MgB2 superconducting wire preparation method based on 3D printing

Abstract

The invention discloses a preparation method of an MgB2 superconducting wire based on 3D printing. The preparation method comprises the following steps: printing powder B into a tube B by adopting a 3D printing technology; the Mg rod is inserted into the B pipe and integrally stuffed into the metal sheath, and a round single-core rod is machined through the rotary swaging or rolling technology; at least one anaerobic Cu rod and a plurality of circular single-core rods are inserted into an NCu30 pipe, and a multi-core complex is obtained; processing the multi-core composite body into a multi-core composite wire by adopting a drawing, rotary swaging or rolling process; and carrying out heat treatment on the multi-core composite wire to obtain the MgB2 superconducting wire. The powder B is printed into the tube B through the 3D printing technology, and the efficiency and stability of preparing the single-core rod and the overall uniformity of the wire rod are improved; and the stacking compactness of the B powder is improved, a compact MgB2 superconducting phase can be conveniently generated, and the current-carrying capacity of the wire is improved.

Description

Technical Field

[0001] The present application relates to the technical field of superconducting wires, and in particular to a method for preparing MgB2 superconducting wires based on 3D printing. Background Art

[0002] MgB2 is a practical superconducting material with a high superconducting transition temperature T c =40K, larger critical current density J c and the upper critical magnetic field H c2 , small anisotropy, excellent grain connectivity, non-toxic and cheap raw materials, light weight and other advantages, and are often used in superconducting wires. At present, the preparation methods of MgB2 superconducting wires mainly include powder in tube method (PIT) and central magnesium diffusion method (IMD). Among them, the central magnesium diffusion method uses Mg rod and B powder as raw materials. First, the Mg rod is inserted into the center of the metal sheath, and B powder is filled between the Mg rod and the metal sheath to form a structure of Mg rod / B powder / metal sheath from the inside to the outside, and then processed into a composite wire by rotary forging, rolling, drawing and other methods. However, it is very troublesome to fill B powder around the Mg rod, especially the gap between the Mg rod and the metal sheath is small, and the B powder has strong viscosity, which poses a great difficulty to the assembly process. It is difficult to achieve uniform distribution of B powder around the Mg rod. This is a major problem that must be overcome for the central magnesium diffusion method to move from laboratory to industrial development.

[0003] In the prior art, Chinese patent CN118098701A discloses a multi-core MgB2 superconducting wire and a preparation method thereof, the preparation method comprising: processing a plurality of holes on an oxygen-free Cu ingot; coating a Mg foil on the surface of a Nb rod and loading it into a Nb tube, filling B powder in the gap between the Mg foil and the Nb tube to obtain a composite rod; loading the composite rod into the hole of the oxygen-free Cu ingot to obtain a rod-loaded composite ingot, loading the rod-loaded composite ingot into a monel alloy tube, and welding both ends to obtain a composite ingot; processing the composite ingot to obtain a multi-core composite wire, and obtaining a multi-core MgB2 superconducting wire after heat treatment of the multi-core composite wire.

[0004] However, the above-mentioned prior art has not improved the operation of filling B powder in the central magnesium diffusion method, and the efficiency, stability and overall uniformity of the wire in preparing a single core rod are low; at the same time, the filling B powder has the disadvantage of poor stacking density, making it difficult to generate a dense MgB2 superconducting phase, and the current carrying capacity of the wire is poor. Summary of the invention

[0005] The present application provides a method for preparing MgB2 superconducting wire based on 3D printing, which is used to solve the problems of low efficiency, stability and overall uniformity of the wire in preparing a single core rod in the prior art, and poor current carrying capacity of the wire.

[0006] On the one hand, the present application provides a method for preparing a MgB2 superconducting wire based on 3D printing, comprising the following steps: Step 1: Use 3D printing technology to print B powder into B tube.

[0007] Step 2: insert the Mg rod into the B tube and insert the whole into the metal sheath, and process it into a round single core rod by rotary forging or rolling.

[0008] Step 3: insert at least one oxygen-free Cu rod and a plurality of the circular single-core rods into the NCu30 tube to obtain a multi-core composite.

[0009] Step 4: Processing the multi-core composite body into a multi-core composite wire by drawing, rotary forging or rolling.

[0010] Step five, heat treating the multi-core composite wire to obtain a MgB2 superconducting wire.

[0011] In a possible implementation, in step one, the printing process is performed in a high-purity Ar gas protection environment or a vacuum environment.

[0012] When printing is performed in a high-purity Ar gas protection environment, the purity of the high-purity Ar gas is >95%.

[0013] When printing is performed in a vacuum environment, the vacuum degree is <1Pa.

[0014] In a possible implementation, in step 1, the B powder is coated with C.

[0015] The average particle size of the C-coated B powder is 20-500 nm, and the mass fraction of C is 0%-10%.

[0016] The outer diameter of the B tube is 6-40 mm, and the inner diameter is 4-21 mm.

[0017] In a possible implementation, in step 2, the purity of the Mg rod is 99.00%-99.99%, and the diameter is 3-20 mm.

[0018] The metal sheath is a Nb tube sheath or a Nb tube-oxygen-free Cu tube composite sheath.

[0019] When the metal sheath is a Nb tube sheath, the purity of the Nb tube is 99.00%-99.99%, the outer diameter is 12-50 mm, and the inner diameter is 11-41 mm.

[0020] When the metal sheath adopts a Nb tube-oxygen-free Cu tube composite sheath, the purity of the inner Nb tube of the Nb tube-oxygen-free Cu tube composite sheath is 99.00%-99.99%, the outer diameter is 12-50mm, and the inner diameter is 11-41mm. The purity of the outer oxygen-free Cu tube is 99.00%-99.99%, the outer diameter is 15-60mm, and the inner diameter is 13-51mm.

[0021] In a possible implementation, in step 2, the processing amount of the rotary forging or rolling process is 5%-25%, and the diameter of the round single core rod is 2-20 mm.

[0022] In a possible implementation, in step three, the oxygen-free Cu rod, the round single-core rod, and the NCu30 tube are all pre-pickled.

[0023] In a possible implementation, in step three, the oxygen-free Cu rod has a circular cross-section, a purity of 99.00%-99.99%, and a diameter of 2-20 mm.

[0024] The NCu30 tube has an outer diameter of 20-70 mm and an inner diameter of 15-61 mm and is in an annealed state.

[0025] In a possible implementation, in step 4, the processing amount of the drawing, rotary forging or rolling process is 5%-25%, and the cross-section of the multi-core composite wire is circular with a diameter of 0.1-2 mm.

[0026] In a possible implementation, in step five, the heat treatment temperature is 550-900° C., and the insulation time is 0.5-20 h.

[0027] A method for preparing MgB2 superconducting wire based on 3D printing in this application has the following advantages: By using 3D printing technology to print B powder into B tubes, the trouble of filling B powder between the metal sheath and Mg in the traditional central magnesium diffusion method is effectively avoided, and the efficiency and stability of preparing single core rods are improved; at the same time, the B tube realizes that B is evenly distributed around Mg, improving the overall uniformity of the wire; the method of printing B powder into B tubes using 3D printing technology also improves the stacking density of B powder, facilitates the generation of dense MgB2 superconducting phase, and improves the current carrying capacity of the wire. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present application 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 application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 A schematic flow chart of a method for preparing MgB2 superconducting wire based on 3D printing provided in an embodiment of the present application. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0031] like Figure 1 As shown, the embodiment of the present application provides a method for preparing a MgB2 superconducting wire based on 3D printing, comprising the following steps: Step 1: Use 3D printing technology to print B powder into B tube.

[0032] Step 2: insert the Mg rod into the B tube and insert the whole into the metal sheath, and process it into a round single core rod by rotary forging or rolling.

[0033] Step 3: insert at least one oxygen-free Cu rod and a plurality of the circular single-core rods into the NCu30 tube to obtain a multi-core composite.

[0034] Step 4: Processing the multi-core composite body into a multi-core composite wire by drawing, rotary forging or rolling.

[0035] Step five, heat treating the multi-core composite wire to obtain a MgB2 superconducting wire.

[0036] Embodiment 1: Illustratively, in this embodiment, in step one, the printing process is performed in a high-purity Ar gas protection environment, and the purity of the high-purity Ar gas is 96%.

[0037] Illustratively, in this embodiment, in step 1, the B powder is coated with C.

[0038] The average particle size of the C-coated B powder is 20 nm, and the mass fraction of C is 0%.

[0039] The outer diameter of the B tube is 6 mm and the inner diameter is 4 mm.

[0040] For example, in this embodiment, in step 2, the purity of the Mg rod is 99.00% and the diameter is 3 mm.

[0041] The metal sheath is a Nb tube-oxygen-free Cu tube composite sheath.

[0042] The purity of the inner Nb tube of the Nb tube-oxygen-free Cu tube composite sheath is 99.00%, the outer diameter is 12mm, the inner diameter is 11mm, and the purity of the outer oxygen-free Cu tube is 99.00%, the outer diameter is 15mm, and the inner diameter is 13mm.

[0043] For example, in this embodiment, in step 2, a rotary forging process is adopted, the processing amount per pass is 5%, and the diameter of the round single core rod is 2 mm.

[0044] Exemplarily, in this embodiment, in step three, the oxygen-free Cu rod, the round single core rod, and the NCu30 tube are all pre-pickled.

[0045] For example, in this embodiment, in step 3, the cross section of the oxygen-free Cu rod is circular, the purity is 99.00%, and the diameter is 2 mm. The number of circular single core rods is 30, the number of oxygen-free Cu rods is 7, and the oxygen-free Cu rod is placed at the central axis of the NCu30 tube.

[0046] The NCu30 tube has an outer diameter of 20 mm and an inner diameter of 15 mm and is in an annealed state.

[0047] For example, in this embodiment, in step 4, a drawing process is adopted, the processing amount per pass is 5%, and the cross-section of the multi-core composite wire is circular, and the diameter is 0.1 mm.

[0048] Illustratively, in this embodiment, in step five, the heat treatment temperature is 550° C., and the insulation time is 20 hours.

[0049] Embodiment 2: Illustratively, in this embodiment, in step one, the printing process is performed in a high-purity Ar gas protection environment, and the purity of the high-purity Ar gas is 97%.

[0050] Illustratively, in this embodiment, in step 1, the B powder is coated with C.

[0051] The average particle size of the C-coated B powder is 200 nm, and the mass fraction of C is 5%.

[0052] The outer diameter of the B tube is 20 mm and the inner diameter is 11 mm.

[0053] For example, in this embodiment, in step 2, the purity of the Mg rod is 99.50% and the diameter is 10 mm.

[0054] The metal sheath is a Nb tube-oxygen-free Cu tube composite sheath.

[0055] The purity of the inner Nb tube of the Nb tube-oxygen-free Cu tube composite sheath is 99.50%, the outer diameter is 25mm, the inner diameter is 21mm, and the purity of the outer oxygen-free Cu tube is 99.50%, the outer diameter is 30mm, and the inner diameter is 26mm.

[0056] For example, in this embodiment, in step 2, a rotary forging process is adopted, the processing amount per pass is 15%, and the diameter of the round single core rod is 10 mm.

[0057] Exemplarily, in this embodiment, in step three, the oxygen-free Cu rod, the round single core rod, and the NCu30 tube are all pre-pickled.

[0058] For example, in this embodiment, in step 3, the cross section of the oxygen-free Cu rod is circular, the purity is 99.50%, and the diameter is 10 mm. The number of circular single core rods is 6, the number of oxygen-free Cu rods is 1, and the oxygen-free Cu rod is placed at the central axis of the NCu30 tube.

[0059] The NCu30 tube has an outer diameter of 35 mm and an inner diameter of 31 mm and is in an annealed state.

[0060] For example, in this embodiment, in step 4, a drawing process is adopted, the processing amount per pass is 15%, and the cross-section of the multi-core composite wire is circular, and the diameter is 0.5 mm.

[0061] Illustratively, in this embodiment, in step five, the heat treatment temperature is 700° C., and the insulation time is 5 hours.

[0062] Embodiment 3: Illustratively, in this embodiment, in step one, the printing process is performed in a high-purity Ar gas protection environment, and the purity of the high-purity Ar gas is 99%.

[0063] Illustratively, in this embodiment, in step 1, the B powder is coated with C.

[0064] The average particle size of the C-coated B powder is 500 nm, and the mass fraction of C is 10%.

[0065] The outer diameter of the B tube is 40 mm and the inner diameter is 21 mm.

[0066] For example, in this embodiment, in step 2, the purity of the Mg rod is 99.99% and the diameter is 20 mm.

[0067] The metal sheath is a Nb tube-oxygen-free Cu tube composite sheath.

[0068] The purity of the inner Nb tube of the Nb tube-oxygen-free Cu tube composite sheath is 99.99%, the outer diameter is 50mm, the inner diameter is 41mm, and the purity of the outer oxygen-free Cu tube is 99.99%, the outer diameter is 60mm, and the inner diameter is 51mm.

[0069] For example, in this embodiment, in step 2, a rotary forging process is adopted, the processing amount per pass is 25%, and the diameter of the round single core rod is 20 mm.

[0070] Exemplarily, in this embodiment, in step three, the oxygen-free Cu rod, the round single core rod, and the NCu30 tube are all pre-pickled.

[0071] For example, in this embodiment, in step 3, the cross section of the oxygen-free Cu rod is circular, the purity is 99.99%, and the diameter is 20 mm. The number of circular single core rods is 6, the number of oxygen-free Cu rods is 1, and the oxygen-free Cu rod is placed at the central axis of the NCu30 tube.

[0072] The NCu30 tube has an outer diameter of 70 mm and an inner diameter of 61 mm and is in an annealed state.

[0073] For example, in this embodiment, in step 4, a drawing process is adopted, the processing amount per pass is 25%, and the cross-section of the multi-core composite wire is circular with a diameter of 2 mm.

[0074] Illustratively, in this embodiment, in step five, the temperature of the heat treatment is 900° C., and the insulation time is 0.5 h.

[0075] The embodiment of the present application uses 3D printing technology to print B powder into a B tube, which effectively avoids the trouble of filling B powder between the metal sheath and Mg in the traditional central magnesium diffusion method, and improves the efficiency and stability of preparing a single core rod; at the same time, the B tube realizes that B is evenly distributed around Mg, thereby improving the overall uniformity of the wire; the method of printing B powder into a B tube using 3D printing technology also improves the stacking density of the B powder, facilitates the generation of a dense MgB2 superconducting phase, and improves the current carrying capacity of the wire.

[0076] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0077] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A method for preparing MgB2 superconducting wire based on 3D printing, characterized in that: The following steps are involved: Step 1: Use 3D printing technology to print B powder into B tube; Step 2: insert the Mg rod into the B tube and insert the whole into the metal sheath, and process it into a round single core rod by rotary forging or rolling process; Step 3, inserting at least one oxygen-free Cu rod and a plurality of the circular single-core rods into the NCu30 tube to obtain a multi-core composite; Step 4, processing the multi-core composite body into a multi-core composite wire by drawing, rotary forging or rolling; Step five, heat treating the multi-core composite wire to obtain a MgB2 superconducting wire.

2. A method for preparing a MgB2 superconducting wire based on 3D printing according to claim 1, characterized in that: In step 1, the printing process is carried out in a high-purity Ar gas protection environment or a vacuum environment; When printing in a high-purity Ar gas protection environment, the purity of the high-purity Ar gas is > 95%; When printing is performed in a vacuum environment, the vacuum degree is <1Pa.

3. The method for preparing a MgB2 superconducting wire based on 3D printing according to claim 1, characterized in that: In step 1, the B powder is coated with C; The average particle size of the C-coated B powder is 20-500nm, and the mass fraction of C is 0%-10%; The outer diameter of the B tube is 6-40 mm, and the inner diameter is 4-21 mm.

4. The method for preparing a MgB2 superconducting wire based on 3D printing according to claim 1, characterized in that: In step 2, the purity of the Mg rod is 99.00%-99.99% and the diameter is 3-20 mm; The metal sheath is a Nb tube sheath or a Nb tube-oxygen-free Cu tube composite sheath; When the metal sheath is a Nb tube sheath, the purity of the Nb tube is 99.00%-99.99%, the outer diameter is 12-50mm, and the inner diameter is 11-41mm; When the metal sheath adopts a Nb tube-oxygen-free Cu tube composite sheath, the purity of the inner Nb tube of the Nb tube-oxygen-free Cu tube composite sheath is 99.00%-99.99%, the outer diameter is 12-50mm, and the inner diameter is 11-41mm. The purity of the outer oxygen-free Cu tube is 99.00%-99.99%, the outer diameter is 15-60mm, and the inner diameter is 13-51mm.

5. The method for preparing a MgB2 superconducting wire based on 3D printing according to claim 1, characterized in that: In step 2, the processing amount of the rotary forging or rolling process is 5%-25%, and the diameter of the round single core rod is 2-20 mm.

6. The method for preparing a MgB2 superconducting wire based on 3D printing according to claim 1, characterized in that: In step three, the oxygen-free Cu rod, the round single-core rod, and the NCu30 tube are all pre-pickled.

7. The method for preparing a MgB2 superconducting wire based on 3D printing according to claim 1, characterized in that: In step 3, the oxygen-free Cu rod has a circular cross-section, a purity of 99.00%-99.99%, and a diameter of 2-20 mm; The NCu30 tube has an outer diameter of 20-70 mm and an inner diameter of 15-61 mm and is in an annealed state.

8. The method for preparing a MgB2 superconducting wire based on 3D printing according to claim 1, characterized in that: In step 4, the processing amount of the drawing, rotary forging or rolling process is 5%-25%, and the cross-section of the multi-core composite wire is circular with a diameter of 0.1-2 mm.

9. The method for preparing a MgB2 superconducting wire based on 3D printing according to claim 1, characterized in that: In step five, the heat treatment temperature is 550-900° C., and the insulation time is 0.5-20 h.

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