CN116994822A - PbMo 6 S 8 Method for preparing base superconducting wire - Google Patents

PbMo 6 S 8 Method for preparing base superconducting wire Download PDF

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Publication number
CN116994822A
CN116994822A CN202311073968.2A CN202311073968A CN116994822A CN 116994822 A CN116994822 A CN 116994822A CN 202311073968 A CN202311073968 A CN 202311073968A CN 116994822 A CN116994822 A CN 116994822A
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Prior art keywords
pbmo
wire
base
superconducting wire
rod
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CN202311073968.2A
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Inventor
邵柏淘
张胜楠
刘吉星
郅磊
李建峰
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Northwest Institute for Non Ferrous Metal Research
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Northwest Institute for Non Ferrous Metal Research
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Priority to CN202311073968.2A priority Critical patent/CN116994822A/en
Publication of CN116994822A publication Critical patent/CN116994822A/en
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    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01BCABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B12/00Superconductive or hyperconductive conductors, cables, or transmission lines
    • H01B12/02Superconductive or hyperconductive conductors, cables, or transmission lines characterised by their form
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01BCABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B12/00Superconductive or hyperconductive conductors, cables, or transmission lines
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01BCABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B13/00Apparatus or processes specially adapted for manufacturing conductors or cables
    • H01B13/0016Apparatus or processes specially adapted for manufacturing conductors or cables for heat treatment

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  • Thermal Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Superconductors And Manufacturing Methods Therefor (AREA)

Abstract

The invention discloses a PbMo 6 S 8 A method of preparing a base superconducting wire, the method comprising: 1. selecting a raw material containing Mo and S elements and a central Pb rod in a glove box protected by argon, and mixing and grinding the raw material containing Mo and S elements to obtain precursor powder; 2. the precursor powder is filled into a metal composite sheath containing a central Pb rod and then processed to prepare PbMo 6 S 8 A base wire; 3. heat treatment to obtain PbMo 6 S 8 A base superconducting wire. The invention adopts a method of combining a central lead rod with a powder tubing to prepare PbMo 6 S 8 The base superconducting wire rod forms a circle of compact superconducting layer in the wire rod by the diffusion of central lead element in the wire rod heat treatment process, thereby effectively improving the loose condition of core wires of the wire rod, improving the density of the core wires and obviously enhancing the crystal thereofInterface connectivity, realization of PbMo 6 S 8 The current-carrying performance of the superconducting wire is effectively improved, the process is simple, required equipment is easy to obtain, the preparation difficulty is reduced, and the implementation is easy.

Description

PbMo 6 S 8 Method for preparing base superconducting wire
Technical Field
The invention belongs to the technical field of superconducting material preparation, and in particular relates to PbMo 6 S 8 A method for preparing a base superconducting wire.
Background
With the rapid development of superconducting magnet technology, the steady-state magnetic field strength is increasingly higher, which puts new demands on the performances of superconducting materials for magnets in all aspects. At present, the superconducting materials for the high-field magnet are mainly low-temperature superconducting materials NbTi and Nb with mature and stable process 3 Sn. But the intrinsic upper critical field (H) c2 ) 18T and 25T respectively, making it impractical to use in high field magnets above 30T, which are currently receiving widespread attention. While the high-temperature superconducting material can be applied in the form of an inserted coil to improve the magnetic field strength of the magnet, the preparation technology of the high-temperature superconducting material is still immature at present, and the preparation cost is still higher. Therefore, development of a novel superconducting material for a high-field magnet is of great importance for further development of superconducting magnet technology and progress of practical application of advancing superconducting materials.
In the seventies of the last century, chevrel et al were first described in PbMo 6 S 8 A represented by the system x Mo 6-x S 6 Superconductivity is found in the compound, which is a ternary superconducting compound found for the first time, and this molybdenum-based chalcogenide is further referred to as a Chevrel phase. In such materials, the Mo and S atoms are represented by Mo 6 S 8 Form of lattice unit, and Pb and other A-site elements are located in Mo 6 S 8 In the cell gap, it plays a critical role in the overall system superconductivity. Through systematic measurement, pbMo is found 6 S 8 Superconducting transition temperature (T) of the base superconducting material c ) Is about 15K and has a higher upper critical field (H c2 (0) 60T) and very little anisotropy, which both ensure the use of such materials in superconducting magnets. Thus, pbMo 6 S 8 The base superconducting material is expected to become a practical superconducting material for a next generation strong magnetic field.
Currently, pbMo 6 S 8 The current carrying capacity of the wire strip is still low due to the weak connection of the grain boundaries of the base superconducting material. Analysis of the current preparation technology shows that PbMo prepared under the condition of the traditional sintering process 6 S 8 The density of the core wire of the base superconducting wire is low, and the connectivity between crystal grains is poor, which is a key factor for causing lower current carrying performance of a system. Thus, a new PbMo was developed 6 S 8 The preparation technology of the base superconducting wire rod improves the core wire density of the wire rod, enhances the connectivity of grain boundaries and can effectively improve the current carrying capacity of the wire rod.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a PbMo for overcoming the defects in the prior art 6 S 8 A method for preparing a base superconducting wire. The method takes a lead bar as the center of a metal composite sheath, and fills precursor powder to prepare PbMo containing the center lead bar 6 S 8 The base superconducting wire forms a circle of compact superconducting layer in the wire by the diffusion of central lead element in the heat treatment process, thereby effectively avoiding PbMo 6 S 8 Holes and microcracks in the core wire of the base superconducting wire are formed, so that the density of the core wire of the wire is improved, the connectivity of grain boundaries is enhanced, and PbMo is realized 6 S 8 Effective improvement of current-carrying performance of superconducting wire rod, solving the problem of PbMo in the prior art 6 S 8 The low density of the core wire of the base superconducting wire and the poor connectivity among grains lead to the difficult problem of lower current carrying performance.
In order to solve the technical problems, the invention adopts the following technical scheme: pbMo 6 S 8 A method of producing a base superconducting wire, characterized in that the method comprises the steps of:
step one, in a glove box protected by argon, according to a target product PbMo 6 S 8 Selecting a raw material containing Mo and S elements and a central Pb rod according to the atomic ratio of Mo to S in the base superconducting wire, and mixing and grinding the raw material containing Mo and S elements to obtain precursor powder;
step two, the precursor powder obtained in the step one is filled into a metal composite sheath containing the central Pb rod selected in the step one, and then the metal composite sheath is processed and preparedPbMo formation 6 S 8 A base wire;
step three, the PbMo processed in the step two is processed 6 S 8 Heat treating the base wire to obtain PbMo 6 S 8 A base superconducting wire.
PbMo of one kind of the above 6 S 8 The preparation method of the base superconducting wire is characterized in that the precursor powder in the first step is simple substance mixed powder of Mo and S or Mo and MoS 2 Mixing the powders.
PbMo of one kind of the above 6 S 8 The preparation method of the base superconducting wire is characterized in that in the second step, the metal composite sheath is arranged according to a barrier layer/outer sheath structure and comprises Mo/Cu, nb/Cu or Ta/Cu pipes.
PbMo of one kind of the above 6 S 8 A process for preparing the base superconducting wire rod includes loading the precursor powder in step two, and using central Pb rod as target product PbMo 6 S 8 The center of the base superconducting wire.
PbMo of one kind of the above 6 S 8 The preparation method of the base superconducting wire is characterized in that the heat treatment temperature in the step three is 700-1000 ℃ and the heat treatment time is 10-100 h.
Compared with the prior art, the invention has the following advantages:
1. according to the invention, the central lead rod is adopted to replace Pb powder or Pb compound in the traditional powder tubing method, so that lead element in the central lead rod is outwards diffused in the heat treatment process, a circle of compact superconducting layer is formed in the wire rod together with precursor powder, the formed holes are concentrated in the center of the wire rod, the formation of holes and microcracks in the superconducting layer of the wire rod core wire is effectively avoided, the wire rod core wire density is improved, the grain boundary connectivity is enhanced, and the PbMo is realized 6 S 8 The current-carrying performance of the superconducting wire is effectively improved, and the problems of low density of the core wire and poor connectivity among grains caused by in-situ hole formation due to Pb element diffusion in precursor powder in the heat treatment phase formation process of the traditional powder tubing method are solved.
2. The center lead rod adopted by the invention has good plasticity and extensibilitySex, effectively improve PbMo 6 S 8 Workability of the wire rod.
3. The preparation method has the advantages of simple preparation process, easy acquisition of required equipment, reduced preparation difficulty and easy realization of application.
The technical scheme of the invention is further described in detail through the drawings and the embodiments.
Drawings
FIG. 1a is a schematic view of the tubing process of the present invention.
FIG. 1b is a schematic view of the construction of the tubulation of the present invention.
FIG. 2a shows PbMo prepared in example 1 of the present invention 6 S 8 A cross-sectional view of the base wire.
FIG. 2b shows PbMo prepared in example 1 of the present invention 6 S 8 A cross-sectional view of the base superconducting wire.
FIG. 3 shows PbMo prepared in example 1 of the present invention 6 S 8 A partial SEM image of the base superconducting wire core wire.
FIG. 4 shows PbMo prepared in comparative example 1 of the present invention 6 S 8 A cross-sectional view of the base superconducting wire.
FIG. 5 shows PbMo prepared in comparative example 1 of the present invention 6 S 8 A partial SEM image of the base superconducting wire core wire.
FIG. 6 shows PbMo prepared in example 2 of the present invention 6 S 8 A partial SEM image of the base superconducting wire core wire.
FIG. 7 shows PbMo prepared in example 3 of the present invention 6 S 8 A partial SEM image of the base superconducting wire core wire.
Detailed Description
Example 1
The embodiment comprises the following steps:
step one, in a glove box protected by argon, according to a target product PbMo 6 S 8 The atomic ratio of Pb to Mo to S in the base superconducting wire is 1:6:8, and the mass purity is over 99.99 percent, and the particle size is more than 200 meshes of MoS 2 Raw Mo powder material and a center Pb rod with a mass purity of 99.99%, and MoS was added 2 Pouring Mo powder raw material into grinding machine to make mixing grindingGrinding for more than 30min to obtain precursor powder;
step two, as shown in figure 1a, placing the central Pb rod selected in the step one in the center of the Nb tube, filling the precursor powder obtained in the step one into the Nb tube barrier layer containing the central Pb rod, filling the Nb tube after powder filling into a Cu tube outer sheath, as shown in figure 1b, and preparing PbMo by drawing 6 S 8 A base wire;
step three, the PbMo processed in the step two is processed 6 S 8 Sintering the base wire rod in argon atmosphere at 950 ℃ for 72h to obtain PbMo 6 S 8 A base superconducting wire.
FIG. 2a shows PbMo prepared in this example 6 S 8 As can be seen from fig. 2a, a cross-sectional view of the base wire, the PbMo 6 S 8 The structure of the base wire is clear, and the base wire is sequentially provided with a Cu sheath, a Nb barrier layer, powder and a center lead rod from outside to inside. FIG. 2b shows PbMo prepared in this example 6 S 8 As can be seen from fig. 2b, a cross-sectional view of the base superconducting wire, a circle of dense superconducting layer is formed in the wire after heat treatment.
FIG. 3 shows PbMo prepared in this example 6 S 8 As can be seen from FIG. 3, which shows a partial SEM image of the core wire of the base superconducting wire, pbMo prepared in this example 6 S 8 The core wire density of the base superconducting wire is higher.
As can be seen from the combination of FIGS. 2a to 2b and FIG. 3, the invention can prepare PbMo with good structure by adopting the central lead diffusion method 6 S 8 A base superconducting wire.
Comparative example 1
This comparative example differs from example 1 in that: in the second step, a central lead bar is not adopted, and Pb, mo, moS is directly added 2 And (5) loading the mixed powder into a tube.
FIG. 4 shows PbMo prepared in this comparative example 6 S 8 As can be seen from fig. 4, which is a cross-sectional view of the base superconducting wire, the PbMo 6 S 8 The structure of the base wire is sequentially provided with a Cu sheath, a Nb barrier layer and superconducting core wires from outside to inside, and the core wires in the wire are very loose. From its local SEM, FIG. 5, it is evident that there is a large presence in the wire core wireA quantity of holes.
Example 2
The embodiment comprises the following steps:
step one, in a glove box protected by argon, according to a target product PbMo 6 S 8 Selecting Mo and S simple substance powder raw materials with mass purity of more than 99.99% and particle size of more than 200 meshes and a central Pb rod with mass purity of 99.99% from Pb and Mo and S in a atomic ratio of 1:6:8 in a base superconducting wire, pouring the Mo and S simple substance powder raw materials into grinding, and mixing and grinding for more than 30min to obtain precursor powder;
step two, as shown in figure 1a, placing the central Pb rod selected in the step one in the center of the Mo tube, filling the precursor powder obtained in the step one into a Mo tube barrier layer containing the central Pb rod, filling the filled Nb tube into a Cu tube outer sheath, as shown in figure 1b, and drawing to prepare PbMo 6 S 8 A base wire;
step three, the PbMo processed in the step two is processed 6 S 8 Sintering the base wire rod for 100 hours in an argon atmosphere at 700 ℃ to obtain PbMo 6 S 8 A base superconducting wire.
FIG. 6 shows PbMo prepared in this example 6 S 8 As can be seen from FIG. 6, which is a partial SEM image of the core wire of the base superconducting wire, the present embodiment adopts a center lead diffusion method to prepare PbMo after changing the tube powder, compared with FIG. 5 of comparative example 1 6 S 8 The core wire density of the base superconducting wire is still significantly increased.
Example 3
The embodiment comprises the following steps:
step one, in a glove box protected by argon, according to a target product PbMo 6 S 8 The atomic ratio of Pb to Mo to S in the base superconducting wire is 1:6:8, and the mass purity is over 99.99 percent, and the particle size is more than 200 meshes of MoS 2 Raw Mo powder material and a center Pb rod with a mass purity of 99.99%, and MoS was added 2 Pouring the Mo powder raw material into grinding, and mixing and grinding for more than 30min to obtain precursor powder;
step two, as shown in FIG. 1a, the first stepPlacing the selected central Pb rod in the center of Ta tube, filling the precursor powder obtained in step one into Ta tube barrier layer containing central Pb rod, filling the Nb tube after filling powder into Cu tube jacket, drawing to obtain PbMo as shown in FIG. 1b 6 S 8 A base wire;
step three, the PbMo processed in the step two is processed 6 S 8 Sintering the base wire rod in argon atmosphere at 1000 ℃ for 10 hours to obtain PbMo 6 S 8 A base superconducting wire.
FIG. 7 shows PbMo prepared in this example 6 S 8 As can be seen from fig. 7, which is a partial SEM view of the core wire of the base superconducting wire, the PbMo prepared in this example is compared with fig. 5 of comparative example 1 6 S 8 The number of holes in the core wire of the base superconducting wire is greatly reduced, and the density of the core wire is obviously improved, which shows that the invention forms high-density PbMo in situ through the diffusion of central Pb element 6 S 8 Phase, effectively increase PbMo 6 S 8 The core wire density of the base superconducting wire rod improves the connectivity of crystal grains.
The above description is only of the preferred embodiments of the present invention, and is not intended to limit the present invention. Any simple modification, variation and equivalent variation of the above embodiments according to the technical substance of the invention still fall within the scope of the technical solution of the invention.

Claims (5)

1. PbMo 6 S 8 A method of producing a base superconducting wire, characterized in that the method comprises the steps of:
step one, in a glove box protected by argon, according to a target product PbMo 6 S 8 Selecting a raw material containing Mo and S elements and a central Pb rod according to the atomic ratio of Mo to S in the base superconducting wire, and mixing and grinding the raw material containing Mo and S elements to obtain precursor powder;
step two, filling the precursor powder obtained in the step one into a metal composite sheath containing the central Pb rod selected in the step one, and then processing to prepare PbMo 6 S 8 A base wire;
step three, the PbMo processed in the step two is processed 6 S 8 Heat treating the base wire to obtain PbMo 6 S 8 A base superconducting wire.
2. A PbMo according to claim 1 6 S 8 The preparation method of the base superconducting wire is characterized in that the precursor powder in the first step is simple substance mixed powder of Mo and S or Mo and MoS 2 Mixing the powders.
3. A PbMo according to claim 1 6 S 8 The preparation method of the base superconducting wire is characterized in that in the second step, the metal composite sheath is arranged according to a barrier layer/outer sheath structure and comprises Mo/Cu, nb/Cu or Ta/Cu pipes.
4. A PbMo according to claim 1 6 S 8 A process for preparing the base superconducting wire rod includes loading the precursor powder in step two, and using central Pb rod as target product PbMo 6 S 8 The center of the base superconducting wire.
5. A PbMo according to claim 1 6 S 8 The preparation method of the base superconducting wire is characterized in that the heat treatment temperature in the step three is 700-1000 ℃ and the heat treatment time is 10-100 h.
CN202311073968.2A 2023-08-24 2023-08-24 PbMo 6 S 8 Method for preparing base superconducting wire Pending CN116994822A (en)

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CN202311073968.2A CN116994822A (en) 2023-08-24 2023-08-24 PbMo 6 S 8 Method for preparing base superconducting wire

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Application Number Priority Date Filing Date Title
CN202311073968.2A CN116994822A (en) 2023-08-24 2023-08-24 PbMo 6 S 8 Method for preparing base superconducting wire

Publications (1)

Publication Number Publication Date
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