Device for forming tantalum wire oxide layer and method for processing tantalum wire

Abstract

The invention relates to a device for forming a tantalum wire oxide layer and a method for processing a tantalum wire, and the device for forming the tantalum wire oxide layer comprises wire releasing equipment which comprises a support and a mounting shaft which is arranged on the support and is used for bearing a tantalum wire disc wound with the tantalum wire; the coating furnace and the wire releasing equipment are arranged side by side; the coating furnace comprises a coating furnace body, a wire inlet, a wire outlet, a heater and an oxygen inlet, wherein the wire inlet is formed in the side, close to the wire releasing equipment, of the coating furnace body and communicated with a hearth of the coating furnace body, the wire outlet is formed in the side, away from the wire releasing equipment, of the coating furnace body and communicated with the hearth, the heater is used for heating the hearth, and the oxygen inlet is used for introducing oxygen into the hearth. The flow meter is used for detecting the amount of oxygen introduced from the oxygen inlet; the coating furnace control part is used for controlling the temperature in the hearth; and the wire collecting equipment is arranged on one side, provided with the wire outlet, of the coating furnace and comprises a motor used for driving the wire winding disc to rotate so as to wind and collect the tantalum wire which is released by the wire releasing equipment and forms the oxide layer in the hearth.

Description

Technical Field

[0001] The present invention relates to the field of tantalum wire processing, and in particular, to a device for forming a tantalum wire oxide layer and a method for processing the tantalum wire. Background Art

[0002] Tantalum capacitors are widely used in high-tech fields such as mobile phone communications, computer chips, automobile control systems, and aerospace. Tantalum wire is used as the anode lead of tantalum capacitors, and plays the role of a conductor for charging and discharging functions. The performance of tantalum wire leads is very important for the tantalum electrolytic capacitors produced. Since tantalum wire can be reduced in diameter, it plays a vital role in producing capacitors with smaller size, larger capacitance, higher reliability, and longer service life.

[0003] Tantalum wire used as anode lead of tantalum capacitors requires good surface finish, high purity, uniform size and precision, good mechanical properties and point performance. For example, our company's specific requirements for the surface finish of tantalum wire are: silvery white metallic luster, no obvious grooves, burrs, pits and other defects on the surface under a 90x microscope; the specific requirements for electrochemical performance are no leakage current, the smaller the leakage current, the better the performance. At present, our customers require leakage current ≤ 0.28μΑ / cm 2 (≤1.8μΑ / in 2 ).

[0004] The production of tantalum wire begins with isostatic pressing of raw tantalum powder. The process is as follows:

[0005] Raw material tantalum powder → isostatic pressing → vertical melting and sintering → rolling → intermediate annealing → surface continuous coating → drawing 2 → cleaning → continuous annealing → fine winding → packaging and warehousing.

[0006] The surface coating treatment of the intermediate specification tantalum wire creates a protective film between the tantalum wire matrix and the die during the drawing process. The mechanism is 2Ta+O2=2Ta2O. The generated Ta2O is a low-valent oxide, which has a certain lubricating effect and is easy to fall off during the processing. While playing a lubricating role, it protects the surface of the finished tantalum wire after drawing, ensuring that the surface of the tantalum wire is smooth and intact during the drawing process.

[0007] Tantalum is a refractory metal with a melting point of 2996°C. It does not react with oxygen at room temperature. It is very slightly oxidized at about 300°C, with the main component being Ta6O. At 350°C, the slightly oxidized surface changes from yellow to red, purple, and blue, turns black from 390°C to 440°C, and turns dark gray at around 480°C. White oxides gradually appear at 500°C, with the main component being Ta4O. As the temperature gradually rises, oxides with the main component being Ta2O are formed. These low-valent oxides are insoluble in various acids other than hydrofluoric acid, forming a dense oxide film on the surface of the tantalum wire. The generated surface oxide layer can easily peel off, break, or delaminate from the substrate during the subsequent drawing process, which helps to remove impure oxygen after drawing. It should be pointed out that within the range of 800-1050°C, the oxidation of tantalum reappears in the parabolic oxidation law stage. When the temperature exceeds 1700°C, the evaporation and volatility of low-valent oxides also help to remove impure oxygen during continuous annealing.

[0008] The surface coating of tantalum wire is the surface oxidation film treatment. The general method is to heat the intermediate specification tantalum wire after drawing 1 in a muffle furnace (box furnace) and perform surface oxidation treatment under atmospheric conditions. An oxide film is formed on the surface of the intermediate specification tantalum wire, which is used to lubricate the tantalum wire matrix and the mold during the drawing process 2 and protect the surface of the tantalum wire. However, the thickness of the oxide layer formed on the surface of the intermediate specification tantalum wire treated with the muffle furnace and its coating process is unstable, and the controllable range of oxygen content after oxidation of the intermediate specification tantalum wire surface is too large, which cannot effectively ensure the smooth surface of the tantalum wire. The finished tantalum wire after drawing is difficult to meet the chemical purity requirements of the tantalum wire used in the current tantalum capacitor. Summary of the invention

[0009] The present invention aims to provide a device for forming an oxide layer of a tantalum wire and a method for processing the tantalum wire, so as to improve the problem of uneven oxide layer on the surface of the tantalum wire existing in the prior art.

[0010] According to one aspect of an embodiment of the present invention, the present invention provides a device for forming an oxide layer of a tantalum wire, and the device for forming an oxide layer of a tantalum wire comprises:

[0011] A wire unwinding device comprises a bracket and a mounting shaft mounted on the bracket and carrying a tantalum wire disc wound with tantalum wire;

[0012] The coating furnace is arranged side by side with the wire-releasing device, and comprises a coating furnace body, a wire inlet provided on a side of the coating furnace body adjacent to the wire-releasing device and communicating with the furnace of the coating furnace body, a wire outlet provided on a side of the coating furnace body away from the wire-releasing device and communicating with the furnace, a heater for heating the furnace, an oxygen inlet for introducing oxygen into the furnace, a flow meter for detecting the amount of oxygen introduced by the oxygen inlet, and a coating furnace control unit for controlling the temperature in the furnace;

[0013] The wire collecting device is arranged on one side of the coating furnace where a wire outlet is provided. The wire collecting device comprises a motor for driving a wire winding disk to rotate so as to wind up the tantalum wire released by the wire releasing device and after an oxide layer is formed in the furnace.

[0014] In some embodiments, the coating furnace also includes a first temperature detection component configured to detect the temperature in the furnace chamber, and the coating furnace control unit is signal-connected to the first temperature detection component and the heater, respectively, to control the power or start and stop of the heater according to the temperature detected by the first temperature detection component, so as to stabilize the temperature in the furnace chamber within a predetermined range.

[0015] In some embodiments, the coating furnace also includes a second temperature detection component configured to detect the temperature in the furnace chamber, and the coating furnace control unit is signal-connected to the second temperature detection component and the heater, respectively, so as to turn off the heater when the difference between the temperature detected by the second temperature detection component and the temperature detected by the first temperature detection component is greater than a predetermined difference.

[0016] In some embodiments,

[0017] The flow meter is configured to adjust the flow rate of oxygen introduced into the oxygen inlet; and / or

[0018] The device for forming the tantalum wire oxide layer also includes a flow regulating valve connected to the oxygen inlet. The coating furnace control unit and the flow regulating valve and the flow meter are respectively connected by signals to adjust the opening of the flow regulating valve according to the flow of oxygen detected by the flow meter to stabilize the flow of oxygen introduced into the oxygen inlet at a predetermined flow value.

[0019] In some embodiments, the device for forming the tantalum wire oxide layer further comprises:

[0020] A wire inlet pipe is arranged on one side of the coating furnace body adjacent to the wire unwinding device and is connected to the wire inlet. The wire inlet pipe extends from the outside of the coating furnace body to the furnace chamber to accommodate the tantalum wire released by the wire unwinding device and extending into the furnace chamber.

[0021] The wire outlet tube is arranged on one side of the coating furnace body adjacent to the wire collecting device and is connected to the wire outlet. The wire outlet tube extends from the furnace of the coating furnace body to the wire collecting device to accommodate the tantalum wire extending to the wire collecting device after forming an oxide layer in the furnace.

[0022] In some embodiments, the wire inlet pipe includes an inner tube of heat-resistant material and an outer tube of heat-dissipating material sleeved outside the inner tube; the wire outlet pipe includes an inner tube of heat-resistant material and an outer tube of heat-dissipating material sleeved outside the inner tube.

[0023] In some embodiments, the wire collecting device further includes a speed detection component for detecting the speed of the tantalum wire moving toward the wire winding disk, and a wire collecting device control unit which is signal-connected to the speed detection component and the motor respectively. The wire collecting device control unit is configured to control the rotation speed of the motor according to the speed detected by the speed detection component to maintain the moving speed of the tantalum wire at a predetermined value.

[0024] Apparatus for forming an oxide layer on a tantalum wire In some embodiments, the apparatus for forming an oxide layer on a tantalum wire further comprises a support mounted on the support for adjusting the tension of the tantalum wire moving from the wire unwinding device through the coating furnace to the wire collecting device.

[0025] According to another aspect of the present invention, a method for processing tantalum wire according to the above-mentioned device for forming an oxide layer of tantalum wire is also provided. The method for processing tantalum wire comprises:

[0026] Mounting a tantalum wire reel wound with tantalum wire to be formed with an oxide layer on a mounting shaft;

[0027] One end of the tantalum wire on the tantalum wire reel passes through the wire inlet and wire outlet of the coating furnace and is connected to the wire winding reel of the wire collection device;

[0028] The continuous rotation of the wire reel drives the tantalum wire to move, and when passing through the coating furnace, it is heated in the coating furnace to form an oxide layer.

[0029] In some embodiments, the method for processing the tantalum wire further includes forming the tantalum wire disc before mounting the tantalum wire disc on the mounting shaft, wherein forming the tantalum wire disc includes:

[0030] Cleaning the tantalum wire to be subjected to oxide layer formation;

[0031] Annealing the tantalum wire;

[0032] The tantalum wire is wound on a wire reel to form a tantalum wire reel.

[0033] In some embodiments,

[0034] Cleaning treatment of the tantalum wire to be subjected to oxide layer formation includes ultrasonic cleaning;

[0035] Annealing the tantalum wire includes heating the tantalum wire to an annealing holding temperature and holding the annealing time T, wherein the holding temperature is 1200° C.-1520° C. and / or the holding time T is 50 to 70 minutes.

[0036] In some embodiments,

[0037] The heating temperature in the coating furnace is 600-880℃;

[0038] The speed of the tantalum wire passing through the coating furnace is 8-15m / min;

[0039] The flow rate of oxygen introduced into the oxygen inlet of the coating furnace is 15-22L / min.

[0040] By applying the technical solution of the present application, one end of the tantalum wire on the tantalum wire reel of the wire unwinding device passes through the wire inlet and wire outlet of the coating furnace and is connected to the wire winding reel of the wire collecting device. The motor of the wire collecting device drives the wire winding reel to rotate, so that the tantalum wire on the tantalum wire reel continuously moves toward the wire collecting device and is wound on the wire winding reel 85. When the tantalum wire moving toward the wire collecting device passes through the furnace, it is oxidized in the stable high-temperature annular and oxygen-supply environment of the furnace to form an oxide layer, thereby improving the problem of uneven oxide layer thickness on the surface of the tantalum wire existing in the prior art.

[0041] Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0043] Figure 1 A device for forming a tantalum wire oxide layer according to an embodiment of the present invention is shown;

[0044] Figure 2 A schematic structural diagram of a wire unwinding device of a device for forming a tantalum wire oxide layer according to an embodiment of the present invention is shown;

[0045] Figure 3 A schematic structural diagram of a wire collecting device of an apparatus for forming an oxide layer of a tantalum wire according to an embodiment of the present invention is shown;

[0046] Figure 4 A schematic diagram showing a first tantalum wire according to an embodiment of the present invention before an oxide layer is formed;

[0047] Figure 5 A schematic diagram showing a first tantalum wire according to an embodiment of the present invention after an oxide layer is formed;

[0048] Figure 6 A schematic diagram showing a finished product formed by further processing of the first tantalum wire according to an embodiment of the present invention after forming an oxide layer;

[0049] Figure 7 A schematic diagram showing a second tantalum wire according to an embodiment of the present invention before an oxide layer is formed;

[0050] Figure 8 A schematic diagram showing a second tantalum wire according to an embodiment of the present invention after an oxide layer is formed;

[0051] Fig. 9 A schematic diagram showing a finished product of the second tantalum wire according to an embodiment of the present invention after an oxide layer is formed and further processed. DETAILED DESCRIPTION

[0052] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. 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.

[0053] like Figure 1 As shown, the device for forming a tantalum wire oxide layer in this embodiment includes a wire unwinding device 1, a coating furnace 4 and a wire collecting device 8.

[0054] Combination Figure 1 and 2 As shown, the wire unwinding device 1 comprises a support 11 and a mounting shaft 13 mounted on the support 11 and carrying a tantalum wire disk wound with tantalum wire.

[0055] like Figure 1 As shown, the coating furnace 4 is arranged side by side with the wire unwinding device 1, and the coating furnace 4 includes a coating furnace body 41, a wire inlet provided on a side of the coating furnace body 4 adjacent to the wire unwinding device 1 and communicating with the furnace of the coating furnace body 41, a wire outlet provided on a side of the coating furnace body 4 away from the wire unwinding device 1 and communicating with the furnace, a heater for heating the furnace, an oxygen inlet for introducing oxygen into the furnace, a flow meter 45 for detecting the amount of oxygen introduced by the oxygen inlet, and a coating furnace control unit 42 for controlling the temperature in the furnace.

[0056] Combination Figure 1 and 3 As shown, the wire collecting device 8 is arranged on the side of the coating furnace 4 where the wire outlet is provided, and the wire collecting device 8 includes a motor 84 for driving the wire winding disk 85 to rotate to wind up the tantalum wire released by the wire releasing device 1 and after an oxide layer is formed in the furnace.

[0057] One end of the tantalum wire on the tantalum wire reel of the wire unwinding device 1 passes through the wire inlet and wire outlet of the coating furnace 4 and is connected to the wire winding reel 85 of the wire collecting device 8. The motor 84 of the wire collecting device 8 drives the wire winding reel 85 to rotate, so that the tantalum wire on the tantalum wire reel continuously moves toward the wire collecting device 8 and is wound on the wire winding reel 85. When the tantalum wire moves toward the wire collecting device 8 passes through the furnace, it is oxidized in the stable high-temperature annular and oxygen-supply environment of the furnace to form an oxide layer, thereby improving the problem of uneven oxide layer thickness on the surface of the tantalum wire in the prior art.

[0058] In some embodiments, the coating furnace 4 further includes a first temperature detection component 43 configured to detect the temperature in the furnace, and the coating furnace control unit 42 is connected to the first temperature detection component 43 and the heater by signals, so as to control the power or start and stop of the heater according to the temperature detected by the first temperature detection component 43, so as to stabilize the temperature in the furnace within a predetermined range, which is conducive to the formation of an oxide layer with uniform thickness on the tantalum wire. In some embodiments, the first temperature detection component 43 includes a thermocouple.

[0059] In some embodiments, the coating furnace 4 further includes a second temperature detection component 44 configured to detect the temperature in the furnace, and the coating furnace control unit 42 is signal-connected to the second temperature detection component 44 and the heater, respectively, so as to turn off the heater when the difference between the temperature detected by the second temperature detection component 44 and the temperature detected by the first temperature detection component 43 is greater than a predetermined difference. In some embodiments, the second temperature detection component 44 includes a thermocouple.

[0060] In some embodiments, the flow meter 45 is configured to adjust the flow rate of oxygen introduced into the oxygen inlet. The flow meter 45 can ensure a stable oxygen supply in the furnace, which is conducive to the formation of a stable oxide layer on the surface of the tantalum wire. The flow meter 45 includes an air inlet, a regulating valve connected to the air inlet, and a flow display connected to the outlet of the regulating valve. The display includes a transparent tubular component connected to the outlet of the regulating valve and a float disposed in the tubular component. Furthermore, the exhaust port of the flow meter is also connected to the outlet of the regulating valve. Optionally, the regulating valve is manually adjustable.

[0061] In other embodiments, the device for forming the tantalum wire oxide layer also includes a flow regulating valve connected to the oxygen inlet, and the coating furnace control unit 42 and the flow regulating valve and the flow meter 45 are respectively signal-connected to adjust the opening of the flow regulating valve according to the flow of oxygen detected by the flow meter 45, so as to stabilize the flow of oxygen introduced by the oxygen inlet at a predetermined flow value, thereby ensuring a stable oxygen supply in the furnace, which is conducive to the formation of a stable oxide layer on the surface of the tantalum wire.

[0062] The coating furnace body 41 has a heater, a heat shield, a water-cooled protective sleeve, and a water-cooled furnace body in order from the inside to the outside. The coating furnace 4 also includes a power control cabinet.

[0063] In some embodiments, the apparatus for forming the tantalum wire oxide layer further includes an oxygen supply unit 5 , which is configured to deliver oxygen to an air inlet of the coating furnace 4 .

[0064] In some embodiments, the device for forming the tantalum wire oxide layer further comprises a wire inlet tube 3 and a wire outlet tube 6. In some embodiments, the wire inlet tube 3 comprises an inner tube of a heat-resistant material and an outer tube of a heat dissipation material sleeved outside the inner tube, and optionally, the material of the inner tube is stainless steel, and the material of the outer tube is copper. The wire outlet tube 6 comprises an inner tube of a heat-resistant material and an outer tube of a heat dissipation material sleeved outside the inner tube, and optionally, the material of the inner tube is stainless steel, and the material of the outer tube is copper.

[0065] The wire inlet pipe 3 is arranged on one side of the coating furnace body 4 adjacent to the wire unwinding device 1 and is connected to the wire inlet. The wire inlet pipe 3 extends from the outside of the coating furnace body 4 to the furnace chamber to accommodate the tantalum wire released by the wire unwinding device 1 and extending into the furnace chamber. The wire inlet pipe 3 is sealed and connected to the coating furnace 4, and the overflow heat of the coating furnace 4 is used to preheat the tantalum wire (the intermediate specification tantalum wire that has not reached the finished product) entering the wire inlet pipe.

[0066] The wire outlet pipe 6 is arranged on one side of the coating furnace body 4 adjacent to the wire collecting device 8 and is connected to the wire outlet. The wire outlet pipe 3 extends from the furnace of the coating furnace body 4 to the wire collecting device 8 to accommodate the tantalum wire extending to the wire collecting device 8 after the oxide layer is formed in the furnace. The wire outlet pipe 6 is sealed and connected to the coating furnace 4 to protect the tantalum wire from oxidation and cooling under controllable conditions in the wire outlet pipe 6.

[0067] In some embodiments, the wire collecting device 8 further includes a speed detection component 82 for detecting the speed of the tantalum wire moving toward the wire winding disk 85, and a wire collecting device control unit 81 connected to the speed detection component 82 and the motor 84 respectively by signals, and the wire collecting device control unit 81 is configured to control the rotation speed of the motor 84 according to the speed detected by the speed detection component 82, so as to maintain the moving speed of the tantalum wire at a predetermined value. In some embodiments, the wire collecting device control unit 81 includes a PLC.

[0068] In some embodiments, the speed detection component 82 includes a meter counter, and the wire collecting device 8 also includes a data processor 86 for processing data detected by the meter counter, and the data processor is connected to the wire collecting device control unit 81 by signal to transmit the data detected by the meter counter to the wire collecting device control unit 81. The wire collecting device control unit 81 controls the rotation speed of the motor 84 to achieve the purpose of controlling the wire collecting line speed.

[0069] See also Figure 1 and 3 The wire collecting device 8 also includes a device for guiding the tantalum wire to move in an axial direction parallel to the winding disk 85 so as to wind the tantalum wire around the wire winding disk 85 in circles along the axial direction of the wire winding disk 85.

[0070] The device for forming the tantalum wire oxide layer also includes a tensioner 12 installed on the bracket 11 to adjust the tantalum wire moving from the wire-unwinding device 1 to the wire-collecting device 8 through the coating furnace 4. The tensioner 12 is conducive to ensuring the tension temperature of the tantalum wire from the wire-unwinding device 1, through the coating furnace 4 to the wire-collecting device 8, thereby ensuring the uniformity of the speed of the tantalum wire passing through the furnace.

[0071] The wire-releasing device 1 is composed of a permanent magnetic tensioner 12 fixed to the main body thereof and a mounting shaft 13 on which a tantalum wire reel is mounted. The permanent magnetic tensioner 12 is fixed to a vertical bracket 11, and a mounting shaft 13 is horizontally mounted on the output shaft of the permanent magnetic tensioner 12 to facilitate mounting of the tantalum wire reel on the mounting shaft 13. The wire-releasing device 1 has a stable slip torque, and is provided with a scale that can continuously adjust the wire-releasing tension during operation between the maximum and minimum values, and the flexible change of the tension between static and dynamic can provide a constant tension without sudden changes.

[0072] The first guide wheel 2 is used to guide the tantalum wire between the wire unwinding device 1 and the coating furnace 4, the first guide wheel 2 is used to limit the entry of the tantalum wire at the inlet of the wire inlet tube 3 in front of the coating furnace 4, the second guide wheel 7 is used to limit the outlet of the tantalum wire at the outlet of the wire outlet tube 6, and the second guide wheel 7 is used to guide and divert the tantalum wire between the coating furnace 4 and the wire collecting device 8.

[0073] Of course, the first guide wheel 2 and the second guide wheel 7 used for guiding the tantalum wire or limiting the pipe mouth can adjust the position and direction according to needs.

[0074] In this embodiment, the wire unwinding device 1, the wire inlet pipe 3, the wire outlet pipe 6 and the wire collecting device 8 are arranged one-to-one. The wire inlet pipe 3 and the corresponding wire outlet pipe 6 are arranged coaxially. The wire unwinding device 1 and the corresponding wire collecting device 8 are arranged on both sides of the furnace to be coated.

[0075] The coating furnace control unit 42 is adjusted to set the temperature and oxygen supply amount in the furnace of the coating furnace 4 to process specified values.

[0076] A spare tantalum wire lead is installed on the wire unwinding device 1 , and before the furnace is opened, the tantalum wire lead passes through the coating furnace 4 in advance and is connected to the wire winding disk clamped on the wire collecting device 8 .

[0077] When the temperature in the coating furnace 4 reaches the target process temperature, the tantalum wire to be coated (forming an oxide layer) is passed through the coating furnace 4 through the lead wire and connected to the winding reel 85 on the wire collecting device 8. The wire collecting device 8 is started, and the wire collecting speed is adjusted to control the residence time of the tantalum wire in the coating furnace, and the continuous coating operation begins.

[0078] The surface of the intermediate specification tantalum wire to be coated must be clean and dry without any burrs, pits, splits or other defects.

[0079] A device for continuous processing of wire materials: it is composed of a wire unwinding device, a coating furnace and a wire collecting device.

[0080] After being wound on the upper drum, the wire can be installed on the wire-releasing device, pass through the guide, coating or other processing equipment in turn, and then be connected to the wire-collecting device through the guide.

[0081] The requirements for the site are not high. During the equipment assembly process, the guide on the middle bracket guides and diverts the direction of the wire, and the direction can be changed at will. The distance and corresponding angle of the wire collecting and releasing equipment are not restricted.

[0082] When the oxide layer is continuously formed on the surface of the tantalum wire by the device for forming the oxide layer of the tantalum wire of this embodiment,

[0083] According to another aspect of the present application, a method for processing tantalum wire based on the above-mentioned device for forming a tantalum wire oxide layer is also provided. The method for processing tantalum wire comprises:

[0084] Mounting a tantalum wire reel wound with tantalum wire to be formed with an oxide layer on the mounting shaft 13;

[0085] One end of the tantalum wire on the tantalum wire reel passes through the wire inlet and the wire outlet of the coating furnace 4 and is connected to the wire winding reel 85 of the wire collecting device 8;

[0086] The wire winding drum 85 continuously rotates to drive the tantalum wire to move, and when passing through the coating furnace 4, the tantalum wire is heated in the coating furnace 4 to form an oxide layer.

[0087] In some embodiments, the method for processing the tantalum wire further includes forming the tantalum wire disc before mounting the tantalum wire disc on the mounting shaft 13, wherein forming the tantalum wire disc includes:

[0088] Cleaning the tantalum wire to be subjected to oxide layer formation;

[0089] Annealing the tantalum wire;

[0090] The tantalum wire is wound on a wire reel to form a tantalum wire reel.

[0091] The cleaning process for the tantalum wire on which the oxide layer is to be formed includes ultrasonic cleaning.

[0092] Annealing the tantalum wire includes heating the tantalum wire to an annealing holding temperature and holding the annealing time T, wherein the holding temperature is 1200° C.-1520° C. and / or the holding time T is 50 to 70 minutes.

[0093] The heating temperature in the coating furnace 4 is 600-880°C.

[0094] The speed at which the tantalum wire passes through the coating furnace 4 is 8-15 m / min.

[0095] The flow rate of oxygen introduced into the oxygen inlet of the coating furnace 4 is 15-22 L / min.

[0096] Specifically, the method for processing tantalum wire in the device for forming a tantalum wire oxide layer of this embodiment includes:

[0097] S1. Ultrasonic cleaning of the surface of tantalum wire (intermediate specification);

[0098] S2. performing intermediate annealing treatment on the tantalum wire;

[0099] S3. Winding the tantalum wire on the coil;

[0100] S4. The tantalum wire is installed on the wire placing device 1;

[0101] S5. Tantalum wire is subjected to continuous coating operation.

[0102] Among them, after ultrasonic cleaning, the surface of the tantalum wire is smooth and free of oil stains and defects. After intermediate annealing, the tantalum wire meets the drawing processing performance. The winding diameter of the tantalum wire on the upper coil is Φ200mm~Φ300mm, the temperature of the continuous coating operation is 800-880℃, the continuous coating wire speed is 8-15m / min, and the oxygen flow rate of the continuous coating furnace is 10-15L / min.

[0103] The intermediate specification tantalum wire controls the length of time it stays in the continuous coating furnace according to the wire feeding speed, and the amount of oxygen supplied is precisely controlled to accurately control the formation of oxide film on the surface of the tantalum wire.

[0104] The uniform speed operation controls the uniformity of the oxide film on the surface of the tantalum wire, and the stable oxygen supply controls the thickness consistency of the oxide film on the surface of the tantalum wire.

[0105] In the embodiment, the oxygen content of the intermediate specification tantalum wire after being treated by the continuous coating furnace is below 200 ppm. The national standard requires that the oxygen content of the tantalum wire after surface treatment is generally ≤300 ppm.

[0106] In the embodiment of the present invention, the oxygen content of the intermediate specification tantalum wire treated with continuous coating after drawing is below 140ppm (test result), and customers generally require ≤200ppm.

[0107] Beneficial effects achieved by the present invention:

[0108] The present invention provides a continuous coating device for the first time in the field of tantalum wire surface treatment. During the oxidation film repair treatment on the tantalum wire surface, the device can control the wire feeding speed of the tantalum wire and the oxygen supply of the coating furnace to make the surface of the tantalum wire evenly oxidized into a film, and the thickness of the tantalum wire oxide film can be easily controlled.

[0109] The oxygen content of the intermediate specification tantalum wire processed by the continuous coating equipment is below 200ppm. It is generally difficult to accurately control the oxygen content of the intermediate specification tantalum wire during the production process using conventional production methods.

[0110] After the tantalum wire is treated by the continuous coating equipment, the oxide film plays a lubricating role between the tantalum wire and the die in the subsequent drawing process, effectively improving the service life of the drawing die. The finished φ0.15mm tantalum wire can be drawn from 36,000 meters (12kg) per set of dies at one time to about 58,000 meters (17kg) per time.

[0111] The oxide layer with consistent thickness protects the tantalum wire matrix well during the drawing process. The surface of the finished tantalum wire is smooth after drawing, which can meet the requirements of the tantalum wire for capacitor anode lead with leakage current ≤0.28μΑ / cm 2 (≤1.8μΑ / in 2 ) requirements.

[0112] During the drawing and subsequent continuous annealing process, the uniform surface oxide film is peeled off, falls off, and volatilized at high temperature. The oxygen content of the final finished tantalum wire is below 200ppm, which can meet the oxygen content requirements of the chemical purity of tantalum capacitors.

[0113] Previously, the surface treatment method of tantalum wire was basically to loosen the rolled tantalum wire and put it into a muffle furnace for treatment under atmospheric conditions. No one had ever thought of or used a continuous treatment method to coat the surface of the tantalum wire to control the uniformity and consistency of the tantalum wire oxidation film.

[0114] The continuous coating equipment of the present invention has a simple structure and is easy to use.

[0115] The continuous coating equipment of the present invention is safe and reliable: the wire unwinding device 1 adopts a passively rotating permanent magnetic tensioner 12, which only supports the wire winding disk (tantalum wire disk) and provides constant tension for the tantalum wire. The wire collecting device has an infrared meter to feedback the line speed, but after the tantalum wire is interrupted, the line speed is unbalanced and the encoder automatically controls the wire collecting device to stop; in the process of providing temperature and oxygen content, the furnace body and furnace tube of the coating furnace 4 are provided with a water-cooling protective layer.

[0116] The present invention improves production efficiency while ensuring the quality of the surface coating of tantalum wire. A continuous coating furnace can be equipped with multiple sets of wire collecting and releasing equipment. The temperature of the continuous coating furnace is set according to the process requirements, and the speed and oxygen supply of the continuous coating furnace are set according to the specifications of the tantalum wire. The number of wire collecting and releasing equipment is increased within the capacity of the coating furnace temperature, and the oxygen supply is appropriately adjusted to improve production efficiency. A continuous coating furnace is equipped with four sets of wire collecting and releasing equipment, and it runs effectively for 6 hours in one shift per day. The continuous coating speed is calculated at 10m / min. The production operation of φ1.280mm intermediate specification tantalum wire can be continuously coated at 313kg / day.

[0117] The present invention improves production efficiency while ensuring the quality of the tantalum wire surface coating. A continuous coating furnace can be equipped with multiple sets of wire collecting and releasing equipment. The temperature of the continuous coating furnace is set according to the process requirements, and the speed and oxygen supply of the continuous coating furnace are set according to the specifications of the tantalum wire. The number of wire collecting and releasing equipment is increased within the capacity of the coating furnace temperature, and the oxygen supply is appropriately adjusted to improve production efficiency. A continuous coating furnace is equipped with four sets of wire collecting and releasing equipment, and it runs effectively for 6 hours per shift per day. The continuous coating speed is calculated at 10m / min, and the production operation is The intermediate specification tantalum wire can be coated continuously at 313kg / day.

[0118] A specific embodiment of processing tantalum wire is provided below:

[0119] Example A method for coating the surface of a tantalum wire

[0120] like Figure 1 The continuous coating device shown comprises a coating furnace, and a wire unwinding device 1 and a wire collecting device 1 located before and after the coating furnace 4 .

[0121] The coating furnace has a controllable temperature heater, a first temperature detection component 43 and a second temperature detection component 44. The first temperature detection component 43 is connected to the temperature control meter on the coating furnace control unit 42 to control the temperature in the furnace of the coating furnace 4. The second temperature detection component 44 monitors the temperature in the furnace of the coating furnace 4. When the first temperature detection component 43 and the second temperature detection component 44 exceed the set deviation value, an alarm is issued to indicate that the temperature control is distorted.

[0122] The continuous coating furnace combination process adjusts the running direction of the tantalum wire through the intermediate guide wheel group 4 and the guide wheel group 13.

[0123] Operate the wire collecting device control unit 81 of the continuous coating furnace wire collecting device to set the wire collecting speed. The speed detection component 82 at the front end of the wire winding disk 85 collects the feedback speed signal to the wire collecting machine encoder (data processor 86). After the encoder obtains the signal, it adjusts the speed of the wire collecting machine motor 84.

[0124] The embodiment is based on the diameter after one drawing. The intermediate specification tantalum wire is ultrasonically cleaned at a speed of 10m / min, wound on a wire winding reel with a diameter of 300mm, and installed in the wire unwinding equipment of the continuous coating furnace.

[0125] Start the continuous coating furnace, set the coating temperature to 800°C, set the constant pressure to 0.35Mpa, the oxygen flow rate to 15L / min with a purity of 99.99%, and start the wire collection equipment to perform continuous coating at a speed of 10m / mim.

[0126] The oxygen content and surface finish of the two batches of numbered materials produced in the example were measured at three different stages: before continuous coating, after continuous coating, and as finished tantalum wire.

[0127] Oxygen content determination method: in accordance with the method specified in the National Standard of the People's Republic of China "GB3463-1995 Tantalum Wire".

[0128] Surface finish measurement method: in accordance with the method specified in the National Standard of the People's Republic of China "GB3463-1995 Tantalum Wire". Smoothness measurement equipment: observation and measurement under SEM electron microscope X100.

[0129] The oxygen content measurement results are shown in Table 1 below.

[0130] Table 1

[0131]

[0132] See also Figures 4 to 5 The test results of the tantalum wire finish are shown in the EMS×100 photo. Figures 4 to 6 The first tantalum wire (sy-908-0162) is shown before the oxide layer is formed, after the oxide layer is formed, and the finished product after reprocessing. Figures 4 to 6 The second tantalum wire (sy-908-0163) is shown before the oxide layer is formed, after the oxide layer is formed, and the finished product after reprocessing.

[0133] Experimental results: As shown in Table 1, the oxygen content on the surface of the tantalum wire treated by the continuous coating equipment of the present invention is far lower than the international standard of 300ppm. The oxygen content of the finished tantalum wire after drawing is less than 200ppm, which can meet the chemical purity requirements of the tantalum wire used in the current tantalum capacitors.

[0134] The tantalum wire treated by the continuous coating device of the present invention has good surface finish and is free of surface defects such as grooves, scratches, burrs, pits, etc.

[0135] The above are merely exemplary embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A device for forming a tantalum wire oxide layer, characterized in that: include: A wire unwinding device (1) comprises a support (11) and a mounting shaft (13) mounted on the support (11) and carrying a tantalum wire disc wound with tantalum wire; A coating furnace (4) is arranged side by side with the wire-releasing device (1), the coating furnace (4) comprising a coating furnace body (41), a wire inlet provided on a side of the coating furnace body (4) adjacent to the wire-releasing device (1) and communicating with a furnace chamber of the coating furnace body (41), a wire outlet provided on a side of the coating furnace body (4) away from the wire-releasing device (1) and communicating with the furnace chamber, a heater for heating the furnace chamber, an oxygen inlet for introducing oxygen into the furnace chamber, a flow meter (45) for detecting the amount of oxygen introduced by the oxygen inlet, and a coating furnace control unit (42) for controlling the temperature in the furnace chamber; A wire collecting device (8) is arranged on a side of the coating furnace (4) where the wire outlet is provided, and the wire collecting device (8) comprises a motor (84) for driving a wire winding disk (85) to rotate so as to wind up the tantalum wire released by the wire releasing device (1) and after an oxide layer is formed in the furnace.

2. The device for forming a tantalum wire oxide layer according to claim 1, characterized in that: The coating furnace (4) also includes a first temperature detection component (43) configured to detect the temperature in the furnace chamber, and the coating furnace control unit (42) is signal-connected to the first temperature detection component (43) and the heater respectively, so as to control the power or start and stop of the heater according to the temperature detected by the first temperature detection component (43), so as to stabilize the temperature in the furnace chamber within a predetermined range.

3. The device for forming a tantalum wire oxide layer according to claim 2, characterized in that: The coating furnace (4) also includes a second temperature detection component (44) configured to detect the temperature in the furnace chamber, and the coating furnace control unit (42) is signal-connected to the second temperature detection component (44) and the heater respectively, so as to turn off the heater when the difference between the temperature detected by the second temperature detection component (44) and the temperature detected by the first temperature detection component (43) is greater than a predetermined difference.

4. The device for forming a tantalum wire oxide layer according to claim 1, characterized in that: The flow meter (45) is configured to adjust the flow rate of oxygen introduced by the oxygen inlet; and / or The device for forming a tantalum wire oxide layer also includes a flow regulating valve connected to the oxygen inlet, and the coating furnace control unit (42), the flow regulating valve and the flow meter (45) are respectively signal-connected to adjust the opening of the flow regulating valve according to the flow of oxygen detected by the flow meter (45) to stabilize the flow of oxygen introduced into the oxygen inlet at a predetermined flow value.

5. The device for forming a tantalum wire oxide layer according to claim 1, characterized in that: Also includes: A wire inlet pipe (3) is arranged on a side of the coating furnace body (4) adjacent to the wire unwinding device (1) and is connected to the wire inlet. The wire inlet pipe (3) extends from the outside of the coating furnace body (4) to the furnace chamber to accommodate the tantalum wire released by the wire unwinding device (1) and extending into the furnace chamber. A wire outlet tube (6) is arranged on one side of the coating furnace body (4) adjacent to the wire collecting device (8) and is connected to the wire outlet. The wire outlet tube (3) extends from the furnace chamber of the coating furnace body (4) to the wire collecting device (8) to accommodate the tantalum wire that extends toward the wire collecting device (8) after an oxide layer is formed in the furnace chamber.

6. The device for forming a tantalum wire oxide layer according to claim 5, characterized in that: The wire inlet pipe (3) comprises an inner pipe made of a heat-resistant material and an outer pipe made of a heat-dissipating material sleeved outside the inner pipe; the wire outlet pipe (6) comprises an inner pipe made of a heat-resistant material and an outer pipe made of a heat-dissipating material sleeved outside the inner pipe.

7. The device for forming a tantalum wire oxide layer according to claim 1, characterized in that: The wire collecting device (8) further includes a speed detecting component (82) for detecting the speed of the tantalum wire moving toward the wire winding disk (85) and a wire collecting device control unit (81) which is signal-connected to the speed detecting component (82) and the motor (84), respectively. The wire collecting device control unit (81) is configured to control the rotation speed of the motor (84) according to the speed detected by the speed detecting component (82) so as to maintain the moving speed of the tantalum wire at a predetermined value.

8. The device for forming a tantalum wire oxide layer according to claim 1, characterized in that: It also includes a device installed on the support (11) to adjust the tension of the tantalum wire moving from the wire unwinding device (1) through the coating furnace (4) to the wire collecting device (8).

9. A method for processing tantalum wire according to the device for forming a tantalum wire oxide layer according to any one of claims 1 to 8, characterized in that: include: Mounting a tantalum wire reel wound with tantalum wire to be formed with an oxide layer on a mounting shaft (13); Passing one end of the tantalum wire on the tantalum wire reel through the wire inlet and the wire outlet of the coating furnace (4) and then connecting it to the wire winding reel (85) of the wire collecting device (8); The wire winding disk (85) continuously rotates to drive the tantalum wire to move, and when passing through the coating furnace (4), the tantalum wire is heated in the coating furnace (4) to form an oxide layer.

10. The method for processing tantalum wire according to claim 9, characterized in that: The method further includes forming the tantalum wire disc before installing the tantalum wire disc on the mounting shaft (13), wherein forming the tantalum wire disc includes: Cleaning the tantalum wire to be subjected to oxide layer formation; Annealing the tantalum wire; The tantalum wire is wound on a wire stock disc to form the tantalum wire disc.

11. The method for processing tantalum wire according to claim 10, characterized in that: The cleaning treatment of the tantalum wire to be formed with an oxide layer comprises ultrasonic cleaning; The annealing treatment of the tantalum wire includes heating the tantalum wire to an annealing holding temperature and holding the annealing time T, wherein the holding temperature is 1200° C.-1520° C. and / or the holding time T is 50 to 70 minutes.

12. The method for processing tantalum wire according to claim 9, characterized in that: The heating temperature in the coating furnace (4) is 600-880° C.; The speed at which the tantalum wire passes through the coating furnace (4) is 8-15 m / min; The flow rate of oxygen introduced into the oxygen inlet of the coating furnace (4) is 15-22 L / min.

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