A glass composition, its preparation method and application

Abstract

This invention discloses a glass composition, its preparation method, and its applications, belonging to the field of inorganic non-metallic materials technology. The glass composition provided by this invention comprises a porous glass matrix and a reinforcing phase filling the pores of the porous glass matrix. The raw materials for preparing the porous glass matrix include high-melting-point oxides and low-melting-point oxides. The reinforcing phase is selected from the high-melting-point oxides; the melting point of the high-melting-point oxides is higher than that of the low-melting-point oxides. The glass composition prepared by this invention exhibits a long service life and reliable sealing during high-temperature cycling. Its flexural strength, service life, sealing performance, and water resistance are all good. The glass composition of this invention has wide applications in the field of sealing materials.

Description

Technical Field

[0001] This invention belongs to the field of inorganic non-metallic materials technology, and particularly relates to a glass composition, its preparation method and application. Background Technology

[0002] Glass materials have excellent properties as sealing materials, such as good high-temperature sealing, insulation, and oxidation-reduction resistance, and therefore have a wide range of applications in sealing materials.

[0003] Taking fuel cells as an example, fuel cells are gradually becoming the preferred choice for environmentally friendly power generation in people's production and daily life due to their high power generation efficiency and excellent reliability. Solid oxide fuel cells (SOFCs), as the most promising type of fuel cell, are extensively studied in order to obtain SOFCs with higher fuel efficiency, longer service life, and better reliability. The sealing performance of SOFCs essentially determines the battery's service life and reliability. Generally, to prevent fuel gas leakage at the anode and cathode, sealing materials are selected for sealing treatment. For example, using sealing glass can ensure that the gas does not leak and that there is good insulation between components even after a long time in high-temperature oxidizing and reducing atmospheres.

[0004] However, in the manufacturing process of existing sealing glass, in order to ensure the strength of the sealing layer, a large amount of high-melting-point oxides are added during the glass melting process. As a result, the reaction between the low-melting-point oxide components and the high-melting-point oxide components during the uniform melting process requires extremely high temperatures for melting treatment, which increases the difficulty and complexity of the production process. In addition, during the use of SOFC, the sealing glass layer is in a high-temperature and high-humidity heat cycle environment for a long time. This makes it very easy for defects such as sintering cracks to occur in pore or grain boundary areas. In severe cases, it may even cause gas leakage and other problems, which greatly reduce the service life and reliability of the device. Summary of the Invention

[0005] In order to overcome the problems existing in the prior art, one of the objectives of the present invention is to provide a glass composition that can melt at a lower temperature and has a long service life and good sealing performance.

[0006] A second objective of this invention is to provide a method for preparing the above-mentioned glass composition.

[0007] A third objective of this invention is to provide an application of the above-mentioned glass composition.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] A first aspect of the present invention provides a glass composition (Q) comprising a porous glass body (D) and a reinforcing phase (A2) filling the pores of the porous glass body, wherein the raw materials for preparing the porous glass body include a high-melting-point oxide (A1) and a low-melting-point oxide (B); the reinforcing phase is selected from the high-melting-point oxide; and the melting point of the high-melting-point oxide is higher than that of the low-melting-point oxide.

[0010] Preferably, the porous glass body is composed of spherical particles.

[0011] Preferably, the average particle size of the porous glass matrix is ​​15–35 μm.

[0012] Preferably, the reinforcing phase comprises 2 to 10% by mass in the glass composition; more preferably, the reinforcing phase comprises 5 to 7% by mass in the glass composition.

[0013] When the content of the reinforcing phase (A2) is too high, due to the difference in the coefficient of thermal expansion between the reinforcing phase and the glass matrix, cracks or pores caused by expansion or contraction will appear at the interface between the glass matrix and the reinforcing phase during the later sintering of the powder, resulting in macroscopic sintering cracks and reducing the sealing performance of the device. When the content of the reinforcing phase (A2) is too low, the strength of the sealing layer will decrease, and the sealing performance will gradually decline after long-term use under high temperature conditions, thereby reducing the service life of the device.

[0014] Preferably, the high-melting-point oxide constitutes 10-20% by mass in the porous glass matrix; more preferably, the high-melting-point oxide constitutes 13-17% by mass in the porous glass matrix.

[0015] High-melting-point oxides (Al), as network forgings or intermediates in glass, primarily function to construct the network framework, providing the glass with good strength, thermal expansion, and chemical stability. Therefore, when the Al content is too high, the mixed components contain an excessive amount of high-melting-point phase, making glass formation difficult and resulting in an excessively high melting point for the desired molten phase, which does not match the target melting temperature of 900–1100℃, thus failing to achieve the goal of lowering the melting temperature. Conversely, when the Al content is too low, it reduces the integrity of the glass's network structure, resulting in a glass bulk with insufficient strength and softening point, failing to meet the requirements for subsequent preparation and sealing.

[0016] High-melting-point oxides and low-melting-point oxides can form a homogeneous melt after melting, and after cooling, they form a glass phase with uniform composition. Furthermore, as a component of the glass composition, high-melting-point oxides can improve the strength of the glass composition. Therefore, high-melting-point oxides can be used as a reinforcing phase in the glass composition.

[0017] Preferably, in the glass composition, the high-melting-point oxide has a melting point of 1600–2500°C.

[0018] Preferably, in the glass composition, the high-melting-point oxide includes at least one of Al2O3, ZrO2, Y2O3, or TiO2.

[0019] In a specific embodiment of the present invention, the high-melting-point oxide in the porous glass body and the high-melting-point oxide as the reinforcing phase may have exactly the same composition, partially the same composition, or completely different composition.

[0020] Preferably, in the glass composition, the melting point of the low-melting-point oxide is 900–1200°C.

[0021] Preferably, in the glass composition, the low-melting-point oxide includes La2O3, CeO2, B2O3, M1 and M2, wherein M1 includes at least one of CaO, SrO, and Bi2O3, and M2 includes at least one of MgO, BaO, or La2O3.

[0022] Preferably, in the glass composition, the low-melting-point oxide comprises a mass ratio of 1:(0.5-2):(0.5-2):

[0023] (0.5~2): La2O3, CeO2, B2O3, M1 and M2 in (0.5~2).

[0024] Preferably, in the glass composition, the pores in the porous glass body are obtained by pore-forming treatment using a pore-forming agent.

[0025] Preferably, the pore-forming agent comprises at least one of silicon carbide, carbon black, water glass, carbonate, sulfate, or nitrate; more preferably, in the glass composition, the pore-forming agent comprises at least one of carbonate, sulfate, or nitrate.

[0026] Preferably, the amount of the pore-forming agent is 3 to 10% of the sum of the mass of the high-melting-point oxide and the low-melting-point oxide; more preferably, the amount of the pore-forming agent is 5 to 8% of the sum of the mass of the high-melting-point oxide and the low-melting-point oxide.

[0027] Excessive pore-forming agent content will result in an excessively large number of pores and pore area in the glass substrate (D), reducing the glass's supporting strength and making it prone to sintering cracks during later use, leading to poor device sealing and even gas leakage. Conversely, insufficient pore-forming agent content will fail to achieve the required porosity and pore size, preventing the reinforcing phase from filling properly and reducing the service life and strength of the sealing layer after sealing preparation. In a specific embodiment of the present invention, after pore-forming treatment, the porosity of the porous glass substrate is 10-30%, and the porosity gradually increases with the increase of pore-forming agent content.

[0028] Preferably, the pore-forming agent is in powder form.

[0029] Preferably, the average particle size of the pore-forming agent is 0.4 to 1.5 μm.

[0030] A second aspect of the present invention provides a method for preparing the glass composition described in the first aspect of the present invention, comprising the following steps:

[0031] S1. High-temperature melting: The high-melting-point oxide and the low-melting-point oxide are melted at high temperature and cooled to obtain a glass body (C) without pores;

[0032] S2. Pore-forming treatment: The glass body without pores described in step S1 is mixed with a pore-forming agent and subjected to pore-forming treatment to obtain the glass body with pores.

[0033] S3. Preparation of glass composition: The porous glass body described in step S2 is mixed with the reinforcing phase, so that the reinforcing phase fills the pores of the porous glass body to obtain the glass composition.

[0034] Preferably, the high-temperature melting temperature in step S1 is 900–1100°C.

[0035] Preferably, the high-temperature melting time in step S1 is 1 to 5 hours.

[0036] Preferably, in step S2, the pore-forming agent includes at least one of silicon carbide, carbon black, water glass, carbonate, sulfate, or nitrate; more preferably, in step S2, the pore-forming agent includes at least one of carbonate, sulfate, or nitrate.

[0037] Preferably, the amount of the pore-forming agent is 3 to 10% of the sum of the mass of the high-melting-point oxide and the low-melting-point oxide; more preferably, the amount of the pore-forming agent is 5 to 8% of the sum of the mass of the high-melting-point oxide and the low-melting-point oxide.

[0038] Preferably, the temperature of the pore-forming process in step S2 is 400–1100°C.

[0039] Preferably, the hole-forming process in step S2 is as follows: heating to 500-600°C at a heating rate of 5-7°C / min and holding for 0.2-1h, then heating to 600-700°C at a heating rate of 8-12°C / min and holding for 0.5-1h, finally heating to 800-950°C at a heating rate of 12-15°C / min and holding for 0.5-2h, then cooling to 500-700°C at a cooling rate of 10-13°C / min, and then cooling to room temperature at a cooling rate of 7-10°C / min.

[0040] In a specific embodiment of the present invention, the porosity of the glass body obtained in step S2 is 10-30%.

[0041] Preferably, in step S3, the reinforcing phase is further surface modified before mixing; the surface modifier for surface modification includes: alcohol solvents and dispersants.

[0042] By surface modification of high-melting-point oxides as reinforcing phases, the dispersibility of high-melting-point oxides in porous glass substrates can be enhanced, preventing subsequent powder agglomeration that would prevent the powder from filling the pores.

[0043] Preferably, the alcohol solvent includes at least one of methanol, ethanol, or propanol.

[0044] Preferably, the dispersant comprises at least one of oleoylsarcosine, triethanolamine, or sodium dodecyl sulfate.

[0045] Preferably, in the surface modification, the mass ratio of the reinforcing phase to the dispersant is (6-55):1.

[0046] Preferably, in the surface modification, the mass ratio of the reinforcing phase to the alcohol solvent is (0.4-1.5):1.

[0047] Preferably, the method for surface modification of the reinforcing phase includes the following steps: mixing the reinforcing phase, an alcohol solvent, and a dispersant to carry out a modification reaction to obtain a surface-modified reinforcing phase.

[0048] Preferably, the surface modification method includes the following steps: mixing 30-55 wt% of reinforcing phase, 40-65 wt% of alcohol solvent and 1-5 wt% of dispersant to carry out a modification reaction to obtain a surface-modified reinforcing phase.

[0049] Preferably, in the surface modification method, the reinforcing phase is further pulverized before mixing, until the average particle size of the reinforcing phase is 0.3 to 1.2 μm.

[0050] Preferably, in the surface modification method, the modification reaction time is 1 to 5 hours.

[0051] Preferably, in the surface modification method, the modification reaction is carried out in a mixing device. In some embodiments of the invention, the mixing device is selected from a ball mill.

[0052] Preferably, the method of mixing the porous glass body with the reinforcing phase in step S3 is selected from ball milling.

[0053] Preferably, the grinding balls of the ball mill comprise alumina, zirconium oxide, or a combination thereof.

[0054] Preferably, the average particle size of the grinding balls in the ball mill is 5 to 10 μm.

[0055] Preferably, the ball milling time is 3 to 7 hours.

[0056] In a specific embodiment of the present invention, the ball milling is selected from wet ball milling.

[0057] Preferably, in the wet ball milling, the mass ratio of the porous glass body to the reinforcing phase, water, and milling balls is 1:(1-2):(6-8).

[0058] Preferably, in step S3, the porous glass body is dried after being mixed with the reinforcing phase.

[0059] Preferably, the pore filling rate of the glass composition obtained in step S3 is 20-50%.

[0060] A third aspect of the invention provides the use of the glass composition described in the first aspect of the invention as a sealing material.

[0061] Preferably, the sealing material is a sealing material used in a fuel cell; more preferably, the fuel cell is a solid oxide fuel cell.

[0062] The beneficial effects of this invention are as follows: This invention divides a high-melting-point oxide into two parts (which can be divided according to different components or only according to different amounts). One part is mixed with a low-melting-point oxide and pore-forming to form a porous glass matrix. The remaining high-melting-point oxide serves as a reinforcing phase and fills the porous glass matrix. The glass matrix of this invention uses a smaller amount of high-melting-point oxide, which can lower the melting temperature of the glass matrix, thereby reducing the volatilization of the low-melting-point oxide during high-temperature melting and making the glass composition more uniform and stable. In addition, in the long-term application of the glass composition of this invention under high-temperature conditions, the reinforcing phase will gradually diffuse into the original glass matrix phase as the reinforcing phase of the glass as a whole, which greatly improves the service life and sealing reliability of the material. Its flexural strength, service life, sealing performance and water resistance are all good.

[0063] Specifically, compared with the prior art, the present invention has the following advantages:

[0064] 1. Traditional glass mixing and melting methods, due to the presence of high-melting-point oxides such as Al2O3, ZrO2, and TiO2, typically require melting temperatures of 1300–1600℃ to obtain glass with a softening point of 700–900℃. However, this invention, through the combination of a porous glass matrix and a reinforcing phase, first obtains a glass matrix with a lower melting temperature, requiring only 900–1100℃. This significantly reduces the processing difficulty and minimizes the volatilization of low-melting-point oxides during high-temperature melting, resulting in a more uniform and stable glass composition. Furthermore, the addition of the reinforcing phase allows the glass composition to gradually diffuse into the original glass phase during long-term operation at high temperatures, acting as a reinforcing component of the overall glass. This slowly improves the strength, sealing properties, and water resistance of the sealing material, significantly enhancing its stability and preventing performance degradation during long-term high-temperature operation, thus greatly extending the service life of the sealing material.

[0065] 2. The present invention uses a pore-forming agent to create pores in a glass matrix that does not have pores, thereby obtaining a glass matrix with a certain porosity. This allows the reinforcing phase to fill the glass matrix better, and the reinforcing phase to be evenly distributed and better bonded in the glass composition, which is beneficial for the reinforcing phase to better perform its sealing function.

[0066] 3. The glass composition of the present invention exhibits a long service life and reliable sealing during high-temperature cycling, demonstrating good flexural strength, service life, sealing performance, and water resistance. Using the glass composition of the present invention as a sealing material can yield single cells with low degradation rates and long service lives. Therefore, the glass composition of the present invention has wide applications in the field of sealing materials, especially in the field of sealing materials for batteries (such as solid oxide fuel cells).

[0067] Instruction manual illustrations

[0068] Figure 1 This is the temperature gradient curve of the hole-forming process in step S2 of Example 1. Detailed Implementation

[0069] The following specific embodiments further illustrate the content of the present invention in detail. It should also be understood that the following embodiments are only for further explanation of the present invention and should not be construed as limiting the scope of protection of the present invention. Non-essential improvements and adjustments made by those skilled in the art based on the principles described herein are all within the scope of protection of the present invention. The specific process parameters, etc., in the following examples are merely examples within a suitable range; that is, those skilled in the art can make selections within a suitable range based on the description herein, and are not intended to be limited to the specific data in the examples below. Unless otherwise specified, the raw materials, reagents, or apparatus used in the following embodiments and comparative examples can be obtained from conventional commercial sources or by existing known methods.

[0070] Example 1

[0071] This example provides a glass composition comprising a porous glass body and a reinforcing phase filling the pores of the porous glass body; the raw materials for preparing the porous glass body include high-melting-point oxides and low-melting-point oxides; the reinforcing phase is selected from the high-melting-point oxides.

[0072] The high-melting-point oxide is Al2O3.

[0073] The low-melting-point oxide powder is obtained by mixing CaO, MgO, La2O3, CeO2, and B2O3 in equal proportions.

[0074] The reinforcing phase is the high-melting-point oxide Al2O3.

[0075] The pores in the porous glass body are obtained by pore-forming treatment using a pore-forming agent; the pore-forming agent is calcium carbonate powder with an average particle size of 0.8 μm.

[0076] The method for preparing the glass composition described in this example includes the following steps:

[0077] S1. High-temperature melting: Weigh 87wt% of low-melting-point oxide B and 13wt% of high-melting-point oxide Al (Al2O3), mix them evenly, and then melt them in a high-temperature furnace at a melting temperature of 1000℃ for 3 hours. After heating, remove the product, cool it, and then ball mill it to obtain a non-porous glass matrix C with a particle size of 25μm. The low-melting-point oxide B is obtained by mixing CaO, MgO, La2O3, CeO2, and B2O3 in equal proportions.

[0078] S2. Pore-forming treatment: Weigh 93wt% of the non-porous glass matrix C obtained in step S1 and 7wt% of the pore-forming agent, and continue to use a high-temperature furnace for gradient heating. The temperature gradient curve is shown below. Figure 1As shown, the specific process is as follows: the temperature is first raised to 550℃ at a heating rate of 6℃ / min and held for 0.33h, then raised to 650℃ at a heating rate of 10℃ / min and held for 0.67h, and finally raised to 900℃ at a heating rate of 13℃ / min and held for 1h. After heating, the temperature is lowered to 600℃ at a cooling rate of 11℃ / min and then lowered to room temperature at a cooling rate of 8℃ / min. After ball milling and granulation, a spherical porous glass body D is obtained.

[0079] S3. Preparation of the glass composition: First, the high-melting-point oxide (Al2O3) is mixed evenly using a ball mill and ground until the powder particle size is 0.5-1 μm to obtain ground Al2O3 powder. 40 wt% of the ground Al2O3 powder, 56 wt% ethanol, and 4 wt% oleoylsarcosine dispersant are mixed and ball-milled in a ball mill for 3 hours to obtain the modified reinforcing phase A2. 94 wt% of the porous glass matrix D obtained in step S2 and 6 wt% of the reinforcing phase A2 obtained in step S2 are weighed and wet-milled with zirconia grinding beads and water to fill the pores. The zirconia grinding beads have a particle size of 5-10 μm, and the mass ratio of D and A2 powder:water:grinding beads is 1:1:7. The ball milling time is 6 hours. After drying, the glass composition (Q) is obtained.

[0080] Examples 2-13 and Comparative Examples 1-6

[0081] The glass compositions of Examples 2-13 and Comparative Examples 1-6 differ from those of Example 1 in the mass percentage of the raw materials used in their preparation. The raw materials used in the preparation of the glass compositions of Examples 1-13 and Comparative Examples 1-6 are shown in Table 1.

[0082] Table 1. Mass percentage of raw materials used in the preparation of glass compositions in Examples 1-13 and Comparative Examples 1-6

[0083]

[0084]

[0085] The glass compositions of Examples 2-13 and Comparative Examples 1-6 were prepared by the same method as in Example 1.

[0086] Comparative Example 7

[0087] The difference between this example and Example 1 is that in the preparation method of the glass composition, only the low-melting-point oxide B is used during melting in step S1, and the high-melting-point oxide A1 is not used.

[0088] Comparative Example 8

[0089] The difference between this example and Example 1 is that in the preparation method of the glass composition, only the high-melting-point oxide A1 is used during melting in step S1, and the low-melting-point oxide B is not used.

[0090] Comparative Example 9

[0091] The difference between this example and Example 1 is that the preparation method of the glass composition does not include step S2, that is, it does not include the pore-forming process, but simply mixes the non-porous glass body C with the reinforcing phase A2.

[0092] Comparative Example 10

[0093] The difference between this example and Example 1 is that the preparation method of the glass composition does not include step S3, that is, it does not include the pore-filling process, and only the glass body D with pores is used for sealing.

[0094] Performance testing

[0095] (1) The performance tests involved in the product mainly include: coefficient of thermal expansion, flexural strength, service life, sealing performance, and water resistance.

[0096] (2) The test procedures and / or industry standards for each property of the glass composition are recorded in Table 2.

[0097] Table 2 Test procedures and / or industry standards for various properties of glass compositions

[0098]

[0099]

[0100] The performance test results are shown in Table 3.

[0101] Table 3 Performance test results of Examples 1-13 and Comparative Examples 1-10

[0102]

[0103]

[0104] In Example 1, the ratio of high-melting-point oxide A1 to low-melting-point oxide B, the content of pore-forming agent used in the preparation of the porous glass body D, and the content of reinforcing phase A2 in the glass composition Q are appropriate, resulting in optimal overall performance.

[0105] Examples 2-5 achieved good performance by controlling the Al content within the range of 10-17 wt%. When the Al content is low, the integrity of the glass network structure is generally poor, resulting in a higher coefficient of thermal expansion; conversely, when the Al content is high, the coefficient of thermal expansion is low.

[0106] In Examples 6-9, controlling the pore-forming agent content within the range of 3-10 wt% yielded better performance. When the pore-forming agent content is high, the number of pores and the pore area are larger, resulting in lower support strength, generally lower flexural strength, and consequently, a shorter service life.

[0107] In glass compositions Q of Examples 10-13, the glass matrix D content was in the range of 90-98 wt%, achieving good performance. When the reinforcing phase A2 content was high, there was a possibility of significant differences from the glass phase during sintering, potentially leading to porosity or cracks, thus resulting in little improvement in sealing service life.

[0108] Comparative Examples 1 and 2 were set with high-melting-point oxide Al content not in the range of 10-17 wt%. In Comparative Example 1, the Al content was too low, resulting in insufficient glass integrity, and thus the coefficient of thermal expansion, sealing performance and water resistance were all unqualified. In Comparative Example 2, the high-melting-point oxide Al content was too high, resulting in the coefficient of thermal expansion being too low, and the service life and sealing performance being unqualified.

[0109] Comparative Examples 3 and 4 were set with pore-forming agent content not in the range of 3-10 wt%. In Comparative Example 3, the pore-forming agent content was too high, resulting in an excessive number and area of ​​pores in the porous glass body D, causing the performance to be unqualified. Conversely, in Comparative Example 4, the pore-forming agent content was too low, and the reinforcing phase was insufficient to play its role, resulting in poor service life and sealing performance.

[0110] In Comparative Examples 5 and 6, the content of reinforcing phase D in glass composition Q was not in the range of 90-98 wt%. In Comparative Example 5, the content of reinforcing phase A2 was too high, resulting in too much high-melting-point oxide, too low coefficient of thermal expansion, and unqualified service life and sealing performance. In Comparative Example 6, the content of reinforcing phase A2 was too low, resulting in unqualified service life, sealing performance and water resistance.

[0111] Comparative Examples 7 and 8 showed that the raw material components for preparing sealing glass were either a single high-melting-point oxide or a single low-melting-point oxide, and the sealing glass obtained had poor performance.

[0112] In Comparative Example 9, a glass composition Q was prepared by simple mixing without a pore-forming process. In this case, the reinforcing phase A2 did not have a reinforcing effect, which greatly reduced the service life. The uneven mixing of the components also resulted in poor sealing performance.

[0113] Comparative Example 10 had no pore-filling process after pore formation. The presence of pores and the absence of a reinforcing phase resulted in poor glass support strength, as well as poor flexural strength, service life, sealing performance, and water resistance.

[0114] Traditional glass melting processes, due to the presence of high-melting-point oxides such as Al2O3, ZrO2, and TiO2, typically involve melting temperatures between 1300 and 1600°C. However, this invention, through the combination of a porous glass matrix and a reinforcing phase, first yields a glass matrix with a lower melting temperature, requiring only 900 to 1100°C. Then, the reinforcing phase is added. During long-term operation at high temperatures, the reinforcing phase gradually diffuses into the original glass phase, slowly improving the strength, sealing properties, and water resistance of the sealing material. This significantly enhances the stability of the sealing material, preventing performance degradation during long-term high-temperature operation and greatly extending its service life.

[0115] This invention uses a pore-forming agent to create pores in a glass matrix that lacks pores, resulting in a glass matrix with a certain porosity. This allows the reinforcing phase to better fill the porous glass matrix, ensuring that the reinforcing phase is evenly distributed and better bonded within the glass composition, which is beneficial for the reinforcing phase to better perform its sealing function.

[0116] The glass composition of this invention exhibits a long service life and reliable sealing during high-temperature cycling, demonstrating excellent flexural strength, service life, sealing performance, and water resistance. Using the glass composition of this invention as a sealing material can yield single cells with low degradation rates and long service lives. Therefore, the glass composition of this invention has wide applications in the field of sealing materials, especially in the field of sealing materials for batteries (such as solid oxide fuel cells).

Claims

1. A glass composition, characterized in that, The invention comprises a porous glass body and a reinforcing phase filling the pores of the porous glass body. The raw materials for preparing the porous glass body include high-melting-point oxides and low-melting-point oxides. The reinforcing phase is selected from the high-melting-point oxides. The melting point of the high-melting-point oxides is higher than that of the low-melting-point oxides. The high-melting-point oxide includes at least one of Al2O3, ZrO2, Y2O3, or TiO2; the low-melting-point oxide includes La2O3, CeO2, B2O3, M1, and M2 in a mass ratio of 1:(0.5~2):(0.5~2):(0.5~2):(0.5~2), wherein M1 includes at least one of CaO, SrO, and Bi2O3, and M2 includes at least one of MgO or BaO; The reinforcing phase comprises 2-10% by mass in the glass composition; the high-melting-point oxide comprises 10-20% by mass in the porous glass bulk. The pores in the porous glass body are obtained by pore-forming treatment using a pore-forming agent; the amount of the pore-forming agent is 3 to 10% of the sum of the mass of the high-melting-point oxide and the low-melting-point oxide of the glass body.

2. The glass composition according to claim 1, characterized in that, The porous glass body is composed of spherical particles.

3. The glass composition according to claim 1, characterized in that, The high-melting-point oxide has a melting point of 1600~2500℃; The melting point of the low-melting-point oxide is 900~1200℃.

4. A method for preparing the glass composition according to any one of claims 1 to 3, characterized in that, Includes the following steps: S1. High-temperature melting: The high-melting-point oxide and the low-melting-point oxide are melted at high temperature, and after cooling, a glass body without pores is obtained; S2. Pore-forming treatment: The glass body without pores described in step S1 is mixed with a pore-forming agent and subjected to pore-forming treatment to obtain the glass body with pores. S3. Preparation of glass composition: The porous glass body described in step S2 is mixed with the reinforcing phase, so that the reinforcing phase fills the pores of the porous glass body to obtain the glass composition.

5. The method for preparing the glass composition according to claim 4, characterized in that, The high-temperature melting temperature in step S1 is 900~1100℃.

6. The method for preparing the glass composition according to claim 4, characterized in that, In step S2, the pore-forming agent includes at least one of silicon carbide, carbon black, water glass, carbonate, sulfate, or nitrate; the amount of the pore-forming agent is 3 to 10% of the sum of the mass of the high-melting-point oxide and the low-melting-point oxide.

7. The method for preparing the glass composition according to claim 4, characterized in that, In step S2, the pore-forming process is as follows: the temperature is increased to 500-600℃ at a heating rate of 5-7℃ / min and held for 0.2-1h; then the temperature is increased to 600-700℃ at a heating rate of 8-12℃ / min and held for 0.5-1h; finally, the temperature is increased to 800-950℃ at a heating rate of 12-15℃ / min and held for 0.5-2h; then the temperature is decreased to 500-700℃ at a cooling rate of 10-13℃ / min; and then the temperature is decreased to room temperature at a cooling rate of 7-10℃ / min.

8. The use of the glass composition according to any one of claims 1 to 3 as a sealing material.

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