Method for reducing the porosity of a sealing layer and its use

Abstract

The application discloses a method for reducing the porosity of a sealing layer and application thereof. The method for reducing the porosity of a sealing layer comprises the following steps: placing sealing glass as a solder at a welding position for sealing treatment, sintering a glass solder source at a preset temperature to form a molten glass solder, applying micro-penetration kinetic energy to the molten glass solder, and removing bubbles in the molten glass solder, and then cooling and solidifying to obtain a sealing layer with low porosity. The micro-penetration kinetic energy comprises at least one of a magnetic field and vibration kinetic energy. The molten glass solder is added with magnetic metal particles with an average particle size of 10 nm-100 microns. According to the embodiment of the application, the bubbles in the sealing glass can be quickly and efficiently removed, the porosity is reduced, and the cost is saved.

Description

Technical Field

[0001] This application belongs to the field of sealing glass, and particularly relates to a method for reducing the porosity of the sealing layer and its application. Background Technology

[0002] Sealing glass is an intermediate glass layer that connects glass, ceramics, metals, and composite materials. Due to limitations in atmosphere and composition, air bubbles are inevitably generated during the sealing process. As a form of defect, air bubbles can lead to stress concentration, creating dangerous sites for crack initiation. This stress concentration is particularly pronounced when two air bubbles are close together, making crack initiation more likely and resulting in a significant reduction in the strength of the glass material on a macroscopic level. The presence of air bubbles also reduces the glass's airtightness, insulation properties, and aging resistance. Existing methods for reducing the porosity of the sealing layer mainly involve adjusting the process temperature, sintering atmosphere, and changing the glass composition.

[0003] However, determining the optimal composition or process conditions for reducing porosity requires extensive experimental exploration, which consumes a significant amount of time and effort. Furthermore, due to the numerous influencing factors and their interactions, it is difficult to determine the optimal composition and process conditions. Additionally, when the required composition is fixed, the goal of reducing porosity cannot be achieved by modifying the composition, and adjusting the process has a very limited impact on porosity. Summary of the Invention

[0004] This application provides a method for reducing the porosity of a sealing layer and its application, which can quickly and efficiently remove air bubbles from the sealing layer, reduce porosity, and thus save costs.

[0005] In a first aspect, embodiments of this application provide a method for reducing the porosity of a sealing layer, wherein sealing glass is placed at the welding point as solder for sealing treatment, comprising: sintering a glass solder source at a preset temperature to form a molten glass solder; applying microscopic penetration kinetic energy to the molten glass solder, causing bubbles in the molten glass solder to overflow, and then cooling and solidifying to obtain a sealing layer with low porosity, wherein the microscopic penetration kinetic energy includes at least one of applying a magnetic field to the molten glass solder and vibration kinetic energy; wherein the conditions required for applying a magnetic field to the molten glass solder include: an ambient temperature of 950-1050°C, and the addition of magnetic metal particles with an average particle size of 10nm-100μm to the molten glass solder; the conditions required for applying vibration kinetic energy to the molten glass solder include: an ambient temperature of 950-1050°C, and applying vibration to the molten glass solder through a high-frequency vibration platform or an ultrasonic device.

[0006] In any embodiment of this application, when a magnetic field is applied to the molten glass solder, bubbles in the molten glass solder form around the magnetic metal particles. The magnetic metal particles can move back and forth under the action of the magnetic field, driving the bubbles to overflow.

[0007] In any embodiment of this application, when vibration is applied to the molten glass solder, the air bubbles in the molten glass solder overflow under the action of buoyancy.

[0008] In any embodiment of this application, the magnetic metal particles comprise an expanded alloy, the coefficient of thermal expansion of which is 3 × 10⁻⁶ within the temperature range of 20-100°C. -6 / ℃-5×10 -6 / ℃.

[0009] In any embodiment of this application, the expansion alloy includes at least one of 4J42 and 4J29.

[0010] In any embodiment of this application, the average particle size of the magnetic metal particles is 10 nm-100 μm.

[0011] In any embodiment of this application, the magnetic field is a static magnetic field.

[0012] In any embodiment of this application, the strength of the magnetic field is 1-100 mT.

[0013] In any embodiment of this application, the porosity of the sealing layer is less than 2 vol.%.

[0014] In any embodiment of this application, the mechanical strength of the sealing layer is greater than 150 MPa.

[0015] Secondly, this application provides an application of the above-described method for reducing the porosity of the sealing layer in electrical penetrations.

[0016] The method and application of reducing the porosity of the sealing layer in this application embodiment can utilize the characteristic of tending to form bubbles around magnetic metal particles, and under the action of a magnetic field, make the magnetic metal particles move upward, driving most of the bubbles in the glass to move upward and be discharged; or, by using vibration in the anti-gravity direction applied to the molten raw material, the fluidity of the molten raw material is increased, and the bubbles are quickly discharged by means of buoyancy, thereby reducing the porosity quickly and efficiently. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1This is a diagram showing the distribution of air bubbles in the sealing glass after adding 4J42 in Embodiment 1 of this application. Detailed Implementation

[0019] To better understand the above-mentioned objectives, features, and advantages of this application, the solution of this application will be further described below. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0020] Numerous specific details are set forth in the following description in order to provide a full understanding of this disclosure, but this application may also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only some embodiments of this application, and not all embodiments.

[0021] The following detailed description, with appropriate reference to the accompanying drawings, discloses the method for reducing the porosity of the sealing layer and its application embodiments. However, unnecessary details may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of essentially the same structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0022] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0023] Unless otherwise specified, all embodiments and optional embodiments of this application may be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of this application.

[0024] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions, and such technical solutions shall be deemed to be included in the disclosure of this application.

[0025] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0026] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.

[0027] Unless otherwise specified, this application uses conventional testing methods or testing methods recommended by the instrument.

[0028] Existing methods for reducing the porosity of sealing glass mainly involve adjusting the process temperature, sintering atmosphere, and changing the glass composition. For example, CN103641312B and US5820989A both disclose a sealing glass with low porosity, achieved through compositional design. CN109153595B discloses a metal sealing glass tube that is less prone to bubbling during sealing, mentioning that pores in the glass are mainly caused by carbon dioxide release during sealing. Replacing a portion of the carbonate raw material with nitrate raw material, or extending the melting time by selecting the type and size of the glass furnace and adjusting the glass flow rate, can promote gas release and thus reduce the porosity of the sealing glass. CN113698074A discloses a manufacturing process for optical glass with low bubble rate and high refractive index, belonging to the field of optical glass. This process involves introducing a radially moving sphere into the molten material during the melting process. Guided by an external magnetic field, the sphere moves within the molten material. When it comes into contact with bubbles, it cuts the bubbles, causing the internal air to escape upwards. Compared to existing mechanical stirring methods for bubble removal, this process achieves stirring within the molten material, effectively preventing the introduction of external air and significantly improving the refractive index of the optical glass. Furthermore, with the radially moving rod, under the influence of gravity, the rod moves along with the sphere, thus radially expanding the cutting range of the outer heat-resistant layer on the bubbles, significantly improving the bubble removal efficiency.

[0029] While CN113698074A also discloses a device that can move back and forth under the influence of a magnetic field, it focuses on the manufacturing process of optical glass. The aim is to utilize the wide-range movement of the radiating spheres to contact air bubbles as much as possible, creating a cutting effect that causes the internal air to escape upwards – essentially a form of agitation to remove air bubbles. Therefore, it easily introduces external air, affecting the expulsion of air bubbles. The additional radiating spheres also need to be separated later, undoubtedly increasing processing costs and the probability of air introduction. During the sealing process, air in the contact layer can reintroduce air bubbles. CN113698074A aims to remove air bubbles from optical glass, while this application aims to remove air bubbles from sealing glass. Sealing glass is typically used in small-scale, small-size applications. For example, in the field of electrical penetrations, hollow cylinders with a diameter of 5mm and a height of 5mm are commonly used sealing glass sizes, and in large quantities; in one model, a single penetration has 320 such cylindrical sealing glass units. The placement and removal of the radiating spheres is impossible within such a confined space and with such a large quantity. Therefore, we added micron-sized spheres, which were added all at once during the preparation of the sealing glass and do not need to be removed.

[0030] Therefore, this application introduces microscopic magnetic metal particles during the preparation of the sealing glass. This causes bubbles to initially form around the magnetic metal particles, and then, under the influence of a magnetic field, the magnetic metal particles move upwards, carrying most of the bubbles in the glass upwards and expelling them. Because the thermal expansion coefficient of the magnetic metal particles matches that of the glass well, excessive residual stress is unlikely to occur, resulting in excellent adhesion to the glass. Therefore, it is never necessary to separate the magnetic metal particles again. Alternatively, vibration applied to the molten raw material can be used to facilitate the rapid expulsion of bubbles through buoyancy, thus significantly saving the time and effort required for composition / process exploration and reducing development costs. This method for reducing the porosity of the sealing layer can be completed within 5-10 minutes after the sealing glass melts, offering high efficiency, simple operation, and significant results.

[0031] Methods to reduce the porosity of the sealing layer

[0032] A method for reducing the porosity of a sealing layer involves placing sealing glass as a solder at the welding point for sealing treatment. The method includes: sintering a glass solder source at a preset temperature to form a molten glass solder; applying microscopic penetration kinetic energy to the molten glass solder, causing bubbles in the molten glass solder to escape; and then cooling and solidifying to obtain a low-porosity sealing layer. The microscopic penetration kinetic energy includes at least one of applying a magnetic field and vibrational kinetic energy to the molten glass solder. The conditions for applying a magnetic field to the molten glass solder include: an ambient temperature of 950-1050℃; and the addition of magnetic metal particles with an average particle size of 10nm-100μm to the molten glass solder. The conditions for applying vibrational kinetic energy to the molten glass solder include: an ambient temperature of 950-1050℃; and applying vibration to the molten glass solder using a high-frequency vibration platform or an ultrasonic device. Applying both a magnetic field and vibration to the molten solder simultaneously can further reduce porosity. The magnetic metal particles can also further enhance the strength and toughness of the sealing layer. The amount of magnetic metal particles added is 1.5 wt.% to 2.5 wt.%. Within this range, porosity can be better reduced, while the strength and toughness of the sealing layer are optimized.

[0033] In some embodiments, when a magnetic field is applied to the molten glass solder, bubbles form around the magnetic metal particles in the molten glass solder. The magnetic metal particles can move back and forth under the influence of the magnetic field, driving the bubbles to overflow. For example... Figure 1As shown in the experiment, it was found that bubbles in the sealing glass tend to form around the additives. Magnetic metal particles, such as iron, cobalt, nickel, their alloys, or magnetic oxides, are added in advance during the preparation of the sealing glass. During sintering, after the glass has completely melted, a unidirectional magnetic field is applied to the glass sample, causing the magnetic metal particles to move upwards, carrying most of the bubbles in the glass upwards and expelling them. If the bubbles are not sufficiently expelled after applying the magnetic field once, the magnetic field can be interrupted, allowing the magnetic metal particles to fall back to the bottom of the molten glass under gravity. Then, the magnetic field can be reapplied, causing the magnetic particles to carry the remaining bubbles upwards and expel them again. Alternatively, if the bubbles are not sufficiently expelled, a reverse, weak magnetic field can be applied, causing the metal particles to slowly return to the bottom of the molten glass. Then, the original magnetic field can be reapplied, causing the magnetic particles to carry the remaining bubbles upwards and expel them again.

[0034] In some embodiments, when vibration is applied to the molten glass solder, air bubbles in the molten glass solder overflow under the action of buoyancy. In this embodiment, the ambient temperature is 950-1050°C. At this sintering temperature, the viscosity of the liquid glass can be reduced, which is beneficial to the movement and expulsion of air bubbles.

[0035] In some embodiments, the magnetic metal particles comprise an expanded alloy, wherein the coefficient of thermal expansion of the expanded alloy is 3 × 10⁻⁶ within the temperature range of 20-100°C. -6 / ℃-5×10 -6 / ℃. Expansion alloys are precision alloys with anomalous thermal expansion characteristics, also known as thermal expansion alloys, and are widely used in the electronics industry, precision measuring tools, precision instruments, and cryogenic engineering. While most metals and alloys expand when heated, with the expansion increasing linearly with temperature, some alloys exhibit a bending point (the intersection of tangents to two line segments with different slopes) in their thermal expansion curves at a certain temperature. Below this bending point, the coefficient of thermal expansion is much lower than the normal coefficient above it; this phenomenon is called anomalous thermal expansion. Expansion alloys are classified into low-expansion alloys and constant-expansion alloys, the latter also known as sealing alloys. Low-expansion alloys have an average coefficient of thermal expansion below the bending point of less than 3 × 10⁻⁶. -6 ℃ -1 The average coefficient of thermal expansion of a constant-expansion alloy below the bending point is approximately (4-10)×10⁻⁶. -6 ℃ -1 Expansion alloys mainly include Fe-Ni, Fe-Ni-Co, and Fe-Ni-Cr alloys. High-chromium steel and Co-Fe-Cr alloys are also used as expansion alloys, but in small quantities. At this coefficient of thermal expansion, they offer high compatibility with glass, are less prone to generating excessive residual stress, and exhibit excellent adhesion to glass.

[0036] In some embodiments, the expansion alloy includes at least one of 4J42 and 4J29. 4J42 and 4J29 are designations. The composition of the 4J42 alloy mainly consists of elements such as iron, nickel, cobalt, chromium, and manganese, with a nickel content of 41.5%-42.5% and a cobalt content of less than or equal to 1.0%. The composition of the 4J29 alloy mainly includes elements such as iron, nickel, chromium, and manganese, with a nickel content of greater than or equal to 29% and a chromium content of 14.2%-17.8%.

[0037] In some embodiments, the average particle size of the magnetic metal particles is 1-10 μm. Magnetic metal particles with this average particle size can facilitate better bubble formation and expulsion.

[0038] In some embodiments, the magnetic field is a static magnetic field. Compared to alternating magnetic fields, pulsed magnetic fields, etc., a static magnetic field exerts a uniform and stable force on the magnetic particles within the field, making it less likely for the magnetic particles and bubbles to separate, thereby improving the efficiency of carrying the bubbles upward and expelling them.

[0039] In some embodiments, the strength of the magnetic field is 1-100 mT.

[0040] In some embodiments, the porosity of the sealing layer is less than 2 vol.%.

[0041] In some embodiments, the mechanical strength of the sealing layer is greater than 150 MPa.

[0042] Application of methods to reduce the porosity of the sealing layer

[0043] The above-mentioned methods for reducing the porosity of the sealing layer are applied in electrical penetrations. In particular, it is especially necessary to reduce the porosity of the sealing glass when sealing glass and metal.

[0044] Example 1

[0045] Step 1: Weigh the following raw materials for sealing glass according to the specified weight proportions:

[0046] 63% SiO2, 13.5% B2O3, 3.9% Al2O3, 5.7% CaO, 6.4% Na2O, 3.4% K2O, 4.1% ZnO.

[0047] Step 2: Add 2 wt.% of a material with a particle size of approximately 1 μm and a coefficient of thermal expansion of 4.1 × 10⁻⁶ to the raw material from Step 1. -6 4J42 with a temperature range of 20℃ to 100℃ is heated to a molten state at 1000℃. Then, a static magnetic field of 20mT is applied, causing the 4J42 to move upward, which in turn drives the bubbles upward and expel them.

[0048] Step 3: After the molten solder from Step 2, which has had its air bubbles removed, is cooled and solidified, a sealing layer with low porosity is obtained.

[0049] Example 2

[0050] Step 1: Weigh the following raw materials for sealing glass according to the specified weight proportions:

[0051] 63% SiO2, 13.5% B2O3, 3.9% Al2O3, 5.7% CaO, 6.4% Na2O, 3.4% K2O, 4.1% ZnO.

[0052] Step 2: Heat the raw material from Step 1 to a molten state at 1000℃, place it on a high-frequency vibration platform, adjust the parameter to a frequency of 10Hz, and after vibration, the bubbles will move upward and be discharged under the action of buoyancy.

[0053] Step 3: After the molten solder from Step 2, which has had its air bubbles removed, is cooled and solidified, a sealing layer with low porosity is obtained.

[0054] Data Analysis:

[0055] The porosity and mechanical strength of the sealing layers obtained in Examples 1 and 2 were tested using the following methods:

[0056] Porosity: Archimedes drainage method

[0057] Compressive strength: Refer to GB / T 4740-1999; Instrument: Universal testing machine.

[0058] The test results are as follows:

[0059] Serial Number Porosity (vol.%) Mechanical strength Example 1 0.8 267MPa Example 2 1.5 203MPa

[0060] The above description is merely a specific implementation of this application. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the protection scope of this application.

Claims

1. A method for reducing the porosity of a sealing layer, wherein sealing glass is used as solder and placed at the welding point for sealing treatment, characterized in that, include: The glass solder source is sintered at a preset temperature to form molten glass solder; Microscopic penetration kinetic energy is applied to the molten glass solder, causing bubbles in the molten glass solder to overflow. After cooling and solidification, a low-porosity sealing layer is obtained. The microscopic penetration kinetic energy includes applying a magnetic field to the molten glass solder to form microscopic penetration kinetic energy. The conditions required for applying a magnetic field to the molten glass solder include: an ambient temperature of 950-1050 ℃, and the addition of magnetic metal particles with an average particle size of 10 nm-100 μm to the molten glass solder.

2. The method according to claim 1, characterized in that, When a magnetic field is applied to the molten glass solder, bubbles in the molten glass solder form around the magnetic metal particles. The magnetic metal particles can move back and forth under the action of the magnetic field, driving the bubbles to overflow.

3. The method according to claim 1, characterized in that, The magnetic metal particles comprise an expanded alloy, the coefficient of thermal expansion of which is 3 × 10⁻⁶ within the temperature range of 20-100 °C. -6 / ℃-5×10 -6 / ℃.

4. The method according to claim 3, characterized in that, The expansion alloy includes at least one of 4J42 and 4J29.

5. The method according to claim 1, characterized in that, The average particle size of the magnetic metal particles is 10 nm-100 μm.

6. The method according to claim 1, characterized in that, The magnetic field is a static magnetic field.

7. The method according to claim 1, characterized in that, The strength of the magnetic field is 1-100 mT.

8. The method according to claim 1, characterized in that, The porosity of the sealing layer is less than 2 vol.%, and the mechanical strength of the sealing layer is greater than 150 MPa.

9. The method for reducing the porosity of the sealing layer according to any one of claims 1-8, applied in electrical penetrations.

Images