Thermal shock resistant composite glass rotating tube, preparation method and application

Abstract

The invention relates to the technical field of glass tube forming, in particular to a thermal shock resistant composite glass rotating tube, a preparation method and application, and aims to ensure the erosion resistance and thermal shock resistance of the rotating tube and reduce the process difficulty. Comprising a surface layer and a matrix layer, zinc oxide micro powder loaded polyethylene glycol of the matrix layer is decomposed to produce gas, the gas is diffused towards carbon fibers, and a boron nitride coating of the carbon fibers guides the gas to form directional pores, so that the porosity of the surface layer is larger than that of the matrix layer, and the directional pores become thermal stress conduction channels. Therefore, the thermal shock performance of the rotating pipe is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of glass tube forming, and in particular to a thermal shock-resistant composite glass rotating tube, a preparation method and an application thereof. Background Art

[0002] Glass is widely used in the fields of aerospace, vehicles, ships, etc., and belongs to advanced inorganic non-metallic materials, including tempered glass, laminated glass, glass ceramics, foam glass, special coated glass, and energy-saving glass. Glass tubes are usually formed by drawing. The glass tube drawing technology is a process of processing molten glass into glass tubes with specific shapes and sizes through glass tube drawing equipment. An important component involved in the glass tube drawing equipment is the rotating tube, which rotates and contacts the molten glass in a high-temperature environment. Classified by the main components, the rotating tubes mainly include mullite rotating tubes and zircon corundum rotating tubes. Mullite rotating tubes have problems of surface erosion due to large pores, and the commonly used alternative material is zircon corundum rotating tubes. Zircon corundum can effectively resist the erosion of molten glass due to its dense surface, thus significantly improving the erosion resistance of the rotating tube. However, zircon corundum has poor thermal shock resistance and is prone to cracks or even fractures under frequent temperature changes, affecting its long-term stability and reliability.

[0003] CN202211586441.5 discloses a gradient pore glass rotating tube and a preparation method thereof. Although it can regulate the gradient pores, this invention involves a multi-layer structure, each layer has multiple components, and the porosity of each layer needs to be precisely controlled, which not only increases the complexity of the process but also may lead to higher production costs.

[0004] How to ensure the erosion resistance and thermal shock resistance of the rotating tube and reduce the process difficulty has become an urgent issue for us to solve. Summary of the Invention

[0005] The present invention provides a thermal shock-resistant composite glass rotating tube, a preparation method and an application thereof to ensure the erosion resistance and thermal shock resistance of the rotating tube and reduce the process difficulty.

[0006] In order to alleviate the above technical problems, the technical solution provided by the present invention lies in: A thermal shock-resistant composite glass rotating tube includes a matrix layer and a surface layer from the inside to the outside along the radial direction of the rotating tube; The surface layer includes the following raw materials in parts by mass: 20-60 parts of mullite fine powder, 5-10 parts of alumina fine powder, 10-20 parts of spinel fine powder, 10-15 parts of white corundum fine powder, 4-10 parts of Cr2O3 fine powder, 10-20 parts of nano titanium oxide, 2-10 parts of modified carbon fiber, 5-10 parts of modified zinc oxide fine powder, and 1-5 parts of binder; The matrix layer includes the following raw materials by mass parts: 20-40 parts of mullite fine powder, 5-10 parts of modified zinc oxide fine powder, 5-10 parts of andalusite fine powder, 0-8 parts of white fused alumina fine powder, 4-10 parts of Cr2O3 fine powder, and 1-4 parts of binder.

[0007] Furthermore, The preparation method of the modified carbon fiber is as follows: Immerse the carbon fiber into the ethanol suspension containing boron nitride nanoparticles, perform ultrasonic treatment for 30 minutes, take it out and dry it, and then perform heat treatment at 1000 °C for 1 hour under argon protection to obtain the modified carbon fiber; the length of the carbon fiber is 3-5 mm.

[0008] Furthermore, The preparation method of the modified zinc oxide fine powder is as follows: Disperse the zinc oxide fine powder in an ethanol solution, add 4-6% of polyethylene glycol and 1-2% of silane coupling agent based on the mass of zinc oxide, stir and then dry to obtain the modified zinc oxide fine powder.

[0009] Furthermore, The binder is at least one of polyvinyl alcohol, hydroxypropyl methylcellulose or polyacrylate.

[0010] Furthermore, The surface porosity of the rotating tube is higher than that of the matrix layer.

[0011] A preparation method of a thermal shock-resistant composite glass rotating tube includes the following steps: (1) Prepare the surface mixture: By mass parts, mix the raw materials including 20-60 parts of mullite fine powder, 5-10 parts of alumina fine powder, 10-20 parts of spinel fine powder, 10-15 parts of white fused alumina fine powder, 4-10 parts of Cr2O3 fine powder, 10-20 parts of nano titanium oxide, 2-10 parts of modified carbon fiber, 5-10 parts of modified zinc oxide fine powder, and 1-5 parts of binder evenly to obtain the surface mixture; (2) Prepare the matrix layer mixture: By mass parts, mix the raw materials including 20-40 parts of mullite fine powder, 5-10 parts of modified zinc oxide fine powder, 5-10 parts of andalusite fine powder, 0-8 parts of white fused alumina fine powder, 4-10 parts of Cr2O3 fine powder, and 1-4 parts of binder evenly to obtain the matrix layer mixture; (3) Prepare the rotating tube blank: Fill the matrix layer mixture into a mold as the matrix layer, and then fill the surface mixture into the mold as the surface layer, and obtain the rotating tube blank through isostatic pressing; (4) Sintering and forming: Sinter the rotating tube blank to obtain the thermal shock-resistant composite glass rotating tube. The whole sintering process includes a low-temperature stage, a medium-temperature stage and a high-temperature stage.

[0012] The low - temperature stage includes heating the rotating tube blank at a rate of 2 °C / min to 300 °C and holding for 1 hour.

[0013] The medium - temperature stage includes heating the rotating tube blank that has undergone the low - temperature stage at a rate of 5 °C / min to 500 °C and holding for 2 hours.

[0014] The high - temperature stage includes heating the rotating tube blank that has undergone the medium - temperature stage under argon protection at a rate of 8 °C / min to 1200 °C, holding for 2 hours, then heating to 1450 °C at a rate of 3 °C / min and holding for 3 hours, and taking it out after cooling to 200 °C in the furnace.

[0015] The application of a thermal - shock - resistant composite glass rotating tube in glass tube drawing equipment.

[0016] The beneficial effects are analyzed as follows: The polyethylene glycol in the modified zinc oxide micropowder of the matrix layer decomposes to produce gas. As a pore - forming agent, polyethylene glycol generates gas, and these gases form tiny pores inside the material. When the gas diffuses inside the material, it tends to move towards the surface layer, especially towards the area containing modified carbon fibers.

[0017] The surface of the modified carbon fiber is coated with a boron nitride coating. The carbon fiber itself has high thermal conductivity, and the boron nitride coating also has strong thermal conductivity, especially its in - plane thermal conductivity is prominent. By coating boron nitride nanoparticles on the surface of the carbon fiber, the thermal conductivity of the fiber - matrix interface is further enhanced, forming a continuous "carbon fiber - boron nitride" high - thermal - conductivity network. Heat will preferentially conduct through the carbon fiber - boron nitride system, resulting in the temperature around the fiber being slightly higher than the matrix region. According to the thermal gradient effect (thermophoresis phenomenon) of gas diffusion, the gas will naturally migrate towards the high - temperature region, thus concentrating towards the surface layer rich in carbon fibers. After the gas is generated in the matrix layer, it will concentrate towards the surface layer region with a higher fiber content and finally escape through the open pores on the surface layer, resulting in the surface porosity being significantly higher than that of the matrix layer, thereby improving the thermal shock performance of the rotating tube. Specific implementation methods

[0018] Example 1: Surface mixture: 40 parts of mullite micropowder, 8 parts of alumina micropowder, 15 parts of spinel micropowder, 12 parts of white fused alumina micropowder, 7 parts of Cr2O3 micropowder, 15 parts of nano - titanium oxide, 6 parts of modified carbon fiber (length 4 mm), 8 parts of modified zinc oxide micropowder, 3 parts of polyvinyl alcohol binder.

[0019] Matrix layer mixture: 30 parts of mullite micropowder, 8 parts of modified zinc oxide micropowder, 8 parts of andalusite micropowder, 5 parts of white fused alumina micropowder, 7 parts of Cr2O3 micropowder, 3 parts of polyvinyl alcohol binder.

[0020] The carbon fiber is immersed in an ethanol suspension containing boron nitride nanoparticles, ultrasonically treated for 30 minutes, dried, and then heat-treated at 1000 °C for 1 hour under argon protection to obtain modified carbon fiber.

[0021] The zinc oxide micropowder is dispersed in an ethanol solution, 5% polyethylene glycol (PEG 6000) and 2% silane coupling agent (KH550) are added, stirred and then dried to obtain modified zinc oxide micropowder.

[0022] The surface layer and matrix layer mixtures are separately ball-milled for 2 hours to ensure uniformity. The matrix layer mixture is filled into a mold as the matrix layer, and then the surface layer mixture is filled into the mold as the surface layer, and a rotary tube blank is obtained by isostatic pressing (pressure 200 MPa).

[0023] It is heated to 300 °C at a rate of 2 °C / min, held for 1 hour, then heated to 500 °C at a rate of 5 °C / min, held for 2 hours, then under argon protection, heated to 1200 °C at a rate of 8 °C / min and held for 2 hours, and then heated to 1450 °C at a rate of 3 °C / min and held for 3 hours, and taken out after cooling to 200 °C in the furnace.

[0024] Performance characterization: (1) The apparent porosity is detected according to the standard GB / T2997 - 2000: the porosity of the surface layer is 18.5%, and the porosity of the matrix layer is 8.2%.

[0025] (2) It is detected according to the standard YB / T376.1 - 1995 Test method for thermal shock resistance of refractories (water quenching method): the rotary tube is quenched from 1000 °C to room temperature, and cracks occur after 40 cycles.

[0026] Example 2 Surface layer mixture: 40 parts of mullite micropowder, 8 parts of alumina micropowder, 15 parts of spinel micropowder, 12 parts of white fused alumina micropowder, 7 parts of Cr2O3 micropowder, 15 parts of nanoscale titanium oxide, 8 parts of modified carbon fiber (length 4 mm), 10 parts of modified zinc oxide micropowder, 3 parts of polyvinyl alcohol binder.

[0027] Matrix layer mixture: 30 parts of mullite micropowder, 10 parts of modified zinc oxide micropowder, 8 parts of andalusite micropowder, 5 parts of white fused alumina micropowder, 7 parts of Cr2O3 micropowder, 3 parts of polyvinyl alcohol binder.

[0028] The carbon fiber is immersed in an ethanol suspension containing boron nitride nanoparticles, ultrasonically treated for 30 minutes, dried, and then heat-treated at 1000 °C for 1 hour under argon protection to obtain modified carbon fiber.

[0029] The zinc oxide micropowder is dispersed in an ethanol solution, 5% polyethylene glycol (PEG 6000) and 2% silane coupling agent (KH550) are added, stirred and then dried to obtain modified zinc oxide micropowder.

[0030] The surface layer and matrix layer mixtures are ball-milled and mixed for 2 hours respectively to ensure uniformity. The matrix layer mixture is filled into a mold as the inner layer, and the surface layer mixture is used as the outer layer. A rotary tube blank is obtained by isostatic pressing (pressure 200 MPa).

[0031] Heat it at 2 °C / min to 300 °C, hold for 1 hour, then heat it at 5 °C / min to 500 °C, hold for 2 hours, then under argon protection, heat it at 8 °C / min to 1200 °C and hold for 2 hours, then heat it to 1450 °C at 3 °C / min and hold for 3 hours, and take it out after furnace cooling to 200 °C.

[0032] Performance characterization: The porosity of the surface layer is 19.4%, and the porosity of the matrix layer is 9.1%. When the rotary tube is quenched from 1000 °C to room temperature, cracks occur after 39 cycles.

[0033] Comparative Example 1 Surface layer mixture: 40 parts of mullite fine powder, 8 parts of alumina fine powder, 15 parts of spinel fine powder, 12 parts of white fused alumina fine powder, 7 parts of Cr2O3 fine powder, 15 parts of nano-titanium oxide, 6 parts of carbon fiber (length 4 mm), 8 parts of zinc oxide fine powder, 3 parts of polyvinyl alcohol binder.

[0034] Matrix layer mixture: 30 parts of mullite fine powder, 8 parts of zinc oxide fine powder, 8 parts of andalusite fine powder, 5 parts of white fused alumina fine powder, 7 parts of Cr2O3 fine powder, 3 parts of polyvinyl alcohol binder.

[0035] The surface layer and matrix layer mixtures are ball-milled and mixed for 2 hours respectively to ensure uniformity. The matrix layer mixture is filled into a mold as the matrix layer, and then the surface layer mixture is filled into the mold as the surface layer. A rotary tube blank is obtained by isostatic pressing (pressure 200 MPa).

[0036] Heat it at 2 °C / min to 300 °C, hold for 1 hour, then heat it at 5 °C / min to 500 °C, hold for 2 hours, then under argon protection, heat it at 8 °C / min to 1200 °C and hold for 2 hours, then heat it to 1450 °C at 3 °C / min and hold for 3 hours, and take it out after furnace cooling to 200 °C.

[0037] Performance characterization: The porosity of the surface layer is 12.3%, and the porosity of the matrix layer is 7.8%. When the rotary tube is quenched from 1000 °C to room temperature, cracks occur after 21 cycles.

[0038] Comparative Example 2 Surface layer mixture: 40 parts of mullite fine powder, 8 parts of alumina fine powder, 15 parts of spinel fine powder, 12 parts of white fused alumina fine powder, 7 parts of Cr2O3 fine powder, 15 parts of nano-titanium oxide, 6 parts of carbon fiber (length 4 mm), 8 parts of modified zinc oxide fine powder, 3 parts of polyvinyl alcohol binder.

[0039] Matrix layer mixture: 30 parts of mullite fine powder, 8 parts of modified zinc oxide fine powder, 8 parts of andalusite fine powder, 5 parts of white fused alumina fine powder, 7 parts of Cr2O3 powder, and 3 parts of polyvinyl alcohol binder.

[0040] Disperse zinc oxide fine powder in ethanol solution, add 5% polyethylene glycol (PEG 6000) and 2% silane coupling agent (KH550), stir and then dry to obtain modified zinc oxide fine powder.

[0041] Ball-mill and mix the surface layer and matrix layer mixtures for 2 hours respectively to ensure uniformity. Fill the matrix layer mixture into the mold as the matrix layer, and then fill the surface layer mixture into the mold as the surface layer, and obtain the rotary tube blank by isostatic pressing (pressure 200 MPa).

[0042] Heat up to 300 °C at a rate of 2 °C / min, hold for 1 hour, then heat up to 500 °C at a rate of 5 °C / min, hold for 2 hours, then under argon protection, heat up to 1200 °C at a rate of 8 °C / min and hold for 2 hours, and then heat up to 1450 °C at a rate of 3 °C / min and hold for 3 hours, and take out after cooling to 200 °C with the furnace.

[0043] Performance characterization: The porosity of the surface layer is 16.5%, the porosity of the matrix layer is 8.5%, and cracks occur after quenching the rotary tube from 1000 °C to room temperature for 25 cycles.

[0044] Comparative Example 3 Surface layer mixture: 40 parts of mullite fine powder, 8 parts of alumina fine powder, 15 parts of spinel fine powder, 12 parts of white fused alumina fine powder, 7 parts of Cr2O3 fine powder, 15 parts of nano-titanium oxide, 6 parts of modified carbon fiber (length 4 mm), 8 parts of zinc oxide fine powder, and 3 parts of polyvinyl alcohol binder.

[0045] Matrix layer mixture: 30 parts of mullite fine powder, 8 parts of zinc oxide fine powder, 8 parts of andalusite fine powder, 5 parts of white fused alumina fine powder, 7 parts of Cr2O3 fine powder, and 3 parts of polyvinyl alcohol binder.

[0046] Immerse the carbon fiber in an ethanol suspension containing boron nitride nanoparticles, ultrasonically treat for 30 minutes, dry and then heat-treat at 1000 °C for 1 hour under argon protection to obtain modified carbon fiber.

[0047] Ball-mill and mix the surface layer and matrix layer mixtures for 2 hours respectively to ensure uniformity. Fill the matrix layer mixture into the mold as the matrix layer, and then fill the surface layer mixture into the mold as the surface layer, and obtain the rotary tube blank by isostatic pressing (pressure 200 MPa).

[0048] Heat up to 300 °C at 2 °C / min, hold for 1 hour, then heat up to 500 °C at 5 °C / min, hold for 2 hours, then under argon protection, heat up to 1200 °C at 8 °C / min, hold for 2 hours, and then heat up to 1450 °C at 3 °C / min, hold for 3 hours, and cool in the furnace to 200 °C before taking out.

[0049] Performance characterization: Surface porosity: 13.9%, matrix layer porosity: 7.9%. Quench the rotating tube from 1000 °C to room temperature, and cracks occur after 22 cycles.

[0050] Summary and analysis: In Example 1, through the synergistic effect of modified carbon fiber (boron nitride coating) and modified zinc oxide micropowder (polyethylene glycol), the surface porosity reached 18.5% and the matrix layer porosity reached 8.2%; cracks appeared after 40 thermal shock cycles.

[0051] In Comparative Example 1, the surface porosity was 12.3% and the thermal shock resistance was 21 cycles. It shows that unmodified carbon fiber and zinc oxide micropowder cannot effectively guide the formation of pores and have poor thermal shock performance.

[0052] In Comparative Example 2, only the zinc oxide micropowder was modified. The surface porosity was 16.5% and the thermal shock resistance was 25 cycles. It shows that the use of modified zinc oxide micropowder alone can increase the porosity, but due to the lack of a heat conduction network of carbon fiber, the improvement of thermal shock performance is limited.

[0053] In Comparative Example 3, only the carbon fiber was modified. The surface porosity was 13.9% and the thermal shock resistance was 22 cycles. It shows that although the modified carbon fiber enhances heat conduction, there is a lack of a gas directional migration mechanism, and the improvement of porosity and thermal shock performance is not obvious.

[0054] The polyethylene glycol in the zinc oxide micropowder of the matrix layer decomposes to produce gas. Polyethylene glycol acts as a pore-forming agent to generate gas, and these gases form tiny pores inside the material. When the gas diffuses inside the material, it tends to move towards the surface layer, especially towards the area containing modified carbon fiber.

[0055] The surface of the carbon fiber is coated with a boron nitride coating. The carbon fiber itself has high thermal conductivity, and the boron nitride coating also has strong thermal conductivity, especially its in-plane thermal conductivity is prominent. By coating boron nitride nanoparticles on the surface of the carbon fiber, the thermal conductivity of the fiber and matrix interface is further enhanced, forming a continuous "carbon fiber - boron nitride" high - thermal - conductivity network. Heat will preferentially conduct through the carbon fiber - boron nitride system, resulting in the temperature around the fiber being slightly higher than the matrix region. According to the thermal gradient effect (thermophoresis) of gas diffusion, the gas will naturally migrate towards the high - temperature region, thus concentrating towards the surface layer rich in carbon fiber. After the gas is generated in the matrix layer, it will concentrate towards the surface layer region with a higher fiber content and finally escape through the open pores on the surface layer, resulting in the surface porosity being significantly higher than that of the matrix layer, thereby improving the thermal shock performance of the rotating tube.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A heat-resistant shock composite glass rotating tube, characterized in that: It includes a matrix layer and a surface layer from the inside to the outside in the radial direction of the rotating tube; The surface layer includes the following raw materials by mass fraction: 20 - 60 parts of mullite fine powder, 5 - 10 parts of alumina fine powder, 10 - 20 parts of spinel fine powder, 10 - 15 parts of white fused alumina fine powder, 4 - 10 parts of Cr2O3 fine powder, 10 - 20 parts of nano-titanium oxide, 2 - 10 parts of modified carbon fiber, 5 - 10 parts of modified zinc oxide fine powder, and 1 - 5 parts of binder; The matrix layer includes the following raw materials by mass fraction: 20 - 40 parts of mullite fine powder, 5 - 10 parts of modified zinc oxide fine powder, 5 - 10 parts of andalusite fine powder, 0 - 8 parts of white fused alumina fine powder, 4 - 10 parts of Cr2O3 fine powder, and 1 - 4 parts of binder.

2. The anti-thermal shock composite glass rotating tube according to claim 1, wherein: The preparation method of the modified carbon fiber is as follows: Immerse the carbon fiber in an ethanol suspension containing boron nitride nanoparticles, perform ultrasonic treatment for 30 minutes, take it out and dry it, and then perform heat treatment at 1000 °C for 1 hour under argon protection to obtain the modified carbon fiber; the length of the carbon fiber is 3 - 5 mm.

3. The anti-thermal shock composite glass rotating tube according to claim 1, wherein: The preparation method of the modified zinc oxide fine powder is as follows: Disperse the zinc oxide fine powder in an ethanol solution, add 4 - 6% of polyethylene glycol and 1 - 2% of silane coupling agent based on the mass of zinc oxide, stir and then dry to obtain the modified zinc oxide fine powder.

4. The anti-thermal shock composite glass rotating tube according to claim 1, wherein: The binder is at least one of polyvinyl alcohol, hydroxypropyl methylcellulose or polyacrylate.

5. The anti-thermal shock composite glass rotating tube according to claim 1, wherein: The porosity of the surface layer of the rotating tube is higher than that of the matrix layer.

6. A method for preparing a heat-resistant shock composite glass rotating tube as described in any one of claims 1-5, characterized in that: It includes the following steps: (1) Prepare the surface layer mixture: By mass fraction, mix the raw materials including 20 - 60 parts of mullite fine powder, 5 - 10 parts of alumina fine powder, 10 - 20 parts of spinel fine powder, 10 - 15 parts of white fused alumina fine powder, 4 - 10 parts of Cr2O3 fine powder, 10 - 20 parts of nano-titanium oxide, 2 - 10 parts of modified carbon fiber, 5 - 10 parts of modified zinc oxide fine powder, and 1 - 5 parts of binder evenly to obtain the surface layer mixture; (2) Prepare the matrix layer mixture: By mass fraction, mix the raw materials including 20 - 40 parts of mullite fine powder, 5 - 10 parts of modified zinc oxide fine powder, 5 - 10 parts of andalusite fine powder, 0 - 8 parts of white fused alumina fine powder, 4 - 10 parts of Cr2O3 fine powder, and 1 - 4 parts of binder evenly to obtain the matrix layer mixture; (3) Prepare the rotating tube blank: Fill the matrix layer mixture into a mold as the matrix layer, and then fill the surface layer mixture into the mold as the surface layer, and obtain the rotating tube blank by isostatic pressing; (4) Sintering and forming: Sinter the rotating tube blank to obtain the anti-thermal shock composite glass rotating tube, and the sintering process includes a low-temperature stage, a medium-temperature stage and a high-temperature stage.

7. The anti-thermal shock composite glass rotating tube according to claim 6, wherein: The low-temperature stage includes heating the rotary tube blank at a rate of 2 °C / min to 300 °C and holding for 1 hour.

8. The heat-shock resistant composite glass rotary tube according to claim 7, wherein: The medium-temperature stage includes heating the rotary tube blank that has undergone the low-temperature stage at a rate of 5 °C / min to 500 °C and holding for 2 hours.

9. The heat-shock resistant composite glass rotary tube according to claim 8, wherein: The high-temperature stage includes heating the rotary tube blank that has undergone the medium-temperature stage under argon protection at a rate of 8 °C / min to 1200 °C and holding for 2 hours, then heating to 1450 °C at a rate of 3 °C / min and holding for 3 hours, and taking it out after cooling in the furnace to 200 °C.

10. Application of the heat-shock resistant composite glass rotary tube according to any one of claims 1-5 in glass tube drawing equipment.