mostly adopts plasma spraying, vapor deposition and magnetron sputtering, which have harsh operating conditions, complex processes and high costs; or after mechanically treating the surface of the quartz tube, the slurry is directly applied to the surface of the quartz tube by simple means such as brushing, cold and hot spraying, but the thickness and uniformity of the coating are difficult to control.

[0005] Therefore, it is an urgent problem to be solved by those skilled in the art to provide a high-temperature resistant coating slurry with strong coatability and a simple and controllable method for preparing the high-temperature resistant coating. Summary of the invention

[0006] The purpose of the present invention is to provide a method for preparing a high-temperature resistant coating slurry with strong coatability and a single controllable high-temperature resistant coating for a quartz tube in view of the problems that the method used in the prior art for coating the slurry on the surface of a quartz tube has harsh operating conditions, complicated processes, high costs, or the thickness and uniformity of the coating are difficult to control.

[0007] In order to achieve the above object, the technical solution provided by the present invention is as follows:

[0008] A high temperature resistant coating slurry, the slurry comprising 4 to 10 parts of phosphate, 4 to 10 parts of liquid sol, 0.1 to 20 parts of silicon carbide, 0.1 to 20 parts of aluminum oxide, 0.1 to 10 parts of aluminum nitride, and 4 to 20 parts of an inorganic solvent;

[0009] Preferably, the slurry comprises 4 to 8 parts of phosphate, 4 to 8 parts of liquid sol, 0.1 to 12 parts of silicon carbide, 0.1 to 12 parts of aluminum oxide, 0.1 to 8 parts of aluminum nitride, and 4 to 18 parts of an inorganic solvent;

[0010] Further preferably, the slurry comprises 6-8 parts of phosphate, 6-8 parts of sol, 0.1-8 parts of silicon carbide, 0.1-8 parts of alumina, 0.1-6 parts of aluminum nitride, and 4-16 parts of inorganic solvent.

[0011] Among them, the phosphate is any one or a combination of more than one of aluminum dihydrogen phosphate, magnesium dihydrogen phosphate, sodium dihydrogen phosphate, sodium hexametaphosphate, and sodium tripolyphosphate; the sol is any one or a combination of more than one of silica sol, alumina sol, and zirconia sol. The silica sol, alumina sol, and zirconia sol are dispersions of nano-silica, nano-alumina, and nano-zirconia in water or other solvents, and the mass fraction of the silica sol, alumina sol, and zirconia sol is 10-40%, preferably 20%.

[0012] Among them, the inorganic solvent is any one or a combination of more than one of phosphoric acid, polyphosphoric acid, and water.

[0013] Among them, the particle sizes of the silicon carbide, alumina, and aluminum nitride are less than 10 μm;

[0014] Preferably, the particle sizes of the silicon carbide, alumina, and aluminum nitride are 0.1-10 μm;

[0015] Further preferably, the particle sizes of the silicon carbide, alumina, and aluminum nitride are 0.1-5 μm;

[0016] Most preferably, the particle sizes of the silicon carbide, alumina, and aluminum nitride are 1-5 μm.

[0017] The present invention also provides a high-temperature resistant quartz tube, comprising a quartz tube and a high-temperature resistant coating covering the surface of the quartz tube; the high-temperature resistant coating is made of the above-mentioned high-temperature resistant coating slurry.

[0018] Among them, the diameter of the quartz tube is 50-1000 mm, the length is 50-4000 mm, and the wall thickness is 2-200 mm; the thickness of the high-temperature resistant coating is 10-1000 μm.

[0019] The present invention also provides a preparation method of the high-temperature resistant quartz tube, comprising the following steps:

[0020] (1) Mix the phosphate with the inorganic solvent to form a solution, and grind and mix it with the sol, silicon carbide, alumina, and aluminum nitride to obtain a high-temperature resistant coating slurry;

[0021] (2) Use a spin coating process to coat the high-temperature resistant coating slurry obtained in step (1) on the surface of the quartz tube, dry it, and sinter it to obtain the product.

[0022] In step (1), the concentration of the phosphate in the solution is 30-70%, preferably 32-68%, more preferably 35-66%, and most preferably 38-65%; the grinding is ball milling, and the rotation speed during ball milling is 200-500 r / min, preferably 250-450 r / min, more preferably 300-400 r / min, and most preferably 320-380 r / min; the ball milling time is 0.5-5 h, preferably 1-4 h, more preferably 1.5-3.5 h, and most preferably 2-3 h.

[0023] In step (2), the spin coating process is to clamp the quartz tube in a rotatable clamping device for the spin coating process. When performing the spin coating process, the quartz tube is partially immersed in the high-temperature resistant coating slurry. The rotation speed of the quartz tube is 0.5-5 r / min, preferably 1-4 r / min, more preferably 1.5-3.5 r / min, and most preferably 2-3 r / min; the rotation time is 0.2-2 min, preferably 0.25-1.6 min, more preferably 0.3-1.2 min, and most preferably 0.4-0.8 min.

[0024] In step (2), the drying temperature is 60-150 °C, preferably 70-130 °C, more preferably 80-120 °C, and most preferably 90-100 °C; the drying time is 0.5-48 h, preferably 1-36 h, more preferably 5-24 h, and most preferably 10-15 h.

[0025] In step (2), the sintering is carried out in stages. First, it is heated to 600-900 °C and held for 0.5-2 h, and then it is heated to 1200-1500 °C and held for 0.5-2 h.

[0026] Beneficial effects:

[0027] (1) By reasonably designing the components of the high-temperature resistant coating slurry, using phosphate and sol as the slurry binder and high-temperature resistant materials as the coating powder, the fluidity and adhesion of the slurry are improved, enabling it to be directly spin-coated on the surface of the quartz tube. By optimizing the slurry components and adjusting the rotation speed and spin coating time of the quartz tube during spin coating, the coating is evenly coated and the thickness is controllable. Therefore, the preparation process of the high-temperature resistant coating of the present invention is simple, easy to operate, and suitable for industrial production.

[0028] (2) The high-temperature resistant coating prepared by the method of the present invention can effectively reduce the deformation rate of the quartz tube at high temperature and improve the service life of the quartz tube. Description of the drawings

[0029] The following further specifically describes the present invention in conjunction with the accompanying drawings and specific embodiments, and the above and / or other advantages of the present invention will become clearer.

[0030] Figure 1 Photo of the quartz tube with a high-temperature resistant coating prepared for Example 1. Specific Embodiments

[0031] The following further illustrates the present invention according to the following embodiments. It should be understood that the following embodiments are only used to illustrate the present invention and not to limit the present invention.

[0032] For specific technologies or conditions not specified in the embodiments, they shall be in accordance with the technologies or conditions described in the literature in this field or in accordance with the product specifications. For reagents or instruments without indicating the manufacturer, they are all conventional products that can be obtained through regular channels.

[0033] Example 1

[0034] Take 6 parts of pure water, add 6 parts of aluminum dihydrogen phosphate to it, stir and mix into a solution, and put it together with 8 parts of silica sol, 8 parts of silicon carbide with a particle size of 1 μm, 8 parts of alumina with a particle size of 1 μm, and 0.1 part of aluminum nitride with a particle size of 1 μm into a ball mill tank for ball milling and mixing. The ball milling speed is 350 r / min, and the ball milling time is 2 h. After the ball milling is completed, a high-temperature resistant coating slurry is obtained. Clamp the left and right ends of a quartz tube with a pipe diameter of 25 mm, a pipe length of 150 mm, and a wall thickness of 2 mm on a rotatable clamping device. Partially immerse the quartz tube in the high-temperature resistant coating slurry and perform a spin coating process. The rotation speed of the quartz tube is 2 r / min, and the rotation time is 0.8 min. After the spin coating is completed, place the quartz tube upright in an environment at 90 °C and dry it for 10 h. Finally, put the quartz tube into a high-temperature furnace, heat it up to 800 °C, keep it warm for 1 h, and then heat it up to 1400 °C and keep it warm for 1 h to obtain a high-temperature resistant quartz tube with a high-temperature resistant coating.

[0035] Figure 1 Photo of the quartz tube with a high-temperature resistant coating prepared in this example. It can be seen that the high-temperature resistant coating on the surface of the quartz tube is firmly adhered and has no obvious defects.

[0036] Example 2

[0037] Take 6 parts of pure water, add 6 parts of aluminum dihydrogen phosphate to it, stir and mix to form a solution. Mix it with 8 parts of silica sol, 8 parts of silicon carbide with a particle size of 1 μm, 8 parts of alumina with a particle size of 1 μm, and 0.1 part of aluminum nitride with a particle size of 1 μm in a ball mill tank for ball milling and mixing. The ball milling speed is 350 r / min, and the ball milling time is 2 h. After the ball milling is completed, a high-temperature resistant coating slurry is obtained. Clamp the left and right ends of a quartz tube with a pipe diameter of 25 mm, a pipe length of 150 mm, and a wall thickness of 2 mm on a rotatable clamping device. The quartz tube is partially immersed in the high-temperature resistant coating slurry for spin coating. The rotation speed of the quartz tube is 4 r / min, and the rotation time is 0.5 min. After the spin coating is completed, place the quartz tube upright in an environment at 90 °C for drying for 10 h. Finally, put the quartz tube into a high-temperature furnace, heat it up to 800 °C, hold for 1 h, then heat it up to 1400 °C and hold for 1 h to obtain a high-temperature resistant quartz tube with a high-temperature resistant coating.

[0038] Example 3

[0039] Take 6 parts of pure water, add 6 parts of aluminum dihydrogen phosphate to it, stir and mix to form a solution. Mix it with 8 parts of silica sol, 12 parts of silicon carbide with a particle size of 1 μm, 12 parts of alumina with a particle size of 1 μm, and 0.1 part of aluminum nitride with a particle size of 1 μm in a ball mill tank for ball milling and mixing. The ball milling speed is 350 r / min, and the ball milling time is 2 h. After the ball milling is completed, a high-temperature resistant coating slurry is obtained. Clamp the left and right ends of a quartz tube with a pipe diameter of 25 mm, a pipe length of 150 mm, and a wall thickness of 2 mm on a rotatable clamping device. The quartz tube is partially immersed in the high-temperature resistant coating slurry for spin coating. The rotation speed of the quartz tube is 2 r / min, and the rotation time is 0.8 min. After the spin coating is completed, place the quartz tube upright in an environment at 90 °C for drying for 10 h. Finally, put the quartz tube into a high-temperature furnace, heat it up to 800 °C, hold for 1 h, then heat it up to 1400 °C and hold for 1 h to obtain a high-temperature resistant quartz tube with a high-temperature resistant coating.

[0040] Example 4

[0041] Measure the coating thickness and detect the high-temperature deformation rate of the quartz tubes with high-temperature resistant coatings prepared in the above Examples 1-3. The detection method of the high-temperature deformation rate is as follows: Place the quartz tubes with high-temperature resistant coatings and the original quartz tubes horizontally on a heat-resistant bracket together, then keep them at a constant temperature of 1500 °C for 2 h, and take out the specimens after cooling to room temperature with the furnace. Measure the maximum vertical displacement ΔH of the center point of the quartz tube relative to the horizontal position respectively. The deformation rate ε = ΔH / 150. The experimental results are shown in Table 1.

[0042] Table 1 Coating thickness and high-temperature deformation rate of high-temperature resistant quartz tubes and original quartz tubes

[0043]

[0044] Compared with Example 2, the only difference in Example 1 lies in the spin coating speed and spin coating time of the quartz tube during the preparation of the high-temperature resistant coating. In Example 1, the rotation speed is 2 r / min and the time is 0.8 min, while in Example 2, the rotation speed is 4 r / min and the time is 0.5 min. The results in Table 1 show that the coating thickness of Example 2 is less than that of Example 1, indicating that the spin coating speed and spin coating time can adjust the coating thickness. The faster the spin coating speed and the shorter the spin coating time, the thinner the coating thickness.

[0045] Compared with Example 1, the only difference in Example 3 lies in the proportion of silicon carbide and alumina in the high-temperature resistant coating slurry. In the slurry of Example 1, the mass fraction of silicon carbide and alumina in the total mass of the slurry is 44.4%, and in the slurry of Example 3, the mass fraction of silicon carbide and alumina is 54.4%. The results in Table 1 show that the coating thickness of Example 3 is greater than that of Example 1, indicating that appropriately increasing the content of the coating powder in the slurry can increase the coating thickness.

[0046] By comparing the deformation rates of the high-temperature resistant quartz tubes and the original quartz tubes in Examples 1 - 3 in Table 1, it can be seen that the high-temperature resistant coating effectively reduces the deformation rate of the quartz tube at high temperatures.

[0047] The present invention provides an idea and method for a high-temperature resistant coating slurry, a high-temperature resistant quartz tube, and their preparation methods and applications. There are many methods and ways to specifically implement this technical solution. The above is only the preferred implementation mode of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention. Each component not clearly defined in this embodiment can be realized by existing technologies.

Claims

1. A high-temperature resistant coating slurry, characterized in that, By mass parts, the slurry includes 4 - 10 parts of phosphate, 4 - 10 parts of sol, 0.1 - 20 parts of silicon carbide, 0.1 - 20 parts of alumina, 0.1 - 10 parts of aluminum nitride, and 4 - 20 parts of inorganic solvent.

2. The high-temperature resistant coating slurry according to claim 1, wherein The phosphate is any one or a combination of more than one of aluminum dihydrogen phosphate, magnesium dihydrogen phosphate, sodium dihydrogen phosphate, sodium hexametaphosphate, and sodium tripolyphosphate; the sol is any one or a combination of more than one of silica sol, alumina sol, and zirconia sol; the inorganic solvent is any one or a combination of more than one of phosphoric acid, polyphosphoric acid, and water.

3. The high-temperature resistant coating slurry according to claim 1, wherein The particle sizes of the silicon carbide, alumina, and aluminum nitride are less than 10 μm.

4. A high-temperature resistant quartz tube, characterized in that, It includes a quartz tube and a high-temperature resistant coating covering the surface of the quartz tube; the high-temperature resistant coating is made of the high-temperature resistant coating slurry described in any one of claims 1 - 3.

5. The high-temperature resistant quartz tube according to claim 4, wherein The diameter of the quartz tube is 25 - 1000 mm, the length is 50 - 4000 mm, and the wall thickness is 2 - 200 mm; the thickness of the high-temperature resistant coating is 10 - 1000 μm.

6. The preparation method of the high-temperature resistant quartz tube according to claim 4 or 5, characterized in that, It includes the following steps: (1) Mix the phosphate with the inorganic solvent to form a solution, and grind and mix it with the sol, silicon carbide, alumina, and aluminum nitride together to obtain the high-temperature resistant coating slurry. (2) Use the spin coating process to coat the high-temperature resistant coating slurry obtained in step (1) on the surface of the quartz tube, dry it, and sinter it to obtain the product.

7. The preparation method according to claim 6, characterized in that, In step (1), the concentration of the phosphate in the solution is 30 - 70 wt%; the grinding is ball milling, and the rotation speed during ball milling is 200 - 500 r / min, and the time is 0.5 - 5 h.

8. The preparation method according to claim 6, characterized in that, In step (2), during the spin coating process, the rotation speed of the quartz tube is 0.5 - 5 r / min, and the rotation time is 0.2 - 2 min.

9. The preparation method according to claim 6, characterized in that In step (2), the drying temperature is 60 - 150 °C, and the time is 0.5 - 48 h; the sintering is carried out in stages. First, heat up to 600 - 900 °C and keep it warm for 0.5 - 2 h, then heat up to 1200 - 1500 °C and keep it warm for 0.5 - 2 h.

10. The application of the high-temperature resistant coating slurry described in any one of claims 1 - 3 in the production and manufacturing of quartz materials.

Images