A residual gas analyzer vacuum electrode, a brazing tool and a brazing method thereof

Abstract

The application provides a residual gas analyzer vacuum electrode, a brazing tool and a brazing method thereof. The vacuum electrode comprises an electrode assembly, a Kovar electrode rod, a ceramic base and a Kovar base. The electrode assembly comprises a signal collection electrode and a shielding electrode. A plurality of Kovar electrode rods are arranged at the periphery of the shielding electrode. The ceramic base is used for accommodating the shielding electrode and the plurality of Kovar electrode rods. The Kovar base is used for positioning the ceramic base. The brazing tool comprises a base, a first pressing block and a second pressing block. The brazing method comprises the following steps: providing the vacuum electrode and the brazing tool; sequentially placing the Kovar electrode rod and the signal collection electrode into the base; sequentially installing the shielding electrode, an insulating ceramic tube, the Kovar base and the ceramic base into the base; placing the first pressing block on the ceramic base; placing the second pressing block on the insulating ceramic tube; and performing brazing after the assembling is completed. The application ensures the brazing reliability and strength of the whole vacuum electrode, and facilitates the batch production of the vacuum electrode.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of welding, in particular relates to a residual gas analyzer vacuum electrode, brazing tool and brazing method thereof. BACKGROUND

[0002] Residual gas is one of the biggest obstacles for the development of surface science, high-energy physics, vacuum electronics and microelectronics science, and the residual gas can have physical or chemical reaction with the atoms on the surface of the material, thereby affecting the performance and service life of the device. How to further reduce the residual gas concentration in the vacuum system and master the residual gas composition and partial pressure is an important issue in the above-mentioned related fields. The mass spectrometer based on quadrupole mass analyzer is a representative device for qualitative and quantitative analysis of residual gas, and is a standard configuration of ultra-high vacuum system.

[0003] The vacuum electrode of the residual gas analyzer is a transition electrode connecting the ion source, lens group, mass analyzer and charge collection electrode in the vacuum atmosphere and the high-voltage power supply, signal extraction and amplification circuit, data acquisition card and control unit in the normal pressure atmosphere. The vacuum electrode is an important component of the residual gas analyzer, and the strength, insulation, sealing and connection reliability between the CCU (interface equipment between computer system and data circuit) control and PCB board of the vacuum electrode are directly related to the performance of the residual gas analyzer.

[0004] Generally, the residual gas analyzer needs to arrange more than ten mutually insulated electrodes in a limited size range (such as 3-4 cm in diameter), which involves weak signal conducting electrodes, electron multiplier high-voltage electrodes, quadrupole rod RF power high-voltage electrodes, ionization source electrodes, ion lens electrodes, etc. During the design of the vacuum electrode, the insulation between the electrode leads, the extraction and protection of the weak signal of the Faraday cup or electron multiplier, and the sealing and strength of the entire vacuum electrode need to be considered comprehensively. The typical form of the residual gas analyzer vacuum electrode is to use metal ceramic sealing, but there is little mention of the sealing tool and brazing method of the vacuum electrode in the residual gas analyzer manufacturers.

[0005] Therefore, it is necessary to provide an improved technical solution to overcome the above-mentioned deficiencies of the prior art. SUMMARY

[0006] In view of the above-mentioned deficiencies of the prior art, the purpose of the present application is to provide a residual gas analyzer vacuum electrode, brazing tool and brazing method thereof, which solves the problems of insufficient welding reliability and strength of the entire vacuum electrode in the prior art, and the lack of vacuum electrode in brazing tool and brazing method, and the problem that the vacuum electrode cannot be mass-produced.

[0007] To achieve the above object and other related objects, the present application provides a residual gas analyzer vacuum electrode, which comprises:

[0008] An electrode assembly, which comprises a signal collection electrode and a shielding electrode, the signal collection electrode is fixedly arranged inside the shielding electrode, and the shielding electrode is used for protecting weak signals collected by the signal collection electrode;

[0009] A plurality of Kovar electrode rods are arranged, and the plurality of Kovar electrode rods are arranged circumferentially on the periphery of the shielding electrode;

[0010] A ceramic base, which comprises a first through hole for accommodating the shielding electrode and a plurality of second through holes for accommodating the plurality of Kovar electrode rods respectively;

[0011] A Kovar base, which comprises an upper base arranged on the periphery of the ceramic base and a lower base fixed to the bottom end of the upper base and positioning the ceramic base.

[0012] Preferably, the outer wall of the shielding electrode is provided with a first edge boss for positioning and welding the ceramic base; the shielding electrode is a 4J33 Kovar shielding electrode;

[0013] The outer wall of the Kovar electrode rod is provided with a second edge boss for positioning and welding the ceramic base; the Kovar electrode rod is a 4J33 Kovar electrode rod;

[0014] After the welding of the ceramic base and the first edge boss is metallized, hydrogen burning treatment is performed;

[0015] After the welding of the ceramic base and the second edge boss is metallized, hydrogen burning treatment is performed.

[0016] Preferably, an insulating ceramic tube is arranged between the signal collection electrode and the shielding electrode, and the insulating ceramic tube is welded to the shielding electrode and the signal collection electrode respectively;

[0017] After the welding of the insulating ceramic tube and the shielding electrode is metallized, hydrogen burning treatment is performed, and after the welding of the insulating ceramic tube and the signal collection electrode is metallized, hydrogen burning treatment is performed.

[0018] Preferably, the first through hole is located at the center of the ceramic base, and the plurality of second through holes are distributed equidistantly circumferentially on the periphery of the first through hole;

[0019] Inner walls of the first through hole and the plurality of second through holes are subjected to a metallization process and then subjected to a hydrogen annealing process.

[0020] Preferably, the outer diameter of the ceramic base matches the inner diameter of the upper base, and the outer diameter of the ceramic base is greater than the inner diameter of the lower base.

[0021] The welding portion of the ceramic base and the Kovar base is subjected to a metallization process and then subjected to a hydrogen annealing process.

[0022] The ceramic base is a 95 ceramic base.

[0023] A brazing tool for a vacuum electrode of a residual gas analyzer as described above, the brazing tool comprising:

[0024] The base comprises a plurality of positioning holes passing through in sequence from bottom to top, and the plurality of positioning holes are respectively a first positioning hole, a second positioning hole, a third positioning hole, a fourth positioning hole, and a fifth positioning hole, the first positioning hole and the second positioning hole are used to accommodate and position the signal collection electrode, the third positioning hole is used to accommodate and position the shielding electrode, the bottom end of the fourth positioning hole is provided with a plurality of first limiting holes in the circumferential direction, and the plurality of first limiting holes are used to accommodate and limit the Kovar electrode rod; the fifth positioning hole is used to accommodate and position the lower base.

[0025] The first pressing block comprises a first accommodating cavity and a second accommodating cavity passing through in sequence from bottom to top, the first accommodating cavity is used to accommodate the Kovar electrode and the electrode assembly, and the bottom end of the first pressing block is extruded on the ceramic base.

[0026] The second pressing block passes through the second accommodating cavity and the first accommodating cavity in sequence and is extruded on the insulating ceramic tube, a second limiting hole is provided at the center position of the second pressing block, and the second limiting hole is used to accommodate and limit the upper end of the signal collection electrode.

[0027] Preferably, the base is a graphite base, and the first pressing block and the second pressing block are stainless steel pressing blocks.

[0028] A brazing method for a vacuum electrode of a residual gas analyzer, the brazing method comprising the following steps:

[0029] Providing a vacuum electrode of a residual gas analyzer as described above, and providing a welding tool as described above;

[0030] Placing the base on a horizontal workbench, placing a plurality of Kovar electrode rods in corresponding first limiting holes, and then placing a signal collection electrode in the first positioning hole and the second positioning hole;

[0031] The shielding electrode is placed in the third positioning hole, then the insulating ceramic tube is inserted between the shielding electrode and the signal collecting electrode, and then the Kovar base is placed in the fifth positioning hole, and the ceramic base is installed in the Kovar base;

[0032] The first pressing block is placed on the ceramic base, and the ceramic base, the Kovar electrode rod and the shielding electrode are pressed;

[0033] The second pressing block is placed on the insulating ceramic tube, and the insulating ceramic tube is pressed, and the vacuum electrode mounting is completed;

[0034] The vacuum electrode and the brazing tool are placed in the brazing furnace together after the mounting is completed, and brazing is performed.

[0035] Preferably, the welding parts of the ceramic base and the Kovar base, the shielding electrode and the Kovar electrode rod are subjected to metallization treatment, and then hydrogen burning treatment is performed;

[0036] The welding parts of the insulating ceramic tube and the shielding electrode and the signal collecting electrode are subjected to metallization treatment, and then hydrogen burning treatment is performed;

[0037] The welding parts of the Kovar electrode rod, the Kovar base, the signal collecting electrode and the shielding electrode are subjected to nickel plating after cleaning, and then hydrogen burning treatment is performed.

[0038] Preferably, the welding parts of the ceramic base and the Kovar base, the shielding electrode and the Kovar electrode rod are filled with solder, and the welding parts of the insulating ceramic tube and the shielding electrode and the signal collecting electrode are filled with solder.

[0039] Preferably, the solder is silver-copper alloy solder.

[0040] As described above, the residual gas analyzer vacuum electrode, the brazing tool and the brazing method thereof have the following beneficial effects:

[0041] The residual gas analyzer vacuum electrode in the application comprises an electrode assembly, a Kovar electrode, a ceramic base and a Kovar base, the ceramic base is located in the Kovar base, the Kovar electrode rod is located in the second through hole of the ceramic base, and the electrode assembly is located in the first through hole of the ceramic base; the ceramic base adopts 95 porcelain with a similar expansion coefficient to the Kovar base, which effectively improves the welding stability of the ceramic base and the Kovar base; the welding parts of the inner walls of the first through hole and the second through hole, the ceramic base and other components, and the welding parts of the insulating ceramic tube and the shielding electrode and the signal collecting electrode are subjected to metallization treatment, which greatly enhances the welding strength between the components, and further ensures the welding reliability of the vacuum electrode after welding.

[0042] The brazing tool in the application comprises a base corresponding to the vacuum electrode, a first pressing block and a second pressing block, a Kovar electrode rod, an electrode assembly and a ceramic base, and the Kovar base are installed in the base, and the vacuum electrode is completed by the extrusion of the first pressing block and the second pressing block, and the vacuum electrode and the brazing tool are put into the brazing furnace for heating and sealing together, and the electrodes, the insulating ceramic tube and the ceramic base are tightly fitted under the gravity of the first pressing block and the second pressing block during the melting of the solder, and the solder seals and infiltrates the welding part under the capillary action, so that the welding seam of the vacuum electrode is sealed to ensure the welding reliability and strength of the whole vacuum electrode; in addition, the base of the brazing tool is a graphite base, which can ensure a certain gap between the graphite base and the vacuum electrode during brazing due to the self-wetting, low expansion and moderate hardness of the graphite base, and the graphite base is easy to demold after brazing, so that the brazing tool is convenient for batch production of the vacuum electrode. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 The first perspective structure schematic diagram of the vacuum electrode in the embodiment of the application is shown.

[0044] Figure 2 The second perspective structure schematic diagram of the vacuum electrode in the embodiment of the application is shown.

[0045] Figure 3 The three-dimensional structure schematic diagram of the Kovar electrode rod in the embodiment of the application is shown.

[0046] Figure 4 The three-dimensional structure schematic diagram of the Kovar base in the embodiment of the application is shown.

[0047] Figure 5 The exploded view of the signal collecting electrode in the embodiment of the application is shown.

[0048] Figure 6 The three-dimensional structure schematic diagram of the shielding electrode in the embodiment of the application is shown.

[0049] Figure 7 The sectional view of the shielding electrode in the embodiment of the application is shown.

[0050] Figure 8 The three-dimensional structure schematic diagram of the insulating ceramic tube in the embodiment of the application is shown.

[0051] Figure 9 The three-dimensional structure schematic diagram of the ceramic base in the embodiment of the application is shown.

[0052] Figure 10 The three-dimensional structure schematic diagram of the brazing tool in the embodiment of the application is shown.

[0053] Figure 11 shows a sectional view of the brazing fixture in the embodiment of the present application.

[0054] Figure 12 shows a structural schematic view of the vacuum electrode and the brazing fixture in the embodiment of the present application.

[0055] Element Number Description

[0056] 101 Kovar electrode rod

[0057] 1011 second edge boss

[0058] 102 Kovar base

[0059] 1021 upper base

[0060] 1022 lower base

[0061] 103 signal collection electrode

[0062] 1031 first collection electrode

[0063] 1032 second collection electrode

[0064] 104 shield electrode

[0065] 1041 first edge boss

[0066] 105 insulating ceramic tube

[0067] 106 ceramic base

[0068] 1061 first through hole

[0069] 1062 second through hole

[0070] 201 base

[0071] 2011 first positioning hole

[0072] 2012 second positioning hole

[0073] 2013 third positioning hole

[0074] 2014 fourth positioning hole

[0075] 2015 fifth positioning hole

[0076] 2016 first limiting hole

[0077] 202 first pressing block

[0078] 2021 first accommodating cavity

[0079] 2022 second accommodating cavity

[0080] 203 Second pressing block

[0081] 2031 Second limiting hole Detailed Implementation

[0082] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0083] Please see Figures 1 to 12 It should be understood that the structures, proportions, sizes, etc., illustrated in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and to facilitate understanding and reading. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed in this invention. Furthermore, the terms such as "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.

[0084] The vacuum electrode of the residual gas analyzer in the application comprises an electrode assembly, a Kovar electrode, a ceramic base and a Kovar base, the ceramic base is located in the Kovar base, the Kovar electrode rod is located in the second through hole of the ceramic base, and the electrode assembly is located in the first through hole of the ceramic base; the ceramic base is made of 95 porcelain with a similar expansion coefficient to the Kovar base, thereby effectively improving the welding stability of the ceramic base and the Kovar base; the inner walls of the first through hole and the second through hole, the welding positions of the ceramic base and other components, and the welding positions of the insulating ceramic tube and the shielding electrode and the signal collection electrode are all subjected to metallization treatment, thereby greatly enhancing the welding strength between the components, and further ensuring the welding reliability of the vacuum electrode after welding; the brazing tool in the application comprises a base, a first pressing block and a second pressing block which are arranged correspondingly to the vacuum electrode, the Kovar electrode rod, the electrode assembly, the ceramic base and the Kovar base are all installed in the base, and the rack of the vacuum electrode is completed through the extrusion of the first pressing block and the second pressing block, the vacuum electrode and the brazing tool after the rack is completed are put into a brazing furnace for temperature rising and sealing, under the action of gravity of the first pressing block and the second pressing block, the electrodes, the insulating ceramic tube and the ceramic base are tightly fitted during the melting process of the solder, the solder seals and infiltrates the welding position under the capillary action, the welding seam of the vacuum electrode is sealed, so as to ensure the welding reliability and strength of the entire vacuum electrode; in addition, the base of the brazing tool is a graphite base, due to the characteristics of self-wetting, low expansion and moderate hardness of the graphite base, a certain gap can be reserved between the graphite base and the vacuum electrode during the brazing process, and the graphite base is easy to demold after the brazing is completed, so that the brazing tool is convenient for batch production of the vacuum electrode.

[0085] Referring to Figures 1 to 9 The application provides a vacuum electrode of a residual gas analyzer, which comprises an electrode assembly, a Kovar electrode rod 101, a ceramic base 106 and a Kovar base 102; wherein the electrode assembly comprises a signal collection electrode 103 and a shielding electrode 104, the signal collection electrode 103 is fixedly arranged inside the shielding electrode 104, and the shielding electrode 104 is used for protecting the weak signal collected by the signal collection electrode 103; the Kovar electrode rod 101 is arranged in plurality, and the plurality of Kovar electrode rods 101 are arranged in a circumferential direction at the periphery of the shielding electrode 104; the ceramic base 106 comprises a first through hole 1061 and a plurality of second through holes 1062, the first through hole 1061 is used for accommodating the shielding electrode 104, and the plurality of second through holes 1062 are respectively used for accommodating the plurality of Kovar electrode rods 101; the Kovar base 102 comprises an upper base 1021 and a lower base 1022, the upper base 1021 is arranged at the outer periphery of the ceramic base 106, the lower base 1022 is fixedly arranged at the bottom end of the upper base 1021 and is used for positioning the ceramic base 106.

[0086] Specifically, the signal collecting electrode 103 can be an integral part or two parts connected together. In order to facilitate sealing, the signal collecting electrode 103 in the embodiment is welded together by two parts. Referring to FIG. 3, which is an exploded view of the signal collecting electrode 103, the signal collecting electrode 103 includes a first collecting electrode 1031 and a second collecting electrode 1032. The outer diameter of the first collecting electrode 1031 is greater than that of the second collecting electrode 1032. A through hole is formed in the first collecting electrode 1031. One end of the second collecting electrode 1032 is inserted into the through hole of the first collecting electrode 1031 and is welded by solder. Preferably, the signal collecting electrode 103 is a 4J33 Kovar signal collecting electrode 103. Figure 5

[0087] The 4J33 Kovar alloy is a ceramic sealing alloy developed in combination with the ceramic characteristics of China. The 4J33 Kovar alloy has a linear expansion coefficient similar to that of 95% Al2O3 ceramic in the temperature range of -60°C to 600°C. It is mainly used for matching and sealing with ceramic and is an important sealing structure material in the electric vacuum industry.

[0088] As an example, the outer wall of the shielding electrode 104 is provided with a first edge boss 1041 for positioning and welding the ceramic base 106. Preferably, the shielding electrode 104 is a 4J33 Kovar shielding electrode 104.

[0089] Specifically, referring to FIG. 4, which is a schematic view of the shielding electrode 104, the shielding electrode 104 is in the shape of a cylinder. The first edge boss 1041 is arranged on the outer wall of the shielding electrode 104 and is arranged in the circumferential direction. The first edge boss 1041 is stopped at the bottom end of the first through hole 1061 of the ceramic base 106, thereby achieving positioning of the ceramic base 106 and facilitating welding of the shielding electrode 104 and the ceramic base 106. In addition, a through hole is formed in the shielding electrode 104, and the inner diameter of the through hole is different from bottom to top. The shape of the shielding electrode 104 and the size change of the inner diameter of the through hole are not limited here as long as they can meet the actual requirements. The main function of the shielding electrode 104 is to protect the weak signal collected by the signal collecting electrode 103 in the center position. Figure 6 Figure 7 As an example, the outer wall of the shielding electrode 104 is provided with a first edge boss 1041 for positioning and welding the ceramic base 106. Preferably, the shielding electrode 104 is a 4J33 Kovar shielding electrode 104.

[0090] Specifically, referring to FIG. 4, which is a schematic view of the shielding electrode 104, the shielding electrode 104 is in the shape of a cylinder. The first edge boss 1041 is arranged on the outer wall of the shielding electrode 104 and is arranged in the circumferential direction. The first edge boss 1041 is stopped at the bottom end of the first through hole 1061 of the ceramic base 106, thereby achieving positioning of the ceramic base 106 and facilitating welding of the shielding electrode 104 and the ceramic base 106. In addition, a through hole is formed in the shielding electrode 104, and the inner diameter of the through hole is different from bottom to top. The shape of the shielding electrode 104 and the size change of the inner diameter of the through hole are not limited here as long as they can meet the actual requirements. The main function of the shielding electrode 104 is to protect the weak signal collected by the signal collecting electrode 103 in the center position.

[0091] Specifically, referring to FIG. 4, which is a schematic view of the shielding electrode 104, the shielding electrode 104 is in the shape of a cylinder. The first edge boss 1041 is arranged on the outer wall of the shielding electrode 104 and is arranged in the circumferential direction. The first edge boss 1041 is stopped at the bottom end of the first through hole 1061 of the ceramic base 106, thereby achieving positioning of the ceramic base 106 and facilitating welding of the shielding electrode 104 and the ceramic base 106. In addition, a through hole is formed in the shielding electrode 104, and the inner diameter of the through hole is different from bottom to top. The shape of the shielding electrode 104 and the size change of the inner diameter of the through hole are not limited here as long as they can meet the actual requirements. The main function of the shielding electrode 104 is to protect the weak signal collected by the signal collecting electrode 103 in the center position. Figure 3 ​​The Kovar electrode rod 101 is needle-shaped, and one end of the Kovar electrode rod 101 is provided with a variable diameter, that is, the Kovar electrode rod 101 comprises a first electrode rod and a second electrode rod, and the outer diameter of the first electrode rod is smaller than the outer diameter of the second electrode rod. Different outer diameter structures can facilitate the close and reliable contact and conduction of the Kovar electrode rod 101 with the spring contact plug of the CCU unit interface.

[0092] As an example, the welding part between the ceramic base 106 and the first edge boss 1041 is metallized; the welding part between the ceramic base 106 and the second edge boss 1011 is metallized.

[0093] As an example, an insulating ceramic tube 105 is arranged between the signal collection electrode 103 and the shielding electrode 104, and the insulating ceramic tube 105 is welded to the shielding electrode 104 and the signal collection electrode 103, respectively; the welding part between the insulating ceramic tube 105 and the shielding electrode 104 is metallized, and the welding part between the insulating ceramic tube 105 and the signal collection electrode 103 is metallized.

[0094] Specifically, as shown in Figure 7 、 Figure 8 The outer diameter of the insulating ceramic tube 105 matches the inner diameter of the smallest through hole in the shielding electrode 104, and the insulating ceramic tube 105 is internally provided with a through hole matched with the signal collection electrode 103, but the specific structure of the insulating ceramic tube 105 is not limited here.

[0095] As an example, the first through hole 1061 is located at the center of the ceramic base 106, and a plurality of second through holes 1062 are distributed at equal intervals in the circumferential direction on the periphery of the first through hole 1061; the inner walls of the first through hole 1061 and the plurality of second through holes 1062 are metallized.

[0096] Specifically, the inner wall of the first through hole 1061 is metallized, which greatly increases the welding reliability of the shielding electrode 104 and the ceramic base 106, and the inner wall of the second through hole 1062 is metallized, which greatly increases the welding reliability between the Kovar electrode rod 101 and the ceramic base 106.

[0097] As an example, the outer diameter of the ceramic base 106 matches the inner diameter of the upper base 1021, and the outer diameter of the ceramic base 106 is greater than the inner diameter of the lower base 1022; the welding part between the ceramic base 106 and the Kovar base 102 is metallized; preferably, the ceramic base 106 is a 95 ceramic base.

[0098] Specifically, the lower base 1022 positions the ceramic base 106, and the outer edge of the ceramic base 106 is welded with the inner wall of the Kovar base 102, and the ceramic base 106 adopts 95 porcelain which is close to the expansion coefficient of the Kovar base 102, thereby effectively improving the welding stability of the ceramic base 106 and the Kovar base 102.

[0099] Referring to Figure 10 , Figure 11 The application further provides a brazing tool for a vacuum electrode of a residual gas analyzer, which comprises a base 201, a first pressing block 202 and a second pressing block 203 which are arranged correspondingly to the vacuum electrode.

[0100] The base 201 comprises a plurality of positioning holes which are sequentially penetrated from bottom to top, and the plurality of positioning holes are respectively a first positioning hole 2011, a second positioning hole 2012, a third positioning hole 2013, a fourth positioning hole 2014 and a fifth positioning hole 2015; the first positioning hole 2011 and the second positioning hole 2012 are used for accommodating and positioning the signal collection electrode 103; the third positioning hole 2013 is used for accommodating and positioning the shielding electrode 104; the bottom end of the fourth positioning hole 2014 is provided with a plurality of first limiting holes 2016 in the circumferential direction, and the plurality of first limiting holes 2016 are used for accommodating and limiting the Kovar electrode rod 101; and the fifth positioning hole 2015 is used for accommodating and positioning the lower base 1022.

[0101] The first pressing block 202 comprises a first accommodating cavity 2021 and a second accommodating cavity 2022 which are sequentially penetrated from bottom to top, and the first accommodating cavity 2021 is used for accommodating the Kovar electrode and the electrode assembly; and the bottom end of the first pressing block 202 is extruded on the ceramic base 106.

[0102] The second pressing block 203 sequentially penetrates the second accommodating cavity 2022 and the first accommodating cavity 2021 and is extruded on the insulating ceramic tube 105; and the second pressing block 203 is provided with a second limiting hole 2031 at the center position, and the second limiting hole 2031 is used for accommodating and limiting the upper end of the signal collection electrode 103.

[0103] Specifically, the signal collection electrode 103 is placed in the first positioning hole 2011 and the second positioning hole 2012, referring to Figure 11 , the bottom end of the signal collection electrode 103 is located in the first positioning hole 2011, and the shape of the first positioning hole 2011 can be consistent with the shape of the bottom end of the accommodated signal collection electrode 103, or can be Figure 11 as shown in the figure, but is not limited thereto, and can be set into other appearances according to needs.

[0104] Specifically, the second positioning hole 2012 is in a stepped shape, the size and shape of the second positioning hole 2012 are consistent with the signal collection electrode 103 accommodated therein, and the signal collection electrode 103 is positioned; the third positioning hole 2013 is used for accommodating the shielding electrode 104, the inner diameter of the third positioning hole 2013 is consistent with the outer diameter of the shielding electrode 104, and the shielding electrode 104 can be positioned; the inner diameter of the fourth positioning hole 2014 is greater than that of the third positioning hole 2013, and a plurality of first limiting holes 2016 are formed at the bottom end of the fourth positioning hole 2014, and the number of the limiting holes is not limited here, and the actual demand can be met; the inner diameter of the fifth positioning hole 2015 is consistent with the outer diameter of the lower base 1022 of the Kovar base 102, and the lower base 1022 is just clamped in the fifth positioning hole 2015.

[0105] As an example, the base 201 is a graphite base 201; the first pressing block 202 and the second pressing block 203 are both stainless steel pressing blocks.

[0106] Specifically, the base 201 is made of high-purity, high-strength and high-density graphite. Since graphite has the characteristics of self-wetting, low expansion and moderate hardness, the graphite base 201 as a brazing tool can keep a certain gap between the base 201 and the vacuum electrode during high-temperature brazing and solder melting, so as to ensure that the base 201 is not clamped during welding, and facilitate the demolding of the vacuum electrode and the base 201 after the sealing is completed. The specific shape of the base 201 is a cylindrical body with a boss in this embodiment, but it is not limited thereto, and other shapes can also be set according to needs.

[0107] Referring to Figure 12 Based on the vacuum electrode and the brazing tool thereof of the residual gas analyzer in the application, in order to better understand, the application further provides a brazing method of the vacuum electrode of the residual gas analyzer, comprising the following steps:

[0108] The vacuum electrode of the residual gas analyzer is provided, and the welding tool is provided;

[0109] The base 201 is placed on a horizontal workbench, the plurality of Kovar electrode rods 101 are respectively placed in the corresponding first limiting holes 2016, and then the signal collection electrode 103 is placed in the first positioning hole 2011 and the second positioning hole 2012;

[0110] The shielding electrode 104 is placed in the third positioning hole 2013, then the insulating ceramic tube 105 is inserted between the shielding electrode 104 and the signal collection electrode 103, and then the Kovar base 102 is placed in the fifth positioning hole 2015, and the ceramic base 106 is installed in the Kovar base 102;

[0111] The first pressing block 202 is placed on the ceramic base 106 to press the ceramic base 106, the Kovar electrode rod 101 and the shielding electrode 104;

[0112] The second pressing block 203 is placed on the insulating ceramic tube 105 to press the insulating ceramic tube 105, and the vacuum electrode mounting is completed;

[0113] The mounted vacuum electrode and the brazing tool are placed in a brazing furnace for brazing.

[0114] Specifically, the mounted vacuum electrode and the brazing tool are placed in a brazing furnace, and a brazing process temperature rising curve is set for temperature rising and sealing. During the melting of the solder, the Kovar electrode rod 101, the shielding electrode 104, the insulating ceramic tube 105, the signal collecting electrode 103, the ceramic base 106 and the Kovar base 102 are tightly fitted under the gravity of the first pressing block 202 and the second pressing block 203. The solder is sealed and infiltrated under the capillary action. After sufficient infiltration, the temperature of the brazing furnace is gradually lowered according to the temperature rising process curve. When the temperature in the brazing furnace is lower than 100℃, the brazed vacuum electrode and the brazing tool are taken out, and then demoulding is performed, so that a sealed vacuum electrode is prepared.

[0115] For example, after the welding of the ceramic base 106 and the Kovar base 102, the shielding electrode 104 and the Kovar electrode rod 101 is metallized, hydrogen burning is performed; after the welding of the insulating ceramic tube 105 and the shielding electrode 104 and the signal collecting electrode 103 is metallized, hydrogen burning is performed; the welding of the Kovar electrode rod 101, the Kovar base 102, the signal collecting electrode 103 and the shielding electrode 104 is cleaned and then plated with nickel, and then hydrogen burning is performed.

[0116] Specifically, before welding, the welding surface of the ceramic material part to be welded is metallized and hydrogen burned, and the surface of the metal material part to be welded is cleaned, plated with nickel and hydrogen burned, so that the ceramic material part and the metal material part can be better sealed and welded together.

[0117] For example, solder is filled at the welding position of the ceramic base 106 and the Kovar base 102, the shielding electrode 104 and the Kovar electrode rod 101; solder is filled at the welding position of the insulating ceramic tube 105 and the shielding electrode 104 and the signal collecting electrode 103.

[0118] Specifically, the outer wall of the insulating ceramic tube 105 is welded with the inner wall of the shielding electrode 104, and the welding position is filled with solder; the inside of the insulating ceramic tube 105 is welded with the outer wall of the signal collecting electrode 103, and the welding position is filled with solder; when the signal collecting electrode 103 is welded by two parts, the welding position of the first collecting electrode 1031 and the second collecting electrode 1032 is also filled with solder; in addition, the first edge boss 1041 of the shielding electrode 104 is positioned and welded with the ceramic base 106, and the welding position is filled with solder; the second edge boss 1011 of the Kovar electrode rod 101 is positioned and welded with the ceramic base 106, and the welding position is filled with solder; the outer wall of the Kovar electrode rod 101 is welded with the inner wall of the second through hole 1062, and the welding position is also filled with solder; the outer circle of the ceramic base 106 is welded with the inner wall of the upper base 1021 of the Kovar base 102, and the welding position is filled with solder; the bottom end of the ceramic base 106 is partially welded with the lower base 1022 of the Kovar base 102, and the welding position is also filled with solder.

[0119] Preferably, the solder is a silver-copper alloy solder; the silver-copper alloy solder includes silver and copper, and the mass ratio of silver to copper is 72:28; the solidus of the solder is 779℃, and the melting point is 810℃.

[0120] Specifically, the vacuum electrode welded by the above brazing method is subjected to insulation and air tightness detection, and the detection result is that the outgassing rate of the vacuum electrode is not higher than 1.5×10 -8 Pa·m 3 / s, and the inter-electrode withstand voltage value is better than 5×10 5 V / cm.

[0121] In summary, the vacuum electrode of the residual gas analyzer comprises an electrode assembly, a Kovar electrode, a ceramic base and a Kovar base, the ceramic base is located in the Kovar base, the Kovar electrode rod is located in the second through hole of the ceramic base, and the electrode assembly is located in the first through hole of the ceramic base; the ceramic base adopts 95 porcelain which is close to the expansion coefficient of the Kovar base, so as to effectively improve the welding stability of the ceramic base and the Kovar base; the inner walls of the first through hole and the second through hole, the welding positions of the ceramic base and other components, and the welding positions of the insulating ceramic tube and the shielding electrode and the signal collection electrode are all subjected to metallization treatment, so as to greatly enhance the welding strength between the components, and then ensure the welding reliability of the vacuum electrode after welding; the brazing tool in the application comprises a base, a first pressing block and a second pressing block which are arranged correspondingly to the vacuum electrode, the Kovar electrode rod, the electrode assembly, the ceramic base and the Kovar base are all installed in the base, and then the vacuum electrode is assembled by extrusion of the first pressing block and the second pressing block, the assembled vacuum electrode and the brazing tool are put into a brazing furnace for heating and sealing, under the action of gravity of the first pressing block and the second pressing block, the electrodes, the insulating ceramic tube and the ceramic base are tightly fitted during the melting process of the solder, the solder seals and infiltrates the welding position under the capillary action, so that the welding seam of the vacuum electrode is sealed, so as to ensure the welding reliability and strength of the whole vacuum electrode; in addition, the base of the brazing tool is a graphite base, due to the self-wetting, low expansion and moderate hardness of the graphite base, a certain gap is reserved between the graphite base and the vacuum electrode during the brazing process, and the graphite base is easy to demold after brazing, so that the brazing tool is convenient for batch production of the vacuum electrode. Therefore, the application effectively overcomes the shortcomings of the prior art and has high industrial utilization value.

[0122] The above embodiments only exemplarily illustrate the principles and effects of the application, and are not used to limit the application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the application. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical thought of the application should be covered by the claims of the application.

Claims

1. A brazing fixture for a vacuum electrode of a residual gas analyzer, characterized by, The vacuum electrode comprises: The electrode assembly comprises a signal collection electrode and a shielding electrode, the signal collection electrode is fixedly arranged inside the shielding electrode, the shielding electrode is used for protecting the signal collected by the signal collection electrode; an insulating ceramic tube is arranged between the signal collection electrode and the shielding electrode, and the insulating ceramic tube is welded with the shielding electrode and the signal collection electrode respectively; after the welding of the insulating ceramic tube and the shielding electrode is subjected to a metallization treatment, then a hydrogen burning treatment is performed; after the welding of the insulating ceramic tube and the signal collection electrode is subjected to a metallization treatment, then a hydrogen burning treatment is performed; A plurality of Kovar electrode rods are arranged, and the plurality of Kovar electrode rods are arranged on the periphery of the shielding electrode in a circumferential direction; The ceramic base comprises a first through hole and a plurality of second through holes, the first through hole is used for accommodating the shielding electrode, and the plurality of second through holes are used for accommodating the plurality of Kovar electrode rods respectively; The Kovar base comprises an upper base and a lower base, the upper base is arranged on the periphery of the ceramic base, and the lower base is fixed to the bottom end of the upper base and positions the ceramic base; The brazing tool comprises: The base comprises a plurality of positioning holes through from bottom to top in sequence, the plurality of positioning holes are respectively a first positioning hole, a second positioning hole, a third positioning hole, a fourth positioning hole and a fifth positioning hole, the first positioning hole and the second positioning hole are used for accommodating and positioning the signal collection electrode, the third positioning hole is used for accommodating and positioning the shielding electrode, a plurality of first limiting holes are arranged on the bottom end of the fourth positioning hole in a circumferential direction, and the plurality of first limiting holes are used for accommodating and limiting the Kovar electrode rod; and the fifth positioning hole is used for accommodating and positioning the lower base; The first pressing block comprises a first accommodating cavity and a second accommodating cavity through from bottom to top in sequence, the first accommodating cavity is used for accommodating the Kovar electrode and the electrode assembly, and the bottom end of the first pressing block is extruded on the ceramic base; The second pressing block passes through the second accommodating cavity and the first accommodating cavity in sequence and is extruded on the insulating ceramic tube, a second limiting hole is arranged at the center position of the second pressing block, and the second limiting hole is used for accommodating and limiting the upper end of the signal collection electrode.

2. The brazing fixture for a vacuum electrode of a residual gas analyzer as defined in claim 1, characterized in that: An outer wall of the shielding electrode is provided with a first edge boss, the first edge boss is used for positioning and welding the ceramic base; and the shielding electrode is a 4J33 Kovar shielding electrode; An outer wall of the Kovar electrode rod is provided with a second edge boss, the second edge boss is used for positioning and welding the ceramic base; and the Kovar electrode rod is a 4J33 Kovar electrode rod; After the welding of the ceramic base and the first edge boss is subjected to a metallization treatment, then a hydrogen burning treatment is performed; and after the welding of the ceramic base and the second edge boss is subjected to a metallization treatment, then a hydrogen burning treatment is performed.

3. The brazing fixture for a vacuum electrode of a residual gas analyzer as defined in claim 1, wherein: The first through hole is located at the center position of the ceramic base, and the plurality of second through holes are distributed on the periphery of the first through hole in a circumferential direction at equal intervals; The inner walls of the first through hole and the plurality of second through holes are subjected to a metallization treatment and then subjected to a hydrogen burning treatment.

4. The soldering fixture for a vacuum electrode of a residual gas analyzer as defined in claim 1, characterized in that: The outer diameter of the ceramic base matches the inner diameter of the upper base, and the outer diameter of the ceramic base is greater than the inner diameter of the lower base. The welding part of the ceramic base and the Kovar base is subjected to a metallization treatment and then subjected to a hydrogen burning treatment. The ceramic base is a 95 ceramic base.

5. The soldering fixture for a vacuum electrode of a residual gas analyzer as defined in claim 1, characterized in that: The base is a graphite base. The first pressing block and the second pressing block are both stainless steel pressing blocks.

6. A brazing method for a vacuum electrode of a residual gas analyzer, characterized by: The brazing method comprises the following steps: The brazing tool of the residual gas analyzer vacuum electrode is provided. The base is placed on a horizontal workbench, and a plurality of Kovar electrode rods are placed in corresponding first limiting holes, and then a signal collecting electrode is placed in the first limiting hole and the second limiting hole. The shielding electrode is placed in the third limiting hole, and then the insulating ceramic tube is inserted between the shielding electrode and the signal collecting electrode, and the Kovar base is placed in the fifth limiting hole, and the ceramic base is installed in the Kovar base. The first pressing block is placed on the ceramic base, and the ceramic base, the Kovar electrode rod and the shielding electrode are extruded. The second pressing block is placed on the insulating ceramic tube, and the insulating ceramic tube is extruded, and the vacuum electrode mounting is completed. The vacuum electrode mounting and the brazing tool are placed in the brazing furnace for brazing.

7. The brazing method of a vacuum electrode of a residual gas analyzer according to claim 6, characterized by: The welding part of the ceramic base and the Kovar base, the shielding electrode and the Kovar electrode rod is subjected to a metallization treatment and then subjected to a hydrogen burning treatment. The welding part of the insulating ceramic tube and the shielding electrode and the signal collecting electrode is subjected to a metallization treatment and then subjected to a hydrogen burning treatment. The welding part of the Kovar electrode rod, the Kovar base, the signal collecting electrode and the shielding electrode is subjected to a nickel plating after cleaning and then subjected to a hydrogen burning treatment.

8. The brazing method of a vacuum electrode of a residual gas analyzer according to claim 6, characterized by: The welding part of the ceramic base and the Kovar base, the shielding electrode and the Kovar electrode rod is filled with solder. The welding part of the insulating ceramic tube and the shielding electrode and the signal collecting electrode is filled with solder. The solder is a silver-copper alloy solder.

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