A method for preparing an erbcO superconducting target

Abstract

The application provides a preparation method of an ErBCO superconducting target material, and belongs to the technical field of oxide target materials. In the application, nitric acid erbium, nitric acid barium, nitric acid copper, high-purity water, a dispersing agent and a binder are sequentially mixed, and then the mixture is subjected to segmented ball milling and spray granulation to obtain a mixed powder. Subsequently, the mixed powder is sequentially subjected to calcination, cold sintering and drying treatment to prepare the ErBCO superconducting target material. The cold sintering process can improve the density and other properties of the target material while reducing the cost, and has the advantages of significantly reducing the ceramic sintering temperature and shortening the sintering time.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of oxide target materials, in particular to a preparation method of an ErBCO superconducting target material. BACKGROUND

[0002] Superconducting materials have a series of advantages such as strong current-carrying capacity and low loss, and are widely applied in various fields and play an important role in their application occasions. At present, the superconducting target material is mainly YBCO target material, and the preparation methods mainly include vacuum or normal pressure sintering, cold pressing and the like. However, the vacuum sintering and normal pressure sintering both have a long sintering time, and the obtained target material has a low density. Although the hot pressure sintering can shorten the sintering time, the use cost is high.

[0003] For example, although patent CN116023127A discloses a YBCO target material prepared by discharge plasma assisted hot pressure sintering and cold pressing, the initial density of the YBCO target material reaches 95%, but the cost is high. Patent CN101492291A discloses a YBCO target material prepared by using cold isostatic pressing followed by normal pressure sintering, and the YBCO target material with a superconducting phase structure is obtained, but the prepared target material has a poor density.

[0004] As a new concept of low-carbon ceramic preparation, the cold sintering adopts the mode that ceramic powder is uniformly mixed with a certain intermediate liquid phase, then poured into a customized mold, and then a certain uniaxial pressure is applied for sintering, so that a dense ceramic is obtained, and the effect that the ceramic powder can be used to prepare a ceramic at a densification temperature of <= 300 DEG C is realized.

[0005] Meanwhile, due to the complex physical mechanism of high-temperature superconductors, some superconducting phenomena are difficult to explain based on existing theories, and the electromagnetic properties of superconducting materials are greatly affected by external magnetic fields, temperature, mechanical factors and the like, so that there are many technical difficulties in the application of high-temperature superconducting materials. However, researches show that, compared with other types of ceramics, Er-123 is the best attenuator for gamma radiation.

[0006] In summary, the existing target material preparation method still has the defects that the target material density cannot be improved and the cost cannot be reduced at the same time, therefore, how to use the cold sintering process to prepare a new type of ErBCO superconducting target material with low cost and high density has become a technical problem to be solved and a research hotspot. SUMMARY

[0007] Therefore, in order to overcome and make up for the above-mentioned shortcomings and deficiencies in the prior art, the application provides a preparation method of an ErBCO superconducting target material, a new type of ErBCO superconducting target material is prepared by using the cold sintering process, the ceramic sintering temperature is greatly reduced, the sintering time is significantly shortened, and the effect of improving the performance of the target material density and reducing the cost at the same time is realized.

[0008] To achieve the above object, the present application provides the following technical solutions.

[0009] The present application provides a preparation method of ErBCO superconducting target material, comprising the following preparation steps:

[0010] 1) sequentially mixing nitric acid erbium, nitric acid barium, nitric acid copper, high-purity water, dispersant and binder, then performing segmented ball milling and spray granulation to obtain a mixed powder;

[0011] 2) performing one-time calcination on the mixed powder to obtain a single-phase ErBCO powder;

[0012] 3) cold sintering and drying the single-phase ErBCO powder to obtain the ErBCO superconducting target material;

[0013] The cold sintering specifically comprises: uniformly mixing the single-phase ErBCO powder and an auxiliary liquid, then placing it in a mold for compression molding, and performing cold sintering at 100-500℃ for 1-5h.

[0014] Preferably, the segmented ball milling in step 1) specifically comprises: first uniformly mixing nitric acid erbium, nitric acid barium, nitric acid copper, high-purity water and dispersant, then ball milling for 20-24h, and then adding a binder and continuing to ball mill for 1-4h.

[0015] Preferably, the grinding balls in the segmented ball milling comprise zirconia ceramic balls or alumina ceramic balls; the content of the grinding balls is 40-60%.

[0016] Preferably, the dispersant in step 1) is a solution with PH=7 prepared from polyacrylic acid, ammonia water, pure water and n-octanol; the content of the dispersant is 0.5-1.0%.

[0017] Preferably, the binder in step 1) comprises polyvinyl alcohol; the content of the binder is 0.5-1.0%.

[0018] Preferably, the molar ratio of nitric acid erbium, nitric acid barium and nitric acid copper in step 1) is 1:2:3.

[0019] Preferably, the solid content of the mixed powder in step 1) is 50-55%.

[0020] Preferably, the calcination temperature in step 2) is 800-1200℃, and the calcination time is 5-10h.

[0021] Preferably, the auxiliary liquid in step 3) comprises deionized water or acetic acid solution; the mass fraction of the auxiliary liquid is 2wt.%-30wt.%.

[0022] The present application also provides an ErBCO superconducting target material prepared according to the above preparation method.

[0023] Compared with the prior art, the present application has the following advantages:

[0024] The present application adopts the method of mixing the erbium nitrate, barium nitrate, copper nitrate, high-purity water, dispersant and binder in sequence, then segmentally ball milling, spray granulating to obtain the mixed powder, and then calcining, cold sintering and drying the mixed powder in sequence to prepare the ErBCO superconducting target material.

[0025] Compared with the traditional method, the present application prepares the high-density ErBCO superconducting target material by the cold sintering technology, effectively prevents the loss of volatile elements in the ceramic densification process, and realizes the effect of accurately controlling the ceramic shrinkage. BRIEF DESCRIPTION OF DRAWINGS

[0026] Fig. 1 It is a process flow diagram of the ErBCO target material preparation method in the present application embodiment 1-3.

[0027] Fig. 2 It is the SEM diagram of the ErBCO target material prepared in the present application embodiment 1.

[0028] Fig. 3 It is the XRD diagram of the ErBCO target material prepared in the present application embodiment 1. DETAILED DESCRIPTION

[0029] The present application provides a preparation method of an ErBCO superconducting target material, which comprises the following preparation steps:

[0030] 1) Mix the erbium nitrate, barium nitrate, copper nitrate, high-purity water, dispersant and binder in sequence, then segmentally ball mill and spray granulate to obtain a mixed powder;

[0031] 2) Calcine the mixed powder once to obtain a single-phase ErBCO powder;

[0032] 3) Cold sinter and dry the single-phase ErBCO powder to obtain the ErBCO superconducting target material;

[0033] The cold sintering is preferably that: after grinding and uniformly mixing the single-phase ErBCO powder and the auxiliary liquid, it is placed in a mold and pressed into a shape, and cold sintering is carried out at 100-500 DEG C for 1-5h;

[0034] The present application mixes the erbium nitrate, barium nitrate, copper nitrate, high-purity water, dispersant and binder in sequence, then segmentally ball mills and spray granulates to obtain a mixed powder.

[0035] In the application, the molar ratio of the erbium nitrate, barium nitrate and copper nitrate is preferably 1:2:3, the purity is preferably 4N, and the particle size range is preferably 50-500nm; the solid content of the mixed powder is preferably 50-55%, more preferably 52%.

[0036] The dispersant is preferably a solution with PH=7 prepared from polyacrylic acid, ammonia water, pure water and n-octanol; the dispersant content is preferably 0.5-1.0%, more preferably 0.7%; the binder is preferably polyvinyl alcohol; and the binder content is preferably 0.5-1.0%, more preferably 0.7%.

[0037] The process of the segmental ball milling is preferably as follows: the erbium nitrate, barium nitrate, copper nitrate, high-purity water and dispersant are mixed and wet ball milled for 20-24h, and then the binder is added and ball milled for 1-4h.

[0038] The grinding balls used in the segmental ball milling are preferably zirconia ceramic balls or alumina ceramic balls, the diameter range is preferably 1-10mm, the diameter difference is preferably 1-3mm, and the mass ratio of large, medium and small balls is preferably 1:1:1; the content of the grinding balls in the segmental ball milling process is preferably 40-60%, more preferably 55%; and the air inlet temperature of the granulation equipment is preferably 190-220℃, and the feeding speed is preferably 10-20r / min.

[0039] After obtaining the mixed powder, the mixed powder is subjected to primary calcination to obtain single-phase ErBCO powder, and the single-phase ErBCO powder is cold sintered and dried to obtain the ErBCO superconducting target material.

[0040] In the initial pressurization stage of the cold sintering process, stress concentration occurs in the contact area between particles, the contact pressure will be much higher than the external pressure, which may cause the particles to yield and deform plastically, and the auxiliary liquid added in the application can act as a lubricant to reduce the friction between particles, improve the particle rearrangement efficiency and promote the densification effect.

[0041] In the technical scheme of the application, the presence of the liquid phase and the auxiliary pressure is conducive to the dissolution of the particle tips, the particle rearrangement and the mass transfer; under the action of the auxiliary pressure and the heat source, the liquid phase evaporates or is discharged, forming a supersaturated solution and precipitating to fill the particle surface or the gap, and sintering the powder into a ceramic bulk with a dense structure.

[0042] The calcination temperature in the step 2) is preferably 800-1200 DEG C, more preferably 900 DEG C; the calcination time is preferably 5-10h, more preferably 10h; the auxiliary liquid in the step 3) is preferably deionized water or acetic acid solution, more preferably deionized water; and the mass fraction of the auxiliary liquid is preferably 2wt.%-30wt.%, more preferably 10wt.%.

[0043] The ErBCO superconducting target material is prepared by sequentially mixing the erbium nitrate, barium nitrate, copper nitrate, high-purity water, dispersant and binder, then segmentally ball milling, spray granulating to obtain a mixed powder, and then sequentially calcining, cold sintering and drying the mixed powder.

[0044] The ErBCO powder is prepared by a solid phase reaction method, and the target material is obtained by placing the ErBCO powder in a mold for cold sintering.

[0045] In order to better understand the present application, the content of the present application is further illustrated below in combination with examples, but the content of the present application is not limited to the following examples only.

[0046] Example 1

[0047] The preparation method of the ErBCO superconducting target material in the embodiment includes the following steps:

[0048] 1) First, the erbium nitrate, barium nitrate and copper nitrate powder are uniformly mixed according to a molar ratio of 1:2:3, then high-purity water and a dispersant are added and uniformly mixed to obtain a mixture; the obtained mixture is placed in a ball mill tank and ball milled for 20h, then a binder is added and ball milled for 2h to obtain a mixed slurry, and finally the mixed slurry is atomized and dried by a spray granulation equipment to obtain a granulated mixed powder;

[0049] The solid content of the mixed powder is 52%, the content of the grinding ball used in the ball milling process is 50%, the content of the dispersant is 0.7%, the content of the binder is 0.5%, the purity of the erbium oxide, barium carbonate and copper oxide powder is 4N (99.99%), the particle size of the erbium oxide, barium carbonate and copper oxide powder is 50-150 nm, the grinding ball used in the ball milling process is a zirconia ceramic ball, the diameters of the large ball, the medium ball and the small ball are 10 mm, 5 mm and 3 mm respectively, the mass ratio of the large ball, the medium ball and the small ball is 1:1:1, the rotating speed of the ball mill is 90 r / min, and the air inlet temperature of the granulation equipment is set to 210 DEG C and the feeding speed is set to 15 r / min.

[0050] 2) The mixed powder is calcined in an air atmosphere, the calcination temperature is 900 DEG C, and the time is 10 h, so as to obtain the ErBCO powder with a superconducting phase.

[0051] 3) 10 wt.% of deionized water is added to the above-mentioned ErBCO powder for grinding, and the uniformly ground powder is placed in a cold sintering mold to be pressed into a shape under the pressure of 200 MPa, when the pressure reaches the maximum load, the pressure is continuously applied, and cold sintering is carried out at 200 DEG C for 1.5 h; after the cold sintering is completed, the cold sintered sample is taken out and dried in an oven for 48 h, so as to obtain the ErBCO superconducting target material.

[0052] Fig. 1 It is a process flow diagram of the preparation method of the ErBCO target material in the embodiments 1-3 of the application;

[0053] Fig. 2 It is an SEM diagram of the ErBCO target material prepared in the embodiment 1 of the application;

[0054] Fig. 3 It is an XRD diagram of the ErBCO target material prepared in the embodiment 1 of the application.

[0055] From the above, Figs. 1-3 It can be known that the application provides a preparation method of an ErBCO superconducting target material, the nitric acid erbium, the nitric acid barium, the nitric acid copper, the high-purity water, the dispersant and the binder are sequentially mixed, then the mixed powder is obtained through the steps of segmented ball milling and spray granulation, and then the mixed powder is sequentially subjected to the steps of calcination, cold sintering and drying treatment, so as to obtain a novel ErBCO superconducting target material, the performance of improving the density of the target material and the effect of reducing the cost are realized at the same time, and the advantages of significantly reducing the sintering temperature of the ceramic and shortening the sintering time are achieved.

[0056] Embodiment 2

[0057] The preparation method of the ErBCO superconducting target material in the embodiment includes the following steps:

[0058] 1) first, the erbium nitrate, barium nitrate, copper nitrate powder is mixed according to the molar ratio of 1:2:3, then high-purity water and dispersant are added and continue to mix, to obtain a mixture; the obtained mixture is placed in a ball mill tank and ball milled for 20h, then a binder is added and continue to ball mill for 2h to obtain a mixed slurry, finally the above mixed slurry is atomized and dried by a spray granulation equipment to obtain a granulated mixed powder;

[0059] The solid content of the mixed powder is 55%, the content of the grinding ball used in the ball milling process is 50%, the content of the dispersant is 0.7%, the content of the binder is 0.7%, the purity of the erbium oxide, barium carbonate and copper oxide powder is 4N (99.99%), the particle size of the erbium oxide, barium carbonate and copper oxide powder is 50-150nm, the grinding ball used in the ball milling process is zirconia ceramic ball, the diameters of the large ball, medium ball and small ball are 10mm, 5mm and 3mm respectively, the mass ratio of the large ball, medium ball and small ball is 1:1:1, the rotation speed of the ball mill is 90r / min, the inlet air temperature of the granulation equipment is set to 210℃, and the feeding speed is set to 15r / min.

[0060] 2) The above mixed powder is calcined in an atmospheric atmosphere, the calcination temperature is 900℃, and the time is 10h, to obtain an ErBCO powder with superconducting phase.

[0061] 3) 7wt.% of deionized water is added to the above ErBCO powder for grinding, and the uniformly ground powder is placed in a cold sintering mold to apply a pressure of 200MPa for compression molding, when the pressure reaches the maximum load, the pressure is continuously applied, and cold sintering is carried out at 300℃ for 1.5h; after cold sintering, the cold sintered sample is taken out and dried in an oven for 48h to obtain the ErBCO superconducting target material.

[0062] Example 3

[0063] The preparation method of the ErBCO superconducting target material in this embodiment includes the following steps:

[0064] 1) first, the erbium nitrate, barium nitrate, copper nitrate powder is mixed according to the molar ratio of 1:2:3, then high-purity water and dispersant are added and continue to mix, to obtain a mixture; the obtained mixture is placed in a ball mill tank and ball milled for 20h, then a binder is added and continue to ball mill for 2h to obtain a mixed slurry, finally the above mixed slurry is atomized and dried by a spray granulation equipment to obtain a granulated mixed powder;

[0065] The solid content of the mixed powder is 58%, the content of the grinding ball used in the ball milling process is 50%, the content of the dispersant is 0.7%, the content of the binder is 1.0%, the purity of the erbium oxide, barium carbonate and copper oxide powder is 4N (99.99%), the particle size of the erbium oxide, barium carbonate and copper oxide powder is 50-150 nm, the grinding ball used in the ball milling process is a zirconia ceramic ball, the diameters of the large ball, the medium ball and the small ball are 10 mm, 5 mm and 3 mm respectively, the mass ratio of the large ball, the medium ball and the small ball is 1:1:1, the rotating speed of the ball mill is 90 r / min, and the air inlet temperature of the granulating equipment is set to 210 DEG C and the feeding speed is set to 15 r / min.

[0066] 2) The mixed powder is calcined in an air atmosphere, the calcination temperature is 900 DEG C, and the time is 10 h, so as to obtain the ErBCO powder with a superconducting phase.

[0067] 3) The 25wt.% acetic acid solution is added to the above-mentioned ErBCO powder for grinding, and the uniformly ground powder is placed in a cold sintering mold to be pressed into a shape under the pressure of 200 MPa, when the pressure reaches the maximum load, the pressure is continuously applied, and the cold sintering is carried out at 250 DEG C for 1 h, after the cold sintering is completed, the cold sintered sample is taken out and dried in an oven for 48 h, so as to obtain the ErBCO superconducting target material.

[0068] As can be seen, the novel ErBCO superconducting target material is prepared by the method that the erbium nitrate, the barium nitrate, the copper nitrate, the high-purity water, the dispersant and the binder are sequentially mixed, then the mixed powder is obtained by the processes of segmented ball milling and spray granulation, and then the mixed powder is sequentially subjected to calcination, cold sintering and drying treatment, the Er is used as a ceramic raw material, the cold sintering process is combined, the properties such as the density of the target material are improved, the cost is reduced, and the advantages of significantly reducing the sintering temperature of the ceramic and shortening the sintering time are achieved.

[0069] The above only describes the preferred embodiments of the present application, and it should be noted that, for those skilled in the art, some improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A method of producing an ErBCO superconducting target material, characterized by, The preparation method comprises the following steps: 1) mixing erbium nitrate, barium nitrate, copper nitrate, high-purity water, a dispersing agent and a binder in sequence, then performing segmented ball milling and spray granulation to obtain a mixed powder; 2) performing one-time calcination on the mixed powder to obtain a single-phase ErBCO powder; 3) cold sintering and drying the single-phase ErBCO powder to obtain the ErBCO superconducting target material; The cold sintering specifically comprises: uniformly mixing the single-phase ErBCO powder and an auxiliary liquid, then placing the mixture in a mold for compression molding, and performing cold sintering at 100-500 ℃ for 1-5 h; The auxiliary liquid in the step 3) comprises deionized water, and the mass fraction of the auxiliary liquid is 2wt.%-30wt.%; The segmented ball milling in the step 1) specifically comprises: uniformly mixing the erbium nitrate, the barium nitrate, the copper nitrate, the high-purity water and the dispersing agent, then performing ball milling for 20-24 h, and then adding the binder to continue ball milling for 1-4 h; The milling balls in the segmented ball milling comprise zirconia ceramic balls or alumina ceramic balls, and the content of the milling balls is 40-60%; The dispersing agent in the step 1) is a solution with PH = 7 prepared from polyacrylic acid, ammonia water, pure water and n-octanol, and the content of the dispersing agent is 0.5-1.0%; The solid content of the mixed powder in the step 1) is 50-55%; The calcination temperature in the step 2) is 800-1200 ℃, and the calcination time is 5-10 h.

2. The production method according to claim 1, characterized by, The binder in the step 1) comprises polyvinyl alcohol, and the content of the binder is 0.5-1.0%.

3. The preparation method according to claim 1, characterized in that, The molar ratio of the erbium nitrate, the barium nitrate and the copper nitrate in the step 1) is 1:2:

3.

4. An ErBCO superconducting target material prepared by the method in any one of claims 1-3.

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