A temperature shock detection method and detection device for high temperature superconducting tape

Abstract

The present invention discloses a temperature shock detection method and detection device for high-temperature superconducting tape, including a sample fixing mechanism, a critical current detection mechanism, a liquid storage mechanism and a driving mechanism; the sample fixing mechanism includes an operating table, a liquid box and a sample fixing rack; the liquid box is arranged on the operating table; at least one sample fixing rack is arranged on the side wall inside the liquid box; the critical current detection mechanism includes a current line and a voltage line; the two ends of the sample fixing rack are respectively connected to the current line; the liquid storage mechanism is connected to the liquid box; and the driving mechanism drives the liquid storage mechanism to move up and down. The detection method is to detect the critical current of the superconducting tape by a temperature shock test and calculate the current retention coefficient. This case realizes temperature shock treatment of the high-temperature superconducting tape and directly performs critical current detection; the operation is simple, the equipment is simple, the cost is low, the repeatability is high, and the applicability is strong; the safety hazards of the operator are reduced; the application reliability of the superconducting tape and the sealing of the coating are verified.

Description

Technical Field

[0001] The invention belongs to the field of superconducting performance detection of superconducting tapes, and in particular relates to a temperature shock test method and an experimental device for high-temperature superconducting tapes. Background Art

[0002] Superconducting materials need to be in a certain temperature environment to change from a normal state to a superconducting state. The transition temperature of high-temperature superconducting materials is in the liquid nitrogen temperature zone. Therefore, high-temperature superconducting tapes need to work in a liquid nitrogen temperature zone during use. The critical current Ic of superconducting tapes is an important performance indicator for their application. If the superconducting layer of a superconducting tape is damaged, its resistance will increase greatly. After a relatively large current shock, the superconducting tape will easily burn. Therefore, in general, we judge the superconducting performance of superconducting tapes by testing the critical current Ic of superconducting tapes.

[0003] Most high-temperature superconducting tapes need to undergo multiple changes between liquid nitrogen temperature and room temperature, which poses a great challenge to their temperature cycle fatigue. Since superconducting tapes may have certain defects, their superconducting performance will also decay to a certain extent after multiple currents. On the other hand, superconducting tapes are prone to defects during the soldering and coating process, which will affect the working performance of the superconducting tapes to varying degrees. First, when the superconducting tape is working, the environmental liquid penetrates into the virtual solder joint. After the environmental liquid vaporizes, it produces thermal expansion and contraction due to different temperatures, which easily causes cracking and bulging of the coating layer. The surface of the superconducting layer of the superconducting tape is plated with an Ag protective layer, and the bonding force between the Ag layer and the coating layer and the superconducting layer is greater than the bonding force between the superconducting layer and the isolation layer. When the coating layer cracks, it is easy to damage the superconducting layer, causing irreversible physical damage to the superconducting layer, thereby causing the superconducting tape to lose its superconducting performance. Secondly, the superconducting tape coating cracks, causing the superconducting layer to lose its outer protective layer and become exposed. In a humid environment, the superconducting layer deliquesces, which will also cause the superconducting performance of the superconducting tape to decay. With the continuous advancement of the industrialization of high-temperature superconducting tapes, the application performance requirements of superconducting tapes continue to be challenged.

[0004] However, there is no special experimental method in the existing technology to test the impact of high-temperature superconducting tapes on their critical current after repeated operation in the liquid nitrogen temperature zone. This requires designing experiments based on the working environment of high-temperature superconducting tapes, verifying the application reliability of superconducting tapes, and testing their performance of repeated operation in the liquid nitrogen temperature zone. It can also be used to verify the sealing of high-temperature superconducting tape coating, which has important reference value for the industrialization of high-temperature superconducting tapes. Summary of the invention

[0005] The purpose of the present invention is to provide a temperature shock detection method and a detection device for high-temperature superconducting tapes. The method can test the fatigue, stability and coating integrity of the superconducting tapes through a designed temperature shock experiment.

[0006] The technical solution of the present invention is: a temperature shock detection device for high-temperature superconducting tape, comprising a sample fixing mechanism, a critical current detection mechanism, a liquid storage mechanism and a driving mechanism; the sample fixing mechanism comprises an operating table, a liquid box and a sample fixing rack; the liquid box is arranged on the operating table; the upper end of the liquid box is open; at least one of the sample fixing racks is arranged on the side wall inside the liquid box; the critical current detection mechanism comprises a current line and a voltage line; the two ends of the sample fixing rack are respectively connected to the current line; the superconducting tape sample strip is pressurized and flowed through by the voltage line and the current line; the liquid storage mechanism is connected to the liquid box; and the driving mechanism drives the liquid storage mechanism to move up and down.

[0007] Preferably, the liquid storage mechanism includes a liquid storage tank, a guide pipe and a liquid inlet; the guide pipe connects the liquid storage tank and the liquid box; a liquid inlet is provided on the upper part of the liquid storage tank, and the liquid inlet can be used as a liquid inlet for injecting environmental liquid from the outside, and can also be used as an exhaust port for balancing the internal air pressure of the liquid storage tank.

[0008] Preferably, the driving mechanism includes a cylinder rod, a cylinder and a cylinder platform; the liquid storage mechanism is arranged on the cylinder platform; the cylinder drives the cylinder rod to drive the cylinder platform to move up and down, adjust the height of the liquid storage mechanism, and then change the liquid level in the liquid tank.

[0009] Preferably, a valve is provided on the liquid box to control the liquid to flow in and out of the liquid box.

[0010] Preferably, the valve is a valve movable block; the valve movable block moves in a vertical direction to block the liquid flow port of the liquid tank, and the valve is detachable.

[0011] Preferably, a voltage wire clamp is provided at the end of the voltage wire.

[0012] A temperature shock detection method for high-temperature superconducting tape, the specific detection steps comprising:

[0013] Step 1: Cut a number of superconducting tape samples from the same superconducting tape, keep the length of each section consistent, and ensure that the length of each superconducting tape sample is sufficient for testing;

[0014] Step 2: Use flux to weld current leads at both ends of the superconducting tape sample to reduce the contact resistance between the electrode and the superconducting tape sample to avoid burning near the electrode due to excessive contact resistance during critical current experiments;

[0015] Step 3: clamping a voltage electrode and a current electrode on the superconducting tape sample welded with a current lead respectively;

[0016] Step 4: placing the superconducting tape sample into liquid nitrogen so that the superconducting tape sample is completely immersed and soaked;

[0017] Step 5: Use the four-lead method to detect the critical current Ic of the superconducting tape sample in liquid nitrogen environment S ;

[0018] Step 6: Take the superconducting tape sample out of liquid nitrogen and allow it to naturally return to room temperature;

[0019] Step 7: Repeat step 4 to place the superconducting tape sample into liquid nitrogen so that the superconducting tape sample is completely immersed and soaked; repeat step 6 to take the superconducting tape sample out of the liquid nitrogen and naturally restore it to room temperature; form a temperature shock; repeat the liquid nitrogen temperature shock process n times;

[0020] Step 8: Repeat step 5 to detect the critical current of the superconducting tape sample after the liquid nitrogen temperature shock in step 7 and record it;

[0021] Step 9: Repeat steps 7 to 8 for m times, and get a critical current Ic each time. i , where i≤m is a positive integer;

[0022] Step 10: Soak the superconducting tape sample after liquid nitrogen temperature shock in water at room temperature, observe whether bubbles emerge around the superconducting tape sample and record them;

[0023] Step 11: After soaking, take out the superconducting tape sample from the room temperature water, wipe off the water stains on its surface, and immediately repeat steps 4 and 5 to detect the critical current Ic of the superconducting tape sample. E ;

[0024] Step 12: According to the critical current Ic S and Ic E Calculate the current retention rate δ and draw the critical current retention rate attenuation curve. The horizontal axis is the number of impacts (n * i) and the vertical axis is the current retention rate δ. The formula is: δ = (Ic / Ic S )*100%;

[0025] Step 13: The experiment terminates when the following conditions occur:

[0026] 1. The experiment is completed;

[0027] Second, the tape loses its superconducting properties irreversibly;

[0028] 3. The current retention rate is lower than the current retention coefficient K value.

[0029] The advantages of the present invention are:

[0030] 1. Realize direct critical current detection of high-temperature superconducting tape after temperature shock;

[0031] 2. Simple operation, simple equipment, low cost and high repeatability;

[0032] 3. Strong applicability, can be used for temperature shock experiments of various high-temperature superconducting tapes;

[0033] 4. Reduce the safety hazards of operators during operation;

[0034] 5. Temperature shock tests can be performed on multiple groups of superconducting tapes at the same time;

[0035] 6. To verify the application reliability of superconducting tapes, and to test their performance in repeated operation in the liquid nitrogen temperature zone, and to verify the sealing of high-temperature superconducting tape coatings. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0037] Figure 1 This is a schematic structural diagram of a temperature shock detection device for high-temperature superconducting tapes described in this case;

[0038] Figure 2 It is a structural schematic diagram of a sample fixing mechanism and a critical current detection mechanism of a temperature shock detection device for high-temperature superconducting tapes described in this case;

[0039] Figure 3 A schematic diagram of the structure of a superconducting tape sample assembly for a temperature shock detection device for high-temperature superconducting tapes described in this case;

[0040] Figure 4 A specific flow chart of a temperature shock detection method for high-temperature superconducting tape described in this case;

[0041] Figure 5 This is a critical current retention rate curve diagram of a temperature shock detection method for high-temperature superconducting tape described in this case. DETAILED DESCRIPTION

[0042] Example:

[0043] As attached Figure 1-5As shown, a temperature shock detection device for high-temperature superconducting tape comprises a sample fixing mechanism 1, a critical current detection mechanism 2, a liquid storage mechanism 3 and a driving mechanism 4; the sample fixing mechanism 1 comprises an operating table 11, a liquid box 12 and a sample fixing rack 13; the liquid box 12 is arranged on the operating table 11; the upper end of the liquid box 12 is open; at least one sample fixing rack 13 is arranged on the side wall inside the liquid box 12; the critical current detection mechanism 2 comprises a current line 21 and a voltage line 22; both ends of the sample fixing rack 13 are respectively connected to the current line 21; the superconducting tape sample 5 is pressurized and flowed through by the voltage line 22 and the current line 21; the liquid storage mechanism 3 is connected to the liquid box 12; the driving mechanism 4 drives the liquid storage mechanism 3 to move up and down; a valve 14 is arranged on the liquid box 12 to control the liquid to enter and exit the liquid box 12; the valve 14 is a valve movable block; the valve movable block moves in the vertical direction to block the liquid flow port of the liquid box 12; a voltage line clamp 23 is arranged at the end of the voltage line 22.

[0044] The liquid storage mechanism 3 includes a liquid storage tank 31 , a guide tube 32 and a liquid inlet 33 ; the guide tube 32 connects the liquid storage tank 31 and the liquid box 12 ; the liquid storage tank 31 is provided with a liquid inlet 33 at the upper part.

[0045] The driving mechanism 4 includes a cylinder rod 41, a cylinder 42 and a cylinder platform; the liquid storage mechanism 3 is arranged on the cylinder platform; the cylinder 42 drives the cylinder rod 41 to drive the cylinder platform to move up and down to adjust the height of the liquid storage mechanism 3.

[0046] Use appropriate soldering flux to weld current leads 15 at both ends of the superconducting tape sample 5. In this example, silver current leads are used. The superconducting tape sample 5 welded with current leads 15 is clamped on the sample fixing frame 13 with a clip. In order to ensure good conductivity, the sample tape fixing frame 13 is made of Cu material. The voltage line 22 is connected to the voltage line clamp 23, and the voltage line clamp 23 is clamped in the middle of the superconducting tape sample 5. The distance between the two voltage line clamps 23 is 30mm. Through the above steps, the superconducting tape sample 5 is pressurized and passed through, and then the critical current Ic of the superconducting tape sample in a liquid environment is tested by the four-lead method. S Liquid nitrogen is poured into the liquid storage tank 31 from the liquid inlet 33, and can also be used as an exhaust port for balancing the internal air pressure of the liquid storage tank. The guide pipe 32 connects the liquid storage tank 31 and the liquid tank 12. Using the principle of communicating vessels, the cylinder 42 drives the liquid storage tank 31 to move up and down, thereby changing the liquid level of the liquid tank 12. The valve 14 can also control the liquid in and out, so as to achieve the action of immersing and exposing the superconducting tape sample 5 fixed on the sample fixing frame 13 to the liquid surface, thereby completing the temperature shock of the superconducting tape sample 5.

[0047] A temperature shock detection method for high-temperature superconducting tape, using the above-mentioned temperature shock detection device, includes the following specific detection steps:

[0048] Step 1: On the same superconducting tape, take a 12 mm wide stainless steel coated high temperature superconducting tape sample 5 to be tested, the sample length is 23 cm, the number is 15, three in a group, a total of five groups;

[0049] Step 2: Use flux to weld silver current leads 15 of the same width at both ends of the superconducting tape sample 5 to reduce the contact resistance between the electrode and the tape, and avoid burning near the electrode due to excessive contact resistance during critical current experiments; the welding points are required to be free of defects such as voids and bubbles;

[0050] Step 3: clamp the superconducting tape sample 5 welded with the silver current lead 15 in step 2 on the sample fixing frame 13 on the side wall inside the liquid box 12, clamp the voltage wire clamp 23 in the middle of the superconducting tape sample 5, and the distance between the two voltage wire clamps 23 is 30 mm;

[0051] Step 4: Pour the required liquid into the liquid storage tank 31 from the liquid inlet 33 above the liquid storage tank 31; adjust the cylinder 42 below the liquid storage tank 31 to change the height of the liquid storage tank 31, open the valve block in the liquid tank 12, and use the communicating vessel principle to change the rise of the liquid level in the liquid tank 12, so that the superconducting tape sample 5 is completely immersed in the liquid environment and soaked for 5 minutes;

[0052] Step 5: Use the four-lead method and short sample current test system to detect the critical current Ic of superconducting tape sample 5 in liquid nitrogen environment S ;

[0053] Step 6: Regulate the cylinder 42 to make all the liquid in the liquid box 12 flow back to the liquid storage tank 31, close the valve block on the wall of the liquid box 12, and let the superconducting tape sample 5 leave the liquid surface and naturally return to room temperature;

[0054] Step 7: Repeat step 4 to place the superconducting tape sample 5 in liquid nitrogen so that the superconducting tape sample 5 is completely immersed and soaked for 5 minutes; repeat step 6 to take the superconducting tape sample 5 out of the liquid nitrogen and naturally restore it to room temperature to form a temperature shock; repeat the liquid nitrogen temperature shock process n times, n is a positive integer, in this example n=10;

[0055] Step 8: Repeat step 5, and perform critical current detection on the superconducting tape sample 5 after the liquid nitrogen temperature shock in step 7, and record the critical current;

[0056] Step 9: Repeat steps 7 to 8 for m times, where m is a positive integer. In this example, m=10. Repeat 10 times to obtain 10 critical currents Ic. i Where i≤10 is a positive integer, the critical current Ic i Respectively: Repeat once to get Ic 1 Repeat twice to get Ic2 Repeat 3 times to get Ic 3 , repeat 4 times to get Ic 4 Repeat 5 times to get Ic 5 Repeat 6 times to get Ic 6 Repeat 7 times to get Ic 7 , repeat 8 times to get Ic 8 , repeat 9 times to get Ic 9 and repeat 10 times to get Ic 10 ;

[0057] Step 10: Open the valve block to adjust the cylinder 42 so that all the liquid in the liquid box 12 flows back to the liquid storage tank 31, close the valve block, and inject water at room temperature into the liquid box 12; put the superconducting tape sample 5 after the liquid nitrogen temperature shock into the liquid box 12 injected with room temperature water and soak it for 24 hours, observe whether there are bubbles around the superconducting tape sample 5, and record it;

[0058] Step 11: After soaking, remove the connection joint between the guide tube 32 and the second liquid tank 12, open the valve block to release the water in the second liquid tank 12; take out the superconducting tape sample 5 from the room temperature water, wipe the water stains on its surface, and immediately reconnect the guide tube 32 to the wall of the liquid tank 12, repeat steps 4 and 5 to detect the critical current Ic of the superconducting tape sample 5 E ;

[0059] Step 12: According to the critical current Ic S and Ic E Calculate the current retention rate δ = (Ic E / Ic S )*100%, draw the critical current retention rate attenuation curve, the horizontal axis is the impact number (n * i), the vertical axis is the current retention rate δ= (Ic i / Ic S )*100%, the last point δ=(Ic E / Ic S )*100%;

[0060] Step 13: The experiment terminates when the following conditions occur:

[0061] 1. The experiment is completed;

[0062] Second, the tape loses its superconducting properties irreversibly;

[0063] 3. The current retention rate is lower than the current retention coefficient K value.

[0064] like Figure 5As shown, curves ad are the relationship curves between the critical current retention rate and the number of shocks of several typical superconducting tapes. Curve a indicates that the critical current of the superconducting tape measured after the liquid nitrogen temperature shock is almost not attenuated, indicating that the sample has good temperature shock resistance and no coating defects; curve b indicates that the critical current of the superconducting tape measured after the liquid nitrogen temperature shock has obvious attenuation, indicating that the sample has poor temperature shock resistance and no coating defects; curve c indicates that after the tested superconducting tape was immersed in room temperature water for 24 hours, the tape lost its superconducting performance when the critical current was measured, indicating that the coating of the sample had defects; the abnormal curve d indicates that the superconducting tape burned when the critical current was measured before the superconducting tape was immersed in room temperature water; when the critical current retention rate When the current retention coefficient K is greater than the current retention coefficient K, the sample is considered to have poor thermal shock resistance. In this embodiment, the current retention coefficient K is 95%, and the current retention coefficient K of different strips is different. In the embodiment, the welding part between the current lead and the strip should be long enough (usually not less than 3 times the strip width) to avoid excessive contact resistance causing the strip to burn.

[0065] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A temperature shock detection method for high temperature superconducting tape, Features: The specific detection steps include: Step 1: Cut a number of superconducting tape samples from the same superconducting tape, keep the length of each section consistent, and ensure that the length of each superconducting tape sample is sufficient for testing; Step 2: Use flux to weld current leads at both ends of the superconducting tape sample to reduce the contact resistance between the electrode and the superconducting tape sample; Step 3: clamping a voltage electrode and a current electrode on the superconducting tape sample welded with a current lead respectively; Step 4: placing the superconducting tape sample into liquid nitrogen so that the superconducting tape sample is completely immersed and soaked; Step 5: Use the four-lead method to detect the critical current Ic of the superconducting tape sample in liquid nitrogen environment S ; Step 6: Take the superconducting tape sample out of liquid nitrogen and allow it to naturally return to room temperature; Step 7: Repeat step 4 to place the superconducting tape sample into liquid nitrogen so that the superconducting tape sample is completely immersed and soaked; repeat step 6 to take the superconducting tape sample out of the liquid nitrogen and naturally restore it to room temperature; form a temperature shock; repeat the liquid nitrogen temperature shock process n times; Step 8: Repeat step 5 to detect the critical current of the superconducting tape sample after the liquid nitrogen temperature shock in step 7 and record it; Step 9: Repeat steps 7 to 8 for m times, and get a critical current Ic each time. i , where i≤m; Step 10: Soak the superconducting tape sample after liquid nitrogen temperature shock in water at room temperature, observe and record whether bubbles emerge around the superconducting tape sample; Step 11: After soaking, take out the superconducting tape sample from the room temperature water, wipe off the water stains on its surface, and immediately repeat steps 4 and 5 to detect the critical current Ic of the superconducting tape sample. E ; Step 12: According to the critical current Ic S and Ic E Calculate the current retention coefficient δ, the formula is: δ = (Ic E / Ic S )*100%.

2. A temperature shock detection method for high temperature superconducting tape according to claim 1, Features: include: The temperature shock detection device of high temperature superconducting tape is used for detection; The temperature shock detection device for high-temperature superconducting tape comprises a sample fixing mechanism, a critical current detection mechanism, a liquid storage mechanism and a driving mechanism; the sample fixing mechanism comprises an operating table, a liquid box and a sample fixing rack; the liquid box is arranged on the operating table; the upper end of the liquid box is open; at least one sample fixing rack is arranged on the side wall inside the liquid box; the critical current detection mechanism comprises a current line and a voltage line; the two ends of the sample fixing rack are respectively connected to the current line; the superconducting tape sample tape is pressurized and flowed through by the voltage line and the current line; the liquid storage mechanism is connected to the liquid box; and the driving mechanism drives the liquid storage mechanism to move up and down.

3. A temperature shock detection method for high temperature superconducting tape according to claim 2, Features: The liquid storage mechanism comprises a liquid storage tank, a flow guide pipe and a liquid inlet; the flow guide pipe connects the liquid storage tank and the liquid box; and the liquid inlet is arranged on the upper part of the liquid storage tank.

4. A temperature shock detection method for high temperature superconducting tape according to claim 2, Features: The driving mechanism comprises a cylinder rod, a cylinder and a cylinder platform; the liquid storage mechanism is arranged on the cylinder platform; the cylinder drives the cylinder rod to drive the cylinder platform to move up and down to adjust the height of the liquid storage mechanism.

5. A temperature shock detection method for high temperature superconducting tape according to claim 2, Features: The liquid box is provided with a valve to control the liquid to flow in and out of the liquid box.

6. A temperature shock detection method for high temperature superconducting tape according to claim 5, Features: The valve is a valve movable block; the valve movable block moves in the vertical direction to block the liquid flow port of the liquid tank.

7. A temperature shock detection method for high temperature superconducting tape according to claim 2, Features: A voltage wire clamp is provided at the end of the voltage wire.

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