Stainless steel and tantalum composite insulator and capacitor thereof

Abstract

This utility model relates to a stainless steel and tantalum composite insulator, comprising a stainless steel shell as a conductive cathode, an mounting position for a tantalum tube anode inside the stainless steel shell, an axially mounted tantalum tube anode inside the mounting position, and a microcrystalline glass layer forming an insulating medium at the connection between the tantalum tube anode and the stainless steel shell; the tantalum content of the tantalum tube anode is 99% or more by mass, with the remainder being impurities; the conductive cathode is either 316L or 2205 duplex stainless steel. By using the tantalum tube anode and stainless steel as the conductive cathode, and the microcrystalline glass forming the insulating layer, a matching seal can be achieved with the stainless steel and tantalum tube, ensuring electrical isolation. The tantalum tube anode can withstand boiling concentrated sulfuric acid, hydrochloric acid, and other strong acids, with a lifespan far exceeding that of traditional electrodes; ensuring the corrosion resistance of the stainless steel and tantalum composite insulator. The stainless steel cathode undergoes surface modification to avoid brittle fracture caused by long-term hydrogen evolution, increasing its conductive stability.

Description

Technical Field

[0001] This utility model relates to a stainless steel and tantalum composite insulator and its capacitor, belonging to the field of power equipment. Background Technology

[0002] In the electrochemical industry, such as electrolysis, electroplating, and hydrometallurgy; and in power equipment, such as high-voltage insulators, traditional electrode materials have the following problems:

[0003] 1. Anodes are prone to corrosion: In strong acid (such as sulfuric acid, hydrochloric acid) or high salt environments, ordinary anodes (such as titanium plating with platinum, lead alloy) are easily dissolved or passivated and fail.

[0004] 2. Risk of cathodic hydrogen embrittlement: Stainless steel may experience hydrogen embrittlement in a long-term hydrogen evolution environment, which reduces its mechanical strength.

[0005] 3. Difficulty in achieving both insulation and corrosion resistance: Conventional insulators (such as ceramics and polymers) are prone to aging in highly corrosive media, while metal electrodes cannot provide insulation.

[0006] Tantalum capacitors, because their dielectric layer is formed by the oxidation of the anode metal in an electrolyte, generate heat under applied voltage, easily leading to the formation of highly resistive oxides. This ensures their long lifespan and reliability. Solid tantalum capacitors have excellent electrical performance, a wide operating temperature range, and diverse forms. They also boast excellent volumetric efficiency and possess unique characteristics: the working dielectric of a tantalum capacitor is an extremely thin tantalum pentoxide film formed on the surface of tantalum metal. This oxide film dielectric is integrated with one end of the capacitor and cannot exist independently. Due to the numerous micropores in the anode block, its capacitance per unit volume is exceptionally large, i.e., high specific capacitance, making it suitable for miniaturized circuit boards.

[0007] However, tantalum capacitors are more expensive than aluminum electrolytic capacitors of the same capacity and voltage rating, and their voltage and current withstand capabilities are weaker. Furthermore, their corrosion resistance needs to be improved.

[0008] Therefore, there is an urgent need for a composite electrode structure that combines high corrosion resistance, stable conductivity, and reliable insulation. Utility Model Content

[0009] To address the aforementioned shortcomings, this invention proposes a stainless steel-tantalum composite insulator and capacitor, along with their fabrication method. By using a tantalum tube anode and stainless steel as the conductive cathode, and a microcrystalline glass layer forming the insulating layer, it can be matched and sealed with the stainless steel and tantalum tube, ensuring electrical isolation. The tantalum tube anode can withstand boiling concentrated sulfuric acid, hydrochloric acid, and other strong acids, with a lifespan far exceeding that of traditional electrodes, thus ensuring the corrosion resistance of the stainless steel-tantalum composite insulator. Furthermore, the stainless steel cathode undergoes surface modification to prevent brittle fracture caused by long-term hydrogen evolution, increasing its conductivity stability; combined with the insulating layer formed by the microcrystalline glass, it maintains high insulation resistance even under high temperature, high humidity, and strong acid environments.

[0010] The technical means adopted by this utility model to solve the above problems are as follows:

[0011] A stainless steel and tantalum composite insulator is disclosed, comprising a stainless steel shell as a conductive cathode, a mounting position for a tantalum tube anode is provided inside the stainless steel shell, the tantalum tube anode is axially installed inside the mounting position, and a microcrystalline glass is provided at the connection between the tantalum tube anode and the stainless steel shell to form an insulating medium; the tantalum content of the tantalum tube anode is 99% or more by mass, with the balance being impurities; the conductive cathode is made of duplex stainless steel, preferably either 316L or 2205 duplex stainless steel.

[0012] Furthermore, the conductive cathode has a regular polyhedral structure, with a recessed mounting position on one side surface, and the mounting position is coaxially arranged with the tantalum tube anode.

[0013] Furthermore, the tantalum tube anode protrudes from the surface of the polyhedral structure, and the tantalum tube anode is a tubular structure with a through hole at its center.

[0014] Furthermore, the microcrystalline glass fills the mounting position and wraps around the outer edge of the tantalum tube anode, so that the tantalum tube anode is firmly connected to the stainless steel shell.

[0015] Furthermore, it also includes a tantalum shell, the inner wall of which is provided with a limiting mounting wall, the tantalum shell including an open end and a closed bottom end; the limiting mounting wall divides the tantalum shell into an open side and a closed side; the stainless steel and tantalum composite insulator is installed on the open side of the limiting mounting wall, and the closed side near the bottom of the tantalum shell contains an anode tantalum core, the top of which is provided with an anode lead extending into the interior of the tantalum tube anode; the anode tantalum core and the stainless steel shell are in clearance fit.

[0016] Furthermore, the limiting mounting wall consists of paired rectangular protrusions, the upper and lower surfaces of which are parallel to the bottom of the stainless steel shell, and the spacing between the rectangular protrusions is set according to the lateral width of the stainless steel shell.

[0017] Furthermore, the volume of the enclosed inner cavity of the tantalum shell is larger than the volume of the anode tantalum core, and the gap between the tantalum shell and the anode tantalum core is filled with electrolyte.

[0018] Furthermore, the vertical distance between the rectangular protrusion and the opening end of the tantalum shell is greater than or equal to the height of the stainless steel shell.

[0019] Furthermore, the open ends of the composite insulator and the tantalum shell are laser-welded, and the top of the tantalum tube anode is sealed, forming a closed cavity inside the capacitor.

[0020] Compared with the prior art, the beneficial effects of this utility model are:

[0021] The stainless steel and tantalum composite insulator of this invention uses microcrystalline glass with ceramic structural strength, which can be matched and sealed with stainless steel and tantalum tubes to ensure electrical isolation.

[0022] The stainless steel and tantalum composite insulator of this invention has ultra-high corrosion resistance: the tantalum tube anode can withstand strong acids such as boiling concentrated sulfuric acid and hydrochloric acid, and its service life far exceeds that of traditional electrodes.

[0023] Meanwhile, the stainless steel cathode undergoes surface modification to prevent brittle fracture caused by long-term hydrogen evolution. The microcrystalline glass maintains a high insulation resistance (>10¹⁰Ω) even under high temperature, high humidity, and strong acid environments.

[0024] Therefore, the capacitor using the stainless steel and tantalum composite insulator of this invention has high corrosion resistance, stable conductivity and reliable insulation, which increases the reliability of use and has high overall performance. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the stainless steel and tantalum composite insulator described in Example 1.

[0026] Figure 2 This is a schematic diagram of the stainless steel and tantalum composite insulator described in Embodiment 2.

[0027] Among them, 1-tantalum tube anode, 2-stainless steel shell, 3-insulating medium, 4-mounting position, 5-anode tantalum core, 6-anode lead, 7-tantalum shell, 8-electrolyte, 11-through hole, 71-open end, 72-bottom closed end, 73-limiting mounting wall. Detailed Implementation

[0028] The present invention will be further described below with reference to the embodiments, but the scope of protection of the present invention is not limited thereto. Example 1

[0029] like Figure 1As shown, the stainless steel and tantalum composite insulator of this embodiment includes a stainless steel shell 2 as a conductive cathode, and a mounting position 4 for a tantalum tube anode 1 inside the stainless steel shell 2. The tantalum tube anode 1 is axially mounted inside the mounting position 4, and a microcrystalline glass layer forms an insulating medium 3 at the connection between the tantalum tube anode 1 and the stainless steel shell 2. The tantalum content of the tantalum tube anode 1 is 99% or more by mass, with the remainder being impurities. The conductive cathode is either 316L or 2205 duplex stainless steel. The tantalum tube anode 1 serves as an inert anode for electrolysis or current input. Its surface can be ground, polished, sandblasted, and oxidized to improve its bonding performance with the glass during high-temperature sintering.

[0030] 316L or 2205 duplex stainless steel (316L stainless steel) has the following main components: carbon (C) ≤0.03%, silicon (Si) ≤1.00%, manganese (Mn) ≤2.00%, phosphorus (P) ≤0.045%, sulfur (S) ≤0.030%, chromium (Cr) 16.00%-18.00%, nickel (Ni) 10.00%-14.00%, molybdenum (Mo) 2.00%-3.00%, with the remainder being iron (Fe). Stainless steel has excellent corrosion resistance. The passivation film that forms on the surface of stainless steel has a strong self-healing ability, which can greatly reduce the corrosion rate in corrosive media. This characteristic extends the service life of capacitor cathodes in humid and corrosive environments.

[0031] Secondly, stainless steel has excellent electrical conductivity. A stainless steel cathode can maintain stable conductivity when current flows through it, reducing energy loss due to increased resistance and thus improving the overall performance of the capacitor.

[0032] In addition, stainless steel has high mechanical strength and toughness. This allows it to withstand mechanical stress under various environmental conditions, preventing equipment failure due to structural deformation or damage, and ensuring the stable operation of capacitors.

[0033] It uses microcrystalline glass with ceramic structural strength, which can be matched and sealed with stainless steel and tantalum tubes to ensure electrical isolation.

[0034] In this embodiment, the tantalum tube undergoes anodizing pretreatment as follows: First, the tantalum tube is cut with electrical discharge wire cutting, then the surface oxide layer is removed by acid pickling, followed by removal of excess burrs using a tumbling polishing machine. After machining on a digital display needle blanking machine and grinding grooves, high-speed sandblasting is performed to ensure a tighter bond between the tantalum tube and the glass at high temperatures.

[0035] Stainless steel cathode processing: High-speed sandblasting and electroplating nickel are performed on the surface of stainless steel to improve its resistance to hydrogen embrittlement.

[0036] Insulation layer molding: The microcrystalline glass used undergoes processes such as glass powder proportioning, high-temperature melting, water quenching, grinding, and sieving, and is then mixed with an organic binder and dry-pressed. After pre-firing into a glass preform, it is assembled with stainless steel and tantalum tubes in a graphite mold and sintered at high temperature.

[0037] In this embodiment, the conductive cathode has a regular polyhedral structure, preferably a cube or cuboid structure; a recessed mounting position 4 is provided on one side surface, and the mounting position 4 is coaxially arranged with the tantalum tube anode 1. Specifically, the size of the tantalum tube anode 1 is smaller than the accommodating space of the mounting position 4, providing space for the filling of the insulating medium.

[0038] The tantalum tube anode 1 protrudes from the surface of the polyhedral structure, and the tantalum tube anode 1 has a tubular structure with a through hole 11 at its center. Its microcrystalline glass fills the mounting position 4 and wraps around the outer edge of the tantalum tube anode 1, so that the tantalum tube anode 1 is firmly connected to the stainless steel shell 2. Example 2

[0039] like Figure 2 As shown, the capacitor in this embodiment includes a capacitor with a stainless steel and tantalum composite insulator, and also includes a tantalum shell 7. The inner wall of the tantalum shell 7 is provided with a limiting mounting wall 73. The tantalum shell 7 includes an open end 71 and a bottom closed end 72. The limiting mounting wall 73 divides the tantalum shell 7 into an open side and a closed side. The stainless steel and tantalum composite insulator is installed on the open side of the limiting mounting wall 73. The closed side near the bottom of the tantalum shell 7 contains an anode tantalum core 5. The top of the anode tantalum core 5 is provided with an anode lead 6 that extends into the interior of the tantalum tube anode 1. The anode tantalum core 5 is clearance-fitted with the stainless steel shell 2.

[0040] In this embodiment, the limiting mounting wall 73 consists of paired rectangular protrusions. The upper and lower surfaces of the rectangular protrusions are parallel to the bottom of the stainless steel shell 2, and the spacing between the rectangular protrusions is set according to the lateral width of the stainless steel shell 2. This design ensures that the stainless steel and tantalum composite insulator is firmly and stably attached to the upper surface of the limiting mounting wall 73. Furthermore, the volume of the enclosed inner cavity of the tantalum shell 7 is larger than the volume of the anode tantalum core 5, and the gap between the tantalum shell 7 and the anode tantalum core 5 is filled with electrolyte 8.

[0041] The vertical distance between the rectangular protrusion and the opening end 71 of the tantalum shell 7 is greater than or equal to the height of the stainless steel shell 2.

[0042] The open end 71 of the composite insulator and the tantalum shell 7 is laser welded, and the top end of the tantalum tube anode 1 is sealed, so that a closed cavity is formed inside the capacitor.

[0043] Specifically, the anode tantalum core 5 is made of 0.5mm thick tantalum powder through pressing and firing, with two anode leads 6 in the middle. In this embodiment, they are made of 0.55mm tantalum wires and inserted into the tantalum tube of the stainless steel composite insulator. The part connecting the composite insulator and the tantalum shell 7 is laser welded. Finally, electrolyte 8 is injected into the tantalum tube. In this embodiment, it is a 38% sulfuric acid solution. The opening of the tantalum tube is then sealed to form a sealed cavity inside the capacitor.

[0044] By using a tantalum tube anode and stainless steel as the conductive cathode, and forming an insulating layer with microcrystalline glass, a matching seal can be achieved between the glass and the stainless steel and tantalum tube, ensuring electrical isolation. The tantalum tube anode can withstand strong acids such as boiling concentrated sulfuric acid and hydrochloric acid, and its lifespan far exceeds that of traditional electrodes; this ensures the corrosion resistance of the stainless steel and tantalum composite insulator. The stainless steel cathode undergoes surface modification to avoid brittle fracture caused by long-term hydrogen evolution, increasing its conductivity stability; combined with the insulating layer formed by the microcrystalline glass, it maintains high insulation resistance even under high temperature, high humidity, and strong acid environments.

[0045] Those skilled in the art can make various changes or modifications without departing from the spirit and scope of this utility model. Therefore, all equivalent technical solutions should also fall within the protection scope of this utility model, which should be defined by the claims.

Claims

1. A stainless steel and tantalum composite insulator, characterized in that, The device includes a stainless steel shell (2) as a conductive cathode, and a mounting position (4) for a tantalum tube anode (1) is provided inside the stainless steel shell (2). The tantalum tube anode (1) is axially installed inside the mounting position (4). A microcrystalline glass is provided at the connection between the tantalum tube anode (1) and the stainless steel shell (2) to form an insulating medium (3). The tantalum content of the tantalum tube anode (1) is 99% or more by mass, and the remainder is impurities. The conductive cathode is made of duplex stainless steel.

2. The stainless steel and tantalum composite insulator according to claim 1, characterized in that, The conductive cathode has a regular polyhedral structure with a recessed mounting position on one side surface, which is coaxially arranged with the tantalum tube anode.

3. The stainless steel and tantalum composite insulator according to claim 2, characterized in that, The tantalum tube anode protrudes from the surface of the polyhedral structure, and the tantalum tube anode is a tubular structure with a through hole in the center.

4. The stainless steel and tantalum composite insulator according to claim 3, characterized in that, The microcrystalline glass fills the mounting position and wraps around the outer edge of the tantalum tube anode, so that the tantalum tube anode is firmly connected to the stainless steel shell.

5. A capacitor using the stainless steel and tantalum composite insulator as described in any one of claims 2-4, characterized in that, It also includes a tantalum shell (7), the inner wall of which is provided with a limiting mounting wall (73), the tantalum shell (7) including an open end (71) and a bottom closed end (72); The limiting mounting wall (73) divides the tantalum shell (7) into an open side and a closed side; the stainless steel and tantalum composite insulator is installed on the open side of the limiting mounting wall (73), and the closed side near the bottom of the tantalum shell (7) contains an anode tantalum core (5), and the top of the anode tantalum core (5) is provided with an anode lead (6) extending into the tantalum tube anode (1); the anode tantalum core (5) is clearance-fitted with the stainless steel shell (2).

6. The capacitor according to claim 5, characterized in that, The limiting mounting wall (73) consists of a pair of rectangular protrusions. The upper and lower surfaces of the rectangular protrusions are parallel to the bottom of the stainless steel shell (2). The spacing between the rectangular protrusions is set according to the lateral width of the stainless steel shell (2).

7. The capacitor according to claim 6, characterized in that, The volume of the closed inner cavity of the tantalum shell (7) is larger than the volume of the anode tantalum core (5), and the gap between the tantalum shell (7) and the anode tantalum core (5) is filled with electrolyte.

8. The capacitor according to claim 7, characterized in that, The vertical distance between the rectangular protrusion and the opening end (71) of the tantalum shell (7) is greater than or equal to the height of the stainless steel shell (2).

9. The capacitor according to claim 8, characterized in that, The open end (71) of the composite insulator and the tantalum shell (7) is laser welded, and the top of the tantalum tube anode (1) is sealed to form a closed cavity inside the capacitor.

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