A method for sealing beryllium foil with stainless steel parts

Abstract

This invention relates to a method for sealing beryllium foil and stainless steel components, comprising the following steps: S1, pretreatment: the beryllium foil is degreased and acid-washed to remove surface oil and oxides; the stainless steel components and solder are pretreated, including degreasing and cleaning, to remove surface oil; S2, assembly: the beryllium foil, solder, and stainless steel components are assembled sequentially from bottom to top to obtain an assembled component to be brazed; S3, brazing: the assembled component is placed in a vacuum furnace, the furnace temperature is increased and maintained, and the oxides on the beryllium foil are decomposed by high temperature, allowing the solder to effectively wet the beryllium foil and react fully and effectively. After the heat preservation is completed, the temperature is controlled to drop to room temperature, and the brazed sealed component is removed. The beryllium foil and stainless steel component sealing method of this invention can effectively remove oxides from the surface of the beryllium foil, and the solder has good wettability to the stainless steel component, reacting directly to achieve welding between the beryllium foil and the stainless steel component, resulting in a high-quality beryllium foil and stainless steel component sealing component.

Description

Technical Field

[0001] This invention relates to the field of beryllium foil and dissimilar material bonding technology, and more specifically, to a method for sealing beryllium foil and stainless steel parts. Background Technology

[0002] Beryllium possesses excellent X-ray penetrability and produces relatively little secondary radiation from X-ray irradiation, making it widely used in X-ray analysis devices, X-ray inspection devices, electron microscopes, accelerator devices, and more. As an important component in radiation detection, the beryllium window's primary function is to seal the vacuum and increase transmittance.

[0003] Currently, there are two main methods for joining beryllium foil: bonding and welding. Bonding typically uses epoxy resin to bond the beryllium foil to stainless steel components, which can effectively meet the airtightness requirements of testing instruments. However, epoxy resin is prone to aging, especially during the fabrication of X-ray vacuum devices, which require baking at 400℃ to remove gas; the high temperature can easily cause the epoxy resin used for bonding to age and fail. Welding, on the other hand, is prone to oxidation and cracking of the beryllium foil before and after welding, particularly during the high-temperature heating process. It also makes it difficult for the solder to wet the beryllium foil, leading to leakage problems. For example, Chinese patent CN103715045, "A Beryllium Window and its Sealing Method," involves first plating a layer of nickel onto the beryllium window sheet, and then welding it with silver-copper solder (AgCu28). This patent adds an electroplating step, and the welding temperature is insufficient to break the beryllium oxide. Chinese patent CN114178639, "A Pulsed Laser Brazing Sealing Method for Beryllium Windows and Stainless Steel Bases," uses a low-heat-input pulsed laser to melt AgCu28 solder paste and fill the gap between the beryllium window and the stainless steel base, achieving a tight seal. However, AgCu28 solder has poor wettability on stainless steel; organic matter in the solder paste easily carbonizes, affecting the reaction between the solder and beryllium; and laser heating is difficult to control when welding beryllium foil with a thickness of tens to hundreds of micrometers.

[0004] Therefore, there is an urgent need to develop a method that can better seal beryllium foil and stainless steel, avoiding the electroplating step and using more suitable welding materials and welding processes to obtain high-quality beryllium foil and stainless steel sealing parts. Summary of the Invention

[0005] The technical problem to be solved by this invention is that beryllium foil is prone to oxidation and brittleness before and after welding, especially when heated at high temperatures during the welding process. This also makes it difficult for the solder to wet the beryllium foil, resulting in problems such as leakage rate.

[0006] To solve the above-mentioned technical problems, the present invention provides a method for sealing beryllium foil and stainless steel parts, comprising the following steps: S1, pretreatment of welding parts and solder, wherein the beryllium foil is degreased and acid-washed to remove surface oil and oxides; the stainless steel parts and solder are pretreated including degreasing and cleaning to remove surface oil; S2, assembly, wherein the beryllium foil, solder and stainless steel parts are assembled sequentially from bottom to top, and an isolator and a sealing block are placed on the upper side of the stainless steel parts, the sealing block being used to press the stainless steel parts downward by its own weight to obtain an assembled component to be brazed, ready for brazing; S3, brazing, wherein the assembled component is placed in a vacuum furnace, the furnace temperature of the vacuum furnace is raised and kept at that temperature, and brazing is performed, wherein the oxides on the beryllium foil are decomposed by high temperature during the brazing process, so that the solder can effectively wet the beryllium foil and react fully and effectively, after the heat preservation is completed, the temperature is controlled to be lowered to room temperature, and the brazed component is taken out, thereby obtaining a beryllium foil and stainless steel part sealing component.

[0007] According to an embodiment of the present invention, in step S3, the assembled component is placed in a vacuum furnace for brazing. It can be first heated to 400°C at a heating rate of 10-20°C / min, then heated to 70-120°C above the melting point of the solder at a heating rate of 5-15°C / min, and held at that temperature for 1-10 min. Then, it is cooled to 500°C at a cooling rate of 5-15°C / min, and finally cooled to room temperature with the furnace, thereby obtaining a beryllium foil and stainless steel sealing component.

[0008] According to embodiments of the present invention, a vacuum level better than 1×10⁻⁶ can be maintained throughout the vacuum furnace heating process. -3 3Pa.

[0009] According to embodiments of the present invention, the solder may be one or more of silver-copper-nickel (AgCuNi) and palladium-silver-copper (PdAgCu) solders.

[0010] According to an embodiment of the present invention, in step S1, the thickness of the beryllium foil can be 0.01 mm to 1 mm.

[0011] According to an embodiment of the present invention, in step S1, when pickling the beryllium foil, it can be prepared according to a 10% hydrofluoric acid solution or a 40% nitric acid solution plus a 5% hydrofluoric acid solution to remove the oxides on the surface.

[0012] According to embodiments of the present invention, the stainless steel material may be one or more of the following: martensitic stainless steel, ferritic stainless steel, and carbon steel.

[0013] According to an embodiment of the present invention, the thickness of the solder can be 0.01 to 0.1 mm.

[0014] According to an embodiment of the present invention, the separator may be made of ceramic material, which does not react with solder or beryllium foil, so as to prevent the solder from climbing upwards.

[0015] According to an embodiment of the present invention, the sealing block can be made of stainless steel, and the weight of the sealing block is 60-200 g / mm² depending on the size of the welding area. 2 design.

[0016] According to an embodiment of the present invention, the brazing process temperature can be set to 850-900°C based on the melting point of the solder silver-copper-nickel (AgCuNi) or palladium-silver-copper (PdAgCu).

[0017] Compared with the prior art, the technical solution provided by the embodiments of the present invention can achieve at least the following beneficial effects:

[0018] This invention effectively removes oxides from the surface of beryllium foil through pickling and high-temperature treatment during welding. The solder used has good wettability on both stainless steel parts and beryllium foil, resulting in a reaction. This directly achieves welding between beryllium foil and stainless steel parts, yielding a high-quality beryllium foil-stainless steel sealing joint.

[0019] This invention uses solders comprising silver-copper-nickel (AgCuNi) or palladium-silver-copper (PdAgCu) as welding materials. These solders can be directly brazed between beryllium foil and stainless steel parts without requiring electroplating or other treatments on the stainless steel parts. For example, palladium-silver-copper (PdAgCu27-5) has a melting point of 807–810°C, and silver-copper-nickel (AgCuNi28-2) has a melting point of 779–815°C. The brazing process temperature of this invention is 850–900°C, which is 70–120°C higher than the solder melting point. This temperature satisfies the requirement of melting the solder to weld the beryllium foil and stainless steel parts; simultaneously, this temperature allows the beryllium oxides generated during the time between pickling and brazing in the furnace to undergo high-temperature decomposition, ensuring the solder effectively wets the beryllium foil and achieves a full and effective reaction.

[0020] The present invention employs pickling treatment on beryllium foil before brazing, which plays a very important role in improving wettability, relieving stress, and obtaining a beryllium foil with good density and a sealing component for stainless steel parts. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention.

[0022] Figure 1 This is a flowchart illustrating a method for sealing beryllium foil and stainless steel components according to an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram showing the sealing position of the beryllium foil and the stainless steel component according to an embodiment of the present invention;

[0024] Figure 3 This is a physical image showing the effect of a beryllium foil and stainless steel component assembly sealed by a sealing method according to an embodiment of the present invention.

[0025] In the diagram: 1-Stainless steel component, 2-Solder, 3-Beryllium foil, 4-Isolation component, 5-Sealing block. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the described embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains. The terms “first,” “second,” and similar terms used in the specification and claims of this patent application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an” or “a” and similar terms do not indicate a limitation of quantity, but rather indicate the presence of at least one.

[0028] Figure 1 This is a flowchart illustrating a method for sealing beryllium foil and stainless steel components according to an embodiment of the present invention; Figure 2 This is a schematic diagram showing the sealing position of beryllium foil and stainless steel component according to an embodiment of the present invention.

[0029] like Figure 1 As shown, the method for sealing beryllium foil to stainless steel parts includes the following steps:

[0030] S1. Pre-treatment of welding parts and solder: The beryllium foil 3 is degreased and pickled to remove surface oil and oxides; the stainless steel parts 1 and solder 2 are pre-treated, including degreasing and cleaning, to remove surface oil.

[0031] S2, Assembly, such as Figure 2 As shown, the beryllium foil 3, solder 2, and stainless steel part 1 are assembled from bottom to top. The separator 4 and sealing block 5 are placed on the upper side of the stainless steel part 1. The sealing block 5 is used to press the stainless steel part 1 downward by its own weight to obtain the assembled component to be brazed, ready for brazing.

[0032] S3. Brazing: The assembled components are placed in a vacuum furnace, the furnace temperature is raised and held, and brazing is performed. During the brazing process, the oxides on the beryllium foil are decomposed by high temperature, so that the solder can effectively wet the beryllium foil and react fully and effectively. After the holding time is completed, the temperature is controlled to drop to room temperature, and the brazed components are taken out, thus obtaining the beryllium foil and stainless steel sealing parts.

[0033] This invention effectively removes oxides from the surface of beryllium foil through pickling and high-temperature treatment during welding. The solder used has good wettability on both stainless steel parts and beryllium foil, resulting in a reaction. This directly achieves welding between beryllium foil and stainless steel parts, yielding a high-quality beryllium foil-stainless steel sealing joint.

[0034] According to one or more embodiments of the present invention, in step S3, the assembled component is placed in a vacuum furnace for brazing. First, it is heated to 400°C at a heating rate of 10-20°C / min, then heated to 70-120°C above the melting point of the solder at a heating rate of 5-15°C / min, and held at that temperature for 1-10 min. Then, it is cooled to 500°C at a cooling rate of 5-15°C / min, and finally cooled to room temperature with the furnace, thereby obtaining a beryllium foil and stainless steel sealing component.

[0035] According to one or more embodiments of the present invention, the vacuum level is maintained at a level better than 1×10⁻⁶ throughout the vacuum furnace heating process. -3 3Pa.

[0036] According to one or more embodiments of the present invention, the solder is one or more of silver-copper-nickel (AgCuNi) and palladium-silver-copper (PdAgCu) solders.

[0037] According to one or more embodiments of the present invention, the brazing process temperature is set to 850-900°C based on the melting point of the solder silver-copper-nickel (AgCuNi) or palladium-silver-copper (PdAgCu).

[0038] This invention uses solders comprising silver-copper-nickel (AgCuNi) or palladium-silver-copper (PdAgCu) as welding materials. These solders can be directly brazed between beryllium foil and stainless steel parts without requiring electroplating or other treatments on the stainless steel parts. For example, palladium-silver-copper (PdAgCu27-5) has a melting point of 807–810°C, and silver-copper-nickel (AgCuNi28-2) has a melting point of 779–815°C. The brazing process temperature of this invention is 850–900°C, which is 70–120°C higher than the solder melting point. This temperature satisfies the requirement of melting the solder to weld the beryllium foil and stainless steel parts; simultaneously, this temperature allows the beryllium oxides generated during the time between pickling and brazing in the furnace to undergo high-temperature decomposition, ensuring the solder effectively wets the beryllium foil and achieves a full and effective reaction.

[0039] According to one or more embodiments of the present invention, in step S1, the thickness of the beryllium foil 3 is 0.01 mm to 1 mm.

[0040] According to one or more embodiments of the present invention, in step S1, when the beryllium foil is acid-washed, the oxides on the surface are removed by preparing a 10% hydrofluoric acid solution or a 40% nitric acid solution plus a 5% hydrofluoric acid solution.

[0041] The present invention employs pickling treatment on beryllium foil before brazing, which plays a very important role in improving wettability, relieving stress, and obtaining a beryllium foil with good density and a sealing component for stainless steel parts.

[0042] According to one or more embodiments of the present invention, the material of the stainless steel part 1 is one or more of the following stainless steels: martensitic stainless steel, ferritic stainless steel, and carbon steel.

[0043] According to one or more embodiments of the present invention, the thickness of the solder is 0.01 to 0.1 mm.

[0044] According to one or more embodiments of the present invention, the separator 4 is made of ceramic material and does not react with solder or beryllium foil to prevent solder from climbing upwards.

[0045] According to one or more embodiments of the present invention, the sealing block 5 is made of stainless steel, and the weight of the sealing block is 60-200 g / mm² depending on the size of the welding area. 2 design.

[0046] Figure 3 This is a physical image showing the effect of a beryllium foil and stainless steel component assembly sealed by a sealing method according to an embodiment of the present invention.

[0047] The following sets of experiments were conducted to verify the effectiveness of the embodiments of the present invention. AgCuNi2, AgCuPd5 (where 2 in AgCuNi2 indicates a 2% Ni mass ratio in the solder, and similarly, AgCuPd5 indicates a 5% Pd mass ratio), and AgCu28 are standard solders with standard grades and specific compositions, which are outside the scope of this patent and will not be detailed here. These solders are available in flake, filament, and powder forms, and are mixed with organic matter to form a paste during actual use.

[0048] Experiment 1 (using AgCuNi2 solder)

[0049] 1) Pretreatment of parts and solder

[0050] First, the beryllium foil with a thickness of 0.1 mm is degreased and cleaned. Then, it is acid-washed with a solution of 10% hydrofluoric acid or 40% nitric acid plus 5% hydrofluoric acid to remove the oxides on the surface. After acid washing, it is ultrasonically cleaned with alcohol and deionized water.

[0051] The solder is silver-copper-nickel (AgCuNi2) with a thickness of 0.05mm. Pre-treatments such as degreasing and cleaning are performed on the stainless steel parts and solder to remove surface oil and contaminants.

[0052] 2) Assembly

[0053] Assemble the parts in the following order: beryllium foil 3, silver-copper-nickel solder 2, and stainless steel part 1. Place the alumina ceramic separator 4 and the stainless steel sealing block 5. The outer diameter of the alumina ceramic is the same as the diameter of the beryllium foil, and the thickness is 0.2 mm. The weight of the stainless steel sealing block 5 is calculated based on the welding area at 100 g / mm². 2 Design and assemble, prepare for brazing.

[0054] 3) Brazing

[0055] The assembled components were placed in a vacuum furnace for brazing. First, the temperature was increased to 400°C at a rate of 15°C / min, then increased to 880°C at a rate of 10°C / min and held for 3 minutes. Subsequently, the temperature was decreased to 500°C at a rate of 8°C / min, and finally cooled to room temperature in the furnace. Throughout the heating process, the vacuum level was maintained to be better than 1×10⁻⁶. -3 Pa. After cooling to room temperature, the beryllium foil-stainless steel sealing component is obtained. A leak detector is used to test the airtightness of the sealing component; the leak rate is ≤1×10⁻⁶. - 10 Pa·m 3 / s.

[0056] Experiment 2 (using AgCuPd5 solder)

[0057] 1) Pretreatment of parts and solder

[0058] First, the beryllium foil with a thickness of 0.1 mm is degreased and cleaned. Then, it is acid-washed with a solution of 10% hydrofluoric acid or 40% nitric acid plus 5% hydrofluoric acid to remove the oxides on the surface. After acid washing, it is ultrasonically cleaned with alcohol and deionized water.

[0059] The solder is silver-copper-palladium (AgCuPd5) with a thickness of 0.05mm. Pre-treatment such as degreasing and cleaning is performed on the stainless steel parts and solder to remove surface oil and contaminants.

[0060] 2) Assembly

[0061] Assemble the parts in the following order: beryllium foil 3, silver-copper-palladium solder 2, and stainless steel component 1. Place the alumina ceramic separator 4 and the stainless steel sealing block 5. The outer diameter of the alumina ceramic is the same as that of the beryllium foil, and the thickness is 0.2 mm. The weight of the stainless steel sealing block 5 is calculated based on the welding area at 100 g / mm². 2 Design and assemble, prepare for brazing.

[0062] 3) Brazing

[0063] The assembled components were placed in a vacuum furnace for brazing. First, the temperature was increased to 400°C at a rate of 15°C / min, then increased to 880°C at a rate of 10°C / min and held for 3 minutes. Subsequently, the temperature was decreased to 500°C at a rate of 8°C / min, and finally cooled to room temperature in the furnace. Throughout the heating process, the vacuum level was maintained to be better than 1×10⁻⁶. -3 Pa. After cooling to room temperature, the beryllium foil-stainless steel sealing component is obtained. A leak detector is used to test the airtightness of the sealing component; the leak rate is ≤1×10⁻⁶. - 10 Pa·m 3 / s.

[0064] Experiment 3 (using AgCu28 solder)

[0065] 1) Pretreatment of parts and solder

[0066] First, the beryllium foil with a thickness of 0.1 mm is degreased and cleaned. Then, it is acid-washed with a solution of 10% hydrofluoric acid or 40% nitric acid plus 5% hydrofluoric acid to remove the oxides on the surface. After acid washing, it is ultrasonically cleaned with alcohol and deionized water.

[0067] The solder is silver-copper (AgCu28) with a thickness of 0.05mm. Pre-treatments such as degreasing and cleaning are performed on the stainless steel parts and solder to remove surface oil and contaminants.

[0068] 2) Assembly

[0069] Assemble the parts in the following order: beryllium foil 3, silver-copper solder 2, and stainless steel component 1. Place the alumina ceramic separator 4 and the stainless steel sealing block 5. The outer diameter of the alumina ceramic is the same as that of the beryllium foil, and its thickness is 0.2 mm. The weight of the stainless steel sealing block 5 is calculated based on the welding area at 100 g / mm². 2 Design and assemble, prepare for brazing.

[0070] 3) Brazing

[0071] The assembled components were placed in a vacuum furnace for brazing. First, the temperature was increased to 400°C at a rate of 15°C / min, then increased to 880°C at a rate of 10°C / min and held for 3 minutes. Subsequently, the temperature was decreased to 500°C at a rate of 8°C / min, and finally cooled to room temperature in the furnace. Throughout the heating process, the vacuum level was maintained to be better than 1×10⁻⁶. -3 Pa. After controlling the temperature to room temperature, the product is removed, resulting in a beryllium foil-stainless steel sealing component. A leak detector is used to test the airtightness of the sealing component, and a leak is found.

[0072] Experiment 4 (without solder)

[0073] 1) Pretreatment of parts and solder

[0074] First, the beryllium foil with a thickness of 0.1 mm is degreased and cleaned. Then, it is acid-washed with a solution of 10% hydrofluoric acid or 40% nitric acid plus 5% hydrofluoric acid to remove the oxides on the surface. After acid washing, it is ultrasonically cleaned with alcohol and deionized water.

[0075] Pre-treatment such as degreasing and cleaning is performed on stainless steel parts to remove surface oil stains.

[0076] 2) Assembly

[0077] Assemble the parts in the order of beryllium foil 3, stainless steel part 1, and then place the alumina ceramic separator 4 and the stainless steel sealing block 5. The outer diameter of the alumina ceramic is the same as the diameter of the beryllium foil, and its thickness is 0.2 mm. The weight of the stainless steel sealing block is calculated at 100 g / mm² based on the welding area. 2 Design and assemble, prepare for brazing.

[0078] 3) Brazing

[0079] The assembled components were placed in a vacuum furnace for brazing. First, the temperature was increased to 400°C at a rate of 15°C / min, then increased to 880°C at a rate of 10°C / min and held for 3 minutes. Subsequently, the temperature was decreased to 500°C at a rate of 8°C / min, and finally cooled to room temperature in the furnace. Throughout the heating process, the vacuum level was maintained to be better than 1×10⁻⁶. -3 Pa. After controlling the temperature to room temperature, the beryllium foil-stainless steel sealing component was obtained. The airtightness of the sealing component was tested using a leak detector, and the sealing component was found to have serious air leakage.

[0080] Experiment 5 (using AgCuNi2 solder, soldering at a lower temperature)

[0081] 1) Pretreatment of parts and solder

[0082] First, the beryllium foil with a thickness of 0.1 mm is degreased and cleaned. Then, it is acid-washed with a solution of 10% hydrofluoric acid or 40% nitric acid plus 5% hydrofluoric acid to remove the oxides on the surface. After acid washing, it is ultrasonically cleaned with alcohol and deionized water.

[0083] The solder is silver-copper-nickel (AgCuNi2) with a thickness of 0.05mm. Pre-treatments such as degreasing and cleaning are performed on the stainless steel parts and solder to remove surface oil and contaminants.

[0084] 2) Assembly

[0085] Assemble the parts in the following order: beryllium foil 3, silver-copper-nickel solder 2, and stainless steel part 1. Place the alumina ceramic separator 4 and the stainless steel sealing block 5. The outer diameter of the alumina ceramic is the same as the diameter of the beryllium foil, and the thickness is 0.2 mm. The weight of the stainless steel sealing block 5 is calculated based on the welding area at 100 g / mm². 2 Design and assemble, prepare for brazing.

[0086] 3) Brazing

[0087] The assembled components were placed in a vacuum furnace for brazing. First, the temperature was increased to 400°C at a rate of 15°C / min, then increased to 800°C at a rate of 10°C / min and held for 3 minutes. Subsequently, the temperature was decreased to 500°C at a rate of 8°C / min, and finally cooled to room temperature in the furnace. Throughout the heating process, the vacuum level was maintained to be better than 1×10⁻⁶. -3 Pa. After controlling the temperature to room temperature, the product is removed, resulting in a beryllium foil-stainless steel sealing component. A leak detector is used to test the airtightness of the sealing component, and a leak is found.

[0088] Experiment 6 (using AgCuNi2 solder, without spacers and clamps)

[0089] 1) Pretreatment of parts and solder

[0090] First, the beryllium foil with a thickness of 0.1 mm is degreased and cleaned. Then, it is acid-washed with a solution of 10% hydrofluoric acid or 40% nitric acid plus 5% hydrofluoric acid to remove the oxides on the surface. After acid washing, it is ultrasonically cleaned with alcohol and deionized water.

[0091] The solder is silver-copper-nickel (AgCuNi2) with a thickness of 0.05mm. Pre-treatments such as degreasing and cleaning are performed on the stainless steel parts and solder to remove surface oil and contaminants.

[0092] 2) Assembly

[0093] Assemble the parts in the order of beryllium foil 3, silver-copper-nickel solder 2, and stainless steel part 1, in preparation for brazing.

[0094] 3) Brazing

[0095] The assembled components were placed in a vacuum furnace for brazing. First, the temperature was increased to 400°C at a rate of 15°C / min, then increased to 880°C at a rate of 10°C / min and held for 3 minutes. Subsequently, the temperature was decreased to 500°C at a rate of 8°C / min, and finally cooled to room temperature in the furnace. Throughout the heating process, the vacuum level was maintained to be better than 1×10⁻⁶. -3 Pa. After controlling the temperature to room temperature, the product is removed, resulting in a beryllium foil-stainless steel sealing component. A leak detector is used to test the airtightness of the sealing component, and a leak is found.

[0096] Compared with the AgCu28 solder used in Experiment 3, which had poor welding effect on stainless steel, the solders in Experiments 1 and 2 improved the welding effect after the addition of Ni and Pd elements. The solder of the present invention has good wettability on stainless steel parts and reacts, thereby directly realizing the welding between beryllium foil and stainless steel parts, and can obtain a beryllium foil and stainless steel sealing part with better airtightness.

[0097] Compared with Experiment 4 (without solder), Experiment 5 (with low-temperature welding), and Experiment 6 (without separators and pressure blocks), the airtightness of the welded parts obtained is not as good as the quality of the beryllium foil and stainless steel sealing parts obtained in Experiments 1 and 2 of the present invention.

[0098] Through experimental comparison, Experiment 1 and Experiment 2 were beryllium foil-stainless steel sealing performed according to the beryllium foil-stainless steel sealing method of the present invention. The airtightness of the sealing parts was tested by using a leak detector, and it was found that the sealing parts had good airtightness, which can achieve better sealing effect between beryllium foil and stainless steel parts.

[0099] The above description is merely an exemplary embodiment of the present invention and is not intended to limit the scope of protection of the present invention, which is determined by the appended claims.

Claims

1. A method of sealing a beryllium foil to a stainless steel piece, characterized by, Includes the following steps: S1. Pre-treatment of welded parts and solder: Beryllium foil is degreased, cleaned, and pickled to remove surface oil and oxides; stainless steel parts and solder undergo pre-treatment including degreasing and cleaning to remove surface oil. When pickling beryllium foil, a solution of 10% hydrofluoric acid or 40% nitric acid plus 5% hydrofluoric acid is used to remove surface oxides. The thickness of the beryllium foil is 0.01 mm to 1 mm. S2. Assembly: The beryllium foil, solder, and stainless steel parts are assembled from bottom to top. A spacer and a sealing block are placed on the upper side of the stainless steel parts. The sealing block is used to press the stainless steel parts downward by its own weight to obtain the assembled component to be brazed, ready for brazing. S3. Brazing: The assembled components are placed in a vacuum furnace, the furnace temperature is raised and held, and brazing is performed. During the brazing process, the oxides on the beryllium foil are decomposed by high temperature, allowing the solder to effectively wet the beryllium foil and react fully. After holding at the temperature, the temperature is controlled to drop to room temperature, and the brazed components are removed, thus obtaining the beryllium foil and stainless steel sealing component. The isolation element is made of a material that does not react with the solder or beryllium foil to prevent the solder from climbing upwards. In step S3, the assembled components are placed in a vacuum furnace for brazing, which includes the following sub-steps: S31. First, heat to 400℃ at a heating rate of 10~20℃ / min. S32. Then heat to 70-120°C above the solder melting point at a heating rate of 5-15°C / min, and hold for 1-10 minutes. S33, then the temperature is reduced to 500℃ at a cooling rate of 5~15℃ / min; S34. Finally, the furnace is cooled to room temperature to obtain the beryllium foil and stainless steel sealing component.

2. The method of sealing a beryllium foil to a stainless steel piece of claim 1, wherein, In step S3, the vacuum degree is always ensured to be better than 1 x 10 -3 Pa during the heating process in the vacuum furnace.

3. The method of sealing a beryllium foil to a stainless steel member as described in claim 1, wherein, The solder is one or more of the following: silver-copper-nickel (AgCuNi) and palladium-silver-copper (PdAgCu).

4. The method of sealing a beryllium foil to a stainless steel member as recited in claim 1, wherein, The stainless steel component is made of one or more types of stainless steel, including martensitic stainless steel, ferritic stainless steel, and carbon steel.

5. The method for sealing beryllium foil and stainless steel parts as described in claim 1, characterized in that, The thickness of the solder is 0.01~0.1mm.

6. The method for sealing beryllium foil and stainless steel parts as described in claim 1, characterized in that, The insulating component is made of ceramic material.

7. The method for sealing beryllium foil and stainless steel parts as described in claim 1, characterized in that, The sealing pressure block is a stainless steel piece, and the mass of the sealing pressure block is 60-200 g / mm according to the size of the welding area 2 Design.

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