CN115787088A - Method for growing superconducting bulk by recycling REBCO bulk intermediate layer crystals - Google Patents

Method for growing superconducting bulk by recycling REBCO bulk intermediate layer crystals Download PDF

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CN115787088A
CN115787088A CN202211513636.7A CN202211513636A CN115787088A CN 115787088 A CN115787088 A CN 115787088A CN 202211513636 A CN202211513636 A CN 202211513636A CN 115787088 A CN115787088 A CN 115787088A
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intermediate layer
rebco
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姚忻
朱彦涵
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Shanghai Jiaotong University
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Abstract

The invention discloses a method for recycling REBCO bulk intermediate layer crystal to grow a superconducting bulk, and relates to the technical field of a method for recycling the regrowth of a superconducting material. The invention prepares the original powder of RE123 and RE211, and the mixture is mixed with CeO according to the proportion after sintering 2 Preparing materials, pressing, adding intermediate layer crystals stripped from the grown REBCO block with the intermediate layer, polishing and flattening the side surface and the lower surface of the intermediate layer crystals by using fine sand paper, and placing the intermediate layer crystals at the center of the upper surface of the REBCO block precursor; and growing in a growth furnace by a top seed crystal melting texture method to obtain the REBCO high-temperature superconducting block. The method realizes the partial replacement of the 'neck' product film seed crystal, and the induced growth sample shows the performance similar to that of the film seed crystal under induction.

Description

Method for growing superconducting bulk by recycling REBCO bulk intermediate layer crystals
Technical Field
The invention belongs to the technical field of a regrowth recovery method of a superconducting material, and particularly relates to a method for recycling intermediate layer crystals of a REBCO block material to grow the superconducting block material, in particular to a method for recycling intermediate layer crystals of the REBCO block material after melting growth to grow the superconducting block material.
Background
self-REBa 2 Cu 3 O x Since the discovery of superconductors (REBCO, RE123, rare earth barium copper oxygen, wherein RE is selected from Y, gd, sm, nd and the like), the huge commercial potential brought by the properties of complete diamagnetism, high critical current density, high freezing magnetic field and the like, such as flywheel energy storage, permanent magnet, magnetic suspension force element and the like, has caused people to haveThere is a wide range of concerns. However, its development has been restricted by its excessively high preparation cost. The cost of expensive seed crystals, such as film seeds or bulk seeds, is one of the factors that make superconductor bulk materials cost prohibitive to produce. On the other hand, the expensive raw material cost, such as rare earth element powder, silver, platinum noble metal, etc., and the failure rate of the conventional melting batch growth process of REBCO bulk material up to 30%, also severely limit the large-scale application thereof. Therefore, in order to seek higher resource utilization rate, it is a popular research topic to recycle REBCO from melt-grown (MTG) REBCO bulk material, so as to effectively save cost.
In the whole REBCO system, seed crystal materials are generally divided into two main categories of thin-film seed crystals and bulk seed crystals. The film seed crystal is used for depositing and growing an NdBCO or YBCO film on an MgO substrate, and the overheating property of the film is utilized to ensure that the film keeps thermal stability at high temperature and induces the growth of a sample along with slow cooling. The bulk seed crystal is that firstly single domain or multi-domain bulk of NdBCO or SmBCO is grown, the single domain area of the sample is cut, and small bulk with good phase is selected as the seed crystal. Bulk seed crystals are generally only used to induce growth of materials with melting points lower than themselves due to compactness caused by pores in the structure, etc. Obviously, the preparation process and the use method of the film seed crystal are simpler and more convenient than those of the bulk seed crystal, and the application range is larger than that of the bulk seed crystal, so the film seed crystal becomes the most popular seed crystal material at present. However, the world now has only one company for mass production and sale of NdBCO thin film seeds from which all national and even worldwide research groups for bulk materials are purchased. Considering that the domestic preparation of NdBCO film is still in the laboratory stage, the NdBCO film does not hatch and land. If a suitable film seed crystal substitute can be found on the premise of convenience, the dependence on the film seed crystal is reduced to a certain extent, and the industrial application of the REBCO superconducting bulk material is further promoted.
Disclosure of Invention
Through the search of the prior art, almost no precedent exists for recycling the intermediate layer crystal of the bulk material grown by the REBCO fusion method at present. Therefore, it is significant to search for the recovery of interlayer crystals.
In order to realize the purpose, the invention provides a method for recycling intermediate layer crystal grown by a REYBCO melting method to grow a superconducting block material, which comprises the following steps:
(1) Weighing RE 2 O 3 、BaCO 3 And CuO powders, formulated as raw powders of RE123 and RE211, respectively;
(2) Fully and uniformly mixing the original powder, sintering for 40-50 hours at 890-910 ℃ in an air environment, grinding again, sintering, and repeating for three times to respectively obtain RE123 and RE211 pure-phase powder;
(3) Mixing 1mol of Re123 pure phase powder and 0.3mol of RE211 pure phase powder with CeO 2 Preparing materials and mixing to obtain precursor powder;
(4) Weighing the precursor powder, putting the precursor powder into a mold, and pressing the precursor powder into a precursor with a cylindrical shape;
(5) Stripping the lower intermediate layer and the MgO substrate of the initial film seed crystal from the grown REBCO block with the intermediate layer;
(6) Grinding and polishing the side surface and the lower surface of the crystal of the obtained REBCO intermediate layer by using fine sand paper, and placing the crystal at the center of the upper surface of the REBCO bulk precursor;
(7) And (3) placing the placed whole precursor in a growth furnace to carry out top seed crystal melt texture method growth to prepare the intermediate layer crystal-induced REBCO high-temperature superconducting block.
Further, the RE is selected from Y, gd, sm and Nd. When RE is Nd, RE211 in steps (1) to (3) is Nd422.
Further, in the step (2), sintering is carried out for 48 hours at 900 ℃ in an air environment.
Further, in the step (2), the CeO 2 Is added in an amount of 1wt% of the sum of the weights of the RE123 and RE211 pure phase powders.
Further, in the step (4), when the diameter of the die is 20mm, 10g of the precursor powder is weighed; or when the diameter of the die is 30mm, weighing 30g of the precursor powder.
Further, in the step (5), the diameter of the intermediate layer crystal is 8mm or 4.5mm.
Further, in the step (7), the specific temperature program of the growth furnace is as follows:
a. heating to 900 ℃ from room temperature for 4h, and keeping the temperature for 4h;
b. continuing heating for 1h, heating to 10-15K above the melting point of the REBCO material, and keeping the temperature for 45min;
c. rapidly cooling to the melting point of the REBCO material within 6 min;
d. slowly cooling at a cooling speed of 0.3-0.6K/h for 100h;
e. and rapidly cooling along with the furnace within 4h.
In another aspect, the present invention provides a REBCO superconducting bulk material prepared by the above method.
Further, the superconducting bulk is selected from YBCO, gdBCCO, smBCO and NdBCO.
Further, when the diameter of the YBCO superconducting block material is 16mm, the freezing magnetic field is 0.4-0.7T; or when the diameter of the YBCO superconducting block is 25mm, the freezing magnetic field is 0.6-0.9T.
Further, when the diameter of the YBCO superconducting block material is 16mm, the magnetic levitation force is 20N; or when the diameter of the YBCO superconducting block is 25mm, the suspension magnetic force is 50-70N.
Technical effects
The invention recovers the crystal of the middle layer and utilizes the crystal to grow a new block material, the middle layer and the block material main body are originally formed by pressing the same powder, and then the crystal is grown by seed crystal induction. Therefore, as the seed crystal is firstly induced, the middle layer has a quite good crystal structure and can play a role of 'seed crystal' to induce the growth of a new bulk material. The invention recycles the intermediate crystal, can be used as a partial substitute of the film seed crystal, and the superconducting bulk material induced to grow shows the performance similar to (even slightly higher than) that of the film seed crystal under the induction.
Secondly, the advantages of the interlayer crystal are rarely recognized before and are often discarded after the growth is finished, and the inventor has a breakthrough in recognizing that the interlayer crystal may have the dual advantages of high crystallinity and high thermal stability, thereby fully meeting the requirement of serving as a seed crystal. By optimizing the process parameters, the invention finds that the intermediate layer crystal can really induce the growth of a new sample under a proper growth program, thereby not only solving the problem of the film seed crystal, but also achieving the purposes of saving resources and cost.
In addition, the intermediate layer crystals, to be able to act as seed crystals, must withstand temperatures above their own melting point to ensure adequate melting of the new precursor powder. Through experiments and characterization, the inventor finds that the intermediate layer crystal can bear the temperature higher than the self melting point by about 10K and has high thermal stability. This is a great advantage. Through ToF-SIMS, the inventors found that the portion of the intermediate layer seed crystal in contact with the original thin film seed crystal contains a small amount of diffused Mg element, and Mg was confirmed to raise the melting point of the REBCO material. Through optical microscopy, the inventors have found that the intermediate layer seed crystal has a low porosity, which means a higher degree of densification, i.e., it is less likely to allow penetration of the melt into the crystal and cause melting of the crystal. The intermediate layer crystal has high thermal stability, can be stabilized at the temperature higher than the melting point of the crystal per se by about 10K for more than 45min, ensures that the crystal structure of the crystal is unchanged, and ensures the subsequent induction of a sample.
Drawings
FIG. 1 is a top view of a YBCO superconducting bulk material successfully induced by an interlayer crystal according to example 1 of the present invention;
fig. 2 is a performance diagram of a YBCO superconducting block successfully induced and grown by an interlayer crystal in example 1 of the present invention, the curve is a magnetic suspension force curve, and a 3D diagram is a frozen magnetic field diagram.
Detailed Description
The technical contents of the preferred embodiments of the present invention will be more clearly and easily understood by referring to the drawings attached to the specification. The present invention may be embodied in many different forms of embodiments and the scope of the invention is not limited to the embodiments set forth herein.
Preparation examples
The embodiment is a method for preparing a YBCO high-temperature superconducting block by using a film seed crystal, which comprises the following steps:
1. weighing Y 2 O 3 、BaCO 3 And CuO powder, prepared as raw powders of Y123 and Y211, respectively;
2. and fully and uniformly mixing the original powder of Y123 and Y211, and sintering for 48 hours at 900 ℃ in an air environment to respectively obtain pure-phase powder of Y123 and pure-phase powder of Y211. In order to ensure that the Y123 and Y211 pure-phase powder with uniform and single components is finally obtained, the sintered powder is ground and sintered again, and the same process is repeated for three times.
3. The obtained pure phase powders of Y123 and Y211 are concentrated by 1mol Y123+0.3mol Y211+1wt% CeO 2 The components (relative to the sum of the weight of the Y123 pure phase powder and the weight of the Y211 pure phase powder) are fully milled and evenly mixed to obtain precursor powder.
4. According to different diameters of the die, the powder is weighed to a proper mass and placed into the die to press 1 cylindrical precursor. If the die diameter is 20mm, 10g is weighed. If the diameter of the die is 30mm, 30g is weighed.
5. And (2) placing a seed crystal material of a c-axis oriented NdBCO/YBCO/MgO film with the size of 2mm multiplied by 2mm on the top of the obtained cylindrical precursor by adopting a top seed crystal melting texture method, wherein the 2mm multiplied by 2mm indicates that the length and the width of the film seed crystal are both 2mm.
6. And (3) placing the placed whole precursor in a growth furnace to carry out top seed crystal melt texture method growth. The specific temperature program of the growth furnace is as follows:
a. the temperature is raised to 900 ℃ from the room temperature for 4h, and the temperature is kept for 4h.
b. And continuously heating for 1h, raising the temperature to 1045-1085 ℃, and preserving the temperature for 1h.
c. Quickly cooling to 1005 ℃ within 20-40 min.
d. Slowly cooling at a cooling speed of 0.3-0.6K/h to grow for 100h.
e. And rapidly cooling along with the furnace within 4h to prepare the YBCO high-temperature superconducting block material induced by the film seed crystal.
Example 1
The method for recycling the intermediate layer crystal grown by the YBCO melting method to grow the superconducting bulk material comprises the following steps:
1. weighing Y: ba: cu =1 in a ratio of Y: ba: cu =1 2 O 3 、BaCO 3 And CuO powder, prepared as raw powders of Y123 and Y211, respectively;
2. and respectively and fully mixing the original powder of Y123 and the original powder of Y211 uniformly, and sintering for 48 hours at 900 ℃ in an air environment to respectively obtain pure-phase powder of Y123 and pure-phase powder of Y211. In order to ensure that the Y123 and Y211 pure-phase powder with uniform and single components is finally obtained, the sintered powder is ground and sintered again, and the same process is repeated for three times.
3. The obtained pure phase powder of Y123 and Y211 is concentrated according to 1mol Y123+0.3mol Y211+1wt% CeO 2 And (relative to the sum of the weight of the Y123 pure-phase powder and the Y211 pure-phase powder), fully grinding and uniformly mixing to obtain precursor powder.
4. And weighing the powder according to different diameters of the die, putting the powder into the die, and pressing 1 cylindrical precursor. If the die diameter is 20mm, 10g should be weighed. If the diameter of the die is 30mm, 30g is weighed.
5. The intermediate layer and the MgO substrate of the initial film seed were peeled from the YBCO bulk with intermediate layer that had been grown in the preparation examples using a utility knife or other cutting device. The intermediate layer is crystallized under the induction of seed crystals in the melting growth process and has a YBCO lattice structure, so the intermediate layer is called as an intermediate layer crystal. The intermediate layer crystals may be about 8mm or 4.5mm in diameter and kept for future use.
6. And lightly grinding and polishing the side surface and the lower surface of the obtained YBCO intermediate layer crystal by using fine sand paper, and placing the crystal at the center of the upper surface of the YBCO block precursor.
7. And placing the whole placed precursor in a growth furnace for growth by a top seed crystal melting texture method. The specific temperature program of the growth furnace is as follows:
a. the temperature is raised to 900 ℃ after 4h from the room temperature, and the temperature is kept for 4h.
b. Heating for 1h, heating to 1015 ℃, and keeping the temperature for 45min.
c. The temperature is rapidly reduced to 1005 ℃ within 6 min.
d. Slowly cooling at a cooling speed of 0.3-0.6K/h to grow for 100h.
e. And rapidly cooling along with the furnace within 4h to obtain the YBCO high-temperature superconducting block material induced by the intermediate layer crystal.
The top view of the obtained YBCO sample induced by the intermediate layer crystal is shown in figure 1, and it can be seen that 4 growth radial lines on the upper surface are clearly visible, and the sample has good single domain characteristics.
The performance test method of the superconducting bulk material comprises the following steps:
the superconducting properties of the samples prepared in this example were characterized by magnetic levitation force and frozen magnetic field.
Prior to testing, the fully grown YBCO samples were seed stripped (i.e., interlayer crystals) and annealed at 450 degrees celsius in a flowing oxygen environment for 240 hours. The magnetic levitation force was measured under a NdFeB permanent magnet with a surface magnetic field of 0.55T with the sample cooled to the temperature of liquid nitrogen in zero field, and the result is shown in fig. 2 (magnetic levitation force curve), it can be seen that when the diameter of the YBCO superconducting bulk is 16mm (using a mold with a diameter of 20 mm), the magnetic levitation force is 20N; or when the diameter of the YBCO superconducting block material is 25mm (the diameter of a used mould is 30 mm), the suspension magnetic force is 50-70N.
The sample is firstly field-cooled to 77K under an external field (parallel to the c axis of the sample) of 2T, and after the sample is stabilized for 15 minutes, a Hall probe (at a position 0.7mm above the sample) scans to obtain a frozen magnetic field, and the result is shown in figure 2 (3D), and when the diameter of the YBCO superconducting bulk material is 16mm (the diameter of a used mould is 20 mm), the frozen magnetic field is 0.4-0.7T; or when the diameter of the YBCO superconducting block is 25mm (the diameter of a used mould is 30 mm), the freezing magnetic field is 0.6-0.9T.
In this embodiment, the YBCO superconducting bulk obtained by induced growth of the intermediate layer crystal and the bulk grown normally have the same superconducting transition temperature and similar superconducting properties (frozen magnetic field, magnetic levitation force, etc.).
Example 2
The embodiment provides a method for recycling an intermediate layer crystal grown by a GdBCO fusion method to grow a superconducting bulk material, which comprises the following steps:
1. in a ratio of Gd: ba: cu =1Weighing Gd 2 O 3 、BaCO 3 And CuO powder, formulated as raw powders of Gd123 and Gd211, respectively;
2. and fully and uniformly mixing the raw powder materials of Gd123 and Gd211, and sintering the mixture for 48 hours at 900 ℃ in an air environment to respectively obtain pure-phase powder of the Gd123 and the Gd 211. In order to ensure that pure-phase Gd123 and Gd211 powders with uniform and single components are finally obtained, the sintered powders are ground and sintered again, and the same process is repeated for three times.
3. The obtained pure phase powder of Gd123 and Gd211 is subjected to a content of 1mol Gd123+0.3mol Gd211+1wt% CeO 2 (relative to the sum of the weight of pure-phase powder of Gd123 and Gd 211), fully grinding and uniformly mixing to obtain precursor powder.
4. And weighing the powder according to different diameters of the die, putting the powder into the die, and pressing 1 cylindrical precursor. If the die diameter is 20mm, 10g should be weighed. If the die diameter is 30mm, 30g is weighed.
5. The intermediate layer and the MgO substrate of the initial film seed were peeled off from the grown GdBCO block with intermediate layer using a utility knife or other cutting device. The middle layer is induced by seed crystals to crystallize in the same way in the melting growth process, and has a GdBCO lattice structure, so the middle layer is called as a middle layer crystal. The intermediate layer crystals may be about 8mm or 4.5mm in diameter and kept for future use.
6. And lightly grinding and polishing the side surface and the lower surface of the obtained GdBCO intermediate layer crystal by using fine sand paper, and placing the crystal at the center of the upper surface of the YBCO block precursor.
7. And placing the whole placed precursor in a growth furnace for growth by a top seed crystal melting texture method. The specific temperature program of the growth furnace is as follows:
a. the temperature is raised to 900 ℃ after 4h from the room temperature, and the temperature is kept for 4h.
b. Heating for 1h, heating to 1055 deg.C, and keeping the temperature for 45min.
c. Quickly cooling to 1045 ℃ within 6 min.
d. Slowly cooling at a cooling speed of 0.3-0.6K/h for 100h.
e. And rapidly cooling along with the furnace within 4h to prepare the GdBCO high-temperature superconducting block material induced by the intermediate layer crystal.
The GdBCO sample obtained by the method has good single-domain characteristics, and 4 growth radial lines are clearly visible.
Through the same performance test in the embodiment 1, the GdBCO superconducting bulk obtained by the induced growth of the intermediate layer crystal and the normally grown bulk have consistent superconducting transition temperature and similar freezing magnetic field and magnetic suspension force.
Example 3
The method for recycling the intermediate layer crystal grown by the SmBCO fusion method to grow the superconducting bulk material comprises the following steps:
1. weighing Sm 2 O 3 、BaCO 3 And CuO powder, which are respectively prepared into Sm123 and Sm211 original powder;
2. fully and uniformly mixing the raw powder of Sm123 and Sm211, and sintering the mixture for 48 hours at 900 ℃ in an air environment to obtain pure-phase powder of Sm123 and Sm 211. In order to ensure that pure-phase powders of Sm123 and Sm211 with uniform and single components are finally obtained, the sintered powders are ground again and sintered, and the same process is repeated for three times.
3. The obtained pure phase powders of Sm123 and Sm211 were subjected to a content of 1mol of Sm123+0.3mol of Sm211+1wt% CeO 2 The components (relative to the sum of the weight of Sm123 and Sm211 pure phase powder) are fully milled and evenly mixed to obtain precursor powder.
4. According to different diameters of the die, the powder is weighed to a proper mass and placed into the die to press 1 cylindrical precursor. If the die diameter is 20mm, 10g should be weighed. If the diameter of the die is 30mm, 30g is weighed.
5. The intermediate layer and the MgO substrate of the initial film seed are peeled off from the grown SmBCO block with the intermediate layer by using a utility knife or other cutting equipment. The intermediate layer is crystallized under the induction of seed crystals in the melting growth process and has a SmBCO lattice structure, so the intermediate layer is called as an intermediate layer crystal. The intermediate layer crystals may be about 8mm or 4.5mm in diameter and kept for future use.
6. And lightly grinding and polishing the side surface and the lower surface of the SmBCO intermediate layer crystal by using fine sand paper, and placing the side surface and the lower surface at the center of the upper surface of the SmBCO bulk precursor.
7. And (3) placing the placed whole precursor in a growth furnace to carry out top seed crystal melt texture method growth. The specific temperature program of the growth furnace is as follows:
a. the temperature is raised to 900 ℃ after 4h from the room temperature, and the temperature is kept for 4h.
b. Heating for 1h, heating to 1075 deg.C, and maintaining for 45min.
c. And rapidly cooling to 1065 ℃ within 15 min.
d. Slowly cooling at a cooling speed of 0.3-0.6K/h to grow for 100h.
e. And rapidly cooling along with the furnace within 4h to prepare the SmBCO high-temperature superconducting block material induced by the intermediate layer crystal.
The SmBCO sample obtained by the method has good single domain characteristics, and 4 growth radial lines are clearly visible.
Through the same performance test in the embodiment 1, the SmBCO superconducting bulk material obtained by the induced growth of the intermediate layer crystal and the bulk material which normally grows have consistent superconducting transition temperature and similar freezing magnetic field and magnetic suspension force.
Example 4
The method for recycling the intermediate layer crystal grown by the NdBCO fusion method to grow the superconducting bulk material comprises the following steps:
1. the Nd: ba: cu =1 2 O 3 、BaCO 3 And CuO powder, prepared as raw powders of Nd123 and Nd422, respectively;
2. the raw powder of Nd123 and Nd422 is fully and uniformly mixed and sintered for 48 hours at 900 ℃ in an air environment to obtain pure phase powder of Nd123 and Nd422. In order to ensure that pure-phase powder of Nd123 and Nd422 with uniform and single components is finally obtained, the sintered powder is ground and sintered again, and the same process is repeated for three times.
3. The obtained pure phase powder of Nd123 and Nd422 was compounded with the ingredients of 1mol Nd123+0.30mol Nd422+1wt% CeO2 (relative to the sum of the weight of the pure phase powder of Nd123 and Nd 422), thoroughly milled and mixed to homogeneity, obtaining a precursor powder.
4. And weighing the powder according to different diameters of the die, putting the powder into the die, and pressing 1 cylindrical precursor. If the die diameter is 20mm, 10g should be weighed. If the diameter of the die is 30mm, 30g is weighed.
5. The intermediate layer and the MgO substrate of the initial film seed were peeled from the grown intermediate layer-bearing NdBCO bulk using a utility knife or other cutting device. The middle layer is induced by seed crystals during the melt growth process to crystallize in the same way, and has an NdBCO lattice structure, so the middle layer is called as middle layer crystal. The intermediate layer crystals may be about 8mm or 4.5mm in diameter and kept ready for use.
6. And lightly grinding and polishing the side surface and the lower surface of the obtained NdBCO intermediate layer crystal by using fine sand paper, and placing the side surface and the lower surface of the obtained NdBCO intermediate layer crystal at the center of the upper surface of the NdBCO bulk precursor.
7. And placing the whole placed precursor in a growth furnace for growth by a top seed crystal melting texture method. The specific temperature program of the growth furnace is as follows:
a. the temperature is raised to 900 ℃ from the room temperature for 4h, and the temperature is kept for 4h.
b. Heating for 1h, heating to 1085 deg.C, and maintaining for 45min.
c. Within 40min, the temperature is reduced to 1075 ℃.
d. Slowly cooling at a cooling speed of 0.2-0.4K/h to grow for 100h.
e. Rapidly cooling along with the furnace within 4h to prepare the NdBCO high-temperature superconducting block material induced by the intermediate layer crystal.
The NdBCO sample obtained in the above way has good single domain characteristics, and 4 growth radial lines are clearly visible.
Through the same performance test in the example 1, the NdBCO superconducting bulk obtained by the induced growth of the intermediate layer crystal and the normally grown bulk have consistent superconducting transition temperature and similar freezing magnetic field and magnetic suspension force.
The foregoing detailed description of the preferred embodiments of the invention has been presented. It should be understood that numerous modifications and variations can be devised by those skilled in the art in light of the above teachings. Therefore, the technical solutions that can be obtained by logical analysis, reasoning or limited experiments based on the prior art by those skilled in the art according to the concept of the present invention, such as using NdBCO or SmBCO intermediate layer crystals with higher melting point to grow GdBCO or YBCO bulk materials with lower melting point, should be within the protection scope defined by the claims.

Claims (10)

1. A method for recycling intermediate layer crystal growth superconducting blocks grown by an REBCO fusion method comprises the following steps:
(1) According to the ratio of RE: ba: cu =1 2 O 3 、BaCO 3 And CuO powders, formulated as raw powders of RE123 and RE211, respectively;
(2) Fully and uniformly mixing the original powder, sintering for 40-50 hours at 890-910 ℃ in an air environment, grinding again, sintering, and repeating for three times to respectively obtain RE123 and RE211 pure-phase powder;
(3) Mixing 1mol of Re123 pure phase powder and 0.3mol of RE211 pure phase powder with CeO 2 Preparing and mixing to obtain precursor powder;
(4) Weighing the precursor powder, putting the precursor powder into a mold, and pressing the precursor powder into a precursor with a cylindrical shape;
(5) Stripping the MgO substrate of the lower intermediate layer crystal and the initial film seed crystal from the grown REBCO block with the intermediate layer;
(6) Grinding and polishing the side surface and the lower surface of the obtained REBCO intermediate layer crystal by using fine sand paper, and placing the crystal at the center of the upper surface of the REBCO bulk precursor;
(7) And (3) placing the placed whole precursor in a growth furnace to carry out top seed crystal melt texture method growth to prepare the intermediate layer crystal-induced REBCO high-temperature superconducting block.
2. The method of claim 1, wherein RE is selected from Y, gd, sm, nd.
3. The method according to claim 1, wherein in the step (2), the sintering is performed at 900 ℃ for 48 hours in an air atmosphere.
4. The method according to claim 1, wherein in the step (2), the CeO 2 Is added in an amount of 1wt% of the sum of the masses of the RE123 and RE211 pure phase powders.
5. The method according to claim 1, wherein in the step (4), when the diameter of the mold is 20mm, the precursor powder is weighed by 10g; or when the diameter of the die is 30mm, weighing 30g of the precursor powder.
6. The method according to claim 1, wherein in the step (7), the specific temperature program of the growth furnace is as follows:
a. heating to 900 ℃ from room temperature for 4h, and keeping the temperature for 4h;
b. continuing heating for 1h, heating to 10-15K above the melting point of the REBCO material, and keeping the temperature for 45min;
c. rapidly cooling to the melting point of the REBCO material within 6 min;
d. slowly cooling at a cooling speed of 0.3-0.6K/h for 100h;
e. and rapidly cooling along with the furnace within 4h.
7. Superconducting bulk material obtainable by the method according to any one of claims 1 to 6.
8. The superconducting bulk according to claim 7, wherein the superconducting bulk is selected from YBCO, gdBCO, smBCO, ndBCO.
9. The superconducting bulk according to claim 8, wherein when the diameter of the YBCO superconducting bulk is 16mm, the freezing magnetic field is 0.4-0.7T; or when the diameter of the YBCO superconducting block is 25mm, the freezing magnetic field is 0.6-0.9T.
10. The superconducting bulk material according to claim 8, wherein when the diameter of the YBCO superconducting bulk material is 16mm, the magnetic levitation force is 20N; or when the diameter of the YBCO superconducting block is 25mm, the suspension magnetic force is 50-70N.
CN202211513636.7A 2022-11-29 2022-11-29 Method for growing superconducting bulk by recycling REBCO bulk intermediate layer crystals Pending CN115787088A (en)

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