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

Abstract

The present invention relates to the field of glass tube forming technology, and more particularly to a thermal shock-resistant composite glass rotary tube, its preparation method, and its application. These methods ensure the rotary tube's corrosion resistance and thermal shock resistance while reducing process complexity. The tube comprises a surface layer and a base layer. Polyethylene glycol loaded with zinc oxide powder in the base layer decomposes to produce gas, which diffuses toward the carbon fibers. The boron nitride coating on the carbon fibers guides the gas to form directional pores, resulting in a greater porosity in the surface layer than in the base layer. Furthermore, the directional pores serve as thermal stress conduction channels, thereby improving the rotary tube's thermal shock resistance.

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 rotary tube, a preparation method and an application thereof. Background Art

[0002] Glass is widely used in aerospace, vehicles, ships and other fields. It is an advanced inorganic non-metallic material and includes tempered glass, laminated glass, microcrystalline glass, foam glass, special coated glass, and energy-saving glass. Glass tubes are usually formed by drawing. Glass tube drawing technology is a process in which glass liquid is processed into glass tubes of specific shapes and sizes through glass tube drawing equipment. The important component involved in the glass tube drawing equipment is the rotating tube, which rotates in contact with the glass liquid under high temperature. According to the main components, the rotating tube mainly includes mullite rotating tube and zirconium corundum rotating tube. Mullite rotating tube has surface erosion problems due to its large pores. The commonly used alternative material is zirconium corundum rotating tube. Zirconium corundum can effectively resist the erosion of glass liquid due to its dense surface, thereby significantly improving the corrosion resistance of the rotating tube. However, zirconium corundum has poor thermal shock resistance and is prone to cracking or even breaking 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 the gradient pores can be regulated, the 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 may also lead to higher production costs.

[0004] How to ensure the corrosion resistance and thermal shock resistance of the rotating tube and reduce the process difficulty has become an issue that we urgently need 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, so as to ensure the corrosion 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 is:

[0007] A heat-shock-resistant composite glass rotating tube comprises a base layer and a surface layer from the inside to the outside along the radial direction of the rotating tube;

[0008] The surface layer includes the following raw materials by mass: 20-60 parts of mullite micropowder, 5-10 parts of alumina micropowder, 10-20 parts of spinel micropowder, 10-15 parts of white corundum micropowder, 4-10 parts of Cr2O3 micropowder, 10-20 parts of nano-sized titanium oxide, 2-10 parts of modified carbon fiber, 5-10 parts of modified zinc oxide micropowder, and 1-5 parts of binder;

[0009] The base layer includes the following raw materials in parts by mass: 20-40 parts of mullite micropowder, 5-10 parts of modified zinc oxide micropowder, 5-10 parts of andalusite micropowder, 0-8 parts of white corundum micropowder, 4-10 parts of Cr2O3 micropowder, and 1-4 parts of binder.

[0010] Furthermore,

[0011] The modified carbon fiber is prepared by immersing the carbon fiber in an ethanol suspension containing boron nitride nanoparticles, ultrasonically treating the carbon fiber for 30 minutes, drying the carbon fiber, and then heat treating the carbon fiber 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.

[0012] Furthermore,

[0013] The preparation method of the modified zinc oxide micropowder is as follows: dispersing the zinc oxide micropowder in an ethanol solution, adding 4-6% polyethylene glycol and 1-2% silane coupling agent based on the mass of the zinc oxide, stirring and drying to obtain the modified zinc oxide micropowder.

[0014] Furthermore,

[0015] The binder is at least one of polyvinyl alcohol, hydroxypropyl methylcellulose or polyacrylate.

[0016] Furthermore,

[0017] The porosity of the surface layer of the rotating tube is higher than that of the base layer.

[0018] A method for preparing a thermal shock resistant composite glass rotating tube comprises the following steps:

[0019] (1) Preparation of surface mixture:

[0020] By weight, the raw materials including 20-60 parts of mullite micropowder, 5-10 parts of alumina micropowder, 10-20 parts of spinel micropowder, 10-15 parts of white corundum micropowder, 4-10 parts of Cr2O3 micropowder, 10-20 parts of nano-sized titanium oxide, 2-10 parts of modified carbon fiber, 5-10 parts of modified zinc oxide micropowder, and 1-5 parts of a binder are mixed uniformly to obtain a surface layer mixture;

[0021] (2) Preparation of base layer mixture:

[0022] By weight, the raw materials including 20-40 parts of mullite micropowder, 5-10 parts of modified zinc oxide micropowder, 5-10 parts of andalusite micropowder, 0-8 parts of white corundum micropowder, 4-10 parts of Cr2O3 micropowder and 1-4 parts of binder are mixed uniformly to obtain a base layer mixture;

[0023] (3) Preparation of rotating tube blank:

[0024] The base layer mixture is filled into a mold as the base layer, and the surface layer mixture is then filled into the mold as the surface layer, and a rotating tube blank is obtained by isostatic pressing;

[0025] (4) Sintering molding:

[0026] The rotating tube blank is sintered to obtain a thermal shock resistant composite glass rotating tube. The entire sintering process includes a low temperature stage, a medium temperature stage and a high temperature stage.

[0027] The low temperature stage includes heating the rotating tube body to 300°C at 2°C / min and keeping the temperature for 1 hour.

[0028] The medium temperature stage includes heating the rotating tube body after the low temperature stage to 500°C at 5°C / min and keeping the temperature for 2 hours.

[0029] The high temperature stage includes heating the rotating tube billet after the medium temperature stage to 1200°C at 8°C / min and keeping it for 2 hours under argon protection, then heating it to 1450°C at 3°C / min and keeping it for 3 hours, and then taking it out after cooling it to 200°C in the furnace.

[0030] The invention discloses an application of a heat-shock-resistant composite glass rotary tube in glass tube drawing equipment.

[0031] The beneficial effects are analyzed as follows:

[0032] The polyethylene glycol in the modified zinc oxide micropowder in the matrix layer decomposes and produces gas. The polyethylene glycol acts as a pore-forming agent, generating gas that forms tiny pores within the material. As the gas diffuses within the material, it tends to move toward the surface, particularly toward areas containing modified carbon fibers.

[0033] 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, and its in-plane thermal conductivity is particularly outstanding. By coating the surface of the carbon fiber with boron nitride nanoparticles, the thermal conductivity of the interface between the fiber and the matrix is further enhanced, forming a continuous "carbon fiber boron nitride" high thermal conductivity network. Heat will preferentially be conducted through the carbon fiber boron nitride system, resulting in a slightly higher temperature around the fiber than in the matrix area. According to the thermal gradient effect of gas diffusion (thermophoresis), the gas will naturally migrate to the high-temperature area and thus concentrate in the surface layer where the carbon fiber is enriched. After the gas is generated in the matrix layer, it will be enriched in the surface area with a higher fiber content, and eventually escape through the open pores of the surface layer, resulting in a significantly higher porosity of the surface layer than the matrix layer, thereby improving the thermal shock resistance of the rotating tube. DETAILED DESCRIPTION

[0034] Example 1:

[0035] Surface mixture: 40 parts of mullite micropowder, 8 parts of alumina micropowder, 15 parts of spinel micropowder, 12 parts of white corundum micropowder, 7 parts of Cr2O3 micropowder, 15 parts of nano-grade titanium oxide, 6 parts of modified carbon fiber (length 4mm), 8 parts of modified zinc oxide micropowder, and 3 parts of polyvinyl alcohol binder.

[0036] Matrix layer mixture: 30 parts of mullite micropowder, 8 parts of modified zinc oxide micropowder, 8 parts of andalusite micropowder, 5 parts of white corundum micropowder, 7 parts of Cr2O3 micropowder, and 3 parts of polyvinyl alcohol binder.

[0037] The carbon fibers were 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 fibers.

[0038] Modified zinc oxide micropowder was prepared by dispersing zinc oxide micropowder in ethanol solution, adding 5% polyethylene glycol (PEG 6000) and 2% silane coupling agent (KH550), stirring and drying.

[0039] The surface layer and base layer mixtures were ball-milled separately for 2 hours to ensure uniformity. The base layer mixture was filled into a mold to form the base layer, and the surface layer mixture was then filled into the mold to form the surface layer. The rotating tube blank was formed by isostatic pressing (pressure 200 MPa).

[0040] Raise the temperature to 300°C at 2°C / min and keep it for 1 hour. Then, raise the temperature to 500°C at 5°C / min and keep it for 2 hours. Then, under argon protection, raise the temperature to 1200°C at 8°C / min and keep it for 2 hours. Then, raise the temperature to 1450°C at 3°C / min and keep it for 3 hours. Cool to 200°C with the furnace and take it out.

[0041] Performance characterization:

[0042] (1) The apparent porosity test was carried out in accordance with the standard GB / T2997-2000: the surface porosity was 18.5%, and the matrix porosity was 8.2%.

[0043] (2) Test according to standard YB / T376.1-1995 Test method for thermal shock resistance of refractory products (water quenching method): quench the rotating tube from 1000℃ to room temperature and cycle 40 times to produce cracks.

[0044] Example 2

[0045] Surface mixture: 40 parts of mullite micropowder, 8 parts of alumina micropowder, 15 parts of spinel micropowder, 12 parts of white corundum micropowder, 7 parts of Cr2O3 micropowder, 15 parts of nano-grade titanium oxide, 8 parts of modified carbon fiber (length 4mm), 10 parts of modified zinc oxide micropowder, and 3 parts of polyvinyl alcohol binder.

[0046] Base layer mixture: 30 parts of mullite micropowder, 10 parts of modified zinc oxide micropowder, 8 parts of andalusite micropowder, 5 parts of white corundum micropowder, 7 parts of Cr2O3 micropowder, and 3 parts of polyvinyl alcohol binder.

[0047] The carbon fibers were 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 fibers.

[0048] Modified zinc oxide micropowder was prepared by dispersing zinc oxide micropowder in ethanol solution, adding 5% polyethylene glycol (PEG 6000) and 2% silane coupling agent (KH550), stirring and drying.

[0049] The surface layer and base layer mixtures were ball milled separately for 2 hours to ensure uniformity. The base layer mixture was filled into a mold as the inner layer, and the surface layer mixture as the outer layer. The rotating tube blank was formed by isostatic pressing (pressure 200 MPa).

[0050] Raise the temperature to 300°C at 2°C / min and keep it for 1 hour. Then, raise the temperature to 500°C at 5°C / min and keep it for 2 hours. Then, under argon protection, raise the temperature to 1200°C at 8°C / min and keep it for 2 hours. Then, raise the temperature to 1450°C at 3°C / min and keep it for 3 hours. Cool to 200°C with the furnace and take it out.

[0051] Performance characterization: The surface porosity is 19.4%, the base layer porosity is 9.1%, and cracks are generated by rapidly cooling the rotating tube from 1000°C to room temperature and cycling it 39 times.

[0052] Comparative Example 1

[0053] Surface mixture: 40 parts of mullite micropowder, 8 parts of alumina micropowder, 15 parts of spinel micropowder, 12 parts of white corundum micropowder, 7 parts of Cr2O3 micropowder, 15 parts of nano-grade titanium oxide, 6 parts of carbon fiber (length 4mm), 8 parts of zinc oxide micropowder, and 3 parts of polyvinyl alcohol binder.

[0054] Matrix layer mixture: 30 parts of mullite micropowder, 8 parts of zinc oxide micropowder, 8 parts of andalusite micropowder, 5 parts of white corundum micropowder, 7 parts of Cr2O3 micropowder, and 3 parts of polyvinyl alcohol binder.

[0055] The surface layer and base layer mixtures were ball-milled separately for 2 hours to ensure uniformity. The base layer mixture was filled into a mold to form the base layer, and the surface layer mixture was then filled into the mold to form the surface layer. The rotating tube blank was formed by isostatic pressing (pressure 200 MPa).

[0056] Raise the temperature to 300°C at 2°C / min and keep it for 1 hour. Then, raise the temperature to 500°C at 5°C / min and keep it for 2 hours. Then, under argon protection, raise the temperature to 1200°C at 8°C / min and keep it for 2 hours. Then, raise the temperature to 1450°C at 3°C / min and keep it for 3 hours. Cool to 200°C with the furnace and take it out.

[0057] Performance characterization: The surface porosity is 12.3%, the base layer porosity is 7.8%, and cracks are generated by rapidly cooling the rotating tube from 1000°C to room temperature and cycling it 21 times.

[0058] Comparative Example 2

[0059] Surface mixture: 40 parts of mullite micropowder, 8 parts of alumina micropowder, 15 parts of spinel micropowder, 12 parts of white corundum micropowder, 7 parts of Cr2O3 micropowder, 15 parts of nano-grade titanium oxide, 6 parts of carbon fiber (length 4mm), 8 parts of modified zinc oxide micropowder, and 3 parts of polyvinyl alcohol binder.

[0060] Base layer mixture: 30 parts of mullite micropowder, 8 parts of modified zinc oxide micropowder, 8 parts of andalusite micropowder, 5 parts of white corundum micropowder, 7 parts of Cr2O3 powder, and 3 parts of polyvinyl alcohol binder.

[0061] Modified zinc oxide micropowder was prepared by dispersing zinc oxide micropowder in ethanol solution, adding 5% polyethylene glycol (PEG 6000) and 2% silane coupling agent (KH550), stirring and drying.

[0062] The surface layer and base layer mixtures were ball-milled separately for 2 hours to ensure uniformity. The base layer mixture was filled into a mold to form the base layer, and the surface layer mixture was then filled into the mold to form the surface layer. The rotating tube blank was formed by isostatic pressing (pressure 200 MPa).

[0063] Raise the temperature to 300°C at 2°C / min and keep it for 1 hour. Then, raise the temperature to 500°C at 5°C / min and keep it for 2 hours. Then, under argon protection, raise the temperature to 1200°C at 8°C / min and keep it for 2 hours. Then, raise the temperature to 1450°C at 3°C / min and keep it for 3 hours. Cool to 200°C with the furnace and take it out.

[0064] Performance characterization: The surface porosity is 16.5%, the base layer porosity is 8.5%, and cracks are generated by rapidly cooling the rotating tube from 1000°C to room temperature and cycling it 25 times.

[0065] Comparative Example 3

[0066] Surface mixture: 40 parts of mullite micropowder, 8 parts of alumina micropowder, 15 parts of spinel micropowder, 12 parts of white corundum micropowder, 7 parts of Cr2O3 micropowder, 15 parts of nano-grade titanium oxide, 6 parts of modified carbon fiber (length 4mm), 8 parts of zinc oxide micropowder, and 3 parts of polyvinyl alcohol binder.

[0067] Matrix layer mixture: 30 parts of mullite micropowder, 8 parts of zinc oxide micropowder, 8 parts of andalusite micropowder, 5 parts of white corundum micropowder, 7 parts of Cr2O3 micropowder, and 3 parts of polyvinyl alcohol binder.

[0068] The carbon fibers were 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 fibers.

[0069] The surface layer and base layer mixtures were ball-milled separately for 2 hours to ensure uniformity. The base layer mixture was filled into a mold to form the base layer, and the surface layer mixture was then filled into the mold to form the surface layer. The rotating tube blank was formed by isostatic pressing (pressure 200 MPa).

[0070] Raise the temperature to 300°C at 2°C / min and keep it for 1 hour. Then, raise the temperature to 500°C at 5°C / min and keep it for 2 hours. Then, under argon protection, raise the temperature to 1200°C at 8°C / min and keep it for 2 hours. Then, raise the temperature to 1450°C at 3°C / min and keep it for 3 hours. Cool to 200°C with the furnace and take it out.

[0071] Performance characterization: surface porosity: 13.9%, substrate porosity: 7.9%. The rotating tube was rapidly cooled from 1000°C to room temperature and cracks occurred after 22 cycles.

[0072] Summary and analysis:

[0073] In Example 1, the modified carbon fiber (boron nitride coating) and modified zinc oxide powder (polyethylene glycol) synergistically achieved a surface porosity of 18.5% and a base layer porosity of 8.2%; cracks appeared after 40 thermal shock cycles.

[0074] The surface porosity of Comparative Example 1 was 12.3%, and the thermal shock resistance was 21 times, indicating that the unmodified carbon fiber and zinc oxide powder could not effectively guide the formation of pores and the thermal shock resistance was poor.

[0075] In comparative example 2, only modified zinc oxide powder was used, the surface porosity was 16.5%, and the thermal shock resistance was 25 times, indicating that the modified zinc oxide powder alone can improve the porosity, but lacks the thermal conductive network of carbon fiber, and the improvement of thermal shock performance is limited.

[0076] Comparative Example 3, which only modified carbon fibers, had a surface porosity of 13.9% and resisted 22 thermal shock cycles. This indicates that while modified carbon fibers enhance thermal conductivity, they lack a directional gas migration mechanism, resulting in insignificant improvements in porosity and thermal shock resistance.

[0077] The polyethylene glycol in the zinc oxide powder in the matrix layer decomposes and produces gas. The polyethylene glycol acts as a pore-forming agent, generating gas that forms tiny pores within the material. As the gas diffuses within the material, it tends to move toward the surface, particularly toward areas containing modified carbon fibers.

[0078] The surface of the carbon fiber is coated with a boron nitride coating. The carbon fiber itself has high thermal conductivity, and the thermal conductivity of the boron nitride coating is also strong, and its in-plane thermal conductivity is particularly outstanding. By coating the surface of the carbon fiber with boron nitride nanoparticles, the thermal conductivity of the interface between the fiber and the matrix is further enhanced, forming a continuous "carbon fiber boron nitride" high thermal conductivity network. Heat will be preferentially conducted through the carbon fiber boron nitride system, resulting in a temperature around the fiber slightly higher than that of the matrix area. According to the thermal gradient effect of gas diffusion (thermophoresis), the gas will naturally migrate to the high-temperature area and thus concentrate in the surface layer where the carbon fiber is enriched. After the gas is generated in the matrix layer, it will be enriched in the surface area with a higher fiber content, and eventually escape through the open pores of the surface layer, resulting in a significantly higher porosity of the surface layer than the matrix layer, thereby improving the thermal shock resistance of the rotating tube.

[0079] 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 it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A thermal shock resistant composite glass rotating tube, characterized by: The rotating tube includes a base layer and a surface layer from the inside to the outside along the radial direction of the rotating tube; The surface layer comprises the following raw materials in parts by mass: 20-60 parts of mullite micropowder, 5-10 parts of alumina micropowder, 10-20 parts of spinel micropowder, 10-15 parts of white corundum micropowder, 4-10 parts of Cr2O3 micropowder, 10-20 parts of nano-sized titanium oxide, 2-10 parts of modified carbon fiber, 5-10 parts of modified zinc oxide micropowder, and 1-5 parts of a binder; The matrix layer comprises the following raw materials in parts by mass: 20-40 parts of mullite micropowder, 5-10 parts of modified zinc oxide micropowder, 5-10 parts of andalusite micropowder, 0-8 parts of white corundum micropowder, 4-10 parts of Cr2O3 micropowder, and 1-4 parts of binder; The modified carbon fiber is prepared by immersing the carbon fiber in an ethanol suspension containing boron nitride nanoparticles, ultrasonically treating the carbon fiber for 30 minutes, drying the carbon fiber, and then heat treating the carbon fiber at 1000° C. for 1 hour under argon protection to obtain the modified carbon fiber; the carbon fiber has a length of 3-5 mm; The preparation method of the modified zinc oxide micropowder is as follows: dispersing the zinc oxide micropowder in an ethanol solution, adding 4-6% polyethylene glycol and 1-2% silane coupling agent based on the mass of the zinc oxide, stirring and drying to obtain the modified zinc oxide micropowder.

2. The thermal shock resistant composite glass rotary tube according to claim 1, characterized in that: The binder is at least one of polyvinyl alcohol, hydroxypropyl methylcellulose or polyacrylate.

3. The thermal shock resistant composite glass rotary tube according to claim 1, characterized in that: The porosity of the surface layer of the rotating tube is higher than that of the base layer.

4. A method for preparing a thermal shock resistant composite glass rotating tube according to any one of claims 1 to 3, characterized in that: The steps include: (1) Preparation of surface mixture: By weight, the raw materials including 20-60 parts of mullite micropowder, 5-10 parts of alumina micropowder, 10-20 parts of spinel micropowder, 10-15 parts of white corundum micropowder, 4-10 parts of Cr2O3 micropowder, 10-20 parts of nano-sized titanium oxide, 2-10 parts of modified carbon fiber, 5-10 parts of modified zinc oxide micropowder, and 1-5 parts of a binder are mixed uniformly to obtain a surface layer mixture; (2) Preparation of base layer mixture: By weight, the raw materials including 20-40 parts of mullite micropowder, 5-10 parts of modified zinc oxide micropowder, 5-10 parts of andalusite micropowder, 0-8 parts of white corundum micropowder, 4-10 parts of Cr2O3 micropowder and 1-4 parts of binder are mixed uniformly to obtain a base layer mixture; (3) Preparation of rotating tube blank: Filling the base layer mixture into a mold as a base layer, and then filling the surface layer mixture into a mold as a surface layer, and forming a rotating tube blank by isostatic pressing; (4) Sintering molding: The rotating tube blank is sintered to obtain a thermal shock resistant composite glass rotating tube, and the sintering process includes a low temperature stage, a medium temperature stage and a high temperature stage.

5. The method for preparing a thermal shock resistant composite glass rotary tube according to claim 4, characterized in that: The low temperature stage includes heating the rotating tube body to 300° C. at a rate of 2° C. / min and keeping the temperature for 1 hour.

6. The method for preparing a thermal shock resistant composite glass rotating tube according to claim 5, characterized in that: The medium temperature stage comprises heating the rotating tube body that has passed the low temperature stage to 500° C. at a rate of 5° C. / min and keeping the temperature for 2 hours.

7. The method for preparing a thermal shock resistant composite glass rotating tube according to claim 6, characterized in that: The high temperature stage includes heating the rotating tube billet after the medium temperature stage to 1200°C at 8°C / min and keeping it for 2 hours under argon protection, then heating it to 1450°C at 3°C / min and keeping it for 3 hours, and then cooling it to 200°C in the furnace and taking it out.

8. Use of the thermal shock resistant composite glass rotary tube according to any one of claims 1 to 3 in glass tube drawing equipment.