Method for preparing water-soluble BaxSryCazAl2O6 ceramic at low temperature

Abstract

The invention provides a method for preparing water-soluble BaxSryCazAl2O6 ceramic at low temperature, which comprises the following steps: step 1, respectively weighing Ba (NO3) 2 powder, Sr (NO3) 2 powder, Ca (NO3) 24H2O powder and Al (NO3) 39H2O powder; step 2, preparing a citric acid solution, and sequentially adding the Ba (NO3) 2 powder, the Sr (NO3) 2 powder, the Ca (NO3) 24H2O powder and the Al (NO3) 39H2O powder into the citric acid solution; step 3, based on the mixed solution, adding a proper amount of ethylene glycol solution as a complexing agent, and heating and stirring to form gel; step 4, drying the gel, placing the dried gel in a box-type furnace, and calcining the dried gel in an air atmosphere to obtain BaxSryCazAl2O6 powder; step 5, carrying out granulation and aging treatment, so as to obtain BaxSryCazAl2O3 / PVA (Polyvinyl Alcohol / Polyvinyl Alcohol) particles; step 6, carrying out tabletting forming treatment, and carrying out de-grinding, so as to form a disc-shaped BaxSryCazAl2O3 / PVA (Polyvinyl Alcohol / Polyvinyl Alcohol) blank body; and step 7, putting the disc-shaped BaxSryCazAl2O6 / PVA into a box-type furnace, sintering the disc-shaped BaxSryCazAl2O6 / PVA in an air atmosphere, and removing the PVA to obtain the compact BaxSryCazAl2O6 ceramic.

Description

Technical Field

[0001] This invention relates to the field of sol-gel method for preparing functional ceramics, specifically to a method for low-temperature preparation of water-soluble Ba. x Sr y Ca z Methods for producing Al2O6 ceramics. Background Technology

[0002] Functional ceramics, as a class of advanced materials primarily utilizing their non-mechanical properties, have broad application potential in microelectronics, communications, automation control, and future intelligent fields. Water-soluble ceramics, as a novel type of ceramic, can be used as targets to grow water-soluble single-crystal thin films via pulsed laser deposition, magnetron sputtering, and other methods. These films are widely used as sacrificial layers in other functional single-crystal thin films (BaTiO3, BiFeO3, PbTiO3, La). 0.7 Ca 0.3 Flexible treatment of MnO3, etc.

[0003] Currently, the most widely used water-soluble material is Ba. x Sr y Ca z Al₂O₆ (x+y+z=3) has the advantage of high lattice constant matching with other functional materials. The lattice constant matching can be further improved by adjusting the proportions of x, y, and z, significantly enhancing the single-crystallinity of epitaxially grown functional oxide films. However, currently, Ba… x Sr y Ca z The preparation methods for Al2O6 ceramics all employ high-temperature solid-state methods, with high calcination and sintering temperatures (≥1200℃). Furthermore, the poor homogeneity of the mixed raw materials easily leads to the generation of impurities. Therefore, a low-temperature method for preparing water-soluble Ba2O6 ceramics is needed. x Sr y Ca z The method of preparing Al2O6 ceramics is very necessary. Summary of the Invention

[0004] This invention provides a method for preparing water-soluble Ba at low temperature. x Sr y Ca z A method for preparing Al2O6 ceramics to address the limitations of existing solid-state methods for Ba. x Sr y Ca z Technical problems with the high calcination and sintering temperatures and numerous impurities in Al2O6 ceramics.

[0005] This invention is achieved through the following technical solution: a method for preparing water-soluble Ba at low temperature. x Sr y Ca zA method for preparing Al2O6 ceramic, comprising the steps of: Step 1, Ba(NO3)2 powder, Sr(NO3)2 powder, Ca(NO3)2·4H2O powder and Al(NO3)3·9H2O powder are weighed according to the molar ratio of x:y:z:2, wherein x is the molar proportion of Ba(NO3)2 powder, y is the molar proportion of Sr(NO3)2 powder, and z is the molar proportion of Ca(NO3)2·4H2O powder; Step 2, an appropriate amount of citric acid is weighed and dissolved in water to prepare a 10wt% citric acid solution, and the Ba(NO3)2 powder, the Sr(NO3)2 powder, the Ca(NO3)2·4H2O powder and the Al(NO3)3·9H2O powder are sequentially added to the citric acid solution, and heated and stirred until the powders are completely dissolved to prepare a mixed solution; Step 3, based on the mixed solution, an appropriate amount of ethylene glycol solution is added as a complexing agent, and a gel is formed by heating and stirring; Step 4, after the gel is dried, it is placed in a box furnace and calcined in an air atmosphere to obtain Ba x Sr y Ca z A l2 O6 powder; Step 5, the Ba x Sr y Ca z Al2O6 powder is placed in an agate mortar, and polyvinyl alcohol (PVA) / ethanol binder is slowly added to bond the Ba x Sr y Ca z Al2O6 powder into particles, and through aging treatment, Ba x Sr y Ca z Al2O6 / PVA particles are prepared; Step 6, an appropriate amount of the Ba x Sr y Ca z Al2O6 / PVA particles are weighed and placed in a stainless steel die, and through tabletting forming treatment, a round Ba x Sr y Ca z Al2O6 / PVA body is formed after grinding; Step 7, the round Ba x Sr y Ca z Al2O6 / PVA is placed in a box furnace and sintered in an air atmosphere, the PVA is removed, and a dense Ba x Sr y Caz Al2O6 ceramic.

[0006] Specifically, x in step 1 is less than or equal to 2, z is less than or equal to 2, and x+y+z=3.

[0007] Specifically, the heating and stirring in step 2 until the powder is completely dissolved comprises: a heating temperature of 70℃ and a stirring time of 2h.

[0008] Specifically, the volume ratio of ethylene glycol to the mixed solution in step 3 is 1:10.

[0009] Specifically, the heating and stirring in step 3 to form a gel comprises: continuously heating and stirring for 2h to form a sol, and continuously heating for 2h to form a gel.

[0010] Specifically, the calcination in air in step 4 comprises: The calcination temperature is 750℃-850℃, the calcination time is 2h-4h, and the heating rate is 5℃ / min.

[0011] Specifically, the slow drop of 10wt% PVA / ethanol binder in step 5 comprises: The amount of 10wt% PVA binder added is 3wt%-5wt%.

[0012] Specifically, the step 7 of placing the round sheet-shaped Ba x Sr y Ca z The Al2O6 / PVA embryo is placed in a box furnace and sintered in an air atmosphere, comprising: The round sheet-shaped Ba x Sr y Ca z The Al2O6 / PVA embryo is placed in a box furnace and sintered in an air atmosphere, and when sintering, the PVA binder is removed by keeping the temperature at 600℃ for 1h, the sintering temperature is 850℃-900℃, the sintering time is 2h-4h, and the heating rate is 5℃ / min. Compared with the prior art, the present application has the following beneficial technical effects: The present application prepares water-soluble Ba x Sr y Ca zThe ceramic of Ba1-xSrxCa1-xAl2O6, the calcination temperature of the ceramic is greatly reduced from 1200 DEG C of the high-temperature solid-phase method to 750 DEG C-850 DEG C, the sintering temperature is greatly reduced from 1400 DEG C of the high-temperature solid-phase method to 850 DEG C-900 DEG C, energy saving and cost reduction are realized; as a liquid-phase method, the sol-gel method realizes full mixing of raw materials, avoids the generation of second-phase impurities (BaAl2O4, SrAl2O4, CaAl2O4) in the calcination and sintering processes, and improves the single-crystal property of the film when the ceramic is used as a target material to epitaxially grow Ba x Sr y Ca z Al2O6. The sol-gel method realizes the preparation of water-soluble Ba x Sr y Ca z Al2O6 powder, provides technical support for the preparation of large-size flexible other functional oxide films by the spin coating method and peeling, and makes it possible for other functional oxide films to be applied to the field of flexible electronics on a large scale. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 The X-ray spectrum of the Ba1-xSrxCa1-xAl2O6 ceramic provided by the embodiment one of the present application. DETAILED DESCRIPTION

[0014] In the following description, a lot of specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be practiced in a number of different ways without departing from the spirit and scope of the present application. It is to be understood that the present application is not limited in its application to the details of the specific implementation described herein. The implementation described herein is intended to be merely exemplary of the application, and therefore specific implementation details should not be construed as limiting the scope of the present application in any manner. Furthermore, the present application is not limited to the specific applications described herein, but is applied to other functional oxide films.

[0015] In order to make the objects, technical schemes and advantages of the present application clearer, the present application is further described in detail below with specific examples, which are the explanation of the present application but not the limitation. In order to facilitate understanding, the technical background and specific application of the present application are simply and generally described herein.

[0016] At present, the preparation method of the Ba1-xSrxCa1-xAl2O6 ceramic all adopts the high-temperature solid-phase method, the calcination and sintering temperature is high (≥1200 DEG C), and the poor uniformity of the mixed raw materials leads to the easy generation of second phases, therefore, the embodiment of the present application provides a low-temperature preparation method of water-soluble Ba x Sr y Ca z Al2O6 ceramic, which greatly reduces the calcination temperature from 1200 DEG C of the high-temperature solid-phase method to 750 DEG C-850 DEG C, greatly reduces the sintering temperature from 1400 DEG C of the high-temperature solid-phase method to 850 DEG C-900 DEG C, realizes energy saving and cost reduction; as a liquid-phase method, the sol-gel method realizes full mixing of raw materials, avoids the generation of second-phase impurities (BaAl2O4, SrAl2O4, CaAl2O4) in the calcination and sintering processes, and improves the single-crystal property of the film when the ceramic is used as a target material to epitaxially grow Ba x Sr y Ca zThe method for producing Al2O6 ceramics has solved the aforementioned problems existing in the prior art.

[0017] This application provides a method for preparing water-soluble Ba at low temperature. x Sr y Ca z The method for preparing Al2O6 ceramics includes the following steps. Step 1: Weigh out Ba(NO3)2 powder, Sr(NO3)2 powder, Ca(NO3)2⋅4H2O powder, and Al(NO3)3⋅9H2O powder according to the molar ratio of x:y:z:2, where x is the molar percentage of Ba(NO3)2 powder, y is the molar percentage of Sr(NO3)2 powder, and z is the molar percentage of Ca(NO3)2⋅4H2O powder. In practical applications, Ba(NO3)2 powder, Sr(NO3)2 powder, Ca(NO3)2⋅4H2O powder, and Al(NO3)3⋅9H2O powder can be dried first, for example, at 80℃ for 24 hours.

[0018] Optionally, in step 1, x is less than or equal to 2, z is less than or equal to 2, and x+y+z=3.

[0019] Step 2: Weigh an appropriate amount of citric acid and dissolve it in water to prepare a 10wt% citric acid solution. Then, add the Ba(NO3)2 powder, the Sr(NO3)2 powder, the Ca(NO3)2⋅4H2O powder, and the Al(NO3)3⋅9H2O powder to the citric acid solution in sequence. Heat and stir until the powders are completely dissolved to prepare a mixed solution. Optionally, the heating and stirring in step 2 until the powder is completely dissolved includes: heating at 70°C and stirring for 2 hours.

[0020] Step 3: Based on the mixed solution, add an appropriate amount of ethylene glycol solution as a complexing agent, and form a gel by heating and stirring; Optionally, the volume ratio of ethylene glycol to the mixed solution in step 3 is 1:10.

[0021] Optionally, the heating and stirring to form a gel in step 3 specifically includes: continuously heating and stirring for 2 hours to form a sol, and continuing to heat for 2 hours to form a gel.

[0022] Step 4: After drying the gel, place it in a box furnace and calcine it in air atmosphere to obtain Ba. x Sr y Ca z A l2 O6 powder; Optionally, the calcination in air atmosphere described in step 4 includes: a calcination temperature of 750℃-850℃, a calcination time of 2h-4h, and a heating rate of 5℃ / min.

[0023] Step 5: Place the Ba x Sr y Ca z Al2O6 powder was placed in an agate mortar, and polyvinyl alcohol (PVA) / ethanol binder was slowly dripped in to make the Ba... x Sr y Ca z Al2O6 powder was bonded into particles, and Ba was prepared by aging. x Sr y Ca z Al2O6 / PVA particles; Optionally, the slow dripping of 10wt% PVA / ethanol binder in step 5 includes: the amount of 10wt% PVA binder added is 3wt%-5wt%, and the addition rate is 5 drops / min.

[0024] The polyvinyl alcohol (PVA) / ethanol binder is a 10wt% polyvinyl alcohol (PVA) / ethanol binder.

[0025] Specifically, the aging process includes: aging for 24 hours after passing through an 80-mesh sieve to obtain Ba. x Sr y Ca z Al2O6 / PVA particles.

[0026] Step 6: Weigh an appropriate amount of the Ba x Sr y Ca z Al2O6 / PVA particles are placed in a stainless steel mold and formed into discs through pressing. After grinding, they are de-ground to form round Ba discs. x Sr y Ca z Al2O6 / PVA embryo; Specifically, the tableting process includes applying pressure at 5MPa for 3 minutes using a tablet press.

[0027] Step 7: Place the circular Ba sheet... x Sr y Ca z Al2O6 / PVA was sintered in a box furnace under air atmosphere to remove the PVA and obtain dense Ba. x Sr y Ca z Al2O6 ceramics.

[0028] Optionally, step 7 involves placing the circular Ba sheet...x Sr y Ca z The Al2O6 / PVA preform is placed in a box furnace and sintered in air atmosphere, including: sintering the circular Ba2O6 / PVA preform by means of burial. x Sr y Ca z The Al2O6 / PVA preform is placed in a box furnace and sintered in air atmosphere. During sintering, it needs to be held at 600℃ for 1 hour to remove the PVA binder. The sintering temperature is 850℃-900℃, the sintering time is 2-4 hours, and the heating rate is 5℃ / min.

[0029] In summary, this invention provides a method for preparing water-soluble Ba at low temperatures. x Sr y Ca z The method for preparing Al2O6 ceramics includes: weighing Ba(NO3)2, Sr(NO3)2, Ca(NO3)2⋅4H2O, and Al(NO3)3⋅9H2O powders in a molar ratio of x:y:z:2, dissolving them in a 10wt% citric acid aqueous solution, adding ethylene glycol solution as a complexing agent, heating and stirring to form a sol and then a gel, followed by calcination at 750℃-850℃ to obtain Ba2O6 ceramics. x Sr y Ca z Al2O6 powder was granulated and compressed into tablets using a 10wt% PVA / ethanol binder, and then sintered at 850℃-900℃ to obtain Ba. x Sr y Ca z Al2O6 ceramics. This method significantly reduces Ba content compared to traditional solid-state methods. x Sr y Ca z The calcination and sintering temperatures of Al2O6 ceramics are controlled, and the generation of second-phase impurities during calcination and sintering is avoided.

[0030] Example 1 A method for preparing water-soluble Ba1Sr1Ca1Al2O6 ceramics at low temperature includes the following steps: (1) Weigh out Ba(NO3)2 powder, Sr(NO3)2 powder, Ca(NO3)2⋅4H2O powder and Al(NO3)3⋅9H2O powder, which have been dried at 80℃ for 24 hours and have a molar ratio of 1:1:1:2 respectively; (2) Weigh an appropriate amount of citric acid and dissolve it in water to make the citric acid concentration reach 10wt% to prepare a 10wt% citric acid solution. Add Ba(NO3)2 powder, Sr(NO3)2 powder, Ca(NO3)2⋅4H2O powder and Al(NO3)3⋅9H2O powder to the citric acid solution in sequence. Heat and stir at 70℃ for 2h until the powder is completely dissolved to prepare a mixed solution. (3) Add ethylene glycol solution with a volume ratio of 1:10 to the above mixed solution as a complexing agent, continue heating and stirring for 2 hours to form a sol, and continue heating for 2 hours to form a gel; (4) After drying the above gel, place it in a box furnace and calcine it in air atmosphere. The calcine temperature is 820℃, the calcine time is 3h, and the heating rate is 5℃ / min to obtain Ba1Sr1Ca1Al2O6 powder. (5) Place the above Ba1Sr1Ca1Al2O6 powder in an agate mortar, and slowly drip 4% of 10wt% PVA / ethanol binder at a rate of 5 drops / min to bind the Ba1Sr1Ca1Al2O6 powder into particles (granulation). After passing through an 80-mesh sieve, age for 24 hours to prepare Ba1Sr1Ca1Al2O6 / PVA particles. (6) Weigh an appropriate amount of Ba1Sr1Ca1Al2O6 / PVA particles and place them in a stainless steel mold. Use a tablet press to apply pressure at 5MPa for 3 minutes. After degrinding, a round Ba1Sr1Ca1Al2O6 / PVA preform is formed. (7) The above-mentioned circular Ba1Sr1Ca1Al2O6 / PVA preforms are placed in a box furnace and sintered in air atmosphere by embedding. During sintering, the preforms need to be held at 600℃ for 1 hour to remove the PVA binder. The sintering temperature is 880℃, the sintering time is 3 hours, and the heating rate is 5℃ / min to obtain dense Ba1Sr1Ca1Al2O6 ceramics.

[0031] To provide a deeper understanding of this solution, this embodiment also provides X-ray spectra of Ba1Sr1Ca1Al2O6 ceramics, such as... Figure 1 As shown, the horizontal axis represents the 2θ angle, and the vertical axis represents the intensity, indicating that the prepared ceramic is a pure phase Ba1Sr1Ca1Al2O6 ceramic, without the generation of other second-phase impurities.

[0032] Example 2 A method for preparing water-soluble Ba at low temperature 1.5 Sr1Ca 0.5 The method for preparing Al2O6 ceramics includes the following steps. (1) Weigh out Ba(NO3)2 powder, Sr(NO3)2 powder, Ca(NO3)2⋅4H2O powder and Al(NO3)3⋅9H2O powder, which have been dried at 80℃ for 24 hours and have a molar ratio of 1.5:1:0.5:2 respectively; (2) Weigh an appropriate amount of citric acid and dissolve it in water to make the citric acid concentration reach 10wt%. Add Ba(NO3)2 powder, Sr(NO3)2 powder, Ca(NO3)2⋅4H2O powder and Al(NO3)3⋅9H2O powder in sequence. Heat and stir at 70℃ for 2h until the powder is completely dissolved. (3) Add ethylene glycol solution with a volume ratio of 1:10 to the above mixed solution as a complexing agent, continue heating and stirring for 2 hours to form a sol, and continue heating for 2 hours to form a gel; (4) After drying the above gel, place it in a box furnace and calcine it in air atmosphere. The calcine temperature is 800℃, the calcine time is 3h, and the heating rate is 5℃ / min to obtain Ba. 1.5 Sr1Ca 0.5 Al2O6 powder; (5) Place the above Ba 1.5 Sr1Ca 0.5 Al2O6 powder was placed in an agate mortar, and 4% of 10wt% PVA / ethanol binder was slowly added at a rate of 5 drops / min to form Ba. 1.5 Sr1Ca 0.5 Al2O6 powder is agglomerated into granules (granulation), passed through an 80-mesh sieve and aged for 24 hours; (6) Weigh out an appropriate amount of Ba 1.5 Sr1Ca 0.5 Al2O6 / PVA particles were placed in a stainless steel mold and pressed at 5MPa for 3 minutes using a tablet press. After grinding, they formed round Ba tablets. 1.5 Sr1Ca 0.5 Al2O6 / PVA embryo; (7) Take the above circular Ba pieces 1.5 Sr1Ca 0.5 Al2O6 / PVA preforms were sintered in an air atmosphere in a box furnace using a buried firing method. Before sintering, the preforms were held at 600℃ for 1 hour to remove the PVA binder. The sintering temperature was 860℃, the sintering time was 3 hours, and the heating rate was 5℃ / min, resulting in dense Ba2O6 / PVA preforms. 1.5 Sr1Ca 0.5 Al2O6 ceramics.

[0033] Example 3 A method for preparing water-soluble Ba at low temperature 0.5 Sr1Ca 1.5 The method for preparing Al2O6 ceramics includes the following steps. (1) Weigh out Ba(NO3)2 powder, Sr(NO3)2 powder, Ca(NO3)2⋅4H2O powder and Al(NO3)3⋅9H2O powder, which have been dried at 80℃ for 24 hours and have a molar ratio of 0.5:1:1.5:2 respectively; (2) Weigh an appropriate amount of citric acid and dissolve it in water to make the citric acid concentration reach 10wt%. Add Ba(NO3)2 powder, Sr(NO3)2 powder, Ca(NO3)2⋅4H2O powder and Al(NO3)3⋅9H2O powder in sequence. Heat and stir at 70℃ for 2h until the powder is completely dissolved. (3) Add ethylene glycol solution with a volume ratio of 1:10 to the above mixed solution as a complexing agent, continue heating and stirring for 2 hours to form a sol, and continue heating for 2 hours to form a gel; (4) After drying the above gel, place it in a box furnace and calcine it in air atmosphere. The calcine temperature is 790℃, the calcine time is 3h, and the heating rate is 5℃ / min to obtain Ba. 0.5 Sr1Ca 1.5 Al2O6 powder; (5) Place the above Ba 0.5 Sr1Ca 1.5 Al2O6 powder was placed in an agate mortar, and 4% of 10wt% PVA / ethanol binder was slowly added at a rate of 5 drops / min to form Ba. 0.5 Sr1Ca 1.5 Al2O6 powder is agglomerated into granules (granulation), passed through an 80-mesh sieve and aged for 24 hours; (6) Weigh out an appropriate amount of Ba 0.5 Sr1Ca 1.5 Al2O6 / PVA particles were placed in a stainless steel mold and pressed at 5MPa for 3 minutes using a tablet press. After grinding, they formed round Ba tablets. 0.5 Sr1Ca 1.5 Al2O6 / PVA embryo; (7) Take the above circular Ba pieces 0.5 Sr1Ca 1.5 Al2O6 / PVA preforms were sintered in an air atmosphere in a box furnace using a buried firing method. Before sintering, the preforms were held at 600℃ for 1 hour to remove the PVA binder. The sintering temperature was 860℃, the sintering time was 3 hours, and the heating rate was 5℃ / min, resulting in dense Ba2O6 / PVA preforms. 0.5 Sr1Ca 1.5 Al2O6 ceramics.

[0034] Example 4 A method for preparing water-soluble Ba at low temperature 0.5 Sr2Ca 0.5 The method for preparing Al2O6 ceramics includes the following steps. (1) Weigh out Ba(NO3)2 powder, Sr(NO3)2 powder, Ca(NO3)2⋅4H2O powder and Al(NO3)3⋅9H2O powder, which have been dried at 80℃ for 24 hours and have a molar ratio of 0.5:2:0.5:2 respectively; (2) Weigh an appropriate amount of citric acid and dissolve it in water to make the citric acid concentration reach 10wt%. Add Ba(NO3)2 powder, Sr(NO3)2 powder, Ca(NO3)2⋅4H2O powder and Al(NO3)3⋅9H2O powder in sequence. Heat and stir at 70℃ for 2h until the powder is completely dissolved. (3) Add ethylene glycol solution with a volume ratio of 1:10 to the above mixed solution as a complexing agent, continue heating and stirring for 2 hours to form a sol, and continue heating for 2 hours to form a gel; (4) After drying the above gel, place it in a box furnace and calcine it in air atmosphere. The calcine temperature is 840℃, the calcine time is 4h, and the heating rate is 5℃ / min to obtain Ba. 0.5 Sr2Ca 0.5 Al2O6 powder; (5) Place the above Ba 0.5 Sr2Ca 0.5 Al2O6 powder was placed in an agate mortar, and 4% of 10wt% PVA / ethanol binder was slowly added at a rate of 5 drops / min to form Ba. 0.5 Sr2Ca 0.5 Al2O6 powder is agglomerated into granules (granulation), passed through an 80-mesh sieve and aged for 24 hours; (6) Weigh out an appropriate amount of Ba 0.5 Sr2Ca 0.5 Al2O6 / PVA particles were placed in a stainless steel mold and pressed at 5MPa for 3 minutes using a tablet press. After grinding, they formed round Ba tablets. 0.5 Sr2Ca 0.5 Al2O6 / PVA embryo; (7) Take the above circular Ba pieces 0.5 Sr2Ca 0.5 Al2O6 / PVA preforms were sintered in an air atmosphere in a box furnace using a buried firing method. Before sintering, the preforms were held at 600℃ for 1 hour to remove the PVA binder. The sintering temperature was 890℃, the sintering time was 4 hours, and the heating rate was 5℃ / min, resulting in dense Ba2O6 / PVA preforms. 0.5 Sr2Ca 0.5 Al2O6 ceramics.

[0035] Water-soluble Ba prepared at low temperature based on the above embodiments x Sr y Ca zAl2O6 ceramics, on the one hand, can significantly improve the lattice constant matching degree by adjusting the proportions of x, y, and z, thereby greatly enhancing the single crystallinity of epitaxially grown other functional oxide films. On the other hand, the low-temperature preparation method drastically reduces the calcination temperature of this ceramic from 1200℃ in the high-temperature solid-state method to 750℃-850℃, and the sintering temperature from 1400℃ in the high-temperature solid-state method to 850℃-900℃, achieving energy saving, consumption reduction, and cost reduction. Furthermore, it avoids the generation of second-phase impurities (BaAl2O4, SrAl2O4, CaAl2O4) during calcination and sintering, improving the performance of epitaxial growth of Ba using this ceramic as a target material. x Sr y Ca z The monocrystalline nature of Al₂O₆ films. A sol-gel method for achieving water-soluble Ba₂O₆ films. x Sr y Ca z The preparation of Al2O6 powder provides technical support for the spin coating method to prepare and peel off large-size flexible oxide films with other functions, making it possible for other functional oxide films to be applied on a large scale in the field of flexible electronics.

Claims

1. A method for preparing water-soluble Ba at low temperature x Sr y Ca z The method for producing Al2O6 ceramics is characterized by, Includes the following steps, Step 1: Weigh out Ba(NO3)2 powder, Sr(NO3)2 powder, Ca(NO3)2⋅4H2O powder, and Al(NO3)3⋅9H2O powder according to the molar ratio of x:y:z:2, where x is the molar percentage of Ba(NO3)2 powder, y is the molar percentage of Sr(NO3)2 powder, and z is the molar percentage of Ca(NO3)2⋅4H2O powder. Step 2: Weigh an appropriate amount of citric acid and dissolve it in water to prepare a 10wt% citric acid solution. Then, add the Ba(NO3)2 powder, the Sr(NO3)2 powder, the Ca(NO3)2⋅4H2O powder, and the Al(NO3)3⋅9H2O powder to the citric acid solution in sequence. Heat and stir until the powders are completely dissolved to prepare a mixed solution. Step 3: Based on the mixed solution, add an appropriate amount of ethylene glycol solution as a complexing agent, and form a gel by heating and stirring; Step 4: After drying the gel, place it in a box furnace and calcine it in air atmosphere to obtain Ba. x Sr y Ca z A l2 O6 powder; Step 5: Place the Ba x Sr y Ca z Al2O6 powder was placed in an agate mortar, and polyvinyl alcohol (PVA) / ethanol binder was slowly dripped in to make the Ba... x Sr y Ca z Al2O6 powder was bonded into particles, and Ba was prepared by aging. x Sr y Ca z Al2O6 / PVA particles; Step 6: Weigh an appropriate amount of the Ba x Sr y Ca z Al2O6 / PVA particles are placed in a stainless steel mold and formed into discs through pressing. After grinding, they are de-ground to form round Ba discs. x Sr y Ca z Al2O6 / PVA embryo; Step 7: Place the circular Ba sheet... x Sr y Ca z Al2O6 / PVA preforms were placed in a box furnace and sintered in air atmosphere to remove the PVA and obtain dense Ba. x Sr y Ca z Al2O6 ceramics.

2. The method according to claim 1, characterized in that, In step 1, x is less than or equal to 2, z is less than or equal to 2, and x + y + z = 3.

3. The method according to claim 1, characterized in that, Step 2, which involves heating and stirring until the powder is completely dissolved, includes heating at 70°C and stirring for 2 hours.

4. The method according to claim 1, characterized in that, In step 3, the volume ratio of ethylene glycol to the mixed solution is 1:

10.

5. The method according to claim 1, characterized in that, Step 3, which involves heating and stirring to form a gel, specifically includes: continuously heating and stirring for 2 hours to form a sol, and then continuing to heat for another 2 hours to form a gel.

6. The method according to claim 1, characterized in that, The calcination in air atmosphere described in step 4 includes: The calcination temperature is 750℃-850℃, the calcination time is 2h-4h, and the heating rate is 5℃ / min.

7. The method according to claim 1, characterized in that, Step 5, which involves slowly dripping in 10 wt% PVA / ethanol binder, includes: The amount of the 10wt% PVA adhesive added is 3wt%-5wt%.

8. The method according to claim 1, characterized in that, Step 7 describes the process of placing the circular Ba sheet... x Sr y Ca z Al2O6 / PVA preforms are placed in a box furnace and sintered in air atmosphere, including: The circular Ba plate was embedded and burned. x Sr y Ca z The Al2O6 / PVA preform was placed in a box furnace and sintered in air atmosphere. During sintering, it was held at 600℃ for 1 hour to remove the PVA binder. The sintering temperature was 850℃-900℃, the sintering time was 2-4 hours, and the heating rate was 5℃ / min.

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