Method for evaluating melting characteristics of an alkali-free substrate glass composition

Abstract

This invention discloses a method for evaluating the melting characteristics of alkali-free substrate glass, belonging to the field of performance evaluation of alkali-free substrate glass. Small samples are prepared by melting the alkali-free substrate glass composition and corresponding raw material ratios. These small samples are then melted into liquid and cooled. The rotational speed and torque of a controlled rotating rotor are measured at different temperatures, and the temperature of the corresponding sample at a fixed viscosity is calculated. Next, a regularly shaped sample to be evaluated is melted into liquid, and the current loss after passing through the molten liquid at different temperatures is detected. The resistivity of the sample is calculated based on the current loss and the sample's geometric parameters. Combining the viscosity and resistivity of the sample at different temperatures, the production parameters required for mass production are calculated. Starting from the performance of small-batch samples, a baseline of process parameters for mass production is provided, effectively shortening the adjustment cycle for process adaptability during new product mass production, obtaining high-quality molten glass more quickly, and improving glass production efficiency.

Description

Technical Field

[0001] This invention belongs to the technical field of performance evaluation of alkali-free substrate glass, and specifically relates to a method for evaluating the melting characteristics of alkali-free substrate glass. Background Technology

[0002] Alkali-free substrate glass is a core material supporting the development of high-end industries such as display panels, photovoltaic thin-film batteries, and flexible electronics. In its production process, the high-temperature melting and clarification stages are key steps that determine the quality of the molten glass (no stones, no bubbles, and uniform composition), directly affecting the yield of subsequent forming, cutting, and end products.

[0003] Generally, high-end display alkali-free substrate glass requires extremely high uniformity of composition. Localized component segregation during melting can directly lead to fluctuations in the glass's coefficient of thermal expansion, causing edge chipping during subsequent cutting or cracking during high-temperature panel manufacturing. However, the high-temperature melting of alkali-free substrate glass is a complex process involving "high temperature, closed system, and multiple physicochemical couplings," encompassing multiple steps such as raw material decomposition, melting, ion diffusion, and bubble escape. The core bottleneck lies in the "invisibility" of the melting process and the lack of parameter correlation. Therefore, to ensure complete melting of the raw materials, companies often employ "ultra-high temperature melting," such as setting the furnace hotspot temperature 50-100°C higher than the theoretical melting temperature. This not only leads to a surge in energy consumption but also exacerbates the erosion of the furnace's refractory materials, shortening their lifespan and increasing production costs. However, if the temperature is too low, unmelted stone residue can remain, causing bright spot defects in the display panel.

[0004] Against this backdrop, there is an urgent need for an evaluation method that can assess the melting characteristics of alkali-free substrate glass. Its parameters can serve as the basis for adjusting process parameters during the production of alkali-free substrate glass, so as to control the melting temperature and achieve the goal of ensuring complete melting of raw materials with the lowest energy consumption. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned shortcomings and provide a method for evaluating the melting characteristics of alkali-free substrate glass composition, providing data support for setting parameters to control the melting temperature in the production line, and achieving the goal of ensuring complete melting of raw materials with the lowest energy consumption.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for evaluating the melting characteristics of alkali-free substrate glass, comprising the following steps: Based on the composition of the glass to be evaluated and the different types of raw materials, the raw material ratio of the glass to be evaluated is calculated and determined. The raw materials are weighed and mixed evenly according to the raw material ratio to obtain the glass composition powder. The glass composition powder to be evaluated is melted and molded to obtain a glass composition sample block to be evaluated; Based on the sample shape and size required by the evaluation method, the glass sample to be evaluated is processed to obtain the corresponding Sample 1 and Sample 2; The temperature of sample 1 at a fixed viscosity and the resistivity of sample 2 at different temperatures were measured respectively. Based on the temperature of sample 1 at a fixed viscosity and the resistivity of sample 2 at different temperatures, the melting characteristics of the glass composition to be evaluated are comprehensively assessed.

[0007] The method for melting and molding the glass composition powder to be evaluated to obtain a glass composition sample block is as follows: after the glass composition powder to be evaluated is mixed evenly in a mixer, it is placed in a high-temperature resistant container that is not corroded by molten glass, and after being melted and clarified in a high-temperature furnace according to a set program, it is poured into a mold to form a sample block.

[0008] The method for processing the glass sample to be evaluated, based on the sample shape and size required by the evaluation method, to obtain corresponding Sample 1 and Sample 2 is as follows: The glass sample to be evaluated was prepared into granules with a diameter of 2-5 mm to obtain sample 1; the glass sample to be evaluated was cut into the shape of a matching grooved container to obtain sample 2.

[0009] In the steps of measuring the temperature of sample 1 at a fixed viscosity and the resistivity of sample 2 at different temperatures, the method for measuring the temperature of sample 1 at a fixed viscosity is as follows: Sample 1 is placed in a high-temperature resistant container that is not corroded by molten glass. The container is then placed in a high-temperature furnace, and the sample 1 is heated and melted according to the set program. Subsequently, a controllable rotor is immersed in the molten glass. The torque and angular velocity are directly measured by rotating the rotor. The temperature of sample 1 at a fixed viscosity is calculated by recording the temperature, torque, and angular velocity.

[0010] The container, which is resistant to high temperatures and not corroded by molten glass, is a platinum crucible or a corundum crucible.

[0011] The method for measuring the resistivity of sample 2 at different temperatures is as follows: The glass sample 2 to be evaluated is placed in a grooved container of a fixed shape that is not corroded by molten glass. Conductive metal sheets of the same size as the end of the container are placed at the two ends of the groove where they contact the glass sample. The sample 2 is heated and melted according to the set program. Then the cooling rate is controlled and a constant current is applied to one end of the sample 2 during the cooling process. The current intensity received by the conductive metal sheet at the other end is measured. At the same time, the resistivity of the sample 2 at different temperatures is calculated based on the size parameters of the sample 2.

[0012] The conductive metal sheet is a platinum sheet, and the grooved container is made of alumina or zirconium oxide.

[0013] In the step of comprehensively evaluating the melting characteristics of the glass composition to be evaluated based on the temperature of sample 1 at a fixed viscosity and the resistivity of sample 2 at different temperatures, the parameters that need to be set for the molten glass are calculated based on the correspondence between the viscosity, temperature and resistivity values ​​of the samples, and the melting characteristics of the alkali-free substrate glass composition to be evaluated are comprehensively evaluated.

[0014] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a method for evaluating the melting characteristics of alkali-free substrate glass. Compared with traditional methods that rely solely on indirect evaluation using a single physical property (such as refining temperature), this invention employs a differentiated sample processing method. Samples are processed into particles with a diameter of 2-5 mm for melting temperature measurement. This size represents the overall composition and facilitates rapid and uniform melting in a small, high-temperature container, ensuring the accuracy of high-temperature viscosity measurements using rotational viscometry, thereby precisely deducing the melting temperature. Simultaneously, another portion of the sample is processed into a regular shape matching a specific grooved container for resistivity measurement. This shape design and contact method (placing conductive metal sheets at both ends) ensure a stable current flow path and low contact resistance during testing, resulting in accurate and repeatable resistivity data. Both sample processing methods are optimized for their measurement principles, guaranteeing the reliability of core measurement data from the outset.

[0015] Furthermore, this invention utilizes the test results of small laboratory samples to evaluate the melting characteristics of the corresponding alkali-free substrate glass composition during mass production, shortening the adjustment cycle for the process adaptability of the production line to new products, reducing the losses caused by the reduction in furnace life due to ultra-high temperature melting, and achieving the goal of ensuring complete melting of raw materials with minimal energy consumption. Attached Figure Description

[0016] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0017] To further understand the content of this invention, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments are merely illustrative and not limiting of the invention.

[0018] A method for evaluating the melting characteristics of alkali-free substrate glass includes the following steps: S1: Based on the composition of the glass to be evaluated and the different types of raw materials, calculate and determine the raw material ratio of the glass to be evaluated, weigh and mix the raw materials according to the raw material ratio to obtain the glass composition powder to be evaluated. S2: Melt the glass composition powder to be evaluated into a sample block to be evaluated; S3: Process the glass sample to be evaluated according to the sample shape and size required by the evaluation method to obtain the corresponding Sample 1 and Sample 2; S4: Measure the temperature of sample 1 and the resistivity of sample 2 at different temperatures; S5: Based on the temperature of sample 1 and the resistivity of sample 2 at different temperatures, comprehensively evaluate the melting characteristics of the glass composition to be evaluated.

[0019] Specifically, in S1, based on the composition of the glass to be evaluated, the types of raw materials to introduce oxides are selected, and the weight of the required raw materials is calculated based on the oxide content in the raw materials; the corresponding raw materials are weighed accurately in sequence using a precision electronic balance and mixed evenly using a mixer to obtain the batch material of the alkali-free substrate glass composition to be evaluated.

[0020] Specifically, in step S2, the batch of the sample to be evaluated is placed in a high-temperature resistant container that is not corroded by molten glass. This container is then placed in a high-temperature furnace with controlled temperature rise, and the glass batch is melted according to a programmed temperature rise. The furnace is held at this temperature for a certain period to allow the molten glass to fully clarify, resulting in a uniform, bubble-free molten glass. This molten glass is then poured into a preheated mold to ensure stable forming of the glass sample without cracking. After the molten glass has completely formed, it is placed in an annealing furnace preheated to a specific temperature for slow annealing, yielding the alkali-free substrate glass composition sample to be evaluated.

[0021] Specifically, in S3, based on the sample shape and size required by the evaluation method, the glass sample to be evaluated is processed to obtain corresponding Sample 1 and Sample 2. Sample 1 is obtained by using a special glass crusher to crush the annealed block glass, and after sieving, obtains granular glass with a diameter of 2~5mm. The sample volume and weight must fill a specific container to meet the requirements of the first performance evaluation. Sample 2 is obtained by using a special wire cutting machine to cut the annealed block glass into a regular cuboid shape required for the second performance evaluation, with dimensions matching the corresponding concave sample container.

[0022] Specifically, in S4, the temperature of sample 1 and the resistivity of sample 2 at different temperatures are measured. The method for measuring the temperature of sample 1 is as follows: Sample 1, consisting of an alkali-free substrate glass block to be evaluated, was placed in a high-temperature resistant container unaffected by molten glass. This container was then placed in a furnace with controlled heating and cooling. The sample 1 was heated and melted according to a pre-programmed heating and cooling sequence. Subsequently, a controllable rotor was immersed in the molten glass while the cooling rate was controlled. During rotor rotation, the viscous resistance of the molten glass changed with temperature, causing variations in the rotor's rotational speed and torque. Therefore, by directly monitoring the rotor's torque and angular velocity at different temperatures, the viscosity was calculated, resulting in a viscosity-temperature curve. Based on this, the temperature corresponding to a specific viscosity was determined and calculated.

[0023] Preferably, the container that is resistant to high temperatures and not corroded by molten glass is a platinum crucible or a corundum crucible.

[0024] The method for measuring the resistivity of sample 2 at different temperatures is as follows: The alkali-free substrate glass sample 2 to be evaluated was placed in a fixed-shape, high-temperature resistant, and non-corrosive confined container. Conductive metal sheets of the same size as the container ends were placed at the points in contact with the glass sample at both ends of the container, and connected to the detector via conductive wires. Sample 2 was first heated to melt according to a pre-programmed temperature rise. Then, the cooling rate was controlled, and a constant current was applied to one conductive metal sheet during the cooling process. The current intensity received by the other conductive metal sheet was measured. By analyzing the current intensity loss at different temperatures and considering the sample's dimensional parameters, the resistivity of sample 2 at different temperatures was calculated.

[0025] Preferably, the conductive metal sheet is a platinum sheet, and the grooved container is made of alumina or zirconium oxide.

[0026] Specifically, in S5, the molten glass needs to undergo reactions such as ion diffusion and bubble removal at a low viscosity. Therefore, by combining the corresponding relationship between viscosity, temperature and resistivity obtained in S4, the parameters that need to be set for high-quality molten glass are calculated. The melting characteristics of the alkali-free substrate glass composition to be evaluated are comprehensively assessed, which effectively shortens the adjustment cycle of process adaptability when mass-producing new products and can obtain high-quality molten glass more quickly, thereby improving the efficiency of glass production.

[0027] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not 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 modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for evaluating the melting characteristics of alkali-free substrate glass, characterized in that, Includes the following steps: Based on the composition of the glass to be evaluated and the different types of raw materials, the raw material ratio of the glass to be evaluated is calculated and determined. The raw materials are weighed and mixed evenly according to the raw material ratio to obtain the glass composition powder. The glass composition powder to be evaluated is melted and molded to obtain a glass composition sample block to be evaluated; Based on the sample shape and size required by the evaluation method, the glass sample to be evaluated is processed to obtain the corresponding Sample 1 and Sample 2; The temperature of sample 1 at a fixed viscosity and the resistivity of sample 2 at different temperatures were measured respectively. Based on the temperature of sample 1 at a fixed viscosity and the resistivity of sample 2 at different temperatures, the melting characteristics of the glass composition to be evaluated are comprehensively assessed.

2. The method for evaluating the melting characteristics of alkali-free substrate glass according to claim 1, characterized in that, The method for melting and molding the glass composition powder to be evaluated to obtain a glass composition sample block is as follows: after the glass composition powder to be evaluated is mixed evenly in a mixer, it is placed in a high-temperature resistant container that is not corroded by molten glass, and after being melted and clarified in a high-temperature furnace according to a set program, it is poured into a mold to form a sample block.

3. The method for evaluating the melting characteristics of alkali-free substrate glass according to claim 1, characterized in that, The method for processing the glass sample to be evaluated, based on the sample shape and size required by the evaluation method, to obtain corresponding Sample 1 and Sample 2 is as follows: The glass sample to be evaluated was prepared into granules with a diameter of 2-5 mm to obtain sample 1; the glass sample to be evaluated was cut into the shape of a matching grooved container to obtain sample 2.

4. The method for evaluating the melting characteristics of alkali-free substrate glass according to claim 3, characterized in that, In the steps of measuring the temperature of sample 1 at a fixed viscosity and the resistivity of sample 2 at different temperatures, the method for measuring the temperature of sample 1 at a fixed viscosity is as follows: Sample 1 is placed in a high-temperature resistant container that is not corroded by molten glass. The container is then placed in a high-temperature furnace, and the sample 1 is heated and melted according to the set program. Subsequently, a controllable rotor is immersed in the molten glass. The torque and angular velocity are directly measured by rotating the rotor. The temperature of sample 1 at a fixed viscosity is calculated by recording the temperature, torque, and angular velocity.

5. The method for evaluating the melting characteristics of alkali-free substrate glass according to claim 4, characterized in that, The container, which is resistant to high temperatures and not corroded by molten glass, is a platinum crucible or a corundum crucible.

6. The method for evaluating the melting characteristics of alkali-free substrate glass according to claim 4, characterized in that, The method for measuring the resistivity of sample 2 at different temperatures is as follows: The glass sample 2 to be evaluated is placed in a grooved container of a fixed shape that is not corroded by molten glass. Conductive metal sheets of the same size as the end of the container are placed at the two ends of the groove where they contact the glass sample. The sample 2 is heated and melted according to the set program. Then the cooling rate is controlled and a constant current is applied to one end of the sample 2 during the cooling process. The current intensity received by the conductive metal sheet at the other end is measured. At the same time, the resistivity of the sample 2 at different temperatures is calculated based on the size parameters of the sample 2.

7. The method for evaluating the melting characteristics of alkali-free substrate glass according to claim 6, characterized in that, The conductive metal sheet is a platinum sheet.

8. The method for evaluating the melting characteristics of alkali-free substrate glass according to claim 6, characterized in that, The grooved container is made of alumina or zirconium oxide.

9. The method for evaluating the melting characteristics of alkali-free substrate glass according to claim 6, characterized in that, In the step of comprehensively evaluating the melting characteristics of the glass composition to be evaluated based on the temperature of sample 1 at a fixed viscosity and the resistivity of sample 2 at different temperatures, the parameters that need to be set for the molten glass are calculated based on the correspondence between the viscosity, temperature and resistivity values ​​of the samples, and the melting characteristics of the alkali-free substrate glass composition to be evaluated are comprehensively evaluated.

Images