High borosilicate glass tube and continuous hot press molding process thereof

Abstract

The invention belongs to the field of glass manufacturing, and discloses a high borosilicate glass tube and a continuous hot press molding process thereof.The high borosilicate glass tube comprises a tube body, and the tube body comprises the following raw materials in percentage by weight: 10-20% of glass powder, 10-20% of glass powder and 10-20% of glass powder. Comprising 18%-19% of diboron trioxide, 3%-4.5% of aluminum oxide, 2%-4% of zinc oxide, 1%-2% of sodium oxide, 0.5%-1.5% of potassium oxide, 0.5%-2% of gallium oxide, 0.1%-1.5% of lanthanum oxide, 0.1%-1% of yttrium oxide, 0.05%-0.3% of cerium oxide, 0.02%-0.1% of nano titanium carbide and the balance silicon dioxide. The wall thickness of the pipe body is 0.8-2.0 mm, the outer diameter of the pipe body is 10-50 mm, the wall thickness of the pipe body is 0.8-2.0 mm, and the outer diameter of the pipe body is 10-50 mm; the invention aims to provide a high borosilicate glass tube with lower thermal expansion coefficient and higher chemical stability and mechanical strength, and a continuous hot press molding process capable of realizing efficient and stable production and improving product quality.

Description

Technical Field

[0001] The present invention relates to the technical field of glass manufacturing, in particular to a high-borosilicate glass tube and a continuous hot pressing molding process thereof. Background Art

[0002] Borosilicate glass tubes, due to their excellent heat resistance, chemical stability, and mechanical strength, are widely used in laboratory instruments, solar collectors, medical equipment, and other fields. Traditional borosilicate glass tubes are primarily based on silicon dioxide and boron trioxide. As their application continues to expand, higher performance requirements are being placed on them, such as lower thermal expansion coefficients and greater chemical stability.

[0003] At the same time, the existing high-borosilicate glass tube molding process has problems such as low production efficiency and unstable product quality. For example, the furnace lining is easily corroded by the glass liquid, resulting in a short service life, and the molding mold has insufficient control over the molding precision of the glass tube.

[0004] Therefore, a high-borosilicate glass tube with better performance and an efficient and stable molding process thereof are proposed. Summary of the Invention

[0005] The object of the present invention is to provide a high borosilicate glass tube with a lower thermal expansion coefficient, higher chemical stability and mechanical strength, and a continuous hot pressing molding process that can achieve efficient and stable production and improve product quality.

[0006] In order to achieve the above object, the present invention provides the following technical solutions: The technical solution provided by the present invention is: a high borosilicate glass tube, including a tube body, wherein the raw materials of the tube body include, by weight percentage, 18%-19% boron trioxide, 3%-4.5% aluminum oxide, 2%-4% zinc oxide, 1%-2% sodium oxide, 0.5%-1.5% potassium oxide, 0.5%-2% gallium oxide, 0.1%-1.5% lanthanum oxide, and 0.1%-1% yttrium oxide; the raw materials of the tube body also contain 0.05%-0.3% cerium oxide, 0.02%-0.1% nano-titanium carbide, and the balance silicon dioxide; the wall thickness of the tube body is 0.8-2.0 mm, and the outer diameter is 10-50 mm.

[0007] Furthermore, the outer wall of the tube body is composited with a zirconium diboride ceramic coating with a thickness of 8-20 μm, and the coating is prepared by plasma chemical vapor deposition. The bonding strength between the coating and the tube body is ≥60 MPa, and the surface hardness is ≥2000 HV.

[0008] A continuous hot pressing process for forming a high borosilicate glass tube, for preparing the high borosilicate glass tube according to any one of claims 1 to 3, comprising the following steps: S1. Raw material preparation: silicon dioxide, boron trioxide, aluminum oxide, zinc oxide, sodium oxide, potassium oxide, gallium oxide, lanthanum oxide, and yttrium oxide are mixed in proportion, and cerium oxide and nano-titanium carbide are optionally added to obtain a mixture; S2. Melting: The mixture is put into a furnace and melted at 1550-1650°C to obtain glass liquid. The furnace lining is made of boron nitride-silicon carbide composite refractory material, in which the boron nitride content is 20%-30% and the silicon carbide content is 70%-80%; S3. Continuous hot pressing: The molten glass is conveyed through a flow channel into a forming mold comprising an upper mold and a lower mold, with a forming cavity formed between the upper and lower molds to match the outer diameter of the high-borosilicate glass tube. During the forming process, the upper mold moves downward at a speed of 0.6-1.4 mm / s, applying a pressure of 0.6-1.4 MPa to the molten glass. Simultaneously, the temperature of the forming mold is controlled at 820-980°C by a heating device, so that the molten glass is formed into a glass tube blank within the forming cavity. The inner wall of the flow channel is provided with a zirconium diboride ceramic coating having a thickness of 0.3-0.7 mm. S4, cooling and shaping: the formed glass tube moves with the forming mold to the cooling area, and the cooling fan blows cold air with a temperature of 15-35°C and a wind speed of 7-12m / s to the glass tube, so that the glass tube is cooled to room temperature at a speed of 6-14°C / min; S5. Cutting: Cut the cooled and shaped glass tube blank into a predetermined length to obtain a high borosilicate glass tube.

[0009] Furthermore, in step S2, the boron nitride-silicon carbide composite refractory material is formed by isostatic pressing, has a density ≥2.8g / cm³, and an erosion rate of high borosilicate glass liquid at 1600°C ≤0.05mm / h. The composite refractory material can effectively increase the service life of the furnace lining and reduce glass liquid contamination caused by lining erosion.

[0010] Furthermore, in step S3, the zirconium diboride ceramic coating is prepared by supersonic plasma spraying, and the ZrB2 phase content in the coating is ≥95%, the porosity is ≤2%, and the thermal shock resistance (1000°C water cooling cycle) is ≥50 times. The zirconium diboride ceramic coating can improve the corrosion resistance and thermal stability of the flow channel, ensuring the stable transportation of the glass liquid.

[0011] Furthermore, the conveying roller in the cooling area in step S4 is made of graphite-carbon fiber composite material, the surface of which is impregnated with polytetrafluoroethylene and has a friction coefficient of ≤0.15, which can reduce friction damage to the glass tube during the cooling process and ensure product quality.

[0012] Furthermore, in step S5, the cutting equipment adopts a diamond wire saw and laser composite cutting device, the wire saw feed speed is 15-25mm / s, the laser preheating temperature is 300-500℃, and the cutting end face parallelism is ≤0.05mm. The composite cutting device can improve cutting accuracy and efficiency and reduce cutting defects.

[0013] The beneficial effects of this technical solution are: (1) To optimize thermal stability, gallium oxide was added to the raw material of high borosilicate glass tube, which can effectively reduce the thermal expansion coefficient of glass. No cracks were generated after 200 cycles of temperature cycling from 250℃ to -40℃. At the same time, the introduction of lanthanum oxide and yttrium oxide reduced the thermal expansion coefficient of glass to 2.0-2.8×10 -6 / ℃, which is significantly lower than that of traditional high borosilicate glass. At the same time, the bending strength is increased to 280-350MPa, which greatly improves the reliability of the glass tube in environments with drastic temperature changes. It can be used in high-temperature furnace observation windows, high-temperature sensor protection covers in the aerospace field and other scenes with extremely high requirements for thermal stability. Cerium oxide releases oxygen to eliminate bubbles in the glass liquid, improving light transmittance, and nano-titanium carbide forms a nano-reinforced skeleton to improve wear resistance; The zinc oxide, aluminum oxide, and other raw material components work synergistically with gallium oxide to improve the glass network structure, significantly enhancing the chemical stability of the glass tube. Acid and alkali corrosion tests have shown that, under the same conditions, the glass tube of this invention exhibits significantly improved acid and alkali corrosion resistance compared to traditional borosilicate glass tubes. It can be used in applications requiring high chemical stability, such as lining chemical reactors and piping for corrosive liquids. (2) The zirconium diboride ceramic coating on the outer wall of the tube is prepared by plasma chemical vapor deposition and has extremely high surface hardness (≥2000HV) and good bonding strength (≥60MPa). In actual use, compared with uncoated glass tubes, it effectively extends the service life of the glass tube and is suitable for occasions requiring frequent friction contact, such as glass guide tubes in mechanical processing. The zirconium diboride ceramic coating has excellent corrosion resistance to a variety of chemical reagents. It can effectively protect the glass tube body from erosion in environments such as strong oxidizing acids and strong alkalis, further expanding the application range of glass tubes. It can be used in highly corrosive media detection instruments in the fields of chemical industry, environmental protection, etc. (3) In the continuous hot pressing process, the upper mold movement speed (0.6-1.4 mm / s), pressure (0.6-1.4 MPa) and molding mold temperature (820-980°C) are precisely controlled to enable the glass liquid to be quickly and stably formed into a glass tube blank in the molding cavity. Compared with the traditional molding process, the production efficiency is improved. At the same time, the cooling area is controlled by a cooling fan and reasonable wind speed (7-12 m / s) and temperature (15-35°C), so that the glass tube blank is cooled and shaped at an appropriate speed (6-14°C / min), avoiding product defects caused by improper cooling, further improving production efficiency and product qualification rate. (4) The furnace lining is made of boron nitride-silicon carbide composite refractory material, which has an erosion rate of ≤0.05mm / h for high-borosilicate glass liquid at 1600℃. Its service life is more than twice that of traditional refractory materials, reducing the frequency and cost of furnace lining replacement. The zirconium diboride ceramic coating on the inner wall of the flow channel has a thermal shock resistance (1000℃ water cooling cycle) of ≥50 times, effectively preventing the erosion and adhesion of glass liquid to the channel, reducing cleaning and maintenance costs. In addition, the optimization of process parameters and the improvement of equipment performance have reduced energy consumption.

[0014] (5) By using a diamond wire saw and laser composite cutting device, the parallelism of the cutting end face is ≤0.05mm, which greatly improves the cutting accuracy and reduces the product scrap rate due to cutting defects. The conveyor rollers in the cooling area are made of graphite-carbon fiber composite materials and are impregnated with polytetrafluoroethylene. The friction coefficient is ≤0.15, which avoids scratches and damage caused by friction during the cooling process of the glass tube blank, ensures the appearance quality and dimensional accuracy of the product, and significantly improves the stability of product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a flow chart of a high borosilicate glass tube and its continuous hot pressing forming process proposed by the present invention; Figure 2 This is a data sheet for Example 1 of a high borosilicate glass tube and its continuous hot pressing forming process proposed by the present invention; Figure 3 This is a data sheet for Example 2 of a high borosilicate glass tube and its continuous hot pressing forming process proposed by the present invention; Figure 4 This is a data sheet for Example 3 of a high borosilicate glass tube and its continuous hot pressing forming process proposed by the present invention; Figure 5 This is a data sheet for Example 4 of a high borosilicate glass tube and its continuous hot pressing forming process proposed by the present invention; Figure 6 This is a data sheet for Example 5 of a high borosilicate glass tube and its continuous hot pressing forming process proposed by the present invention; Figure 7This is a data comparison table of various embodiments of a high borosilicate glass tube and its continuous hot pressing forming process proposed in the present invention. DETAILED DESCRIPTION

[0016] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0017] The specific implementation process is as follows: Example 1: See also Figure 1-2 The present invention provides a technical solution: a high borosilicate glass tube and a continuous hot pressing process thereof, comprising the following steps: S1. Raw material preparation: by weight percentage, 19% boron trioxide, 3% aluminum oxide, 4% zinc oxide, 1% sodium oxide, 1.5% potassium oxide, 2% gallium oxide, 0.1% lanthanum oxide, 0.1% yttrium oxide, 0.05% cerium oxide, 0.02% nano-titanium carbide and the balance silicon dioxide, and fully mix the raw materials to obtain a mixture; S2, melting: put the mixture into the lining of boron nitride-silicon carbide composite refractory material (boron nitride content 20%, silicon carbide content 80%, isostatic pressing, density 2.8g / cm 3 , in a furnace with an erosion rate of 0.05mm / h for high borosilicate glass liquid at 1600℃, melted at 1550℃ to obtain glass liquid; S3. Continuous hot pressing: The glass liquid is conveyed into a forming mold through a flow channel whose inner wall is provided with a 0.3 mm thick zirconium diboride ceramic coating (prepared by supersonic plasma spraying, with a ZrB2 phase content of 95%, a porosity of 2%, and thermal shock resistance (1000°C water cooling cycle 50 times)). A forming cavity is formed between the upper and lower molds of the forming mold, which is compatible with a high borosilicate glass tube with an outer diameter of 10 mm and a wall thickness of 0.8 mm. The upper mold moves downward at a speed of 0.6 mm / s, applying a pressure of 0.6 MPa to the glass liquid. At the same time, the temperature of the forming mold is controlled at 820°C by a heating device, so that the glass liquid is formed into a glass tube blank in the forming cavity. S4, cooling and shaping: The formed glass tube moves with the forming mold to the cooling area, and the cooling fan blows cold air with a temperature of 15°C and a wind speed of 7m / s to the glass tube, so that the glass tube is cooled to room temperature at a rate of 6°C / min; the conveyor roller in the cooling area is made of graphite-carbon fiber composite material, and the surface is impregnated with polytetrafluoroethylene, with a friction coefficient of 0.15; S5. Cutting: Using a diamond wire saw and laser composite cutting device, with a wire saw feed speed of 15 mm / s and a laser preheating temperature of 300°C, the cooled and shaped glass tube blank is cut into a predetermined length to obtain a high borosilicate glass tube; This embodiment takes basic heat resistance as the core goal, supplemented by 3% aluminum oxide and 4% zinc oxide to improve chemical stability and mechanical strength. The newly added lanthanum oxide (0.1%) and yttrium oxide (0.1%), through the network filling effect of rare earth ions, preliminarily improve the thermal stability of the glass, and control the thermal expansion coefficient to 3.3×10 -6 / °C, and showed no cracks after 200 cycles from 250°C to -40°C, meeting the requirements of typical temperature fluctuation scenarios. A trace amount of cerium oxide (0.05%) acts as a clarifier, effectively reducing bubbles in the glass liquid and improving the matrix transparency, while the dispersed distribution of nano-titanium carbide (0.02%) provides a preliminary wear-resistant enhancement effect for the glass matrix.

[0018] The manufacturing process utilizes a low-temperature melt temperature of 1550°C and a low-pressure molding process of 0.6 MPa, coupled with a mold temperature of 820°C. This reduces energy consumption but results in insufficient fluidity of the molten glass. The resulting glass tubes exhibit poor surface finish and a surface hardness of only 580 HV. The cooling process utilizes a controlled cooling rate of 6°C / min using 15°C cold air at a wind speed of 7 m / s, thus avoiding internal stress concentration. However, the low-pressure molding results in a coating bond strength of only 60 MPa, resulting in limited improvement in wear resistance.

[0019] The advantage of this embodiment lies in the first demonstration of the compatibility of the rare earth-micro-nano composite system with traditional borosilicate glass. The basic components are balanced, and the raw material cost is 18% lower than that of the functional formula. It is suitable for applications where surface quality requirements are low but basic heat resistance is important, such as common laboratory beakers and reagent tubes, achieving reliable temperature adaptability at a low cost.

[0020] Example 2: See also Figure 1 and Figure 3 The present invention provides a technical solution: a high borosilicate glass tube and a continuous hot pressing process thereof, comprising the following steps: S1. Raw material preparation: by weight percentage, 18% boron trioxide, 4.5% aluminum oxide, 2% zinc oxide, 2% sodium oxide, 0.5% potassium oxide, 0.5% gallium oxide, 1.5% lanthanum oxide, 1% yttrium oxide, 0.3% cerium oxide, 0.1% nano-titanium carbide and the balance silicon dioxide, and fully mix the raw materials to obtain a mixture; S2, melting: put the mixture into the inner lining of boron nitride-silicon carbide composite refractory material (boron nitride content 30%, silicon carbide content 70%, isostatic pressing, density 2.9g / cm 3, in a furnace with an erosion rate of 0.04 mm / h for high borosilicate glass liquid at 1600°C, melted at 1650°C to obtain glass liquid; S3. Continuous hot pressing: The glass liquid is conveyed into a forming mold through a flow channel whose inner wall is provided with a 0.7 mm thick zirconium diboride ceramic coating (prepared by supersonic plasma spraying, with a ZrB2 phase content of 96%, a porosity of 1.5%, and thermal shock resistance (1000°C water cooling cycle) 52 times). A forming cavity is formed between the upper and lower molds of the forming mold, which is compatible with a high borosilicate glass tube with an outer diameter of 50 mm and a wall thickness of 2.0 mm. The upper mold moves downward at a speed of 1.4 mm / s, applying a pressure of 1.4 MPa to the glass liquid. At the same time, the temperature of the forming mold is controlled at 980°C by a heating device, so that the glass liquid is formed into a glass tube blank in the forming cavity. S4, cooling and shaping: The formed glass tube moves with the forming mold to the cooling area, and the cooling fan blows cold air at a temperature of 35°C and a wind speed of 12m / s to the glass tube, so that the glass tube is cooled to room temperature at a rate of 14°C / min; the conveyor roller in the cooling area is made of graphite-carbon fiber composite material, and the surface is impregnated with polytetrafluoroethylene, with a friction coefficient of 0.14; S5. Cutting: Using a diamond wire saw and laser composite cutting device, with a wire saw feed speed of 25 mm / s and a laser preheating temperature of 500°C, the cooled and shaped glass tube blank is cut into predetermined lengths to obtain a high borosilicate glass tube; Example 2 focuses on high-end optical performance and extreme thermal stability. By introducing the upper limit concentration of lanthanum oxide (1.5%) and yttrium oxide (1%) and utilizing the strong bonding effect of rare earth ions, the thermal expansion coefficient is reduced to 2.5×10 -6 / °C, meeting aviation-grade heat resistance standards. The addition of 0.3% cerium oxide significantly enhances the glass's purity, reaching a transmittance of 95%. It also absorbs 200-300nm UV light through 4f electron transitions. Combined with the nano-enhancement effect of 0.1% nano-titanium carbide, the matrix hardness is increased to 620HV, providing a more stable bonding base for the zirconium diboride coating on the outer wall.

[0021] During the production process, high-temperature melting at 1650°C and high-pressure molding at 1.4MPa, combined with a mold temperature of 980°C, significantly improve the fluidity of the glass liquid and molding accuracy, and control the outer diameter deviation to ±0.04mm. However, the high temperature and high pressure result in a 25% increase in energy consumption compared to traditional processes. The cooling process uses 35°C hot air at a wind speed of 12m / s for rapid cooling, with a cooling rate of 14°C / min. This shortens the production cycle while ensuring the coating bond strength reaches 65MPa, the surface hardness reaches 2050HV, and the acid and alkali corrosion resistance is 60% higher than that of traditional glass.

[0022] The technological breakthrough of this embodiment lies in the deep synergy between rare earth elements and micro-nano materials. The infrared shielding rate (8-14μm) reaches 60%, which is suitable for the optical window of infrared detection equipment.

[0023] Example 3: See also Figure 1 and Figure 4 The present invention provides a technical solution: a high borosilicate glass tube and a continuous hot pressing process thereof, comprising the following steps: S1. Raw material preparation: by weight percentage, 19% boron trioxide, 4% aluminum oxide, 3% zinc oxide, 1.5% sodium oxide, 1% potassium oxide, 1% gallium oxide, 0.8% lanthanum oxide, 0.6% yttrium oxide, 0.15% cerium oxide, 0.08% nano-titanium carbide and the balance silicon dioxide, and fully mix the raw materials to obtain a mixture; S2. Melting: The mixture is placed into a furnace lined with a boron nitride-silicon carbide composite refractory material (boron nitride content of 25%, silicon carbide content of 75%, formed by isostatic pressing, density of 2.85g / cm³, erosion rate of high borosilicate glass liquid of 0.045mm / h at 1600°C), and melted at 1600°C to obtain glass liquid; S3. Continuous hot pressing: The glass liquid is conveyed into a forming mold through a flow channel whose inner wall is provided with a 0.5 mm thick zirconium diboride ceramic coating (prepared by supersonic plasma spraying, with a ZrB2 phase content of 95.5%, a porosity of 1.8%, and thermal shock resistance (1000°C water cooling cycle) 51 times). A forming cavity is formed between the upper and lower molds of the forming mold, which is compatible with a high borosilicate glass tube with an outer diameter of 30 mm and a wall thickness of 1.5 mm. The upper mold moves downward at a speed of 1.0 mm / s, applying a pressure of 1.0 MPa to the glass liquid. At the same time, the temperature of the forming mold is controlled at 900°C by a heating device, so that the glass liquid is formed into a glass tube blank in the forming cavity. S4, cooling and shaping: The formed glass tube moves with the forming mold to the cooling area, and the cooling fan blows cold air at a temperature of 25°C and a wind speed of 9m / s to the glass tube, so that the glass tube is cooled to room temperature at a rate of 10°C / min; the conveyor roller in the cooling area is made of graphite-carbon fiber composite material, and the surface is impregnated with polytetrafluoroethylene, with a friction coefficient of 0.145; S5. Cutting: Using a diamond wire saw and laser composite cutting device, with a wire saw feed speed of 20 mm / s and a laser preheating temperature of 400°C, the cooled and shaped glass tube blank is cut into predetermined lengths to obtain a high borosilicate glass tube; As a comprehensive performance optimization scheme, Example 3 uses 4% aluminum oxide and 3% zinc oxide to form a composite network intermediate, and adds 0.8% lanthanum oxide and 0.6% yttrium oxide in a medium concentration to reduce the thermal expansion coefficient (2.8×10-6 / °C) while avoiding the cost surge caused by excessive rare earth elements. The synergistic effect of 0.15% cerium oxide and 0.08% nano-titanium carbide reduces the bubble rate in the glass melt by 40% and improves wear resistance by 35%, creating a ternary composite system of "clarification, enhancement, and thermal stability."

[0024] During the preparation process, the 1600°C melting temperature and 1.0MPa molding pressure form the optimal process window. The mold temperature of 900°C ensures that the glass liquid evenly fills the molding cavity, the outer diameter accuracy is ±0.03mm, and the parallelism of the cutting end face is ≤0.04mm. The cooling process controls the cooling rate to 10°C / min through 25°C room temperature air and 9m / s wind speed to avoid coating peeling caused by rapid cooling. The coating bonding strength is 63MPa and the surface hardness is 2020HV. Acid and alkali corrosion tests show that the weight loss in 24 hours is only 0.18mg / cm 2 , 75% higher than traditional glass.

[0025] The advantage of this embodiment lies in the balanced optimization of ingredients and process parameters. It exhibits no significant shortcomings in thermal stability, mechanical strength, chemical stability, or optical properties. Furthermore, it reduces energy consumption by 18% compared to Example 2, keeping raw material costs within a reasonable range. This embodiment is suitable for mainstream markets with high comprehensive performance requirements, such as solar collector tubes, medical device catheters, and chemical corrosion-resistant piping. It combines technical advantages with mass production feasibility and has broad industrial application prospects.

[0026] Example 4: See also Figure 1 and Figure 5 The present invention provides a technical solution: a high borosilicate glass tube and a continuous hot pressing process thereof, comprising the following steps: S1. Raw material preparation: by weight percentage, 19% boron trioxide, 4.5% aluminum oxide, 3% zinc oxide, 1.2% sodium oxide, 1.3% potassium oxide, 1.2% gallium oxide, 0.3% lanthanum oxide, 0.2% yttrium oxide, 0.07% cerium oxide, 0.03% nano-titanium carbide and the balance silicon dioxide, fully mix the raw materials to obtain a mixture; S2, melting: put the mixture into the lining of boron nitride-silicon carbide composite refractory material (boron nitride content 22%, silicon carbide content 78%, isostatic pressing, density 2.82g / cm 3 , in a furnace with an erosion rate of 0.048mm / h for high borosilicate glass liquid at 1600℃, melted at 1580℃ to obtain glass liquid; S3. Continuous hot pressing: The glass liquid is conveyed into a forming mold through a flow channel whose inner wall is provided with a 0.4 mm thick zirconium diboride ceramic coating (prepared by supersonic plasma spraying, with a ZrB2 phase content of 95.2%, a porosity of 1.9%, and thermal shock resistance (1000°C water cooling cycle 50 times)). A forming cavity is formed between the upper and lower molds of the forming mold, which is compatible with a high borosilicate glass tube with an outer diameter of 20 mm and a wall thickness of 1.2 mm. The upper mold moves downward at a speed of 0.8 mm / s, applying a pressure of 0.8 MPa to the glass liquid. At the same time, the temperature of the forming mold is controlled at 850°C by a heating device, so that the glass liquid is formed into a glass tube blank in the forming cavity. S4, cooling and shaping: The formed glass tube moves with the forming mold to the cooling area, and the cooling fan blows cold air at a temperature of 20°C and a wind speed of 8m / s to the glass tube, so that the glass tube is cooled to room temperature at a rate of 8°C / min; the conveyor roller in the cooling area is made of graphite-carbon fiber composite material, and the surface is impregnated with polytetrafluoroethylene, with a friction coefficient of 0.148; S5. Cutting: Using a diamond wire saw and laser composite cutting device, with a wire saw feed speed of 18 mm / s and a laser preheating temperature of 350°C, the cooled and shaped glass tube blank is cut into predetermined lengths to obtain a high borosilicate glass tube; Example 4 prioritizes high dimensional accuracy and molding stability, combining low concentrations of rare earth elements (0.3% lanthanum oxide, 0.2% yttrium oxide) with micro-nano materials (0.07% cerium oxide, 0.03% nano-titanium carbide), and a balance of silicon dioxide. This ensures the fluidity of the molten glass while minimizing the impact of compositional fluctuations on molding accuracy. Aluminum oxide (4.5%) and zinc oxide (3%) enhance structural rigidity, maintaining a stable outer diameter deviation of ±0.02mm at a die speed of 0.8mm / s, meeting the stringent dimensional requirements of industrial piping.

[0027] During the production process, a medium melting temperature of 1580°C and a molding pressure of 0.8MPa, combined with a mold temperature of 850°C, effectively control the flow inertia of the molten glass. A zirconium diboride coating (0.4mm thick) on the inner wall of the flow channel reduces glass adhesion and further improves molding consistency. The cooling process uses 20°C cold air at a wind speed of 8m / s and a cooling rate of 8°C / min to avoid uneven dimensional shrinkage caused by temperature gradients. The conveyor roller friction coefficient is 0.148, ensuring that the glass tube is scratch-free. The finished product has a thermal expansion coefficient of 3.0×10 -6 / ℃, which is lower than traditional glass but higher than functional formula. The infrared shielding rate is only 20% and the optical performance is weak.

[0028] The technical highlight of this embodiment is that through component streamlining and process fine-tuning, high-precision molding of ±0.02mm is achieved, reducing production costs by 15% compared to similar products, making it suitable for large-scale industrial production. However, some thermal stability and optical performance are sacrificed. This makes it suitable for applications such as mechanical material guides and industrial sight glass tubes, where high dimensional accuracy but low optical performance are required. It also offers significant advantages in the field of supporting glass components for automated production lines.

[0029] Embodiment 5: See also Figure 1 and Figure 6 The present invention provides a technical solution: a high borosilicate glass tube and a continuous hot pressing process thereof, comprising the following steps: S1. Raw material preparation: by weight percentage, 18% boron trioxide, 3.5% aluminum oxide, 4% zinc oxide, 1% sodium oxide, 1.3% potassium oxide, 1.5% gallium oxide, 1.2% lanthanum oxide, 0.8% yttrium oxide, 0.25% cerium oxide, 0.05% nano-titanium carbide and the balance silicon dioxide, and fully mix the raw materials to obtain a mixture; S2. Melting: The mixture is placed into a furnace lined with a boron nitride-silicon carbide composite refractory material (boron nitride content of 28%, silicon carbide content of 72%, formed by isostatic pressing, density of 2.88g / cm³, erosion rate of high borosilicate glass liquid of 0.042mm / h at 1600°C), and melted at 1620°C to obtain glass liquid; S3. Continuous hot pressing: The glass liquid is conveyed into a forming mold through a flow channel whose inner wall is provided with a 0.6 mm thick zirconium diboride ceramic coating (prepared by supersonic plasma spraying, with a ZrB2 phase content of 95.8%, a porosity of 1.6%, and thermal shock resistance (1000°C water cooling cycle) 52 times). A forming cavity is formed between the upper and lower molds of the forming mold, which is compatible with a high borosilicate glass tube with an outer diameter of 40 mm and a wall thickness of 1.8 mm. The upper mold moves downward at a speed of 1.2 mm / s, applying a pressure of 1.2 MPa to the glass liquid. At the same time, the temperature of the forming mold is controlled at 950°C by a heating device, so that the glass liquid is formed into a glass tube blank in the forming cavity. S4, cooling and shaping: The formed glass tube moves with the forming mold to the cooling area, and the cooling fan blows cold air at a temperature of 30°C and a wind speed of 10m / s to the glass tube, so that the glass tube is cooled to room temperature at a rate of 12°C / min; the conveyor roller in the cooling area is made of graphite-carbon fiber composite material, and the surface is impregnated with polytetrafluoroethylene, with a friction coefficient of 0.142; S5. Cutting: Using a diamond wire saw and laser composite cutting device, with a wire saw feed speed of 22 mm / s and a laser preheating temperature of 450°C, the cooled and shaped glass tube blank is cut into predetermined lengths to obtain a high borosilicate glass tube; As a flagship solution for infrared shielding and high temperature tolerance, Example 5 uses high-concentration lanthanum oxide (1.2%) and yttrium oxide (0.8%), and utilizes the broadband absorption characteristics of rare earth ions to achieve a shielding rate of 85% in the 8-14μm infrared band, while reducing the thermal expansion coefficient to 2.6×10 -3 / °C, approaching the level of quartz glass, and can withstand 50 cycles of 1200°C water cooling without cracking. 0.25% cerium oxide deeply clarifies the glass liquid, achieving a transmittance of 96%. 0.05% nano-titanium carbide forms a nano-scale reinforcement phase within the matrix, increasing the flexural strength to 320MPa, providing a stronger substrate support for the coating.

[0030] During the manufacturing process, a 1620°C melt temperature and 1.2MPa molding pressure, combined with a 950°C mold temperature, ensure that the high-viscosity glass liquid fully fills the mold cavity. The flow channel coating has a thermal shock resistance of 52 times, ensuring stable conveying in high-temperature environments. The cooling process uses 30°C warm air at a wind speed of 10m / s to control the cooling rate to 12°C / min, preventing the precipitation of rare earth elements due to rapid cooling. The coating has a bond strength of 64MPa, a surface hardness of 2090HV, and an 80% increase in corrosion resistance to strong oxidizing acids (such as 98% concentrated sulfuric acid).

[0031] The core advantage of this embodiment lies in the deep synergy of "rare earth optical modulation + nanostructure enhancement," which surpasses the infrared shielding limit of traditional borosilicate glass while also offering ultra-high heat and wear resistance. It is suitable for cutting-edge applications such as infrared spectrometer optical windows, aircraft engine temperature measuring tubes, and corrosion-resistant casings for the nuclear industry, providing key material support for high-end equipment manufacturing.

[0032] Methods for obtaining experimental data 1. Raw material composition analysis: X-ray fluorescence spectrometry (XRF) was used to test the composition of the glass tube raw materials and finished products of each example. By comparing and calibrating with standard samples, the composition detection accuracy was ensured to reach ±0.1% (weight percentage) to verify whether the raw material ratio met the design requirements; 2. Physical properties test: Determination of thermal expansion coefficient: Using a thermomechanical analyzer (TMA), cut the glass tube sample into 5mm×5mm×20mm specifications, heat it at a temperature range of 20℃-300℃ at a heating rate of 5℃ / min, record the change of sample length with temperature, and calculate the thermal expansion coefficient according to the formula. The test accuracy is ±0.1×10 -6 / ℃; 3. Thermal shock resistance test: The glass tube is heated to 250°C in a high-temperature furnace and kept at this temperature for 30 minutes. The tube is then quickly immersed in a coolant at -40°C. This cycle is repeated 200 times. The surface of the glass tube is observed under an optical microscope to see if there are any cracks. This is used to evaluate the thermal shock resistance. 4. Hardness test: Use a Vickers hardness tester to apply a load of 200g to the outer wall of the glass tube and hold for 15 seconds. Measure the diagonal length of the indentation and calculate the surface hardness. Test 5 points on each sample and take the average value. The accuracy is ±10HV. 5. Coating bonding strength test: Use a scratch tester (refer to ISO26443 standard) and a Rockwell C scale diamond indenter to apply a vertical load at a rate of 100N / min until the coating peels off. Record the critical load when the coating peels off to evaluate the bonding strength between the coating and the pipe body. The accuracy is ±1MPa. 6. Process parameter monitoring: Temperature sensors, pressure sensors, and speed sensors are installed in the melting, molding, cooling and other process links to collect real-time data such as furnace temperature, molding pressure, upper mold movement speed, cooling wind speed, etc. The data collection frequency is 1 time / second to ensure the accuracy of process parameters; In summary, the five embodiments each have their own advantages and disadvantages. By adjusting the raw material ratio and process parameters, high borosilicate glass tubes with different performances can be prepared for different application scenarios, providing technical support for the diversified application of this product.

[0033] See also Figure 1-7 The present invention discloses a high borosilicate glass tube and its continuous hot pressing process. Traditional high borosilicate glass is limited by the silicon dioxide-boron trioxide basic network, and its thermal expansion coefficient has long been stagnant at 3.8-5.0×10 -6 / ℃, and lacks optical control capabilities. This technology introduces rare earth oxides such as lanthanum oxide and yttrium oxide with cerium oxide and nano-titanium carbide micro-nano materials to construct a ternary composite system to achieve a synergistic leap in thermal, optical and mechanical properties. Example 1: With an extremely low addition of 0.1% lanthanum oxide + 0.1% yttrium oxide, the thermal expansion coefficient is reduced to 3.3×10 -6 / ℃, which is 13% lower than that of traditional glass. At the same time, 0.05% cerium oxide eliminates 90% of micron-level bubbles, and the transmittance is increased from 85% to 88%, verifying for the first time the compatibility of the rare earth-micro-nano system with the traditional formula.

[0034] In Example 2, the rare earth concentration was further increased to 1.5% lanthanum oxide and 1% yttrium oxide, and the thermal expansion coefficient dropped sharply to 2.5×10 -6 / °C, breaking the lowest value of existing technologies, and 200 cycles without cracking at -40°C to 250°C, doubling the thermal shock resistance. The broadband absorption characteristics of rare earth ions achieve an infrared shielding rate of 60% in the 8-14μm range. Combined with deep clarification of 0.3% cerium oxide and dispersion strengthening of 0.1% nano-titanium carbide, the glass matrix hardness is increased to 620HV. Combined with the outer wall zirconium diboride coating (hardness 2000HV), a "matrix strengthening + surface hardening" dual protection system is constructed, increasing wear resistance by more than 5 times. Compared with existing technologies that rely on coating to achieve optical functions, this solution achieves full-band UV-IR control through intrinsic material modification. The coating bonding strength reaches 65MPa, a 62.5% increase over traditional coating processes, solving the industry problem of easy coating peeling.

[0035] 2. A Double Leap in Extreme Environment Performance and Process Efficiency: System Optimization from Materials to Processes In response to the lifespan bottleneck of traditional glass in high-temperature and highly corrosive environments, this technology achieves long-life service in extreme environments by upgrading the rare earth stabilized network structure and coating technology. Example 5 uses 1.2% lanthanum oxide + 0.8% yttrium oxide to construct a high-temperature stable network, which increases the softening point of the glass from 820°C to 950°C. It can withstand instantaneous high-temperature shocks of 1200°C and more than 50 water-cooling cycles at 1000°C, which is a 60% improvement over existing technologies. At the same time, the zirconium diboride coating has a bonding strength of 64MPa and a surface hardness of 2090HV. The corrosion rate in hydrofluoric acid vapor is less than 0.01μm / h, which is 90% lower than that of traditional glass, extending the product life from less than 3 months to more than 12 months, meeting the needs of extreme scenarios such as the nuclear industry and aerospace.

[0036] At the process level, the continuous hot pressing process achieves both high precision and high efficiency through dynamic matching of "pressure, speed, and temperature." Example 3, using 1.0 MPa pressure, 1.0 mm / s die speed, and a 900°C mold temperature, controls the outer diameter deviation to ±0.03 mm (compared to ±0.3 mm with the existing technology), increasing production capacity to 12 m / h (compared to 8 m / h with the traditional process). Furthermore, the boron nitride-silicon carbide composite lining extends the furnace life from 6 months to 18 months, reducing maintenance costs by 66% and energy consumption by 15%. Example 4, through ingredient simplification (total rare earth micro-nano content of 0.6%) and process fine-tuning, achieves ultra-high precision forming of ±0.02 mm, achieving a yield rate of 98%, a 13% improvement over traditional processes, and a 15% reduction in production costs. This makes it suitable for large-scale industrial pipeline production and promotes the replacement of domestic equipment.

[0037] III. Systematic Innovation and Industrial Value of Technical Solutions: From Theoretical Breakthroughs to Implementation The core creativity of this technology lies in the non-obvious innovation of the component system and process. 3+ 、Y 3+By filling network gaps and forming a strongly bonded coordination structure, the nanomaterials (TiC and CeO2) achieve a synergistic effect with their clarifying and strengthening properties, rather than simply adding performance. For example, 0.02%-0.1% nano-titanium carbide forms a nanoscale reinforcement framework within the matrix, increasing wear resistance by eightfold, defying the conventional wisdom that nanomaterials require high concentrations for effectiveness. Cerium oxide also achieves dual functions of clarification and UV absorption, demonstrating cross-dimensional thinking in component design.

[0038] At the industrial application level, this technology has built a "basic-functional-customized" product matrix, covering the full range of scenarios from laboratory utensils to high-end aerospace equipment. The infrared shielding glass of Examples 2 and 5 fills the gap in domestic high-end optical glass, and the cost is only 60%-70% of imported products; the cost-effective solutions of Examples 3 and 4 are adapted to the mainstream industrial market, and the increase in production capacity and reduction in energy consumption are in line with the trend of green manufacturing. In addition, technological breakthroughs such as the supersonic plasma spraying-chemical vapor deposition combined process and the boron nitride-silicon carbide composite lining are not only applicable to high borosilicate glass, but can also be derived from other special glass systems, providing the industry with a universal innovation methodology.

[0039] The above is only an embodiment of the present invention, and common knowledge such as the specific technical solutions or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several variations and improvements can be made, which should also be regarded as the scope of protection of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the description can be used to interpret the content of the claims.

Claims

1. A borosilicate glass tube, characterized in that: The invention comprises a tube body, the raw materials of which, by weight percentage, include: 18%-19% boron trioxide, 3%-4.5% aluminum oxide, 2%-4% zinc oxide, 1%-2% sodium oxide, 0.5%-1.5% potassium oxide, 0.5%-2% gallium oxide, 0.1%-1.5% lanthanum oxide, and 0.1%-1% yttrium oxide. The raw materials of the tube body also contain 0.05%-0.3% cerium oxide, 0.02%-0.1% nano-titanium carbide, and the balance silicon dioxide. The wall thickness of the tube body is 0.8-2.0 mm, and the outer diameter is 10-50 mm.

2. The high borosilicate glass tube according to claim 1, characterized in that: The outer wall of the tube body is composited with a zirconium diboride ceramic coating with a thickness of 8-20 μm. The coating is prepared by plasma chemical vapor deposition. The bonding strength between the coating and the tube body is ≥60 MPa, and the surface hardness is ≥2000 HV.

3. A continuous hot pressing process for forming a borosilicate glass tube, characterized in that: For preparing the high borosilicate glass tube according to any one of claims 1 to 3, the process comprises the following steps: S1. Raw material preparation: silicon dioxide, boron trioxide, aluminum oxide, zinc oxide, sodium oxide, potassium oxide, gallium oxide, lanthanum oxide, and yttrium oxide are mixed in proportion, and cerium oxide and nano-titanium carbide are optionally added to obtain a mixture; S2. Melting: The mixed material is put into a melting furnace and melted at 1550-1650° C. to obtain molten glass. The melting furnace is lined with a boron nitride-silicon carbide composite refractory material, wherein the boron nitride content of the refractory material is 20%-30% and the silicon carbide content is 70%-80%. S3. Continuous hot pressing: The molten glass is conveyed through a flow channel into a forming mold comprising an upper mold and a lower mold, with a forming cavity formed between the upper and lower molds to match the outer diameter of the high-borosilicate glass tube. During the forming process, the upper mold moves downward at a speed of 0.6-1.4 mm / s, applying a pressure of 0.6-1.4 MPa to the molten glass. Simultaneously, the temperature of the forming mold is controlled at 820-980° C. by a heating device, so that the molten glass is formed into a glass tube in the forming cavity. The inner wall of the flow channel is provided with a zirconium diboride ceramic coating having a thickness of 0.3-0.7 mm. S4, cooling and shaping: the formed glass tube is moved to the cooling area along with the forming mold, and a cooling fan blows cold air at a temperature of 15-35°C and a wind speed of 7-12 m / s to the glass tube, so that the glass tube is cooled to room temperature at a speed of 6-14°C / min; S5, cutting: cutting the cooled and shaped glass tube blank into a predetermined length to obtain the high borosilicate glass tube.

4. The continuous hot pressing forming process according to claim 3, characterized in that: The boron nitride-silicon carbide composite refractory material in step S2 is formed by isostatic pressing, has a density of ≥2.8 g / cm³, and an erosion rate of ≤0.05 mm / h for high borosilicate glass liquid at 1600°C.

5. The continuous hot pressing forming process according to claim 3, characterized in that: The zirconium diboride ceramic coating in step S3 is prepared by supersonic plasma spraying, and the ZrB2 phase content in the coating is ≥95%, the porosity is ≤2%, and the thermal shock resistance (1000°C water cooling cycle) is ≥50 times.

6. The continuous hot pressing forming process according to claim 3, characterized in that: The conveying roller in the cooling area in step S4 is made of a graphite-carbon fiber composite material, the surface of which is impregnated with polytetrafluoroethylene and has a friction coefficient of ≤0.

15.

7. The continuous hot pressing process according to claim 3, characterized in that: The cutting equipment in step S5 adopts a diamond wire saw and laser composite cutting device, the wire saw feed speed is 15-25 mm / s, the laser preheating temperature is 300-500° C., and the parallelism of the cutting end face is ≤0.05 mm.

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