Multi-channel NbTi superconducting coaxial cable and preparation method thereof

Abstract

The invention belongs to the technical field of superconducting wires, and discloses a multichannel NbTi superconducting coaxial cable and a preparation method thereof. The method comprises the following steps: introducing an Hf element into NbTi alloy powder to prepare an NbTi wire doped with the Hf element, respectively preparing an NbTi flat rectangular shell and a hole-containing insulating block, assembling the NbTi flat rectangular shell and the hole-containing insulating block, and inserting the NbTi wire into the hole of the insulating block to prepare the multi-channel NbTi superconducting coaxial cable. Through verification, the multi-channel NbTi superconducting coaxial cable can transmit a plurality of high-strength quantum bit signals at the same time, and is excellent in performance.

Description

Technical Field

[0001] The invention belongs to the technical field of superconducting wires 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. They mainly play the role of quantum signal transmission, modulation and output from quantum chips in the mK temperature zone to the measurement and control system in the K temperature zone in superconducting quantum computers. Superconducting coaxial cables mainly transmit low-frequency signals. However, with the development of quantum superconducting computers, the number of superconducting quantum bits is increasing, and the signal strength is also increasing accordingly. Conventional coaxial cables may not be able to transmit high-intensity signals, resulting in unstable transmission signals and reducing the calculation accuracy of quantum computers. In addition, the dilution refrigerators used in superconducting quantum computers are developing towards miniaturization and the transmission of more quantum bits. This also requires that the cables used for quantum signal transmission should have the ability to withstand the transmission of a higher number of quantum bits.

[0003] In the prior art, the patent publication number CN117936185A provides a method for preparing a superconducting cable for a multi-channel clustered quantum computer. The technical solution prepares a multi-channel clustered superconducting cable, which can improve the transmission of multi-channel quantum bit signals in a quantum computer. However, the technology still uses pure Nb or NbTi alloy as the inner and outer layer superconductors, and the quantum signal current intensity is still relatively low, and does not consider the use conditions of the multi-channel quantum bit measurement problem of a quantum computer under high signal intensity.

[0004] In view of this, it has become an urgent problem to prepare a superconducting coaxial cable that can meet the multi-channel quantum bit measurement requirements of quantum computers 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 method for preparing a multi-channel NbTi superconducting coaxial cable, comprising: S1. Mixing NbTi alloy powder and Hf metal powder to obtain a mixed metal powder; filling the mixed metal powder into a mold, pressing and molding to obtain a compact and sintering to obtain a NbTi rod doped with the Hf element, and then stretching the NbTi rod into a NbTi wire; S2. Using 3D printing to prepare the insulating material into a flat rectangular insulating block, with a number of holes evenly distributed in the center of the insulating block; S3. Take another mixed metal powder of S1, fill it into a mold for preparing a flat rectangular shell, press it and sinter it to obtain a NbTi flat rectangular shell doped with Hf element; S4. The insulating block prepared in S2 is loaded into the NbTi flat rectangular shell prepared in S3, and the NbTi wire prepared in S1 is inserted into the holes of the insulating block. After the assembly is completed, a composite material is obtained, which is rolled to obtain a multi-channel NbTi superconducting coaxial cable.

[0006] Furthermore, in S1 of the above preparation method, the mass fraction of Ti element in NbTi alloy powder is 45-48%; the purity of Hf metal powder is 99.99%. The mass fraction of Hf element in the mixed metal powder is 2-5%, which mainly plays the role of introducing artificial pinning centers in NbTi alloy, improving the current carrying strength of the cable and enhancing the stability of low-frequency signal transmission.

[0007] Furthermore, in S1 of the above preparation method, the particle size of the NbTi alloy powder is 70~100μm, and the particle size of the Hf metal powder is 50~70nm, 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 can improve the density of the mold pressing.

[0008] Furthermore, in S1 of the above preparation method, the material of the mold used is graphite. Pressing conditions: pressure is 250-500 MPa, and pressing time is 60-100 s. Sintering conditions: carried out in a vacuum furnace, and the vacuum degree is less than 2×10 -4 Mpa, sintering temperature is 1300~1500℃, and holding time is 2~4h.

[0009] Furthermore, in S1 of the above preparation method, when the NbTi rod is stretched into the NbTi wire, a saponified emulsion with a concentration of not less than 95% is used for lubrication, and the NbTi rod needs to be continuously immersed in the saponified emulsion. The diameter of the NbTi rod is 2.000±0.010mm, and the diameter of the NbTi wire is 0.200~0.500mm.

[0010] Furthermore, 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.

[0011] Furthermore, in S3 of the above preparation method, the pressing and sintering conditions are the same as S1.

[0012] 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 inner space of the shell are respectively 0.005 mm larger than the width and height of the insulating block for ease of assembly.

[0013] Furthermore, in S4 of the above preparation method, a universal four-way rolling mill is used for rolling, and rolling can be performed in the width and height directions at the same time. The rolling speed is 5~15m / min, and the processing rate is 2~3%. The purpose of rolling is to remove the gaps between the components during the assembly process to ensure the density of the cable.

[0014] The present invention also seeks to protect the multi-channel NbTi superconducting coaxial cable obtained by the above preparation method.

[0015] Compared with the prior art, the present invention "a multi-channel NbTi superconducting coaxial cable and a preparation method thereof" has at least the following beneficial effects: The present invention provides a method for preparing a multi-channel NbTi superconducting coaxial cable, wherein Hf element is introduced into NbTi alloy powder to prepare NbTi wire doped with Hf element, and then a NbTi flat rectangular shell and an insulating block containing holes are separately prepared, the two are assembled, and the NbTi wire is inserted into the holes of the insulating block 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 quantum bit signals with excellent performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The present invention is a flow chart of the preparation method of the multi-channel NbTi superconducting coaxial cable.

[0017] Figure 2 The schematic diagram of the insulating block structure of the present invention is shown in FIG. 1- insulating block, 2- central hole of the insulating block.

[0018] Figure 3 This is a schematic diagram of the NbTi flat rectangular shell structure of the present invention.

[0019] Figure 4 This is a schematic diagram of the structure of the multi-channel NbTi superconducting coaxial cable prepared by the present invention. DETAILED DESCRIPTION

[0020] The technical solution of the present invention is clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] The embodiment of the present invention provides a method for preparing a multi-channel NbTi superconducting coaxial cable (see the flow chart of the preparation method). Figure 1 ),include: S1. Mix NbTi alloy powder and Hf metal powder to obtain mixed metal powder; fill the mixed metal powder into a mold, press-form to obtain a compact and sinter to obtain a NbTi rod doped with the Hf element, and then stretch the NbTi rod into a NbTi wire.

[0022] S2. Use 3D printing to prepare the insulating material into a flat rectangular insulating block, with a number of holes evenly distributed in the center of the insulating block; see the schematic diagram of the insulating block Figure 2 .

[0023] S3. Take another mixed metal powder of S1, fill it into a 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; Schematic diagram of NbTi flat rectangular shell is shown in Figure 3 .

[0024] S4. The insulating block prepared in S2 is loaded into the NbTi flat rectangular shell prepared in S3, and the NbTi wire prepared in S1 is inserted into the hole of the insulating block. After the assembly is completed, a composite material is obtained, which is rolled to obtain a multi-channel NbTi superconducting coaxial cable (see Figure 4 ).

[0025] For example, 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%; and the mass fraction of Hf element in the mixed metal powder is 2-5%.

[0026] For example, 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.

[0027] For example, in S1 of the above preparation method, the material of the mold used is graphite. Pressing conditions: pressure is 250-500 MPa, and pressing time is 60-100 s. Sintering conditions: carried out in a vacuum furnace with a vacuum degree of less than 2×10 -4 Mpa, sintering temperature is 1300~1500℃, and holding time is 2~4h.

[0028] For example, in S1 of the above preparation method, when the NbTi rod is stretched into the NbTi wire, a saponified emulsion with a concentration of not less than 95% is used for lubrication, and the NbTi rod needs to be continuously immersed in the saponified emulsion. The diameter of the NbTi rod is 2.000±0.010mm, and the diameter of the NbTi wire is 0.200~0.500mm.

[0029] For example, 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.

[0030] Illustratively, in S3 of the above preparation method, the pressing and sintering conditions are the same as S1.

[0031] For example, 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 inner space of the shell are respectively 0.005 mm larger than the width and height of the insulating block for ease of assembly.

[0032] Illustratively, 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%.

[0033] Example 1 This embodiment provides a method for preparing a multi-channel NbTi superconducting coaxial cable.

[0034] S1. Mix NbTi alloy powder with a Ti mass fraction of 46.5% and a particle size of 80 μm with Hf metal powder with a purity of 99.99% and a particle size of 55 nm to obtain a mixed metal powder, wherein the Hf mass fraction in the mixed metal powder is 2%. The mixed metal powder is loaded into a graphite mold, pressed to obtain a compact and sintered. The pressing conditions are: pressure of 400 MPa, pressing time of 70 s; sintering conditions: in a vacuum furnace, the vacuum degree is less than 2×10 -4 Mpa, sintering temperature of 1350℃, holding time of 2.5h, obtain NbTi rod doped with Hf element with a diameter of 2.000mm. NbTi rod is stretched into NbTi wire, and saponified emulsion is used for lubrication during stretching, and the concentration of saponified emulsion is 95%, and the diameter of the obtained NbTi wire is 0.300mm.

[0035] S2. Using 3D printing, polytetrafluoroethylene powder (powder particle size 60 μm) is prepared into a flat rectangular insulating block. 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.

[0036] S3. Take another mixed metal powder of S1, fill it into a 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 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.

[0037] S4. The insulating block prepared in S2 is loaded into the NbTi flat rectangular shell prepared in S3, and the NbTi wire prepared in S1 is inserted into the holes of the insulating block. After the assembly is completed, a composite material is obtained. 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.

[0038] Example 2 This embodiment provides a method for preparing a multi-channel NbTi superconducting coaxial cable.

[0039] S1. Mix NbTi alloy powder with a Ti mass fraction of 46.0% and a particle size of 90 μm with Hf metal powder with a purity of 99.99% and a particle size of 60 nm to obtain a mixed metal powder, wherein the Hf mass fraction in the mixed metal powder is 3%. The mixed metal powder is loaded into a graphite mold, pressed to obtain a compact and sintered. The pressing conditions are: pressure of 450 MPa, pressing time of 80 s; sintering conditions: carried out in a vacuum furnace, the vacuum degree is less than 2×10 -4 Mpa, sintering temperature is 1400℃, holding time is 3.0h, and a NbTi rod doped with Hf element with a diameter of 2.000mm is obtained. The NbTi rod is stretched into NbTi wire, and saponified emulsion is used for lubrication during stretching. The concentration of saponified emulsion is 95%, and the diameter of the obtained NbTi wire is 0.400mm.

[0040] S2. Using 3D printing, polytetrafluoroethylene powder (powder particle size 55 μm) was prepared into a flat rectangular insulating block. The insulating block was 8.000 mm wide and 2.600 mm high, and 8 holes with a diameter of 0.405 mm were evenly distributed in the center of the insulating block.

[0041] S3. Take another mixed metal powder of S1, fill it into a 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 S1, the outer wall thickness of the NbTi flat rectangular shell is 1.4 mm, the internal space of the shell is 8.005 mm wide and 2.605 mm high.

[0042] S4. The insulating block prepared in S2 is loaded into the NbTi flat rectangular shell prepared in S3, and the NbTi wire prepared in S1 is inserted into the holes of the insulating block. After the assembly is completed, a composite material is obtained. 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.

[0043] Example 3 This embodiment provides a method for preparing a multi-channel NbTi superconducting coaxial cable.

[0044] S1. Mix NbTi alloy powder with a Ti mass fraction of 47.0% and a particle size of 85 μm with Hf metal powder with a purity of 99.99% and a particle size of 55 nm to obtain a mixed metal powder, wherein the Hf mass fraction in the mixed metal powder is 4%. The mixed metal powder is loaded into a graphite mold, pressed to obtain a compact and sintered. The pressing conditions are: pressure of 470 MPa, pressing time of 85 s; sintering conditions: in a vacuum furnace, the vacuum degree is less than 2×10 -4 Mpa, sintering temperature of 1430℃, holding time of 3.0h, and a 2.000mm diameter NbTi rod doped with Hf element was obtained. The NbTi rod was stretched into NbTi wire, and saponified emulsion was used for lubrication during stretching. The concentration of saponified emulsion was 95%, and the diameter of the obtained NbTi wire was 0.500mm.

[0045] S2. Using 3D printing, polytetrafluoroethylene powder (powder particle size 60 μm) is prepared into a flat rectangular insulating block. 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.

[0046] S3. Take another mixed metal powder of S1, fill it into a 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 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.

[0047] S4. The insulating block prepared in S2 is loaded into the NbTi flat rectangular shell prepared in S3, and the NbTi wire prepared in S1 is inserted into the holes of the insulating block. After the assembly is completed, a composite material is obtained, and the composite material is rolled by a universal four-way rolling mill at a rolling speed of 12 m / min and a processing rate of 2.5% to obtain a multi-channel NbTi superconducting coaxial cable.

[0048] Example 4 This example describes the performance test of the multi-channel NbTi superconducting coaxial cables prepared in Examples 1 to 3.

[0049] Table 1 shows the performance test results of superconducting coaxial cables of Examples 1 to 3 and Comparative Examples. 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 inner and outer superconductors.

[0050] Table 1. Comparison of superconducting coaxial cable performance test results of Examples 1 to 3 and the comparative example

[0051] It can be found from Table 1 that the characteristic impedance and thermal conductivity of Examples 1 to 3 are basically equivalent to those of Comparative Example 1, indicating that the stability of signal transmission is basically equivalent, but Examples 1 to 3 have multiple channels and are much better than Comparative Example 1 in 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 strength when transmitting signals, and thus can be applied to quantum computers with higher signal strength to improve signal transmission quality.

[0052] In summary, the present invention provides a method for preparing a multi-channel NbTi superconducting coaxial cable, wherein the Hf element is introduced into the NbTi alloy powder to prepare a NbTi wire doped with the Hf element; then a NbTi flat rectangular shell and an insulating block containing holes are separately prepared, the two are assembled, and the NbTi wire is inserted into the holes of the insulating block 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 quantum bit signals with excellent performance.

[0053] The embodiments described above are only some embodiments of the present invention, not all embodiments. The detailed description of the embodiments of the present invention is not intended to limit the scope of the invention claimed for protection, but only represents selected embodiments of the present invention. All other embodiments obtained without creative work and related deductions and substitutions made by ordinary technicians in the field under the conditions of the concept of the present invention belong to the scope of protection of the present invention.

Claims

1. A method for preparing a multi-channel NbTi superconducting coaxial cable, characterized in that: include: S1. Mixing NbTi alloy powder and Hf metal powder to obtain a mixed metal powder; filling the mixed metal powder into a mold, pressing and molding to obtain a compact and sintering to obtain a NbTi rod doped with the Hf element, and then stretching the NbTi rod into a NbTi wire; S2. Using 3D printing to prepare the insulating material into a flat rectangular insulating block, with a number of holes evenly distributed in the center of the insulating block; S3. Take another mixed metal powder of S1, fill it into a mold for preparing a flat rectangular shell, press it and sinter it to obtain a NbTi flat rectangular shell doped with Hf element; S4. The insulating block prepared in S2 is loaded into the NbTi flat rectangular shell prepared in S3, and the NbTi wire prepared in S1 is inserted into the holes of the insulating block. After the assembly is completed, a composite material is obtained, which is rolled to obtain a multi-channel NbTi superconducting coaxial cable.

2. The preparation method according to claim 1, characterized in that: In S1, the mass fraction of Ti element in NbTi alloy powder is 45~48%; the purity of Hf metal powder is 99.99%; and the mass fraction of Hf element in 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: pressure is 250~500Mpa, pressing time is 60~100s; Sintering conditions: carried out in a vacuum furnace with a vacuum degree of less than 2×10 -4 Mpa, sintering temperature is 1300~1500℃, and holding time is 2~4h.

5. The preparation method according to claim 1, characterized in that: In S1, when the NbTi rod is stretched into the NbTi wire, a saponified emulsion with a concentration of not less than 95% is used 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 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, and the number of holes is 6-8.

7. The preparation method according to claim 1, characterized in that: In S3, the pressing and sintering conditions are the same as 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 inner space of the shell are respectively 0.005 mm larger than the width and height of the insulating block.

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

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

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