A multi-channel NbTi superconducting coaxial cable and its preparation method

Abstract

The present invention belongs to the technical field of superconducting wire materials, and discloses a multi-channel NbTi superconducting coaxial cable and a preparation method thereof. The present invention introduces Hf element into NbTi alloy powder to prepare NbTi wires doped with Hf element, then separately prepares a NbTi flat rectangular shell and an insulating block body with holes, assembles the two, and inserts the NbTi wires into the holes of the insulating block body to prepare a multi-channel NbTi superconducting coaxial cable. It has been verified that the multi-channel NbTi superconducting coaxial cable can simultaneously transmit multiple high-strength qubit signals and has excellent performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of superconducting wire materials, and relates to a multi-channel NbTi superconducting coaxial cable and a preparation method thereof. Background Art

[0002] Superconducting coaxial cables have the characteristics of low thermal conductivity and signal attenuation, and mainly play the role of quantum signal transmission, modulation, and output between quantum chips in the mK temperature range and the measurement and control system in the K temperature range in superconducting quantum computers. Superconducting coaxial cables mainly transmit low-frequency signals. However, with the development of superconducting quantum computers, the number of superconducting qubits is increasing day by day, and the signal intensity is also correspondingly enhanced. For conventional coaxial cables, it may not be possible to transmit high-intensity signals, resulting in unstable transmitted signals and reducing the computing accuracy of quantum computers. In addition, the dilution refrigerators used in superconducting quantum computers are developing towards the trend of miniaturization in volume and transmitting more qubits, which also requires that the cables used for quantum signal transmission should have the ability to withstand the transmission of a higher number of qubits.

[0003] In the prior art, the patent with the publication number CN117936185A gives a preparation method of a multi-channel bundled superconducting cable for a quantum computer. Its technical solution prepares a multi-channel bundled superconducting cable, which can improve the transmission of multi-channel qubit signals in a quantum computer. However, in this technology, pure Nb or NbTi alloy is still used as the inner and outer layer superconductors, and the quantum signal carrier strength is still relatively low. The use conditions for the measurement of multi-channel qubits in a quantum computer under high signal intensity are not considered.

[0004] In view of this, it has become an urgent problem to prepare a superconducting coaxial cable that can meet the measurement requirements of multi-channel qubits in a quantum computer under high signal intensity conditions. Summary of the Invention

[0005] In order to overcome the defects of the prior art, the present invention provides a preparation method of a multi-channel NbTi superconducting coaxial cable, including:

[0006] S1. Mix NbTi alloy powder and Hf metal powder to obtain mixed metal powder; load the mixed metal powder into a mold, press and mold to obtain a green compact and sinter it to obtain a NbTi rod doped with Hf element, and then stretch the NbTi rod into NbTi wire;

[0007] S2. Use 3D printing to prepare an insulating material into a flat rectangular insulating block, and a number of holes are evenly distributed in the center of the insulating block;

[0008] S3. Take another portion of the mixed metal powder of S1, load it into a mold for preparing a flat rectangular shell, press and mold and sinter it to obtain a NbTi flat rectangular shell doped with Hf element;

[0009] S4. Load the insulating block prepared in S2 into the NbTi flat rectangular shell prepared in S3, insert the NbTi wire prepared in S1 into the holes of the insulating block. After assembly, a composite material is obtained, and it is rolled to obtain a multi-channel NbTi superconducting coaxial cable.

[0010] Furthermore, in S1 of the above preparation method, the mass fraction of Ti element in the NbTi alloy powder is 45-48%; the purity of the Hf metal powder is 99.99%. The mass fraction of Hf element in the mixed metal powder is 2-5%, which mainly plays a role in introducing artificial pinning centers in the NbTi alloy, improving the current-carrying strength of the cable, and enhancing the stability of low-frequency signal transmission.

[0011] Furthermore, in S1 of the above preparation method, the particle size of the NbTi alloy powder is 70-100 μm, and the particle size of the Hf metal powder is 50-70 nm, so as to ensure that the Hf metal particles can be evenly distributed at the interface of the NbTi alloy particles during mixing, and at the same time, the compactness of die filling and pressing can be improved.

[0012] Furthermore, in S1 of the above preparation method, the material of the used die is graphite. Pressing conditions: the pressure is 250-500 Mpa, and the pressing time is 60-100 s. Sintering conditions: carried out in a vacuum furnace, the vacuum degree is less than 2×10 -4 Mpa, the sintering temperature is 1300-1500 °C, and the holding time is 2-4 h.

[0013] Furthermore, in S1 of the above preparation method, when stretching the NbTi rod into NbTi wire, it is lubricated with a saponified emulsion with a concentration not less than 95%, and the NbTi rod needs to be continuously immersed in the saponified emulsion. The diameter of the NbTi rod is 2.000±0.010 mm, and the diameter of the NbTi wire is 0.200-0.500 mm.

[0014] Furthermore, in S2 of the above preparation method, the insulating material used is polytetrafluoroethylene powder. The width of the insulating block is 6-8 mm, the height is 2-3 mm, the diameter of the holes in the insulating block is 0.005 mm larger than the diameter of the NbTi wire prepared in S1 for assembly, and the number of holes is 6-8.

[0015] Furthermore, in S3 of the above preparation method, the pressing and sintering conditions are the same as those in S1.

[0016] Furthermore, in S3 of the above preparation method, the thickness of the NbTi flat rectangular shell is 1-1.5 mm, and the width and height of the internal space of the shell are 0.005 mm larger than the width and height of the insulating block for assembly.

[0017] Further, in S4 of the above preparation method, a universal four-way rolling mill is used for rolling, which can perform rolling in both the width and height directions simultaneously. The rolling speed is 5 - 15 m / min, and the processing rate is 2 - 3%. The function of rolling is to remove the gaps between components during the assembly process and ensure the density of the cable.

[0018] The present invention also claims the multi-channel NbTi superconducting coaxial cable obtained by the above preparation method.

[0019] Compared with the prior art, the "multi-channel NbTi superconducting coaxial cable and its preparation method" of the present invention has at least the following beneficial effects:

[0020] The present invention provides a preparation method of a multi-channel NbTi superconducting coaxial cable. Hf element is introduced into NbTi alloy powder to prepare NbTi wire doped with Hf element. Then, an NbTi flat rectangular shell and an insulating block body with holes are respectively prepared. The two are assembled, and the NbTi wire is inserted into the holes of the insulating block body to obtain a multi-channel NbTi superconducting coaxial cable. It has been verified that the multi-channel NbTi superconducting coaxial cable can simultaneously transmit multiple high-strength qubit signals with excellent performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a flowchart of the preparation method of the multi-channel NbTi superconducting coaxial cable.

[0022] Figure 2 is a schematic structural diagram of the insulating block body of the present invention. 1 - insulating block body, 2 - central hole of the insulating block body.

[0023] Figure 3 is a schematic structural diagram of the NbTi flat rectangular shell of the present invention.

[0024] Figure 4 is a schematic structural diagram of the multi-channel NbTi superconducting coaxial cable prepared by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0026] The embodiment of the present invention provides a preparation method of a multi-channel NbTi superconducting coaxial cable (see the flowchart of the preparation method in Figure 1 ), including:

[0027] S1. Mix NbTi alloy powder and Hf metal powder to obtain mixed metal powder; load the mixed metal powder into a mold, press it into a compact and sinter it to obtain an NbTi rod doped with Hf element, and then stretch the NbTi rod into NbTi wire.

[0028] S2. Use 3D printing to prepare an insulating block in the shape of a flat rectangle with several holes evenly distributed in the center; see the schematic diagram of the insulating block in Figure 2 .

[0029] S3. Take another portion of the mixed metal powder from S1, load it into a mold for preparing a flat rectangular shell, press it into shape and sinter it to obtain an NbTi flat rectangular shell doped with Hf element; see the schematic diagram of the NbTi flat rectangular shell in Figure 3 .

[0030] S4. Load the insulating block prepared in S2 into the NbTi flat rectangular shell prepared in S3, and insert the NbTi wire prepared in S1 into the holes of the insulating block. After assembly, a composite material is obtained and rolled to obtain a multi-channel NbTi superconducting coaxial cable (see Figure 4 ).

[0031] Exemplarily, in S1 of the above preparation method, the mass fraction of Ti element in the NbTi alloy powder is 45 - 48%; the purity of the Hf metal powder is 99.99%; the mass fraction of Hf element in the mixed metal powder is 2 - 5%.

[0032] Exemplarily, in S1 of the above preparation method, the particle size of the NbTi alloy powder is 70 - 100 μm, and the particle size of the Hf metal powder is 50 - 70 nm.

[0033] Exemplarily, in S1 of the above preparation method, the material of the mold used is graphite. Pressing conditions: the pressure is 250 - 500 Mpa, and the pressing time is 60 - 100 s. Sintering conditions: carried out in a vacuum furnace, the vacuum degree is less than 2×10 -4 Mpa, the sintering temperature is 1300 - 1500 °C, and the heat preservation time is 2 - 4 h.

[0034] Exemplarily, in S1 of the above preparation method, when stretching the NbTi rod into NbTi wire, use a saponified emulsion with a concentration of not less than 95% for lubrication, and the NbTi rod needs to be continuously immersed in the saponified emulsion. The diameter of the NbTi rod is 2.000 ± 0.010 mm, and the diameter of the NbTi wire is 0.200 - 0.500 mm.

[0035] Exemplarily, in S2 of the above preparation method, the insulating material used is polytetrafluoroethylene powder. The insulating block is 6 - 8 mm wide and 2 - 3 mm high. The diameter of the holes in the insulating block is 0.005 mm larger than the diameter of the NbTi wire prepared in S1 for assembly, and the number of holes is 6 - 8.

[0036] Exemplarily, in S3 of the above preparation method, the pressing and sintering conditions are the same as those in S1.

[0037] Exemplarily, in S3 of the above preparation method, the thickness of the NbTi flat rectangular shell is 1 - 1.5 mm, and the width and height of the internal space of the shell are 0.005 mm larger than the width and height of the insulating block respectively for assembly.

[0038] Exemplarily, in S4 of the above preparation method, a universal four - way rolling mill is used for rolling, the rolling speed is 5 - 15 m / min, and the processing rate is 2 - 3%.

[0039] Example 1

[0040] This example provides a preparation method for a multi - channel NbTi superconducting coaxial cable.

[0041] S1. Mix NbTi alloy powder with a Ti element mass fraction of 46.5% and a particle size of 80 μm and Hf metal powder with a purity of 99.99% and a particle size of 55 nm to obtain a mixed metal powder, where the mass fraction of the Hf element in the mixed metal powder is 2%. Fill the mixed metal powder into a graphite mold, press it into a green compact and sinter it. The pressing conditions are: the pressure is 400 Mpa and the pressing time is 70 s; the sintering conditions are: carried out in a vacuum furnace, the vacuum degree is less than 2×10 -4 Mpa, the sintering temperature is 1350 °C, and the holding time is 2.5 h to obtain a NbTi rod doped with Hf element with a diameter of 2.000 mm. Stretch the NbTi rod into NbTi wire, and use saponified emulsion for lubrication during stretching. The concentration of the saponified emulsion is 95%, and the obtained NbTi wire has a diameter of 0.300 mm.

[0042] S2. Use 3D printing to prepare a flat rectangular insulating block from polytetrafluoroethylene powder (powder particle size 60 μm). The insulating block is 6.000 mm wide and 2.200 mm high, and 6 holes with a diameter of 0.305 mm are evenly distributed in the center of the insulating block.

[0043] S3. Take another portion of the mixed metal powder from S1, fill it into the mold for preparing the flat rectangular shell, press it into shape and sinter it to obtain a NbTi flat rectangular shell doped with Hf element. The pressing and sintering conditions are the same as those in S1. The outer wall thickness of the NbTi flat rectangular shell is 1.2 mm, and the internal space of the shell is 6.005 mm wide and 2.205 mm high.

[0044] S4. Load the insulating block prepared in S2 into the NbTi flat rectangular shell prepared in S3, and insert the NbTi wire prepared in S1 into the holes of the insulating block. After assembly, a composite material is obtained, and the composite material is rolled by a universal four-way rolling mill at a rolling speed of 10 m / min and a processing rate of 2% to obtain a multi-channel NbTi superconducting coaxial cable.

[0045] Example 2

[0046] This example provides a method for preparing a multi-channel NbTi superconducting coaxial cable.

[0047] S1. Mix NbTi alloy powder with a Ti element mass fraction of 46.0% and a particle size of 90 μm and Hf metal powder with a purity of 99.99% and a particle size of 60 nm to obtain mixed metal powder, and the mass fraction of Hf element in the mixed metal powder is 3%. Load the mixed metal powder into a graphite mold, press it into a compact and sinter it. Pressing conditions: pressure is 450 Mpa, pressing time is 80 s; sintering conditions: carried out in a vacuum furnace, the vacuum degree is less than 2×10 -4 Mpa, the sintering temperature is 1400 °C, and the holding time is 3.0 h to obtain a NbTi rod doped with Hf element with a diameter of 2.000 mm. Stretch the NbTi rod into NbTi wire, and use saponified emulsion for lubrication during stretching. The concentration of the saponified emulsion is 95%, and the obtained NbTi wire has a diameter of 0.400 mm.

[0048] S2. Use 3D printing to prepare a flat rectangular insulating block from polytetrafluoroethylene powder (powder particle size 55 μm). The insulating block is 8.000 mm wide and 2.600 mm high, and 8 holes with a diameter of 0.405 mm are evenly distributed in the center of the insulating block.

[0049] S3. Take another portion of the mixed metal powder in S1, load it into the mold for preparing a flat rectangular shell, press it into shape and sinter it to obtain a NbTi flat rectangular shell doped with Hf element. The pressing and sintering conditions are the same as those in S1. The outer wall thickness of the NbTi flat rectangular shell is 1.4 mm, and the internal space of the shell is 8.005 mm wide and 2.605 mm high.

[0050] S4. Load the insulating block prepared in S2 into the NbTi flat rectangular shell prepared in S3, and insert the NbTi wire prepared in S1 into the holes of the insulating block. After assembly, a composite material is obtained, and the composite material is rolled by a universal four-way rolling mill at a rolling speed of 10 m / min and a processing rate of 2.2% to obtain a multi-channel NbTi superconducting coaxial cable.

[0051] Example 3

[0052] This embodiment provides a method for preparing a multi-channel NbTi superconducting coaxial cable.

[0053] S1. Mix NbTi alloy powder with a Ti element mass fraction of 47.0% and a particle size of 85 μm and Hf metal powder with a purity of 99.99% and a particle size of 55 nm to obtain mixed metal powder, where the mass fraction of Hf element in the mixed metal powder is 4%. Fill the mixed metal powder into a graphite mold, press and form to obtain a green compact and perform sintering. Pressing conditions: pressure is 470 Mpa, pressing time is 85 s; sintering conditions: carried out in a vacuum furnace, the vacuum degree is less than 2×10 -4 Mpa, the sintering temperature is 1430 °C, and the holding time is 3.0 h to obtain a NbTi rod doped with Hf element with a diameter of 2.000 mm. Stretch the NbTi rod into NbTi wire, using saponified emulsion for lubrication during stretching, the concentration of saponified emulsion is 95%, and the obtained NbTi wire has a diameter of 0.500 mm.

[0054] S2. Use 3D printing to prepare a flat rectangular insulating block from polytetrafluoroethylene powder (powder particle size 60 μm). The insulating block is 8.000 mm wide and 3.000 mm high, and 8 holes with a diameter of 0.505 mm are evenly distributed in the center of the insulating block.

[0055] S3. Take another portion of the mixed metal powder from S1, fill it into a mold for preparing a flat rectangular shell, press and form and perform sintering to obtain a NbTi flat rectangular shell doped with Hf element. The pressing and sintering conditions are the same as those in S1. The outer wall thickness of the NbTi flat rectangular shell is 1.5 mm, and the internal space of the shell is 8.005 mm wide and 3.005 mm high.

[0056] S4. Fill the insulating block prepared in S2 into the NbTi flat rectangular shell prepared in S3, and insert the NbTi wire prepared in S1 into the holes of the insulating block. After assembly, a composite material is obtained, and the composite material is rolled using a universal four-way rolling mill, the rolling speed is 12 m / min, and the processing rate is 2.5% to obtain a multi-channel NbTi superconducting coaxial cable.

[0057] Example 4

[0058] This embodiment describes the performance test of the multi-channel NbTi superconducting coaxial cable prepared in Examples 1 - 3.

[0059] Table 1 shows the performance test results of the superconducting coaxial cables in Examples 1 - 3 and the comparative examples. Among them, Comparative Example 1 is the performance test of a single-channel superconducting NbTi coaxial cable, and Comparative Example 2 is a multi-channel NbTi coaxial cable using pure Nb or NbTi alloy as the inner and outer layer superconductors.

[0060] Table 1. Comparison of superconducting coaxial cable performance test results between Examples 1 to 3 and the comparative example

[0061]

[0062] It can be found from Table 1 that the characteristic impedance and thermal conductivity of Examples 1 to 3 and Comparative Example 1 are basically equivalent, indicating that the stability of signal transmission is basically equivalent. However, Examples 1 to 3 have multiple channels and are far superior to Comparative Example 1 in terms of signal transmission efficiency. The signal attenuation performance of Examples 1 to 3 is significantly lower than that of Comparative Examples 1 and 2, indicating that the coaxial cables of Examples 1 to 3 can carry higher signal intensities when transmitting signals, and thus can be applied to quantum computers with higher signal intensities to improve signal transmission quality.

[0063] In summary, the present invention provides a method for preparing a multi-channel NbTi superconducting coaxial cable. The Hf element is introduced into the NbTi alloy powder to prepare NbTi wires doped with the Hf element; then, an NbTi flat rectangular shell and an insulating block body with holes are respectively prepared, and the two are assembled, and the NbTi wires are inserted into the holes of the insulating block body to prepare a multi-channel NbTi superconducting coaxial cable. It has been verified that the multi-channel NbTi superconducting coaxial cable can simultaneously transmit multiple high-intensity qubit signals and has excellent performance.

[0064] The above-described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. The detailed description of the embodiments of the present invention is not intended to limit the scope of the present invention claimed, but merely represents selected embodiments of the present invention. All other embodiments obtained by relevant deductions and substitutions made by those of ordinary skill in the art under the premise of not making creative efforts based on the concept of the present invention belong to the scope of protection of the present invention.

Claims

1. A preparation method of a multi-channel NbTi superconducting coaxial cable, characterized in that, Including: S1. Mix NbTi alloy powder and Hf metal powder to obtain mixed metal powder; load the mixed metal powder into a mold, press it into a compact and sinter it to obtain an NbTi rod doped with Hf element, and then draw the NbTi rod into NbTi wire; S2. Use 3D printing to prepare an insulating material into a flat rectangular insulating block body, and a number of holes are evenly distributed in the center of the insulating block body; S3. Take another portion of the mixed metal powder in S1, load it into a mold for preparing a flat rectangular shell, press it into shape and sinter it to obtain an NbTi flat rectangular shell doped with Hf element; S4. Load the insulating block body prepared in S2 into the NbTi flat rectangular shell prepared in S3, and insert the NbTi wire prepared in S1 into the holes of the insulating block body. After assembly, a composite material is obtained, and it is rolled to obtain a multi-channel NbTi superconducting coaxial cable.

2. The preparation method according to claim 1, wherein In S1, the mass fraction of Ti element in the NbTi alloy powder is 45-48%; the purity of the Hf metal powder is 99.99%; the mass fraction of Hf element in the mixed metal powder is 2-5%.

3. The preparation method according to claim 1, characterized in that, In S1, the particle size of the NbTi alloy powder is 70-100μm, and the particle size of the Hf metal powder is 50-70nm.

4. The preparation method according to claim 1, characterized in that, The material of the mold used in S1 is graphite; Pressing conditions: the pressure is 250-500 Mpa, and the pressing time is 60-100 s; Sintering conditions: carried out in a vacuum furnace, with a vacuum degree less than 2×10 -4 Mpa, the sintering temperature is 1300~1500°C, and the holding time is 2~4h.

5. The preparation method according to claim 1, wherein In S1, when drawing the NbTi rod into NbTi wire, use a saponified emulsion with a concentration of not less than 95% for lubrication, and the NbTi rod needs to be continuously immersed in the saponified emulsion; The diameter of the NbTi rod is 2.000±0.010 mm, and the diameter of the NbTi wire is 0.200-0.500 mm.

6. The preparation method according to claim 1, characterized in that, The insulating material used in S2 is polytetrafluoroethylene powder; The width of the insulating block body is 6-8 mm, the height is 2-3 mm, the diameter of the holes in the insulating block body is 0.005 mm larger than the diameter of the NbTi wire prepared in S1, and the number of holes is 6-8.

7. The preparation method according to claim 1, wherein In S3, the pressing and sintering conditions are the same as those in S1.

8. The preparation method according to claim 1, characterized in that, In S3, the thickness of the NbTi flat rectangular shell is 1-1.5 mm, and the width and height of the internal space of the shell are 0.005 mm larger than the width and height of the insulating block body respectively.

9. The preparation method according to claim 1, characterized in that, In S4, use a universal four-way rolling mill for rolling, the rolling speed is 5-15 m / min, and the processing rate is 2-3%.

10. A multi-channel NbTi superconducting coaxial cable obtained by the preparation method described in claim 1.

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