CN113430646B - A method for the growth of REBCO superconducting bulk materials induced by single-seed bridge structure - Google Patents

Abstract

The invention provides a method for inducing the growth of REBCO superconducting bulk materials by utilizing a single seed crystal bridge structure, comprising the following steps: preparing RE123 and RE211 pure phase powders, preparing according to the components of RE123+30mol% RE211+1wt% CeO2, fully Milling and mixing uniformly to obtain precursor powder; according to the diameter of the mold, the powder is weighed to an appropriate quality, put into the mold, and pressed into a cylindrical seed crystal bridge, 2 to 3 buffer layers and a precursor 1 place the seed crystal, the seed crystal bridge, the buffer layer, and the precursor in sequence from top to bottom; the seed crystal, the seed crystal bridge, and the buffer layer form a single-seed crystal bridge structure; wherein, the seed crystal The crystal is placed in the center of the upper surface of the seed crystal bridge, the seed crystal bridge is erected above the buffer layer, and the buffer layer is arranged in a row along the [110] crystal direction of the seed crystal; The precursor together with the single-seed bridge structure is placed in a growth furnace for top seed melt texture growth, so as to achieve (110)∥(110) orientation induced growth of REBCO superconducting bulk.

Description

A method for the growth of REBCO superconducting bulk materials induced by single-seed bridge structure

technical field

The invention belongs to the technical field of superconducting material growth methods, and in particular relates to a method for realizing (110)∥(110) orientation induced growth of REBCO superconducting bulk materials by utilizing thin film seed crystals combined with a bridge structure.

Background technique

Since REBa ₂ Cu ₃ O _7-δ (referred to as REBCO, RE123, rare earth barium copper oxide, where RE is selected from Y, Gd, Sm, Nd, etc.) high-temperature superconductor was discovered, because of its complete diamagnetism, high critical current density and The huge commercial potential brought by properties such as high freezing magnetic fields, such as flywheel energy storage, permanent magnets, magnetic levitation force elements, etc., has attracted widespread attention. As an inevitable prerequisite for application, the preparation of REBCO blocks with large size and high performance is a problem that must be solved. So far, Top-Seeded Melt Textured Growth (TSMTG) is generally considered to be a promising method for preparing REBCO high-temperature superconducting bulk materials. During the growth process, a single seed crystal is placed in the center of the upper surface of the REBCO precursor, as the only nucleation point to induce the REBCO bulk to solidify and grow according to the seed crystal orientation, and finally form a single c-axis oriented single-domain superconducting bulk material . However, due to the low growth rate of RE123, it takes a long time to obtain large-sized superconducting bulk materials; and excessive growth time will lead to problems such as spontaneous nucleation and grain coarsening of high-temperature phase RE211. Therefore, it is particularly important to shorten the preparation time for large-sized samples.

The multi-seed melt texture method is an extremely effective method to solve the excessive growth time of superconducting bulk materials, that is, placing multiple seed crystals in a certain orientation on the upper surface of the sample. Since multiple seed crystals induce growth at the same time, the time required for the entire preparation process is greatly shortened. However, the study found that because the traditional multi-seed method is generally placed at (100)∥(100), a large number of non-superconducting phases will remain at the grain boundary of the sample, which hinders the superconducting current loop from passing through the grain boundary, and eventually leads to the existence of multiple non-superconducting phases inside the sample. A small superconducting current loop instead of a whole large superconducting current loop, the overall performance is greatly reduced. At the same time, in the process of traditional multi-seed equidistant placement to induce bulk preparation, with the increase of the number of seeds used, the weak connection of grain boundaries inside the bulk will be further reduced, thereby reducing the superconducting properties of the bulk.

SUMMARY OF THE INVENTION

In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a method for realizing (110)∥(110) orientation induced growth of REBCO superconducting bulk materials by utilizing thin film seed crystals and combining bridge structures, which is used for more Cost-effectively promote the application of REBCO superconducting bulk materials.

The present invention provides a method for realizing (110)∥(110) orientation induced growth of REBCO superconducting bulk material with a single seed crystal bridge structure, comprising the following steps:

Step 1, according to the ratio of RE:Ba:Cu=1:2:3 and RE:Ba:Cu=2:1:1, RE ₂ O ₃ , BaCO ₃ and CuO powders are formulated into the original powders of RE123 and RE211.

In step 2, the original powder is fully mixed and sintered at 900° C. for 48 hours in an air environment. In order to ensure that RE123 and RE211 phases with uniform and single composition are finally obtained, the sintered powders are ground and sintered again, and the same process is repeated three times in total.

In step 3, the pure phase powders of RE123 and RE211 obtained in step ₂ are prepared according to the components of RE123+30mol% RE211+1wt% CeO2, fully milled and mixed uniformly to obtain precursor powder.

Step 4: According to the different diameters of the molds, the powder is weighed into a suitable mass, put into the mold, and pressed into one cylindrical seed bridge, two to three buffer layers and one precursor.

Step 5, place the seed crystal, the seed crystal bridge, the buffer layer, and the precursor in sequence from top to bottom; the seed crystal, the seed crystal bridge, and the buffer layer form a single-seed crystal bridge structure; wherein, the The seed crystal is placed in the center of the upper surface of the seed crystal bridge, the seed crystal bridge is erected above the buffer layer, and the buffer layer is arranged in a row along the [110] crystal direction of the seed crystal (that is, in the seed crystal [110] crystal direction. 110] on the extension of the crystal orientation).

Step 6, placing the precursor together with the single-seed bridge structure in a growth furnace to perform top seed melting texture growth.

Further, the top seed melt texture growth process includes the following steps:

raising the temperature in the growth furnace to the first temperature within the first time, and keeping the temperature for 1-3 hours;

raising the temperature in the growth furnace to a second temperature within a second time, and keeping the temperature for 1 to 3 hours;

lowering the temperature in the growth furnace to a third temperature within a third time;

reducing the temperature in the growth furnace to a fourth temperature within a fourth time;

Finally, quenched to obtain REBCO superconducting bulk.

Further, the first time is 3-5 hours, the first temperature is 850-950° C.; the second time is 1-2 hours, and the second temperature is higher than the REBCO superconducting material. The peritectic reaction temperature is 40 to 80°C; the third time is 0.5 to 1 hour, and the third temperature is the peritectic reaction temperature of the REBCO material; the fourth time is 10 to 80 hours, and the third temperature is 10 to 80 hours. The temperature is 5-40°C lower than the peritectic reaction temperature.

Optionally, the number of buffer layers is 2-3, which is selected according to the size of the block material that needs to be grown.

Preferably, the seed crystal is an NdBCO/YBCO/MgO thin film seed crystal.

Preferably, the size of the seed crystal is 2mm×2mm.

Further, the precursor can also be doped with cerium oxide, platinum, etc. to suppress the melt loss.

Further, the diameter of the seed bridge is 10mm, and generally needs to be weighed 0.6g to be pressed; the diameter of the buffer layer is 5mm, and generally needs to be weighed 0.15-0.2g to be pressed; the diameter of the precursor is greater than or equal to 30mm.

Further, RE in the REBCO superconducting material is Y, Gd, Sm or Nd.

The present invention provides a method for realizing (110)∥(110) orientation induced growth of REBCO superconducting bulk material by utilizing a single seed crystal bridge structure, which has the following beneficial effects:

1. The present invention adopts the multi-seed arrangement of (110)∥(110), which effectively avoids the generation of (100)/(100) grain boundaries between different seed crystals, and can effectively discharge the residual melt at the grain boundaries. It is beneficial to improve the performance of REBCO block.

2. The present invention realizes the effect of multi-seed induction through the structure of the seed crystal bridge combined with the buffer layer, which can not only effectively shorten the time for growing the bulk material, but also ensure the orientation between multiple "seed crystals" (actually each buffer layer). Consistent. The method is simple, easy to operate, and repeatable and controllable.

3. The present invention only needs one seed crystal to achieve the goal, uses less material, can effectively reduce the time cost and economic cost of REBCO superconducting block material preparation, and has a positive effect on saving resources and improving resource utilization rate, and has a positive effect on ecological Environmental protection has a positive impact.

4. Since the present invention adopts the thin film seed crystal with high thermal stability, it is also applicable to the orientation-induced growth of REBCO (such as GdBCO, SmBCO, NdBCO, etc.) bulk materials with high peritectic reaction temperature.

Description of drawings

The present invention will be further described below with reference to the accompanying drawings.

Figure 1 illustrates the formation and growth process of the (100)/(100) grain boundary when the traditional polyseed crystal is placed at 0°; the arrows indicate the direction of the growth front.

Figure 2 illustrates the formation and growth process of the (110)/(110) grain boundary when the multi-seed crystal is placed at 45°; the arrows indicate the direction in which the growth front moves forward.

Figure 3 illustrates a GdBCO bulk sample grown using a four-seed 45° placement; the arrows indicate the growth lines of the grains on the left side of the photo.

FIG. 4 is a schematic diagram of the seed positions and the growth process corresponding to the two growth methods when the GdBCO bulk sample is grown using the four-seed 45° placement method.

Figure 5 shows the top view of the sample with single-seed bridge structure to achieve (110)∥(110) orientation induction; (a)-(d) show the change of crystal growth with time when two buffer layers are used.

Figure 6 shows the growth of the crystal when three buffer layers are used in the single-seed bridge structure.

FIG. 7 illustrates a cross-sectional view of a sample in which the single-seed bridge structure uses two buffer layers to achieve (110)∥(110) orientation induction.

FIG. 8 illustrates the cross-sectional view of the sample in which the single-seed bridge structure uses three buffer layers to achieve (110)∥(110) orientation induction.

FIG. 9 illustrates the crystal-induced growth of the single-seed bridge structure using 4 buffer layers (top view of the sample).

Detailed ways

The embodiments of the present invention are described below through specific specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

The inventive concept of the present invention is as follows:

In the traditional multi-seed melt texturing method, most of the seed crystals are arranged in the (100)∥(100) orientation (hereinafter referred to as 0° arrangement). As the growth front advances, the high temperature and impurity phases in the bulk material are pushed out accordingly. Taking 2 seed crystals as an example, as shown in Figure 1, since the (100) crystal plane contacts in the form of a whole plane to generate grain boundaries, the non-superconducting phase at the growth front has no chance to be excluded and captured. near grain boundaries. Such grain boundaries enriched in non-superconducting phases, known as "contaminated" grain boundaries, impede the passage of superconducting current loops and greatly degrade the performance of the bulk material.

The difference is that if multiple seed crystals are arranged in the orientation of (110)∥(110) (hereinafter referred to as 45° arrangement), there will be no "contaminated" grain boundaries. Taking 2 seed crystals as an example, as shown in Figure 2, since the (110) crystal plane contacts in the form of a point to generate grain boundaries when arranged at 45°, the non-superconducting phase at the growth front will not be captured at this time. into the grain boundary. Furthermore, these non-superconducting phases are also pushed towards the edge of the sample as the growth continues, ensuring "cleanness" throughout the sample. Therefore, the (110)/(110) grain boundary will not hinder the passage of the superconducting current loop, thereby improving the performance of the multi-seed-induced growth bulk material. On the other hand, it is well known that for REBCO system superconducting materials, the (110) crystal face is a non-equilibrium growth face, so it is also a fast growth face. When multi-seed crystals are arranged at 45°, this advantage of rapid growth helps to further shorten the sample preparation time on the basis of simultaneous growth of multiple seed crystals, which is especially suitable for large-sized samples and meets the needs of industrialization.

The disadvantage is that, first of all, the 45° arrangement does not change the number of seeds used. For industrial application requirements, such a growth method undoubtedly has a much higher cost than the single-seed method. Secondly, the 45° arrangement of seed crystals is theoretically easy to achieve, but in fact, due to manual operation or seed crystal drift under high temperature melting state, it is easy to appear that individual seed crystals and other seed crystals do not fully display 45 ° Arrange. For the GdBCO bulk grown with four seed crystals as shown in Figure 3, the two seed crystals on the left did not fully achieve (110)∥(110) when placed, resulting in the induced grain boundary without (110)/(110 ) fast growth characteristics of grain boundaries, and more likely to trap the non-superconducting phase to some extent during the growth process. In contrast, the two seeds on the right are in a standard 45° arrangement. Figure 4 shows the seed positions and growth processes corresponding to the two growth modes.

Based on the advantages and disadvantages of the above 45° arrangement of multi-seed crystals, the present invention eliminates its disadvantages on the premise of retaining its advantages, and at the same time reduces the number of seeds used and greatly reduces the cost. Specifically, through the use of seed bridges, a single seed crystal has the ability to induce multiple buffer layers at the same time, and the buffer layers will play the role of secondary seed crystals and continue to induce precursors after the growth is complete. At this time, the precursor is induced by multiple buffer layers at the same time, and the effect of multiple seeds is realized. On the other hand, because the buffer layers are all induced by the same seed crystal through growth, there will be a fixed and consistent (110)∥(110) orientation between these buffer layers, thus avoiding the 45° alignment Defects caused by the most influential manual operations in the method. As a result, the two most important advantages of fast growth capability and "clean" grain boundaries of 45° arrangement are also guaranteed. Figures 5 to 8 show the top view and cross-sectional view of the sample in which the single-seed bridge structure realizes (110)∥(110) orientation induction, respectively. In Figures 5-6, 501 and 601 denote the equilibrium shape of the crystallographic domain tendencies in the states shown, 502 and 602 denote clean (110)/(110) grain boundaries obtained using the method described in the present invention, and arrows 503 and 603 denote The direction in which the growth front moves forward. In FIGS. 7-8, 701 and 801 represent thin film seeds, 702 and 802 represent seed bridges, and 703 and 803 represent buffer layers. The difference between using 2 and 3 buffer layers is also reflected in the figure. Obviously, under the same growth time, the equilibrium crystal plane shape obtained by using 3 buffer layers is larger, which is also conducive to the preparation of larger size bulk materials. . It is worth mentioning that, as shown in FIG. 9 , the single-seed bridge structure cannot achieve the purpose of the present invention when four buffer layers are used, because at this time, due to the center-symmetrical arrangement, the buffer layers are finally arranged between multiple buffer layers. Still (100)/(100) grain boundaries are formed, not (110)/(110) grain boundaries.

Based on the above concept, the present invention provides a method for realizing (110)∥(110) orientation-induced growth of REBCO superconducting bulk material with a single-seed bridge structure, comprising the following steps:

Step 1, according to the ratio of RE:Ba:Cu=1:2:3 and RE:Ba:Cu=2:1:1, RE ₂ O ₃ , BaCO ₃ and CuO powders are prepared into original powders of RE123 and RE211;

In step 2, the original powder is fully mixed and sintered at 900° C. for 48 hours in an air environment. In order to ensure that RE123 and RE211 phases with uniform and single composition are finally obtained, the sintered powders are ground and sintered again, and the same process is repeated three times in total.

In step 3, the obtained pure phase powder is prepared according to the components of RE123 ₊ 30mol% RE211+1wt% CeO2, fully milled and mixed uniformly to obtain a precursor powder.

Step 4: According to the different diameters of the molds, the powder is weighed into a suitable mass, put into the mold, and pressed into one cylindrical seed bridge, two to three buffer layers and one precursor.

In step 5, the seed crystal, the seed crystal bridge, the buffer layer and the precursor are placed in order from top to bottom according to the described layers.

Step 6, placing the placed precursor together with the single-seed bridge structure in a growth furnace to perform top seed melting texture growth.

The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. The following examples do not constitute a limitation of the present invention.

Example 1

A method for realizing (110)∥(110) orientation-induced growth of a YBCO superconducting bulk material with a single-seed bridge structure in this embodiment includes the following steps:

1. According to the ratio of Y:Ba:Cu=1:2:3 and Y:Ba:Cu=2:1:1, Y ₂ O ₃ , BaCO ₃ and CuO powders were prepared into the original powders of Y123 and Y211;

2. Mix the original powder evenly and sinter at 900℃ for 48 hours in an air environment. In order to ensure that the Y123 and Y211 phases with uniform and single composition are finally obtained, the sintered powder is ground and sintered again, and the same process is repeated three times in total.

3. The obtained pure phase powder is prepared according to the components of Y123 ₊ 30mol% Y211+1wt% CeO2, fully milled and mixed uniformly to obtain precursor powder.

4. According to the different diameters of the molds, the powder is weighed into a suitable mass, put into the mold, and pressed into one cylindrical seed bridge, two to three buffer layers and one precursor. The diameter of the seed crystal bridge is 10mm, and it generally needs to be weighed 0.6g for pressing; the diameter of the buffer layer is 5mm, and it generally needs to be weighed 0.15-0.2g for pressing; the diameter of the precursor is 30mm, and it needs to be weighed 30g.

5. The seed crystal, the seed crystal bridge, the buffer layer and the precursor are placed in order from top to bottom according to the described layers. Specifically, a NdBCO/YBCO/MgO thin film seed crystal with a size of 2mm×2mm oriented along the c-axis was placed in the center of the upper surface of the seed bridge, and the buffer layer was arranged in a row along the [110] crystal direction of the seed crystal (ie On the extension line of the seed crystal [110] orientation).

6. Place the placed precursor together with the single-seed bridge structure in a growth furnace for melting texture growth of the top seed crystal. The specific temperature program of the growth furnace is:

a. The temperature is raised from room temperature to 900°C for 4 hours, and the temperature is kept for 4 hours.

b. Continue to heat for 1 hour, raise the temperature to 1065°C, and keep the temperature for 1 hour.

c. Within 30min, rapidly cool down to 1005℃.

d. Slowly cool down and grow at a cooling rate of 0.3°C/h for 100h.

e. Rapidly cooling with the furnace within 4h to obtain the (110)∥(110) orientation-induced YBCO high temperature superconducting bulk material.

Embodiment 2

A method for realizing (110)∥(110) orientation-induced growth of a GdBCO superconducting bulk material with a single-seed bridge structure in this embodiment includes the following steps:

1. According to the ratio of Gd:Ba:Cu=1:2:3 and Gd:Ba:Cu=2:1:1, Gd ₂ O ₃ , BaCO ₃ and CuO powders were prepared into original powders of Gd123 and Gd211;

2. Mix the original powder evenly and sinter at 900℃ for 48 hours in an air environment. In order to ensure that the Gd123 and Gd211 phases with uniform and single composition are finally obtained, the sintered powder is ground and sintered again, and the same process is repeated three times in total.

3. The obtained pure phase powder is prepared according to the components of Gd123 ₊ 30mol% Gd211+1wt% CeO2, fully milled and mixed uniformly to obtain precursor powder.

4. According to the different diameters of the molds, the powder is weighed into a suitable mass, put into the mold, and pressed into one cylindrical seed bridge, two to three buffer layers and one precursor. The diameter of the seed crystal bridge is 10mm, and it generally needs to be weighed 0.6g for pressing; the diameter of the buffer layer is 5mm, and it generally needs to be weighed 0.15-0.2g for pressing; the diameter of the precursor is 30mm, and it needs to be weighed 30g.

5. The seed crystal, the seed crystal bridge, the buffer layer and the precursor are placed in order from top to bottom according to the described layers. Specifically, a NdBCO/YBCO/MgO thin film seed crystal with a size of 2mm×2mm oriented along the c-axis was placed in the center of the upper surface of the seed bridge, and the buffer layer was arranged in a row along the [110] crystal direction of the seed crystal (ie On the extension line of the seed crystal [110] orientation).

6. Place the placed precursor together with the single-seed bridge structure in a growth furnace for melting texture growth of the top seed crystal. The specific temperature program of the growth furnace is:

a. The temperature is raised from room temperature to 900°C for 4 hours, and the temperature is kept for 4 hours.

b. Continue to heat for 1 hour, raise the temperature to 1095°C, and keep the temperature for 1 hour.

c. Within 30min, rapidly cool down to 1045℃.

d. Slowly cool down and grow at a cooling rate of 0.3°C/h for 100h.

e. Rapid cooling with the furnace within 4h to obtain (110)∥(110) orientation-induced GdBCO high-temperature superconducting bulk.

Embodiment 3

A method for realizing (110)∥(110) orientation-induced growth of a SmBCO superconducting bulk material with a single-seed bridge structure in this embodiment includes the following steps:

1. According to the ratio of Sm:Ba:Cu=1:2:3 and Sm:Ba:Cu=2:1:1, Sm ₂ O ₃ , BaCO ₃ and CuO powders are prepared into the original powders of Sm123 and Sm211;

2. Mix the original powder evenly and sinter at 900℃ for 48 hours in an air environment. In order to ensure that the Sm123 and Sm211 phases with uniform and single composition are finally obtained, the sintered powder is ground and sintered again, and the same process is repeated three times in total.

3. The obtained pure phase powder is prepared according to the components of Sm123+30mol% Sm211 ₊ 1wt% CeO2, fully milled and mixed uniformly to obtain the precursor powder.

4. According to the different diameters of the molds, the powder is weighed into a suitable mass, put into the mold, and pressed into one cylindrical seed bridge, two to three buffer layers and one precursor. The diameter of the seed crystal bridge is 10mm, and it generally needs to be weighed 0.6g for pressing; the diameter of the buffer layer is 5mm, and it generally needs to be weighed 0.15-0.2g for pressing; the diameter of the precursor is 30mm, and it needs to be weighed 30g.

5. The seed crystal, the seed crystal bridge, the buffer layer and the precursor are placed in order from top to bottom according to the described layers. Specifically, a NdBCO/YBCO/MgO thin film seed crystal with a size of 2mm×2mm oriented along the c-axis was placed in the center of the upper surface of the seed bridge, and the buffer layer was arranged in a row along the [110] crystal direction of the seed crystal (ie On the extension line of the seed crystal [110] orientation).

6. Place the placed precursor together with the single-seed bridge structure in a growth furnace for melting texture growth of the top seed crystal. The specific temperature program of the growth furnace is:

a. The temperature is raised from room temperature to 900°C for 4 hours, and the temperature is kept for 4 hours.

b. Continue to heat for 1 hour, raise the temperature to 1100°C, and keep the temperature for 1 hour.

c. Within 30min, rapidly cool down to 1065℃.

d. Slowly cool down and grow at a cooling rate of 0.3°C/h for 100h.

e. Rapid cooling with the furnace within 4h to obtain (110)∥(110) orientation-induced SmBCO high temperature superconducting bulk material.

Embodiment 4

A method for realizing (110)∥(110) orientation-induced growth of NdBCO superconducting bulk material with a single-seed bridge structure in this embodiment includes the following steps:

1. According to the ratio of Nd:Ba:Cu=1:2:3 and Nd:Ba:Cu=4:2:2, Nd ₂ O ₃ , BaCO ₃ and CuO powders were prepared into original powders of Nd123 and Nd211;

2. Mix the original powder evenly and sinter at 900℃ for 48 hours in an air environment. In order to ensure that the Nd123 and Nd211 phases with uniform and single composition are finally obtained, the sintered powder is ground and sintered again, and the same process is repeated three times in total.

3. The obtained pure phase powder is prepared according to the components of Nd123 ₊ 30mol% Nd211+1wt% CeO2, fully milled and mixed uniformly to obtain the precursor powder.

4. According to the different diameters of the molds, the powder is weighed into a suitable mass, put into the mold, and pressed into one cylindrical seed bridge, two to three buffer layers and one precursor. The diameter of the seed crystal bridge is 10mm, and it generally needs to be weighed 0.6g for pressing; the diameter of the buffer layer is 5mm, and it generally needs to be weighed 0.15-0.2g for pressing; the diameter of the precursor is 30mm, and it needs to be weighed 30g.

5. The seed crystal, the seed crystal bridge, the buffer layer and the precursor are placed in order from top to bottom according to the described layers. Specifically, a NdBCO/YBCO/MgO thin film seed crystal with a size of 2mm×2mm oriented along the c-axis was placed in the center of the upper surface of the seed bridge, and the buffer layer was arranged in a row along the [110] crystal direction of the seed crystal (ie On the extension line of the seed crystal [110] orientation).

6. Place the placed precursor together with the single-seed bridge structure in a growth furnace for melting texture growth of the top seed crystal. The specific temperature program of the growth furnace is:

a. The temperature is raised from room temperature to 900°C for 4 hours, and the temperature is kept for 4 hours.

b. Continue to heat for 1 hour, raise the temperature to 1120°C, and keep the temperature for 1 hour.

c. Within 30min, rapidly cool down to 1090℃.

d. Slowly cool down and grow at a cooling rate of 0.3°C/h for 100h.

e. Rapid cooling with the furnace within 4 hours to obtain (110)∥(110) orientation-induced NdBCO high temperature superconducting bulk materials.

The invention provides a method for realizing (110)∥(110) orientation induced growth of REBCO high temperature superconducting bulk material by utilizing thin film seed crystal combined with bridge structure. The present invention utilizes a seed crystal bridge and a buffer layer to form a bridge-type seed crystal structure, realizes the effect of multiple seed crystals by using a single seed crystal, and achieves the effect of accelerating growth. At the same time, by adopting a specific arrangement along the [110] crystal direction, the lower buffer layer realizes the (110)∥(110) orientation induced growth of the buffer layer to the bulk material. Since the (110) crystal plane is a fast growth plane, this structure can further accelerate the growth of bulk materials on the basis of multi-seed crystals, and shorten the preparation time of large-sized superconducting bulk materials. Because the (110)/(110) grain boundary is not easy to accumulate high temperature phase or impurities, the influence of the residual non-superconducting relative superconducting properties at the (100)/(100) grain boundary of the sample can be eliminated, and the performance of the bulk material can be improved.

The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and changes according to the concept of the present invention without creative efforts. Therefore, any technical solutions that can be obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the prior art according to the concept of the present invention shall fall within the protection scope determined by the claims.

Claims (6)

1. a method utilizing single seed crystal bridge structure to induce growth of REBCO superconducting bulk material, is characterized in that, described method comprises the following steps: Step 1, according to the ratio of RE:Ba:Cu=1:2:3 and RE:Ba:Cu=2:1:1, RE ₂ O ₃ , BaCO ₃ and CuO powders are prepared into original powders of RE123 and RE211; In step 2, the original powder is fully mixed and sintered at 900° C. for 48 hours in an air environment; the sintered powder is ground and sintered again, and the same process is repeated three times in total; In step 3, the RE123 powder and RE211 powder obtained in step 2 are prepared according to the components of RE123+30mol% RE211+1wt% CeO ₂ , fully milled and mixed uniformly to obtain precursor powder; Step 4: According to the different diameters of the molds, the powder is weighed into a suitable mass, put into the mold, and pressed into one cylindrical seed bridge, 2 to 3 buffer layers and one precursor; the seed bridge The diameter of the buffer layer is 10mm, weighing 0.6g for pressing; the diameter of the buffer layer is 5mm, weighing 0.15-0.2g for pressing; the diameter of the precursor is greater than or equal to 30mm; Step 5, place the seed crystal, the seed crystal bridge, the buffer layer, and the precursor in sequence from top to bottom; the seed crystal, the seed crystal bridge, and the buffer layer form a single-seed crystal bridge structure; wherein, the The seed crystal is placed in the center of the upper surface of the seed crystal bridge, the seed crystal bridge is erected above the buffer layer, and the buffer layer is arranged in a row along the [110] crystal direction of the seed crystal; In step 6, the precursor and the single-seed bridge structure are placed in a growth furnace for melting and texture growth of the top seed crystal, so as to achieve (110)∥(110) orientation induced growth of REBCO superconducting bulk material. 2. The method according to claim 1, wherein the top seed melt texture growth process comprises the following steps: raising the temperature in the growth furnace to the first temperature within the first time, and keeping the temperature for 1-3 hours; raising the temperature in the growth furnace to a second temperature within a second time, and keeping the temperature for 1 to 3 hours; lowering the temperature in the growth furnace to a third temperature within a third time; reducing the temperature in the growth furnace to a fourth temperature within a fourth time; Finally, quenched to obtain REBCO superconducting bulk. 3 . The method according to claim 2 , wherein: the first time is 3-5 hours, the first temperature is 850-950° C.; the second time is 1-2 hours, the The second temperature is 40-80°C higher than the peritectic reaction temperature of the REBCO superconducting material; the third time is 0.5-1 hour, and the third temperature is the peritectic reaction temperature of the REBCO material; the The fourth time is 10-80 hours, and the fourth temperature is 5-40° C. lower than the peritectic reaction temperature. 4 . The method according to claim 1 , wherein the seed crystal is c-axis oriented, and the seed crystal is an NdBCO/MgO or NdBCO/YBCO/MgO thin film seed crystal. 5 . 5 . The method according to claim 1 , wherein the size of the seed crystal is 2 mm×2 mm. 6 . 6. The method according to claim 1, wherein the RE is Y, Gd, Sm or Nd.

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