Electrolytic polishing device for tantalum cathode in penning ion source

Abstract

The electrolytic polishing device comprises an electrolysis cavity with an opening in the top, the upper portion of the electrolysis cavity is sealed by an electrolysis cavity cover, a cathode through hole is formed in the center of the electrolysis cavity cover, a cathode is inserted into the cathode through hole, an anode through hole is further formed in the electrolysis cavity cover, and the anode through hole is communicated with the electrolysis cavity cover. An anode is inserted into the cathode through hole; a plurality of hangers which are distributed in a central symmetry mode with the cathode through hole as the center are arranged on the face, facing the electrolysis cavity, of the electrolysis cavity cover, the anode is connected with an anode wire, and the anode wire sequentially penetrates through all the hangers around the cathode and is hung and supported by the hangers. And a hook is hung on the anode wire between every two adjacent hangers. And the surface treatment work can be specially carried out on the tantalum cathode of the penning ion source in the cyclotron, multiple tantalum cathodes can be electrolyzed at a time, and the surface treatment efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of nuclear physics, and in particular relates to an electrolytic polishing device for a tantalum cathode in a Penning ion source. Background Art

[0002] For the Penning ion source that provides the original beam in the center of the cyclotron, the cathode is generally made of metal tantalum, which has a lower work function, high chemical activity, and is easy to absorb air, requiring a higher degree of vacuum than other metals. Since the tantalum metal cathode will form an oxide film when exposed to the atmosphere for a long time, it will also absorb more gas. When the ion source forms plasma when working normally, more impurity gases and heavy particles will be formed to affect the service life of the cathode and the generation of target ions. In addition, carbon impurities are easily introduced during the machining process of the tantalum cathode, so it is necessary to perform surface treatment on the impurities on the surface of the tantalum cathode.

[0003] Generally, there are three methods for treating the surface oxide layer of tantalum metal: physical polishing, acid-base cleaning polishing and electrolytic polishing. For the physical polishing method, the precision is difficult to control, the processing time is long and the cost is high, and it is easy to have dead corners that cannot be processed; there are few public reports on the electrolytic polishing technology of tantalum at home and abroad, and the electrolytes that can be used for tantalum polishing are: 1. sulfuric acid and hydrofluoric acid system; 2. sodium sulfate system; 3. sulfuric acid and methanol system. Among them, the sulfuric acid and hydrofluoric acid system is a commonly used electrolyte for tantalum polishing. The use of sulfuric acid and hydrofluoric acid as a polishing electrolyte can make the sample surface roughness value greater than 50nm.

[0004] Regarding the treatment method of the oxide layer on the surface of the tantalum cathode of the Penning ion source in the cyclotron: the traditional physical polishing technology has difficulty in controlling the precision, long processing time, high cost, and the physical fixture is easy to affect the size, flatness and flatness of the tantalum cathode rod; while the electrolytic polishing technology has a complicated operation process, and open-air operation is easy to contaminate the surface and is difficult to operate. Summary of the invention

[0005] In order to overcome the defects of the prior art, the present invention discloses an electrolytic polishing device for a tantalum cathode in a Penning ion source.

[0006] The electrolytic polishing device for tantalum cathode in Penning ion source of the present invention comprises an electrolytic chamber with an opening at the top, the upper part of the electrolytic chamber is closed by an electrolytic chamber cover, a cathode through hole is arranged at the center of the electrolytic chamber cover, a cathode is inserted in the cathode through hole, and an anode through hole is also arranged on the electrolytic chamber cover, an anode is inserted in the cathode through hole; A plurality of hangers are arranged on one side of the electrolysis chamber cover facing the electrolysis chamber body and are centrally symmetrically distributed with the cathode through hole as the center. The anode is connected to an anode wire, which passes through all the hangers in sequence around the cathode and is suspended and supported by the hangers. A hook is hung on the anode wire between every two adjacent hangers.

[0007] Preferably, a sealing groove is provided on the side of the electrolysis chamber cover, and an O-ring is installed in the sealing groove.

[0008] Preferably, the anode wire is a platinum wire.

[0009] Preferably, the hanger is a hexagonal screw made of insulating material, and holes are punched on the six sides of the hexagonal screw. A plurality of symmetrically distributed blind holes are arranged under the electrolysis chamber cover, and the internal threads of the blind holes cooperate with the external threads of the hexagonal screw. The hexagonal screw is located inside the blind hole, and the anode wire passes through the through holes on two sides of the hexagonal screw.

[0010] Preferably, a vent hole is provided on the electrolysis chamber cover, and an exhaust valve is installed on the vent hole.

[0011] Preferably, the electrolytic chamber cover is further provided with an anode wire screw hole, in which an anode screw is installed, the anode wire is connected to the anode screw, and the anode screw is electrically connected to the anode.

[0012] Preferably, the cathode comprises a central metal piece, the upper end of which is a wiring point for connecting a wire, the lower end of which extends into the center of the electrolysis chamber and is a platinum sheet, and the outside of the central metal piece is wrapped with an insulating layer; the anode is a metal screw.

[0013] Preferably, the electrolysis chamber and the electrolysis chamber cover are both made of polytetrafluoroethylene.

[0014] The electrolytic polishing device for tantalum cathode in Penning ion source described in the present invention can be specifically used to carry out surface treatment work on tantalum cathode of Penning ion source in cyclotron, and multiple tantalum cathodes can be electrolyzed at one time, which greatly improves the surface treatment efficiency; the present invention uses platinum wire as anode parallel wire, and reduces the bending degree of platinum wire through the annular distribution of the hanger, thereby improving electrolysis efficiency and increasing the service life of the platinum wire.

[0015] Through a large number of experimental verifications on the cathode rod after electrolysis treatment in the 11MTS cyclotron, the present invention can better meet the surface state and stability requirements of the Penning ion source for the tantalum cathode. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of a specific embodiment of the electrolytic polishing device for a tantalum cathode in a Penning ion source according to the present invention; Figure 2 A schematic diagram of a specific embodiment of the electrolytic chamber cover of the present invention; Figure 3 A specific distribution diagram of the suspension device in the electrolytic chamber cover of the present invention; Figure 4 This is a schematic diagram showing the comparison of photos of the tantalum cathode surface before and after polishing in a specific embodiment of the present invention; The names of the reference numerals in the figure are: 1. electrolytic chamber; 2. electrolytic chamber cover; 3. sealing ring; 4. hexagonal screw; 5. anode wire; 6. hook; 7. tantalum cathode; 8. vent; 9. cathode; 10. anode; 11. cathode through hole; 12. anode through hole; 13. anode wire screw hole; 14. blind hole. DETAILED DESCRIPTION

[0017] The specific implementation modes of the present invention are further described in detail below.

[0018] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely explained below in combination with the specific implementation methods of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] like Figure 1 As shown, the electrolytic polishing device for tantalum cathode in Penning ion source of the present invention comprises an electrolytic chamber 1 with an opening at the top, the upper part of the electrolytic chamber 1 is closed by an electrolytic chamber cover 2, a cathode through hole 11 is provided at the center of the electrolytic chamber cover, a cathode 9 is inserted into the cathode through hole, and an anode through hole 12 is also provided on the electrolytic chamber cover, an anode 10 is inserted into the cathode through hole; A plurality of hangers are arranged on one side of the electrolysis chamber cover facing the electrolysis chamber and are symmetrically distributed with the cathode through hole 11 as the center. The anode is connected to an anode wire 5, which passes through all the hangers in sequence around the cathode and is suspended and supported by the hangers. A hook 6 is hung on the anode wire between every two adjacent hangers.

[0020] Figure 1 In the specific embodiment shown, a sealing groove is provided on the side of the electrolysis chamber cover, and an O-type sealing ring 3 is installed in the sealing groove to strengthen the sealing of the electrolysis chamber cover to the electrolysis chamber.

[0021] When in use, electrolyte is injected into the electrolytic chamber 1, the tantalum cathode 7 that needs electrolytic polishing is hung on the hook, the ends of the cathode terminal and the anode terminal exposed outside the electrolytic chamber cover are respectively connected to the cathode and anode of the electrolysis power supply, the electrolytic chamber cover 2 is closed, and the power supply is turned on for electrolysis.

[0022] The electrolytic chamber cover is generally provided with a vent hole 8, on which an exhaust valve is installed, which can be opened in time during the electrolysis process to perform exhaust operation.

[0023] Since ordinary metal wires are very easy to oxidize during the electrolysis process, the anode wire is preferably a platinum wire with strong inertness and conductivity. Since platinum wire is expensive and has poor mechanical properties, it is easy to break in the electrolysis state if the bending angle is high during use. The present invention uses multiple hangers to suspend the anode wire, such as Figure 3 As shown, the bending degree of the anode wire portion that bears the weight of the tantalum cathode is greatly reduced, for example Figure 3 Ten suspension devices are used, and a circular passage can be achieved when the bending angle at each location is less than 45 degrees, thereby increasing the life of the platinum wire.

[0024] like Figure 3 As shown, in the present invention, it is preferred to use a hexagonal screw 4 made of an existing insulating material as a hanger, and holes are punched on the six sides of the hexagonal screw for passing the anode wire, and a plurality of symmetrically distributed blind holes 14 are provided under the electrolysis chamber cover, and the internal threads of the blind holes match the external threads of the hexagonal screw. When in use, the hexagonal screw is screwed into the blind hole, and the anode wire passes through the through holes on two sides of the hexagonal screw to achieve the suspension of the anode wire 5.

[0025] The use of the existing mass-produced hexagonal screws is not only low-cost and easy to replace and process, but also convenient to adjust the angle of the hexagonal screw when screwing it into the blind hole of the electrolytic chamber cover, so that there is always a suitable face facing the adjacent screw, and the anode wire can be suspended at a smaller bending angle.

[0026] like Figure 1 In the specific embodiment shown, the electrolysis chamber cover 2 is further provided with an anode wire screw hole 13, in which an anode screw is installed, and the anode wire 5 is connected to the anode screw, and the anode screw is then connected to the anode 10 through the anode wire or other wires. After the anode wire screw hole and the anode screw are provided, the anode wire does not need to be directly connected to the anode, which facilitates the use of wires of different costs to electrically connect the external part of the anode. At the same time, the anode wire 5 needs to suspend the tantalum cathode to be electrolyzed, and the anode wire needs to have a pulling force upward. If it is directly connected to the anode 10, the platinum wire is easy to break. After the anode screw is installed, the platinum wire as the anode wire can be firstly wound around the anode screw, and then the top of the anode screw is connected to the anode through other wires. The anode screw is also convenient to move up and down on the anode wire screw hole, and the height of the platinum wire in the electrolysis chamber can be finely adjusted to prevent the suspended multiple tantalum cathodes from tilting and contacting each other due to bottoming out within a certain range.

[0027] The electrolytic polishing device for tantalum cathode in Penning ion source described in the present invention can be specifically used to carry out surface treatment work on tantalum cathode of Penning ion source in cyclotron, and multiple tantalum cathodes can be electrolyzed at one time, which greatly improves the surface treatment efficiency; the present invention uses platinum wire as anode parallel wire, and reduces the bending degree of platinum wire through the annular distribution of the hanger, thereby improving electrolysis efficiency and increasing the service life of the platinum wire.

[0028] Through a large number of experimental verifications on the cathode rod after electrolysis treatment in the 11MTS cyclotron, the present invention can better meet the surface state and stability requirements of the Penning ion source for the tantalum cathode. Specific embodiments

[0029] The electrolysis chamber 1 has an outer diameter of 75.5 mm, an inner diameter of 55 mm, a height of 70 mm, and is made of polytetrafluoroethylene.

[0030] The top cover of the electrolytic chamber cover 2 has a diameter of 75.5 mm, a lower cylindrical body with a diameter of 55 mm and a thickness of 18 mm, and is also made of polytetrafluoroethylene. like Figure 2 As shown, the inner diameter of the vent hole 8 is 6mm, the inner diameter of the cathode through hole 11 is 6mm, the inner diameter of the anode through hole 12 is 3.5mm, and the inner diameter of the anode wire screw hole 13 is 1mm. 10 polytetrafluoroethylene hexagon socket screws are used as hangers, with a height of 13.5mm and a nut height of 3mm. There is a through hole with a diameter of 1mm at the center of each of the six sides of the hexagon socket screws for connecting the platinum wire 5 as the anode wire. The platinum wire has a diameter of 0.3mm and a length of 200mm. The hook is two mutually perpendicular S-shaped flat hook rings, which are also made of platinum material.

[0031] The cathode includes a central metal piece with a diameter of 6 mm and a height of 63 mm. The upper end of the central metal piece is a connection point for connecting the wire, and the lower end extending into the center of the electrolysis chamber has a 20*10 mm rectangular platinum sheet. The outside of the central metal piece is wrapped with an insulating layer formed by polytetrafluoroethylene material. The anode 10 is a metal screw with a diameter of 3.5 mm and a height of 7.5 mm.

[0032] Since the anode does not enter the electrolysis chamber, there is no need to consider corrosion resistance. The cathode needs to extend into the electrolysis chamber, so a highly inert platinum sheet is used as the exposed part in the electrolysis chamber, and other parts can be made of cheaper technical materials such as copper-wrapped insulation layer.

[0033] The composition of the polishing solution used for electrolytic polishing of tantalum cathodes is as follows: HF: 5% H2SO4: 32% H2O: 63% Constant current output is used during the electrolysis process, and the polishing process parameters are as follows: Anode current density: 0.1-0.15A / dm2 Cathode and anode area ratio: 1:2.2 Polishing process duration: 300s.

[0034] The images of the tantalum cathode taken by electron microscope at the same magnification before and after polishing are as follows: Figure 4 As shown, it can be seen that the surface morphology after polishing is smoother and simpler than before polishing, and there are basically no linear surface scratches, thus achieving the polishing effect.

[0035] The foregoing describes various preferred embodiments of the present invention. Unless the preferred implementation modes in various preferred embodiments are obviously self-contradictory or based on a certain preferred implementation mode, various preferred implementation modes can be arbitrarily superimposed and used in combination. The embodiments and specific parameters in the embodiments are only for clearly describing the invention verification process of the inventor, and are not used to limit the patent protection scope of the present invention. The patent protection scope of the present invention shall still be based on its claims. All equivalent structural changes made using the contents of the description and drawings of the present invention should be included in the protection scope of the present invention.

Claims

1. An electrolytic polishing device for a tantalum cathode in a Penning ion source, characterized in that: The electrolysis chamber comprises an electrolysis chamber (1) with an opening at the top, the upper part of the electrolysis chamber being closed by an electrolysis chamber cover (2), a cathode through hole (11) being provided at the center of the electrolysis chamber cover, a cathode (9) being inserted into the cathode through hole, and an anode through hole (12) being provided on the electrolysis chamber cover, an anode (10) being inserted into the cathode through hole; A plurality of hangers are arranged on one side of the electrolysis chamber cover (2) facing the electrolysis chamber body (1) and are centrally symmetrically distributed with the cathode through hole as the center. The anode is connected to an anode wire (5). The anode wire (5) passes through all the hangers in sequence around the cathode and is suspended and supported by the hangers. A hook (6) is hung on the anode wire (5) between every two adjacent hangers.

2. The electrolytic polishing device according to claim 1, characterized in that: A sealing groove is provided on the side of the electrolysis chamber cover, and an O-type sealing ring (3) is installed in the sealing groove.

3. The electrolytic polishing device according to claim 1, characterized in that: The anode wire (5) is a platinum wire.

4. The electrolytic polishing device according to claim 1, characterized in that: The hanger is a hexagonal screw (4) made of insulating material, and holes are drilled on the six sides of the hexagonal screw (4). A plurality of symmetrically distributed blind holes (14) are arranged below the electrolysis chamber cover (2), and the internal threads of the blind holes (14) cooperate with the external threads of the hexagonal screw. The hexagonal screw is located inside the blind hole, and the anode wire passes through the through holes on two sides of the hexagonal screw.

5. The electrolytic polishing device according to claim 1, characterized in that: The electrolysis chamber cover is provided with a vent hole (8), and an exhaust valve is installed on the vent hole.

6. The electrolytic polishing device according to claim 1, characterized in that: The electrolysis chamber cover is also provided with an anode wire screw hole (13), in which an anode screw is installed, the anode wire (5) is connected to the anode screw, and the anode screw is electrically connected to the anode (10).

7. The electrolytic polishing device according to claim 1, characterized in that: The cathode (9) comprises a central metal piece, the upper end of which is a connection point for connecting a wire, the lower end of which extends into the center of the electrolysis chamber and is a platinum sheet, and the outside of the central metal piece is wrapped with an insulating layer; the anode (10) is a metal screw.

8. The electrolytic polishing device according to claim 1, characterized in that: The electrolysis chamber (1) and the electrolysis chamber cover (2) are both made of polytetrafluoroethylene material.

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