A high-toughness REBCO high-temperature superconducting target material and a preparation method thereof

Abstract

The application discloses a high-toughness REBCO high-temperature superconducting target material and a preparation method thereof, and belongs to the field of high-temperature superconducting materials. The target material is made of silver-coated REBCO particles through hot pressing forming, silver is distributed at the grain boundaries of the REBCO crystal to form a metal silver network, the REBCO particles are pure REBCO particles or doped REBCO particles, and RE is selected from Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu. The preparation method comprises the following steps: firstly, preparing a mixture of REBCO particles and silver powder through low-speed ball milling, then preparing silver-coated REBCO particles through high-speed ball milling, and finally preparing the high-toughness REBCO high-temperature superconducting target material through hot pressing forming. The high-toughness REBCO high-temperature superconducting target material has the characteristics of high density, high uniformity and high toughness, and effectively solves the problems of large brittleness, easy cracking, cracking and edge collapse in the processing and installation process of the hot-pressed REBCO target material.

Description

Technical Field

[0001] This invention belongs to the field of high-temperature superconducting materials, specifically relating to a high-toughness REBCO high-temperature superconducting target and its preparation method. Background Technology

[0002] Second-generation high-temperature superconductor (REBa2Cu3O) 7-δ REBCO (RE, where RE represents rare earth elements) targets are key raw materials for preparing REBCO superconducting thin films using physical vapor deposition (PVD) technology. Currently, commonly used hot-pressed REBCO powder-based REBCO targets often fail to achieve complete densification, exhibiting high porosity, particularly a large number of closed pores, with a density typically below 95%. In terms of microstructure, these targets are prone to abnormal grain growth, resulting in uneven microstructures. These structural defects lead to high brittleness and fragility, making them susceptible to cracking and edge chipping during processing and installation. Furthermore, during PVD deposition, target cracking interferes with deposition stability, while the poor thermal conductivity of the target can easily cause localized overheating, inducing large particle sputtering and rapid surface degradation, ultimately affecting the process stability and film quality of long-term continuous PVD deposition. Summary of the Invention

[0003] To address the problems of brittleness, fragility, and cracking and chipping during installation and use of existing hot-pressed REBCO targets, the main objective of this invention is to provide a method for preparing a high-toughness REBCO high-temperature superconducting target, selecting a median particle size (d... 50 REBCO particles of 1-5 µm and d 50 REBCO high-temperature superconducting targets were prepared by sequentially processing 5-30 µm flake silver particles through low-speed ball milling, high-speed ball milling, and hot pressing. Silver elements were introduced during the target preparation process and distributed at the REBCO grain boundaries, which significantly enhanced the toughness of the target.

[0004] Another object of the present invention is to provide the high-toughness REBCO high-temperature superconducting target, which is prepared by the above-described method for preparing silver-toughened REBCO high-temperature superconducting target.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a method for preparing a high-toughness REBCO high-temperature superconducting target, comprising the following steps:

[0007] S1. Select the median particle size (d) 50 REBCO particles of 1-5 µm and d 50Using 5-30 µm flake silver particles as raw material, they are put into a ball mill jar for low-speed ball milling. The milled particles are then sieved to obtain a uniformly mixed mixture of REBCO particles and silver powder.

[0008] S2. The uniformly mixed REBCO particles and silver powder mixture is placed in a ball mill jar for high-speed ball milling. High-purity argon is filled into the ball mill jar as a protective gas, and anhydrous ethanol is added as a process control agent. The ball-milled particles are sieved to obtain silver-coated REBCO particles.

[0009] S3. The silver-coated REBCO particles are placed in a target mold, loaded into a hot press, and argon or nitrogen is introduced as a protective gas. The mixture is kept at a temperature of 700-900 ℃ and a pressure of 10-100 MPa for 2-6 h. After hot pressing, the mixture is cooled in a furnace to obtain a high-toughness REBCO high-temperature superconducting target.

[0010] Preferably, the REBCO particles are pure REBCO particles or doped REBCO particles, obtained by uniformly mixing the doping material with pure REBCO particles;

[0011] The doping material is selected from one or more of BaMO3, Ba2RERO6, RE2O3, SiO2, and BaCuO2, M is selected from one of zirconium (Zr), hafnium (Hf), and tin (Sn), and R is selected from niobium (Nb) and / or tantalum (Ta).

[0012] RE represents rare earth elements, selected from one or more of the following: scandium (Sc), yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu).

[0013] Preferably, the REBCO particles are made of one or more of the following materials: ScBCO, YBCO, LaBCO, CeBCO, PrBCO, NdBCO, SmBCO, EuBCO, GdBCO, TbBCO, DyBCO, HoBCO, ErBCO, TmBCO, YbBCO, and LuBCO.

[0014] Preferably, the material of the REBCO particles is selected from RE1. x RE2 y RE3 z RE4 1-x-y-zIn the BCO, the values ​​of x, y, and z are all in the range of 0-1. RE1, RE2, RE3, and RE4 are selected from one of Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, and RE1, RE2, RE3, and RE4 are all different. Preferably, in step S1, the flake-like silver particles account for 1-10 wt% of the REBCO particles.

[0015] Preferably, in step S1, the ball-to-material ratio is 1:0.5-2, the grinding ball size is φ3-8 mm with φ5 mm accounting for more than 50%, the rotation speed is 50-100 rpm, the ball milling time is 0.5-1 h, and the milled particles pass through a 500-mesh sieve.

[0016] Preferably, in step S2, the amount of anhydrous ethanol added is 1-3% of the total mass of the uniformly mixed REBCO particles and silver powder mixture.

[0017] Preferably, in step S2, the ball-to-material ratio is 5-15:1, the grinding ball size is φ10-20 mm with φ10 mm accounting for more than 50%, the rotation speed is 100-250 rpm, the grinding time is 1-4 h, and the milled particles pass through a 500-mesh sieve.

[0018] Preferably, in step S3, the temperature is increased to 700-900 ℃ at a heating rate of 5-10 ℃ / min.

[0019] In a second aspect, the present invention provides a high-toughness REBCO high-temperature superconducting target, which is prepared by any of the above-described methods for preparing high-toughness REBCO high-temperature superconducting targets, wherein silver is distributed at the grain boundaries of the REBCO crystal to form a metallic silver network.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] 1. The high-toughness REBCO high-temperature superconducting target of the present invention is a silver-toughened REBCO high-temperature superconducting target, which has high density (density ≥ 85% of theoretical density), high uniformity, and high toughness (fracture toughness K). IC >8 MPa.m 1 / 2 The properties of this technology effectively solve the problems of high brittleness, easy breakage, and cracking and edge chipping that exist in existing hot-pressed REBCO sputtering materials during processing and installation.

[0022] 2. This invention introduces silver during the target preparation process, distributing it at the REBCO grain boundaries. The addition of silver effectively reduces the sintering activation energy, promotes the densification process, thereby inhibiting abnormal grain growth and reducing porosity. Simultaneously, the silver forms a continuous metallic network structure at the REBCO grain boundaries, significantly enhancing the toughness of the target, making it less prone to breakage during processing and installation, and also greatly improving the overall thermal conductivity of the target, reducing surface degradation. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of silver-coated REBCO particles in the embodiment.

[0024] Figure 2 This is a schematic diagram of the grain boundary structure on the surface of the high-toughness REBCO high-temperature superconducting target in the embodiment.

[0025] Figure 3 This is a photograph of the grain boundaries on the surface of the silver-toughened EuBCO high-temperature superconducting target material in Example 1. Detailed Implementation

[0026] To more fully understand and demonstrate the technical solutions, objectives, and advantages of the present invention, the technical effects produced by the present invention will be further described in detail and completely below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. It should be noted that other embodiments obtained by those skilled in the art without departing from the concept of the present invention are all within the protection scope of the present invention.

[0027] The following embodiments propose a high-toughness REBCO high-temperature superconducting target material, which is made by hot pressing silver-coated REBCO particles. The silver is distributed at the grain boundaries of the REBCO crystal to form a metallic silver network. The REBCO particles are doped REBCO particles, which are obtained by uniformly mixing the doping material with the REBCO particles. RE represents rare earth elements and is selected from one or more of Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu.

[0028] The doping material is selected from one or more of BaMO3, Ba2RERO6, RE2O3, SiO2, and BaCuO2; M is selected from one of Zr, Hf, and Sn; RE element is selected from one or more of Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu; and R is selected from Nb and / or Ta.

[0029] In some embodiments, the REBCO particle material formed from a single RE element is selected from one of ScBCO, YBCO, LaBCO, CeBCO, PrBCO, NdBCO, SmBCO, EuBCO, GdBCO, TbBCO, DyBCO, HoBCO, ErBCO, TmBCO, YbBCO, and LuBCO.

[0030] In some embodiments, the REBCO particles are made of RE1 material. x RE2 y RE3 z RE4 1-x-y-z BCO, where the values ​​of x, y, and z are all in the range of 0-1, and RE1, RE2, RE3, and RE4 are selected from one of Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, and RE1, RE2, RE3, and RE4 are all different.

[0031] The following embodiments also provide a method for preparing the above-mentioned high-toughness REBCO high-temperature superconducting target, including the following steps:

[0032] S1. Preparation of a mixture of REBCO particles and silver powder by low-speed ball milling: Select d 50 REBCO particles of 1-5 µm and d 50 Using 5-30 µm flake silver particles as raw material, they are put into a ball mill jar for low-speed ball milling. The milled particles are then sieved to obtain a uniformly mixed mixture of REBCO particles and silver powder.

[0033] S2. Preparation of silver-coated REBCO particles by high-speed ball milling: A uniformly mixed REBCO particle and silver powder mixture is placed in a ball mill jar for high-speed ball milling. High-purity argon is introduced into the jar as a protective gas, and anhydrous ethanol is added as a process control agent. The milled particles are sieved to obtain silver-coated REBCO particles, as shown below. Figure 1 As shown;

[0034] S3. Hot pressing for target preparation: Silver-coated REBCO particles are placed in a target mold, loaded into a hot press, and argon or nitrogen is introduced as a protective gas. The mixture is held at 700-900 ℃ and 10-100 MPa for 2-6 hours. After hot pressing, it is cooled in a furnace to obtain a high-toughness REBCO high-temperature superconducting target. Its grain boundary structure is as follows: Figure 2 As shown.

[0035] In some embodiments, in step S1, the flake silver particles are 1-10 wt% of REBCO particles.

[0036] In some embodiments, in step S1, the ball-to-material ratio is 1:0.5-2, the grinding ball size is φ3-8 mm with φ5 mm accounting for more than 50%, the rotation speed is 50-100 rpm, the ball milling time is 0.5-1 h, and the ball-milled particles pass through a 500-mesh sieve.

[0037] In some embodiments, in step S2, the amount of anhydrous ethanol added is 1-3% of the total mass.

[0038] In some embodiments, in step S2, the ball-to-material ratio is 5-15:1, the grinding ball size is φ10-20 mm with φ10 mm accounting for more than 50%, the rotation speed is 100-250 rpm, the ball milling time is 1-4 h, and the milled particles pass through a 500-mesh sieve.

[0039] In some embodiments, in step S3, the temperature is increased to 700-900 °C at a heating rate of 5-10 °C / min.

[0040] The above technical solutions of the present invention will be explained and illustrated below through specific embodiments.

[0041] Example 1

[0042] This embodiment prepares a silver-toughened EuBCO high-temperature superconducting target material, and the specific steps are as follows:

[0043] d 50 EuBCO particles of 5 µm with 5 wt% d 50 20µm flake silver particles were placed in a ball mill jar, and grinding balls with a diameter ratio of φ5:φ3:φ8=5:3:2 were added. The ball-to-particle ratio was 1:1. The mixture was ball-milled at 50 rpm for 1 h. The ball-milled powder was then passed through a 500-mesh sieve to obtain a uniformly mixed EuBCO and silver powder.

[0044] Next, the uniformly mixed EuBCO and silver powder are placed into a ball mill jar, and grinding balls with a diameter ratio of φ10:φ15:φ20=3:1:1 are added, with a ball-to-material ratio of 15:1. High-purity argon is filled into the ball mill jar as a protective gas, and anhydrous ethanol is added as a process control agent at a rate of 3% of the total mass of EuBCO and silver powder. The mixture is ball-milled at 200 rpm for 4 hours. The milled particles are then passed through a 500-mesh sieve to obtain silver-coated EuBCO particles.

[0045] Then, the silver-coated EuBCO particles were placed into a target mold and transferred to a hot press. Under vacuum, the temperature was increased to 850 °C at a rate of 5 °C / min, and a pressure of 10 MPa was applied. The temperature and pressure were maintained for 3 h. Afterward, the pressure was removed, and the material was cooled to room temperature in the furnace to obtain the silver-toughened EuBCO high-temperature superconducting target.

[0046] Tests showed that the grain boundaries on the surface of the aforementioned silver-toughened EuBCO high-temperature superconducting target material were as... Figure 3 As shown. The target density, measured by the Archimedes method, is 6.31 g / cm³. 3 (89.7% theoretical density), the fracture toughness of the target material measured by nanoindentation is 5.1 MPa.m. 1 / 2 .

[0047] Example 2

[0048] d 50 YBCO particles of 1 µm and 1 wt% d 50 Flake-shaped silver particles with a diameter of 5 µm were placed in a ball mill jar, and grinding balls with a diameter ratio of φ5:φ3:φ8=3:1:1 were added. The ball-to-material ratio was 1:2. The mixture was ball-milled at 100 rpm for 0.5 h. The ball-milled powder was then passed through a 500-mesh sieve to obtain a uniformly mixed YBCO and silver powder.

[0049] The uniformly mixed YBCO and silver powder were then placed into a ball mill jar, and grinding balls with a diameter ratio of φ10:φ15:φ20=5:3:2 were added, with a ball-to-material ratio of 5:1. High-purity argon was filled into the ball mill jar as a protective gas, and anhydrous ethanol was added as a process control agent at a rate of 2% of the total mass of YBCO and silver powder. The mixture was ball-milled at 250 rpm for 1 hour. The milled particles were then passed through a 500-mesh sieve to obtain silver-coated YBCO particles.

[0050] Then, the silver-coated YBCO particles were placed into a target mold and transferred to a hot press. Under an argon protective atmosphere, the temperature was increased to 700°C at a rate of 5°C / min, and a pressure of 100 MPa was applied. The temperature and pressure were maintained for 6 hours. Afterward, the pressure was removed, and the material was cooled to room temperature in the furnace to obtain the silver-toughened YBCO high-temperature superconducting target.

[0051] Testing revealed that the density of the silver-toughened YBCO high-temperature superconducting target, measured using the Archimedes method, was 6.07 g / cm³. 3 (90.6% theoretical density), the fracture toughness of the target material measured by nanoindentation is 12.1 MPa·m. 1 / 2 .

[0052] Example 3

[0053] d 50 3 µm BHO-doped GdBCO particles with 10 wt% d 50 10 µm flake silver particles were placed in a ball mill jar, and grinding balls with a ratio of φ5:φ3:φ8=5:3:2 were selected, with a ball-to-material ratio of 1:2. The mixture was ball-milled at 100 rpm for 1 h. After ball milling, the mixture was passed through a 500-mesh sieve to obtain a uniformly mixed BHO-doped GdBCO and silver powder.

[0054] Next, the uniformly mixed BHO-doped GdBCO and silver powder were placed into a ball mill jar, and grinding balls with a diameter ratio of φ10:φ15:φ20=6:3:1 were added, with a ball-to-material ratio of 10:1. The ball mill jar was filled with high-purity argon as a protective gas, and anhydrous ethanol was added as a process control agent at a rate of 2% of the total mass of BHO-doped GdBCO and silver powder. The mixture was ball-milled at 200 rpm for 2 hours. The milled particles were then passed through a 500-mesh sieve to obtain silver-coated BHO-doped GdBCO particles.

[0055] Then, silver-coated BHO-doped GdBCO particles were placed into a target mold and transferred to a hot press. Under a nitrogen protective atmosphere, the temperature was increased to 850 °C at a rate of 10 °C / min, and a pressure of 100 MPa was applied, holding the temperature and pressure for 6 h. Afterward, the pressure was removed, and the material was cooled to room temperature in the furnace to obtain a silver-toughened BHO-doped GdBCO high-temperature superconducting target.

[0056] Testing revealed that the density of the silver-toughened BHO-doped GdBCO high-temperature superconducting target, measured by the Archimedes method, was 6.85 g / cm³. 3 (89.9% theoretical density), the fracture toughness of the target material measured by nanoindentation is 9.6 MPa·m. 1 / 2 .

[0057] Example 4

[0058] d 50 Y with a diameter of 3 µm 0.5 Eu 0.2 Nd 0.1 Gd 0.2 BCO particles with 10 wt% d 50 Flake-shaped silver particles of 30 µm were placed in a ball mill jar. Grinding balls with a ratio of φ5:φ3:φ8 = 6:2:2 (ball-to-particle ratio 1:1) were used. The mixture was ball-milled at 100 rpm for 1 hour. After milling, the particles were passed through a 500-mesh sieve to obtain a uniformly mixed Yp. 0.5 Eu 0.2 Nd 0.1 Gd 0.2 BCO and silver powder.

[0059] Then mix the Y evenly 0.5 Eu 0.2 Nd 0.1 Gd 0.2 BCO and silver powder were placed in a ball mill jar, and grinding balls with a diameter ratio of φ10:φ15:φ20 = 3:1:1 were added, resulting in a ball-to-powder ratio of 10:1. The ball mill jar was filled with high-purity argon as a protective gas, and anhydrous ethanol was added as a process control agent at a dosage of Y. 0.5 Eu 0.2 Nd 0.1 Gd0.2 BCO and silver powder, at a total mass of 2%, were ball-milled at 200 rpm for 2 hours. The milled particles were then passed through a 500-mesh sieve to obtain silver-coated Y. 0.5 Eu 0.2 Nd 0.1 Gd 0.2 BCO granules.

[0060] Then, the silver-coated Y 0.5 Eu 0.2 Nd 0.1 Gd 0.2 BCO particles were placed into a target mold and transferred to a hot press. Under a nitrogen protective atmosphere, the temperature was increased to 800 °C at a rate of 10 °C / min, and a pressure of 60 MPa was applied, holding the temperature and pressure for 4 h. Afterwards, the pressure was removed, and the material was cooled to room temperature in the furnace to obtain silver-toughened Y. 0.5 Eu 0.2 Nd 0.1 Gd 0.2 BCO high-temperature superconducting target.

[0061] After testing, the above Y 0.5 Eu 0.2 Nd 0.1 Gd 0.2 The target density of BCO and silver powder, measured by the Archimedes method, was 6.90 g / cm³. 3 (90.5% theoretical density), the fracture toughness of the target material measured by nanoindentation is 11.3 MPa·m. 1 / 2 .

[0062] Example 5

[0063] d 50 YBCO particles doped with Y₂O₃ at 1 µm and 1 wt% d 50 Flake-shaped silver particles with a diameter of 15 µm were placed in a ball mill jar, and grinding balls with a diameter ratio of φ5:φ3:φ8=3:1:1 were added. The ball-to-material ratio was 1:2. The mixture was ball-milled at 100 rpm for 0.5 h. The ball-milled powder was then passed through a 500-mesh sieve to obtain a uniformly mixed Y2O3-doped YBCO and silver powder.

[0064] Next, the uniformly mixed Y2O3-doped YBCO and silver powder were placed in a ball mill jar, and grinding balls with a diameter ratio of φ10:φ15:φ20=5:3:2 were added, with a ball-to-material ratio of 5:1. High-purity argon was filled into the ball mill jar as a protective gas, and anhydrous ethanol was added as a process control agent at a rate of 2% of the total mass of Y2O3-doped YBCO and silver powder. The mixture was ball-milled at 250 rpm for 1 hour. The milled particles were then passed through a 500-mesh sieve to obtain silver-coated Y2O3-doped YBCO particles.

[0065] Then, silver-coated Y2O3-doped YBCO particles were placed into a target mold and transferred to a hot press. Under an argon protective atmosphere, the temperature was increased to 700°C at a rate of 5°C / min, and a pressure of 100 MPa was applied. The temperature and pressure were maintained for 6 hours. Afterward, the pressure was removed, and the material was cooled to room temperature in the furnace to obtain a silver-toughened Y2O3-doped YBCO high-temperature superconducting target.

[0066] Testing revealed that the density of the silver-toughened Y₂O₃-doped YBCO high-temperature superconducting target, measured by the Archimedes method, was 6.01 g / cm³. 3 (89.7% theoretical density), the fracture toughness of the target material measured by nanoindentation is 10.5 MPa·m. 1 / 2 .

[0067] Comparative Example 1

[0068] d 50 EuBCO particles of 5 µm were placed into a target mold and transferred to a hot press. The temperature was increased to 850 °C at a rate of 5 °C / min under vacuum, and a pressure of 10 MPa was applied. The temperature and pressure were held for 3 h. Afterward, the pressure was removed, and the material was cooled to room temperature in the furnace to obtain the EuBCO target.

[0069] The density of the EuBCO target, as measured by the Archimedes method, was 5.5 g / cm³. 3 The fracture toughness of the target material, measured by nanoindentation, is 1.1 MPa·m. 1 / 2 .

[0070] Comparative Example 2

[0071] d 50 EuBCO particles of 5 µm with 30 wt% d 50 Silver particles with a diameter of 20 µm were placed in a ball mill jar, and grinding balls with a diameter ratio of φ5:φ3:φ8=5:3:2 were added. The ball-to-particle ratio was 1:1. The mixture was ball-milled at 50 rpm for 3 hours. The ball-milled powder was then passed through a 500-mesh sieve to obtain a uniformly mixed EuBCO and silver powder.

[0072] Next, the uniformly mixed EuBCO and silver powder are placed into a ball mill jar, and grinding balls with a diameter ratio of φ10:φ15:φ20=3:1:1 are added, with a ball-to-material ratio of 15:1. The ball mill jar is filled with high-purity argon as a protective gas, and anhydrous ethanol is added as a process control agent at a rate of 3% of the total mass of EuBCO and silver powder. The mixture is ball-milled at 200 rpm for 4 hours. The milled particles are then passed through a 500-mesh sieve to obtain silver-coated EuBCO particles.

[0073] Then, the silver-coated EuBCO particles were placed into a target mold and transferred to a hot press. Under vacuum, the temperature was increased to 850 °C at a rate of 5 °C / min, and a pressure of 10 MPa was applied. The temperature and pressure were held for 3 h. Afterward, the pressure was removed, and the material was cooled to room temperature in the furnace to obtain the silver-toughened EuBCO target.

[0074] Testing revealed that the density of the silver-toughened EuBCO sputtering target, measured using the Archimedes method, was 6.7 g / cm³. 3 The fracture toughness of the target material, measured by nanoindentation, is 13.2 MPa·m. 1 / 2 However, the EuBCO film deposited using this target with optimized parameters exhibits a critical current density of only 0.1 MA / cm² under a self-field at 77 K. 2 It is evident that the EuBCO film prepared from this target material has poor performance due to excessive silver addition.

[0075] Comparative Example 3

[0076] d 50 EuBCO particles of 5 µm with 0.5 wt% d 50 Silver particles with a diameter of 20 µm were placed in a ball mill jar, and grinding balls with a diameter ratio of φ5:φ3:φ8=5:3:2 were added. The ball-to-material ratio was set to 1:1. The mixture was ball-milled at 50 rpm for 3 hours. The ball-milled powder was then passed through a 500-mesh sieve to obtain a uniformly mixed EuBCO and silver powder.

[0077] Next, the uniformly mixed EuBCO and silver powder were placed into a ball mill jar, and grinding balls with a diameter ratio of φ10:φ15:φ20=3:1:1 were added, with a ball-to-material ratio of 15:1. The ball mill jar was filled with high-purity argon as a protective gas, and anhydrous ethanol was added as a process control agent at a rate of 3% of the total mass of EuBCO and silver powder. The mixture was ball-milled at 200 rpm for 4 hours. The milled particles were then passed through a 500-mesh sieve to obtain partially silver-coated EuBCO particles.

[0078] Then, some of the silver-coated EuBCO particles were placed into a target mold and transferred to a hot press. Under vacuum, the temperature was increased to 850°C at a rate of 5°C / min, and a pressure of 10 MPa was applied. The temperature and pressure were maintained for 3 hours. Afterward, the pressure was removed, and the material was cooled to room temperature in the furnace to obtain the EuBCO target.

[0079] The density of the EuBCO target, as measured by the Archimedes method, was 5.92 g / cm³. 3 The fracture toughness of the target material measured by nanoindentation is 3 MPa·m. 1 / 2 .

[0080] Comparative Example 4

[0081] d50 EuBCO particles of 5 µm with 5 wt% d 50 Silver particles with a diameter of 20 µm were placed in a ball mill jar, and grinding balls with a diameter ratio of φ5:φ3:φ8=5:3:2 were added. The ball-to-particle ratio was 1:1. The mixture was ball-milled at 50 rpm for 3 hours. The ball-milled powder was then passed through a 500-mesh sieve to obtain a uniformly mixed EuBCO and silver powder.

[0082] Next, the uniformly mixed EuBCO and silver powder were placed into a ball mill jar, and grinding balls with a diameter ratio of φ10:φ15:φ20=3:1:1 were added, with a ball-to-material ratio of 15:1. The ball mill jar was filled with high-purity argon as a protective gas, and the balls were milled at 200 rpm for 4 hours. After milling, the particles clump together and cannot be used.

[0083] Comparative Example 5

[0084] d 50 EuBCO particles of 5 µm with 5 wt% d 50 20µm flake-shaped silver particles were placed in a ball mill jar, and grinding balls with a diameter ratio of φ5:φ3:φ8=5:3:2 were added. The ball-to-material ratio was 1:1. The mixture was ball-milled at 50 r for 1 h. The ball-milled powder was then passed through a 500-mesh sieve to obtain a uniformly mixed EuBCO and silver powder.

[0085] Next, the uniformly mixed EuBCO and silver powder are placed into a ball mill jar, and grinding balls with a diameter ratio of φ10:φ15:φ20=3:1:1 are added, with a ball-to-material ratio of 15:1. High-purity argon is filled into the ball mill jar as a protective gas, and anhydrous ethanol is added as a process control agent at a rate of 3% of the total mass of EuBCO and silver powder. The mixture is ball-milled at a speed of 200 r for 4 h. The milled particles are then passed through a 500-mesh sieve to obtain silver-coated EuBCO particles.

[0086] Then, the silver-coated EuBCO particles were placed into a target mold and transferred to a hot press. Under vacuum, the temperature was increased to 500 °C at a rate of 5 °C / min, and a pressure of 10 MPa was applied. The temperature and pressure were maintained for 3 hours. Afterward, the pressure was removed, and the target was cooled to room temperature in the furnace. The target was not formed.

[0087] The above are merely preferred embodiments of the present invention and are not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a high-toughness REBCO high-temperature superconducting target, characterized in that, Includes the following steps: S1. Select the median particle size d 50 REBCO particles of 1-5 µm and d 50 Using 5-30 µm flake silver particles as raw material, they are put into a ball mill jar for low-speed ball milling. The milled particles are then sieved to obtain a uniformly mixed mixture of REBCO particles and silver powder. S2. The uniformly mixed REBCO particles and silver powder mixture is placed in a ball mill jar for high-speed ball milling. High-purity argon is filled into the ball mill jar as a protective gas, and anhydrous ethanol is added as a process control agent. The ball-milled particles are sieved to obtain silver-coated REBCO particles. S3. The silver-coated REBCO particles are placed in a target mold, loaded into a hot press, and argon or nitrogen is introduced as a protective gas. The mixture is kept at a temperature of 700-900 ℃ and a pressure of 10-100 MPa for 2-6 h. After hot pressing, the mixture is cooled in a furnace to obtain a high-toughness REBCO high-temperature superconducting target.

2. The method for preparing the high-toughness REBCO high-temperature superconducting target according to claim 1, characterized in that, In step S1, the flake-shaped silver particles account for 1-10 wt% of the REBCO particles.

3. The method for preparing the high-toughness REBCO high-temperature superconducting target according to claim 1, characterized in that, In step S1, the ball-to-material ratio is 1:0.5-2, the grinding ball size is φ3-8 mm with φ5 mm accounting for more than 50%, the rotation speed is 50-100 rpm, the grinding time is 0.5-1 h, and the milled particles pass through a 500-mesh sieve.

4. The method for preparing the high-toughness REBCO high-temperature superconducting target according to claim 1, characterized in that, In step S2, the amount of anhydrous ethanol added is 1-3% of the total mass of the uniformly mixed REBCO particles and silver powder mixture.

5. The method for preparing the high-toughness REBCO high-temperature superconducting target according to claim 1, characterized in that, In step S2, the ball-to-material ratio is 5-15:1, the grinding ball size is φ10-20 mm with φ10 mm accounting for more than 50%, the rotation speed is 100-250 rpm, the ball milling time is 1-4 h, and the milled particles pass through a 500-mesh sieve.

6. The method for preparing the high-toughness REBCO high-temperature superconducting target according to claim 1, characterized in that, In step S3, the temperature is increased to 700-900 ℃ at a heating rate of 5-10 ℃ / min.

7. The method for preparing the high-toughness REBCO high-temperature superconducting target according to claim 1, characterized in that, The REBCO particles are pure REBCO particles or doped REBCO particles, wherein the doped REBCO particles are obtained by uniformly mixing the doping material with the pure REBCO particles. The doping material is selected from one or more of BaMO3, Ba2RERO6, RE2O3, SiO2, and BaCuO2, M is selected from one of Zr, Hf, and Sn, and R is selected from Nb and / or Ta; RE represents rare earth elements, selected from one or more of Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu.

8. The method for preparing the high-toughness REBCO high-temperature superconducting target according to claim 7, characterized in that, The REBCO particles are made of one or more of the following materials: ScBCO, YBCO, LaBCO, CeBCO, PrBCO, NdBCO, SmBCO, EuBCO, GdBCO, TbBCO, DyBCO, HoBCO, ErBCO, TmBCO, YbBCO, and LuBCO.

9. The method for preparing the high-toughness REBCO high-temperature superconducting target according to claim 7, characterized in that, The REBCO particles are made of RE1 material. x RE2 y RE3 z RE4 1-x-y-z BCO, where the values ​​of x, y, and z are all in the range of 0-1, and RE1, RE2, RE3, and RE4 are selected from one of Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, and RE1, RE2, RE3, and RE4 are all different.

10. A high-toughness REBCO high-temperature superconducting target, characterized in that, The high-toughness REBCO high-temperature superconducting target material is prepared by the method described in any one of claims 1 to 9, wherein silver is distributed at the grain boundaries of the REBCO crystal to form a metallic silver network.

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