A design and preparation method for improving the force and thermal performance of YBCO composite superconducting bulk material

Abstract

This application discloses a design and fabrication method for synergistically improving the mechanical and thermal properties of YBCO composite superconducting bulk materials, comprising: S1, taking a dual-structure network composite of a continuously connected YBCO superconducting functional network and a metal mechanical and thermal reinforcement network as the core, and designing a continuously connected YBCO superconducting network and a corresponding metal mechanical and thermal reinforcement structure according to the low-temperature service load and heat conduction requirements, to obtain a composite structure with continuous and stable superconducting current path and structural reinforcement; S2, preparing YBCO precursor slurry and low-temperature metal reinforcement slurry respectively; S3, using a dual-nozzle additive manufacturing platform, loading the YBCO precursor slurry and low-temperature metal reinforcement slurry into different printing channels, and printing them layer by layer alternately according to the composite structure; S4, performing post-processing on the printed integral composite structure, and finally obtaining a YBCO / metal composite superconducting structure with continuous superconducting phase, effective mechanical support and complete thermal conduction path.

Description

Technical Field

[0001] This application relates to the field of composite superconducting material design and manufacturing, specifically to a design and preparation method for synergistically improving the mechanical and thermal properties of YBCO composite superconducting bulk materials. Background Technology

[0002] Superconducting materials are materials whose electrical resistance drops to zero and which completely repel magnetic fields at specific temperatures. Their main characteristics include zero resistance, perfect diamagnetism (Meissner effect), and quantization. Superconducting materials are widely used in power transmission (superconducting cables), medical imaging (MRI), particle accelerators, magnetic levitation trains, and quantum computing. Based on their properties and composition, superconducting materials can be classified into conventional superconductors, high-temperature superconductors, and organic superconductors, among which high-temperature superconductors are particularly important, with critical temperatures above 40K. YBCO has a critical temperature of approximately 92K and possesses advantages such as high critical temperature, high critical magnetic field, and high critical current, exhibiting particularly outstanding performance under liquid nitrogen cooling. It is currently recognized internationally as the most promising high-temperature superconducting material for applications. Current research on improving the mechanical and thermal properties of YBCO materials mainly focuses on composite methods such as silver addition, metal coating, fiber or particle reinforcement, pore structure control, and subsequent metal infiltration. These methods can improve the crack resistance, thermal conductivity, and processing adaptability of YBCO materials to some extent, but they still have the following shortcomings: On the one hand, existing composite processes mainly focus on material composition control or post-treatment reinforcement. The metallic phase, reinforcing phase, or pore structure are often difficult to design precisely according to the actual stress and heat conduction paths, making it difficult to form a three-dimensional reinforced structure with clear load-bearing, crack-limiting, and thermal conductivity functions. On the other hand, the distribution of the reinforcing phase in some composite methods has a certain degree of randomness, which can easily lead to problems such as local agglomeration, uneven interface bonding, and discontinuity in the reinforced region. While improving mechanical properties, this may adversely affect the continuity of the YBCO superconducting phase and the stability of superconducting performance. In addition, traditional YBCO composite processes usually have the characteristic of "preparing the superconducting ceramic body first and then performing subsequent reinforcement treatments," such as post-infiltration, coating, filling, or external reinforcement. The reinforcement structure is often introduced after the superconducting skeleton is formed, making it difficult to participate in the structural load-bearing and heat conduction of the material from the early stages of forming. For complex three-dimensional structures, subsequent composite processes may encounter problems such as insufficient metal filling, difficulty in fully connecting complex channels, cracking of the ceramic skeleton under pressure or heat, uncontrollable bonding at the two-phase interface, and residual stress concentration due to thermal expansion mismatch. Therefore, although existing processes can improve the individual properties of YBCO materials to some extent, systematic research and engineering methods for achieving synergistic improvement of the mechanical and thermal properties of YBCO bulk materials through structural design are still relatively lacking. Summary of the Invention

[0003] The purpose of this application is to provide a design and preparation method for synergistically improving the mechanical and thermal properties of YBCO composite superconducting bulk materials. The specific technical solution is as follows:

[0004] A design and fabrication method for synergistically improving the mechanical and thermal properties of YBCO composite superconducting bulk materials includes: S1, using a dual-structure network composite of a continuously connected YBCO superconducting functional network and a metal mechanical and thermal reinforcement network as the core, and designing a continuously connected YBCO superconducting network and a corresponding metal mechanical and thermal reinforcement structure according to the low-temperature service load and heat conduction requirements, to obtain a composite structure with continuous and stable superconducting current path and structural reinforcement; S2, preparing YBCO precursor slurry and low-temperature metal reinforcement slurry respectively; S3, using a dual-nozzle additive manufacturing platform, loading the YBCO precursor slurry and low-temperature metal reinforcement slurry obtained in S2 into different printing channels, and printing them layer by layer alternately according to the composite structure designed in S1, so that the YBCO precursor slurry and low-temperature metal reinforcement slurry obtained in S2 are integrally formed into the composite structure designed in S1; S4, performing post-processing on the integrally formed composite structure obtained in S3, and finally obtaining a YBCO / metal composite superconducting structure with continuous superconducting phase, effective mechanical support and complete thermal conduction path.

[0005] The preparation of YBCO precursor slurry in S2 includes: S2.1, mixing Y2O3, BaCO3, CuO and ethanol according to a preset ratio and grinding thoroughly to obtain submicron mixed precursor powder; S2.2, drying the mixed precursor powder in S2.1 to remove ethanol, and then taking a preset proportion of sodium carboxymethyl cellulose aqueous solution and epoxidized soybean oil and stirring to mix to obtain YBCO precursor slurry.

[0006] In S2, when preparing the low-temperature metal-reinforced slurry, the metal powder and water-based binder are thoroughly mixed according to the preset ratio to obtain the low-temperature metal-reinforced slurry. The metal powder is mainly composed of 316L or 316LN austenitic stainless steel powder, and copper powder and / or silver-coated copper powder are added according to the heat conduction requirements. The water-based binder includes polyvinyl alcohol, polyethylene glycol and deionized water in a preset ratio.

[0007] In S2.2, the mass ratio of the mixed precursor powder, sodium carboxymethyl cellulose aqueous solution, and epoxidized soybean oil is 15:8:2, and the mass fraction of the sodium carboxymethyl cellulose aqueous solution is 6 to 8 wt%.

[0008] When preparing low-temperature metal-reinforced slurry in S2, the mass ratio of polyvinyl alcohol, polyethylene glycol and deionized water in the water-based binder is 19:16:26, and the mass ratio of metal powder to water-based binder is 90:10 to 92:8.

[0009] When preparing low-temperature metal-reinforced slurry in S2, the mass fraction of copper powder and / or silver-coated copper powder added is 5 to 10 wt%.

[0010] When performing alternating layer-by-layer printing in S3, the deposition position, linewidth, layer height, nozzle spacing, and extrusion amount of the two materials are matched and controlled in the printing path of YBCO precursor slurry and low-temperature metal reinforced slurry. The adjacent deposition areas of YBCO precursor slurry and low-temperature metal reinforced slurry are designed to overlap, intersect, or partially overlap to ensure that the two slurries form close contact during the printing stage.

[0011] Post-processing in S4 includes: S4.1, subjecting the integrally formed composite structure from S3 to low-temperature cold casting at -40 to -45°C for 24 to 36 hours, followed by vacuum freeze-drying to obtain a YBCO / metal bimaterial composite billet; S4.2, subjecting the composite billet obtained in S4.1 to staged degreasing treatment to allow the YBCO... Organic components in the precursor slurry and metal-reinforced slurry are gradually removed to avoid structural cracking, interface debonding, and porosity defects caused by rapid heating or gas release; S4.3, Based on S4.2, YBCO superconducting phase formation is performed under an atmosphere at a sintering temperature of approximately 910 to 920°C for 20 to 30 hours, with a heating / cooling rate of approximately 1°C / min. After annealing, a YBCO / metal composite superconducting structure with a complete structure, continuous superconducting phase, and metal-reinforced phase distributed along a predetermined path is obtained; S4.4, The YBCO / metal composite superconducting structure obtained in S4.3 is oxygenated in an oxygen atmosphere at 400 to 450°C for 12 to 20 hours to improve superconducting performance and stabilize the continuous superconducting pathway.

[0012] The beneficial effects of this application lie in its innovative combination of mechanical structural design and dual-material synergistic additive manufacturing technology, with a core of a dual-structure network composite consisting of a continuously connected YBCO superconducting functional network and a designed metal mechanothermal reinforcement network. By pre-designing superconducting pathways, mechanical load-bearing pathways, and thermal conductivity pathways, the YBCO phase remains continuously connected throughout the overall structure, ensuring the continuous and stable superconducting current pathways. Simultaneously, the metal reinforcement phase can be placed in stress concentration areas, crack initiation-prone areas, or areas with high heat conduction requirements, forming a metal mechanothermal reinforcement structure with supporting, constraining, and thermally conductive functions. Subsequently, using dual-needle or multi-nozzle additive manufacturing technology, the YBCO precursor slurry and the low-temperature metal reinforcement slurry are alternately printed along a preset path, enabling the superconducting functional structure and the metal mechanothermal reinforcement structure to achieve spatial composite and integral molding during the forming stage. Compared to other composite methods, this avoids problems that may occur during post-impregnation, such as insufficient impregnation, uneven pore filling, ceramic skeleton damage under pressure, and uncontrollable interface bonding, thus improving the designability, forming consistency, and interface stability of the composite structure. This application not only provides a feasible new process route for the structural design and integrated fabrication of YBCO composite superconducting materials, but also offers a class of structured superconducting composite materials with both high damage resistance and good thermal conductivity for cryogenic engineering applications. The continuously connected YBCO superconducting functional network ensures superconducting performance, while the metal mechanothermal reinforcement network provides support, protection, and thermal conductivity enhancement for the brittle YBCO phase. This achieves a synergistic improvement in mechanical properties, thermal conductivity, and cryogenic service reliability while maintaining the stability and usability of the superconducting pathway. Compared to traditional bulk YBCO superconducting materials, single-reinforcement phase composite methods, and post-infiltration metal composite methods, this invention fully leverages the structural design and integrated molding advantages of dual-material synergistic 3D printing, providing new material preparation ideas for cryogenic high-field magnets, structured superconducting supports, and other complex cryogenic service components. Attached Figure Description

[0013] Figure 1 This is a flowchart illustrating the application process.

[0014] Figure 2 This is a schematic diagram of the printing area of ​​the dual-nozzle additive manufacturing platform in this application;

[0015] Wherein: 1-X-axis moving assembly, 2-Y-axis moving assembly, 3-Z-axis moving assembly, 4-collecting plate, 5-nozzle head moving assembly, 6-first nozzle, 7-second nozzle. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to specific embodiments and accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of this application. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concepts of this application.

[0017] like Figure 1 As shown, a design and fabrication method for synergistically improving the mechanical and thermal properties of YBCO composite superconducting bulk materials includes:

[0018] S1. A composite structure is designed with a continuously connected YBCO superconducting functional network and a metal-reinforced thermal network as its core. Based on the requirements of low-temperature service loads and heat conduction, a continuously connected YBCO superconducting network and a corresponding metal-reinforced thermal structure are designed to obtain a composite structure with continuous and stable superconducting current paths and structural reinforcement. In practical applications, by pre-designing superconducting, mechanically supported, and thermally conductive pathways, the YBCO phase is kept continuously connected throughout the overall structure, ensuring the continuous and stable superconducting current paths. Simultaneously, the metal reinforcement phase is placed in stress concentration areas, crack initiation-prone areas, or areas with high heat conduction requirements, forming a metal-reinforced thermal structure with supporting, constraining, and thermally conductive functions.

[0019] S2. Prepare YBCO precursor slurry and low-temperature metal-reinforced slurry respectively. Specifically, the preparation of YBCO precursor slurry includes: S2.1, mixing Y2O3, BaCO3, CuO and ethanol according to a preset ratio and grinding thoroughly to obtain submicron-sized mixed precursor powder; S2.2, drying the mixed precursor powder in S2.1 to remove ethanol, then taking a preset proportion of sodium carboxymethyl cellulose aqueous solution and epoxidized soybean oil and stirring to mix to obtain YBCO precursor slurry.

[0020] In preparing the low-temperature metal-reinforced slurry, metal powder and a water-based binder are thoroughly mixed according to a preset ratio to obtain the low-temperature metal-reinforced slurry. The metal powder is primarily composed of 316L or 316LN austenitic stainless steel powder, with copper powder and / or silver-coated copper powder added according to thermal conductivity requirements. The water-based binder includes polyvinyl alcohol, polyethylene glycol, and deionized water in a preset ratio. The mass ratio of the mixing precursor powder, sodium carboxymethyl cellulose aqueous solution, and epoxidized soybean oil is 15:8:2, and the mass fraction of the sodium carboxymethyl cellulose aqueous solution is 6 to 8 wt%. In preparing the low-temperature metal-reinforced slurry, the mass ratio of polyvinyl alcohol, polyethylene glycol, and deionized water in the water-based binder is 19:16:26, and the mass ratio of metal powder to water-based binder is 90:10 to 92:8. The mass fraction of copper powder and / or silver-coated copper powder added in preparing the low-temperature metal-reinforced slurry is 5 to 10 wt%.

[0021] S3. Using a dual-nozzle additive manufacturing platform, the YBCO precursor slurry and the low-temperature metal-reinforced slurry obtained in S2 are loaded into different printing channels, and printed layer by layer alternately according to the composite structure designed in S1. This is used to integrally form the YBCO precursor slurry and the low-temperature metal-reinforced slurry obtained in S2 into the composite structure designed in S1. In applications, such as... Figure 2 As shown, YBCO precursor slurry is loaded into the first nozzle 6, and low-temperature metal-reinforced slurry is loaded into the second nozzle 7. During the printing process, three-dimensional movement is achieved through the X-axis moving component 1, the Y-axis moving component 2, and the Z-axis moving component 3, respectively. The nozzle up-and-down moving component 5 controls the up-and-down movement of the first nozzle 6 and the second nozzle 7. The specific movement process is controlled by the additive manufacturing equipment, which is existing technology and will not be elaborated further. During layer-by-layer alternating printing, when a superconducting network structure needs to be printed, the additive manufacturing equipment controls the first nozzle 6 to move downward to the positioning point for printing. After printing, the first nozzle 6 returns to its original position. When a metal structure needs to be printed, the additive manufacturing equipment controls the second nozzle 7 to move downward to the positioning point (it should be noted that the positioning points of the first nozzle 6 and the second nozzle 7 are relatively independent points, and the additive manufacturing equipment selects them according to the printing requirements) for printing. After printing, the second nozzle 7 returns to its original position. This alternating process continues until the entire structure is printed on the collection plate 4.

[0022] S4. Post-processing is performed on the integrally formed composite structure obtained in S3 to finally obtain a YBCO / metal composite superconducting structure with continuous superconducting phase, effective mechanical support, and complete thermal conductivity path. Specifically, the post-processing includes: S4.1, subjecting the integrally formed composite structure in S3 to low-temperature cold casting at -40 to -45℃ for 24 to 36 hours, followed by vacuum freeze-drying to obtain a YBCO / metal bimaterial composite preform; S4.2, performing staged debinding treatment on the composite preform obtained in S4.1 to allow the YBCO phase to fully absorb the heat. Organic components in the precursor slurry and metal-reinforced slurry are gradually removed to avoid structural cracking, interface debonding, and porosity defects caused by rapid heating or gas release; S4.3, Based on S4.2, YBCO superconducting phase formation is performed under an atmosphere at a sintering temperature of approximately 910 to 920°C for 20 to 30 hours, with a heating / cooling rate of approximately 1°C / min. After annealing, a YBCO / metal composite superconducting structure with a complete structure, continuous superconducting phase, and metal-reinforced phase distributed along a predetermined path is obtained; S4.4, The YBCO / metal composite superconducting structure obtained in S4.3 is oxygenated in an oxygen atmosphere at 400 to 450°C for 12 to 20 hours to improve superconducting performance and stabilize the continuous superconducting pathway.

Claims

1. A design and fabrication method for synergistically improving the mechanical and thermal properties of YBCO composite superconducting bulk materials, characterized in that, include: S1. Taking the dual-structure network composite of a continuously connected YBCO superconducting functional network and a metal mechanical and thermal enhancement network as the core, based on the low-temperature service load and heat conduction requirements, a continuously connected YBCO superconducting network and a matching metal mechanical and thermal enhancement structure are designed to obtain a composite structure with continuous and stable superconducting current path and structural enhancement. S2. Prepare YBCO precursor slurry and low-temperature metal-reinforced slurry respectively; S3. Using a dual-nozzle additive manufacturing platform, the YBCO precursor slurry and the low-temperature metal reinforcing slurry obtained in S2 are loaded into different printing channels respectively, and printed layer by layer according to the composite structure designed in S1, so that the YBCO precursor slurry and the low-temperature metal reinforcing slurry obtained in S2 are integrally formed into the composite structure designed in S1. S4. Post-process the integrally formed composite structure printed in S3 to finally obtain a YBCO / metal composite superconducting structure with continuous superconducting phase, effective mechanical support and complete thermal conduction path.

2. The design and preparation method for synergistic improvement of the mechanical and thermal properties of YBCO composite superconducting bulk material as described in claim 1, characterized in that, The preparation of YBCO precursor slurry in S2 includes: S2.

1. Y2O3, BaCO3, CuO and ethanol are mixed according to the preset ratio and then ground thoroughly to obtain submicron mixed precursor powder; S2.2 After drying the mixed precursor powder in S2.1 to remove ethanol, take a preset proportion of sodium carboxymethyl cellulose aqueous solution and epoxidized soybean oil and stir to mix to obtain YBCO precursor slurry.

3. The design and preparation method for synergistic improvement of the mechanical and thermal properties of YBCO composite superconducting bulk material as described in claim 2, characterized in that, In step S2, when preparing the low-temperature metal-reinforced slurry, the metal powder and water-based binder are thoroughly mixed according to a preset ratio to obtain the low-temperature metal-reinforced slurry. The metal powder is mainly composed of 316L or 316LN austenitic stainless steel powder, and copper powder and / or silver-coated copper powder are added according to the thermal conductivity requirements. The water-based binder includes polyvinyl alcohol, polyethylene glycol and deionized water in a preset ratio.

4. The design and preparation method for synergistic improvement of the mechanical and thermal properties of YBCO composite superconducting bulk material as described in claim 3, characterized in that, In S2.2, the mass ratio of the mixed precursor powder, sodium carboxymethyl cellulose aqueous solution, and epoxidized soybean oil is 15:8:2, and the mass fraction of the sodium carboxymethyl cellulose aqueous solution is 6 to 8 wt%.

5. The design and preparation method for synergistically improving the mechanical and thermal properties of YBCO composite superconducting bulk material as described in claim 4, characterized in that, When preparing the low-temperature metal-reinforced slurry in S2, the mass ratio of polyvinyl alcohol, polyethylene glycol and deionized water in the water-based binder is 19:16:26, and the mass ratio of metal powder to water-based binder is 90:10 to 92:

8.

6. The design and preparation method for synergistic improvement of the mechanical and thermal properties of YBCO composite superconducting bulk material as described in claim 5, characterized in that, When preparing the low-temperature metal-reinforced slurry in S2, the mass fraction of copper powder and / or silver-coated copper powder added is 5 to 10 wt%.

7. The design and preparation method for synergistic improvement of the mechanical and thermal properties of YBCO composite superconducting bulk material as described in claim 1, characterized in that, In the S3 process, during alternating layer-by-layer printing, the deposition position, linewidth, layer height, nozzle spacing, and extrusion amount of the two materials are matched and controlled in the printing path of the YBCO precursor slurry and the low-temperature metal reinforced slurry. The adjacent deposition areas of the YBCO precursor slurry and the low-temperature metal reinforced slurry are designed to overlap, intersect, or partially overlap to ensure that the two slurries form close contact during the printing stage.

8. The design and preparation method for synergistic improvement of the mechanical and thermal properties of YBCO composite superconducting bulk material as described in claim 1, characterized in that, Post-processing in S4 includes: S4.1 After the composite structure integrally formed in S3 is subjected to low-temperature cold casting treatment at -40 to -45℃ for 24 to 36 hours, it is then freeze-dried under vacuum to obtain a YBCO / metal bimaterial composite billet. S4.

2. Perform a staged degreasing treatment on the composite preform obtained in S4.1 to gradually remove the organic components in the YBCO precursor slurry and the metal reinforcement slurry, thereby avoiding structural cracking, interface debonding and pore defects caused by rapid heating or gas release. S4.

3. Based on S4.2, YBCO superconducting phase formation treatment is carried out under an atmosphere, with a sintering temperature of about 910 to 920°C, a holding time of 20 to 30 hours, and a heating and cooling rate of about 1°C / min. After annealing, a YBCO / metal composite superconducting structure with complete structure, continuous superconducting phase, and metal reinforcement phase distributed along a preset path is obtained. S4.4 The YBCO / metal composite superconducting structure obtained in S4.3 is supplemented with oxygen in an oxygen atmosphere at 400 to 450°C for 12 to 20 hours to improve superconducting performance and stabilize the continuous superconducting pathway.

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