Ceramic coating die and method of making same

Abstract

The application provides a ceramic coating die and a preparation method thereof, and particularly relates to the technical field of battery coating dies. The preparation method comprises the following steps: A, a zirconium-containing compound, an aluminum-containing compound and a doping stabilizer are added into deionized water and stirred uniformly, and an alkali solution is added to perform a hydrolysis precipitation reaction; after the completion, a mixed solution is obtained; B, the mixed solution is subjected to solid-liquid separation, and finally, the precipitate is dried to obtain a precursor powder; C, the precursor powder is pre-fired, and the powder obtained after the pre-firing is wet-milled to obtain a slurry; the slurry is subjected to spray granulation to obtain a spherical powder; D, the spherical powder is loaded into a mold to perform isostatic pressing forming to obtain a green body; the green body is processed to obtain a ceramic coating die green body; and finally, the ceramic coating die green body is subjected to high-temperature sintering to obtain a ceramic coating die.

Description

Technical Field

[0001] This invention relates to the field of battery coating die technology, and in particular to a ceramic coating die and its preparation method. Background Technology

[0002] Secondary battery products form the foundation of application technologies and engineering technologies for hybrid vehicles, pure electric vehicles, and energy storage systems. The electrode manufacturing process is the fundamental process in rechargeable battery production, and this step demands extremely high precision, reliability, and scientific design from the equipment used. The electrode surface needs to be coated with active materials. Common electrode active material coating processes include transfer coating and slot extrusion coating. Slot extrusion coating involves a certain flow rate of slurry entering the die cavity from the feed port of the extrusion head, forming a stable pressure, and finally the slurry flows out from the slot outlet of the die head, coating the foil material.

[0003] Currently, most coating dies are made of stainless steel. During the coating process, wear of the coating die is unavoidable, allowing metal powders such as Fe and Ni to enter the battery slurry and affect battery performance. Moreover, metal materials are not corrosion-resistant and are prone to corrosion pitting, affecting the uniformity of coating.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] One of the objectives of this invention is to provide a method for preparing a ceramic coating die to solve at least one of the aforementioned technical problems in the prior art.

[0006] The second objective of this invention is to provide a ceramic coating die.

[0007] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: The first aspect of this invention provides a method for preparing a ceramic coating die, comprising the following steps: A. Add zirconium-containing compound, aluminum-containing compound and doping stabilizer to deionized water and stir until homogeneous. Add alkaline solution to carry out hydrolysis precipitation reaction. After completion, adjust the pH of the system to ≥9 and continue stirring for 0.5-1h to obtain a mixed solution.

[0008] B. Perform a first solid-liquid separation on the mixture; add an alkaline solution to the precipitate obtained from the first solid-liquid separation for a first wash, and perform a second solid-liquid separation after the wash is completed.

[0009] Deionized water is added to the precipitate obtained from the second solid-liquid separation for a second washing, and a third solid-liquid separation is performed after the washing is completed.

[0010] After the pH of the liquid obtained from the third solid-liquid separation is ≤7.0, ethanol is added to the precipitate obtained from the third solid-liquid separation for a third washing. After the washing is completed, a fourth solid-liquid separation is performed. Finally, the precipitate obtained from the fourth solid-liquid separation is dried to obtain the precursor powder.

[0011] C. The precursor powder is pre-calcined, and the powder obtained after pre-calcination is wet-milled to obtain a slurry; the slurry is spray-granulated to obtain spherical powder.

[0012] D. The spherical powder is loaded into a mold and isostatically pressed to obtain a green body; the green body is processed to obtain a ceramic coating die green body; finally, the ceramic coating die green body is sintered at high temperature to obtain the ceramic coating die.

[0013] Further, in step D, the highest temperature for high-temperature sintering is 1480-1600℃; the temperature control curve for high-temperature sintering is as follows: The heating rate from room temperature to 250℃ is 0.01-0.1℃ / min, and the temperature is held at 250℃ for 5-12 hours. The heating rate from 250℃ to 500℃ is 0.1-0.5℃ / min, and the temperature is held at 500℃ for 1-5 hours. The heating rate from 500℃ to 900℃ is 0.5-1℃ / min, and the temperature is held at 900℃ for 0.5-2 hours. The heating rate from 900℃ to 1200℃ is 0.2-1℃ / min, and the temperature is held at 1200℃ for 0.5-2 hours. The heating rate from 1200℃ to the highest temperature is 0.5-3℃min, and the highest temperature is held for 3-6 hours; The cooling rate from the highest temperature to 600℃ is 1-3℃ / min, and the temperature is naturally cooled from 600℃ to 50℃.

[0014] Furthermore, in step B, the methods of the first solid-liquid separation, the second solid-liquid separation, the third solid-liquid separation, and the fourth solid-liquid separation each independently include vacuum filtration or centrifugation.

[0015] Preferably, the second washing is performed ≥1 time until the pH of the liquid after the third solid-liquid separation is ≤7.0.

[0016] Preferably, in step B, the drying method includes baking or spray drying.

[0017] Preferably, the drying temperature is 100-150℃.

[0018] Preferably, the inlet temperature of the spray dryer is 200-240°C, and the outlet temperature is 80-120°C.

[0019] Further, in step A, the zirconium-containing compound includes at least one of zirconium oxide, zirconium oxychloride, zirconium chloride, and zirconium nitrate.

[0020] The aluminum-containing compound includes at least one of α-Al₂O₃, aluminum nitrate, aluminum chloride, and hydrated aluminum oxide.

[0021] The doping stabilizer includes at least one of yttrium oxide, yttrium nitrate, yttrium chloride, cerium oxide, cerium nitrate, and cerium chloride.

[0022] Further, in step A, the zirconium-containing compound comprises 78-96 parts by weight, the aluminum-containing compound comprises 0.2-20 parts by weight, and the doping stabilizer comprises 0.2-20 parts by weight.

[0023] Preferably, the hydrolysis precipitation reaction is carried out at a temperature of 60-90℃ for 1-2 hours.

[0024] Preferably, in steps A and B, the alkaline solution each independently includes ammonia.

[0025] Preferably, the concentration of the ammonia water is 10-15 wt.%.

[0026] Furthermore, in step C, the pre-firing temperature is 600-1100℃, and the temperature is maintained for 1-2 hours.

[0027] Preferably, in step C, the particle size D50 of the powder in the slurry is 0.5-1.2 μm.

[0028] Preferably, in step C, the wet milling method includes sand milling, planetary ball milling, or stirred milling.

[0029] Further, in step C, the spray granulation is performed after adding a binder, dispersant, and defoamer to the slurry.

[0030] Preferably, the adhesive comprises at least one of polyvinyl alcohol, polyacrylic acid emulsion, and methylcellulose.

[0031] Preferably, the dispersant comprises a polymeric ammonium salt.

[0032] Preferably, the polymeric ammonium salt comprises ammonium polyacrylate and / or PC67.

[0033] Preferably, the defoamer includes at least one of tributyl phosphate, fatty acid, and silicone emulsion.

[0034] Furthermore, in step C, the inlet temperature of the spray granulation is 200-240℃, and the outlet temperature is 80-120℃.

[0035] Furthermore, in step D, the isostatic pressing pressure is 150-300 MPa, and the pressure is held for 5-30 minutes.

[0036] Preferably, in step D, the green blank is obtained by wire cutting or CNC machining.

[0037] The second aspect of the present invention provides a ceramic coating die head prepared by the preparation method described above.

[0038] Compared with the prior art, the present invention has at least the following beneficial effects: The method for preparing a ceramic coating die provided by this invention includes a solid-liquid separation and spray granulation step, which provides clean spherical powder for the coating die, which is beneficial for obtaining a dense ceramic coating die. The ceramic coating die green is obtained by fine processing during the greening process, and the ceramic coating die can be obtained by high-temperature sintering. This method controls the accuracy of the die size and improves the yield of the die.

[0039] The ceramic coating die provided by this invention uses all-ceramic material, overcoming the problems of metal impurities contaminating the battery slurry after wear of metal coating dies and the corrosion resistance of metal dies affecting coating uniformity. The ceramic coating die is entirely made of ceramic material, possessing advantages such as high hardness, high wear resistance, corrosion resistance, no metal contamination, and no slurry sticking during the coating process. This improves the quality of the coated electrode sheet, indirectly enhancing the performance and lifespan of the secondary battery. Attached Figure Description

[0040] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0041] Figure 1 This is a flowchart of the method for preparing the ceramic coating die provided in Example 3; Figure 2 An optical microscope image of the ceramic granulated powder provided in Example 3; Figure 3 Photographs of the ceramic surface morphology obtained in Test Example 3; Figure 4 The surface morphology photograph of SUS630 obtained in Test Example 3; Figure 5 Photographs of the ceramic surface morphology after electrochemical corrosion provided for Test Example 3; Figure 6Photographs of the surface morphology of SUS630 after electrochemical corrosion provided for Test Example 3. Detailed Implementation

[0042] The embodiments and examples of the present invention will be described in detail below with reference to the implementation methods and examples. However, those skilled in the art will understand that the following implementation methods and examples are only for illustrating the present invention and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] The first aspect of this invention provides a method for preparing a ceramic coating die, comprising the following steps: A. Add zirconium-containing compound, aluminum-containing compound and doping stabilizer to deionized water and stir until homogeneous. Add alkaline solution to carry out hydrolysis precipitation reaction. After completion, adjust the pH of the system to ≥9 and continue stirring for 0.5-1h to obtain a mixed solution.

[0044] B. Perform a first solid-liquid separation on the mixture; add an alkaline solution to the precipitate obtained from the first solid-liquid separation for a first wash, and perform a second solid-liquid separation after the wash is completed.

[0045] Deionized water is added to the precipitate obtained from the second solid-liquid separation for a second washing, and a third solid-liquid separation is performed after the washing is completed.

[0046] After the pH of the liquid obtained from the third solid-liquid separation is ≤7.0, ethanol is added to the precipitate obtained from the third solid-liquid separation for a third washing. After the washing is completed, a fourth solid-liquid separation is performed. Finally, the precipitate obtained from the fourth solid-liquid separation is dried to obtain the precursor powder.

[0047] C. The precursor powder is pre-calcined, and the powder obtained after pre-calcination is wet-milled to obtain a slurry; the slurry is spray-granulated to obtain spherical powder.

[0048] D. The spherical powder is loaded into a mold and isostatically pressed to obtain a green body; the green body is processed to obtain a ceramic coating die green body; finally, the ceramic coating die green body is sintered at high temperature to obtain the ceramic coating die.

[0049] The method for preparing a ceramic coating die provided by this invention includes a solid-liquid separation and spray granulation step, which provides clean spherical powder for the coating die, which is beneficial for obtaining a dense ceramic coating die. The ceramic coating die green is obtained by fine processing during the greening process, and the ceramic coating die can be obtained by high-temperature sintering. This method controls the accuracy of the die size and improves the yield of the die.

[0050] In step A, the pH of the system is adjusted to ≥9, so that the system has a sufficiently alkaline environment and enough hydroxide ions to coprecipitate with aluminum and zirconium to obtain aluminum and zirconium precipitates.

[0051] In step B, an alkaline solution is added for the first wash, mainly to ensure that the co-precipitation reaction in the solution can proceed completely and to obtain more aluminum and zirconium precipitates.

[0052] In this embodiment of the invention, the cleaning is performed under ultrasonic vibration, because ultrasonic vibration can fully disperse the precipitate and break up some of the agglomerated particles, thus ensuring thorough cleaning. Specifically, the cleaning time is preferably 5-10 minutes.

[0053] In step B, the third cleaning uses ethanol to disperse the precipitate in the ethanol and reduce the agglomeration of the powder.

[0054] In step C, spray granulation yields spherical powder. The spherical powder has good flowability, which is beneficial for rolling during the subsequent isostatic pressing process, filling the gaps in the material, and forming a dense green body.

[0055] Further, in step D, the highest temperature for high-temperature sintering is 1480-1600℃; the temperature control curve for high-temperature sintering is as follows: The heating rate from room temperature to 250℃ is 0.01-0.1℃ / min, and the temperature is held at 250℃ for 5-12 hours. The heating rate from 250℃ to 500℃ is 0.1-0.5℃ / min, and the temperature is held at 500℃ for 1-5 hours. The heating rate from 500℃ to 900℃ is 0.5-1℃ / min, and the temperature is held at 900℃ for 0.5-2 hours. The heating rate from 900℃ to 1200℃ is 0.2-1℃ / min, and the temperature is held at 1200℃ for 0.5-2 hours. The heating rate from 1200℃ to the highest temperature is 0.5-3℃min, and the highest temperature is held for 3-6 hours; The cooling rate from the highest temperature to 600℃ is 1-3℃ / min, and the temperature is naturally cooled from 600℃ to 50℃.

[0056] In the specific implementation process, the highest temperature for high-temperature sintering is typically, but not limited to, 1480℃, 1500℃, 1520℃, 1540℃, 1560℃, 1580℃ or 1600℃, or any value within the range of 1480-1600℃.

[0057] When heating from room temperature to 250°C, the heating rate is typically, but not limited to, 0.01°C / min, 0.03°C / min, 0.05°C / min, 0.07°C / min, 0.09°C / min, or 0.1°C / min; it can also be any value within the range of 0.01-0.1°C / min. Similarly, the holding time at 250°C is typically, but not limited to, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, or 12 hours; it can also be any value within the range of 5-12 hours.

[0058] The heating process described below can have any heating rate or holding time within the range, and will not be elaborated further here.

[0059] Furthermore, in step B, the methods of the first solid-liquid separation, the second solid-liquid separation, the third solid-liquid separation, and the fourth solid-liquid separation each independently include vacuum filtration or centrifugation.

[0060] Preferably, the second washing is performed ≥1 time until the pH of the liquid after the third solid-liquid separation is ≤7.0.

[0061] The purpose of adding deionized water multiple times is to dilute the residual NH4 in the precipitate. + and Cl - This allows for better removal of the NH4+ by filtration or centrifugation. + and Cl - During high-temperature calcination, the precipitate generates volatile and corrosive gases that can harm the human body and pollute the environment.

[0062] If the pH of the liquid obtained after the second cleaning is ≤7.0, the third cleaning can be performed; however, if the pH of the liquid obtained after the third solid-liquid separation is >7.0, multiple cleanings and solid-liquid separations with deionized water are required.

[0063] During solid-liquid separation, the vacuum degree of vacuum filtration can be -0.09 MPa; if centrifugation is used for solid-liquid separation, the centrifugation speed is 3000-5000 r / min.

[0064] Preferably, in step B, the drying method includes baking or spray drying.

[0065] Preferably, the drying temperature is 100-150℃.

[0066] Preferably, the inlet temperature of the spray dryer is 200-240°C, and the outlet temperature is 80-120°C.

[0067] It should be noted that during spray drying, the precipitate obtained from the fourth solid-liquid separation needs to be made into a slurry before spray drying, and the moisture content of the slurry is ≥50wt.%.

[0068] Further, in step A, the zirconium-containing compound includes at least one of zirconium oxide, zirconium oxychloride, zirconium chloride, and zirconium nitrate.

[0069] The aluminum-containing compound includes at least one of α-Al₂O₃, aluminum nitrate, aluminum chloride, and hydrated aluminum oxide.

[0070] The doping stabilizer includes at least one of yttrium oxide, yttrium nitrate, yttrium chloride, cerium oxide, cerium nitrate, and cerium chloride.

[0071] Further, in step A, the zirconium-containing compound comprises 78-96 parts by weight, the aluminum-containing compound comprises 0.2-20 parts by weight, and the doping stabilizer comprises 0.2-20 parts by weight.

[0072] In the implementation of this invention, the weight parts of the zirconium-containing compound are typically, but not limited to, 78, 80, 82, 84, 86, 88, 90, 92, 94, or 96; the weight parts of the aluminum-containing compound are typically, but not limited to, 0.2, 1, 5, 10, 15, or 20; and the weight parts of the doping stabilizer are typically, but not limited to, 0.2, 1, 5, 10, 15, or 20.

[0073] Preferably, the hydrolysis precipitation reaction is carried out at a temperature of 60-90℃ for 1-2 hours.

[0074] Preferably, in steps A and B, the alkaline solution each independently includes ammonia.

[0075] Preferably, the concentration of the ammonia water is 10-15 wt.%.

[0076] In the specific implementation of this invention, the concentration of ammonia water is typically, but not limited to, 10 wt.%, 11 wt.%, 12 wt.%, 13 wt.%, 14 wt.%, or 15 wt.%.

[0077] Further, in step C, the pre-firing temperature is 600-1100℃, and the holding time is 1-2 hours. During pre-firing, the precursor powder is placed in a corundum mullite or corundum ceramic crucible and placed in a furnace with a temperature rise rate of 1-5℃ / min for pre-firing.

[0078] Preferably, in step C, the particle size D50 of the powder in the slurry is 0.5-1.2 μm.

[0079] Preferably, in step C, the wet milling method includes sand milling, planetary ball milling, or stirred milling.

[0080] Further, in step C, the spray granulation is performed after adding a binder, dispersant, and defoamer to the slurry.

[0081] Preferably, the adhesive comprises at least one of polyvinyl alcohol, polyacrylic acid emulsion, and methylcellulose.

[0082] Preferably, the dispersant comprises a polymeric ammonium salt.

[0083] Preferably, the polymeric ammonium salt comprises ammonium polyacrylate and / or PC67.

[0084] Preferably, the defoamer includes at least one of tributyl phosphate, fatty acid, and silicone emulsion.

[0085] Furthermore, in step C, the inlet temperature of the spray granulation is 200-240℃, and the outlet temperature is 80-120℃.

[0086] Furthermore, in step D, the isostatic pressing pressure is 150-300 MPa, and the pressure is held for 5-30 minutes.

[0087] Preferably, in step D, the green blank is obtained by wire cutting or CNC machining.

[0088] The second aspect of the present invention provides a ceramic coating die head prepared by the preparation method described above.

[0089] The ceramic coating die provided by this invention uses all-ceramic material, overcoming the problems of metal impurities contaminating the battery slurry after wear of metal coating dies and the corrosion resistance of metal dies affecting coating uniformity. The ceramic coating die is entirely made of ceramic material, possessing advantages such as high hardness, high wear resistance, corrosion resistance, no metal contamination, and no slurry sticking during the coating process. This improves the quality of the coated electrode sheet, indirectly enhancing the performance and lifespan of the secondary battery.

[0090] The present invention is further illustrated below with specific embodiments and comparative examples. However, it should be understood that these embodiments are merely for illustrative purposes and should not be construed as limiting the invention in any way. Unless otherwise specified, the raw materials used in the embodiments and comparative examples of the present invention were carried out under conventional conditions or conditions recommended by the manufacturer. Reagents or instruments used, unless otherwise specified, are all commercially available conventional products.

[0091] Example 1 This embodiment provides a ceramic coating die head, and the specific process is as follows: 1. Weigh 49.5 kg of zirconium oxychloride octahydrate (ZrOCl2·8H2O), 3.5 kg of yttrium nitrate hexahydrate (Y(NO3)3·6H2O), and 294 g of aluminum nitrate nonahydrate (Al(NO3)3·9H2O). Add them to 60 kg of deionized water, stir thoroughly, and heat in a water bath to 60°C for hydrolysis reaction for 2 hours. After the mixed solution cools to room temperature, start adding 10 wt.% ammonia solution dropwise. Stir the mixture continuously during the ammonia addition. When the pH of the mixed solution reaches 9, stop adding ammonia solution and continue stirring for 1 hour to obtain a precipitated mixture.

[0092] 2. The obtained mixture was subjected to five vacuum filtrations. After the first filtration, the precipitate was added to ammonia solution with a concentration of 10 wt.%, and ultrasonically vibrated for 5 minutes before the second filtration. After the second filtration, the precipitate was added to deionized water, and ultrasonically vibrated for 5 minutes before the third filtration. The fourth filtration repeated the steps of the third filtration. After the fourth filtration, the precipitate was added to anhydrous ethanol, and ultrasonically vibrated for 5 minutes before the fifth filtration. The obtained precipitate was mixed with water to prepare a slurry with a moisture content of 50 wt.% and then spray-dried (inlet air temperature of 220℃, outlet air temperature of 90℃).

[0093] 3. The spray-dried powder is placed in a corundum crucible and heated to 800℃ at a rate of 2℃ / min in a furnace, and held for 2 hours. The pre-fired powder is then ground to a D50 of 0.5μm using a sand milling process. The wet-milled slurry is then ball-milled, with PVA binder, PC67 dispersant, and tributyl phosphate defoamer added simultaneously. After mixing and ball-milling for 1 hour, it is then spray-granulated (inlet air temperature 240℃, outlet air temperature 90℃) to obtain ceramic granulated powder with good flowability.

[0094] 4. The prepared ceramic granulation powder is loaded into the designated mold, sealed, and then hoisted into the cylinder of the isostatic pressing equipment for isostatic pressing molding. The isostatic pressing pressure is 300MPa, and the pressure is held for 5mins. After forming, the green blank is wire-cut and CNC machined according to the drawings, and finally put into an electric furnace for high-temperature sintering. The sintering temperature rise curve is as follows: the heating rate from room temperature to 250℃ is 0.01℃ / min, and it is held at 250℃ for 10 hours; the heating rate from 250℃ to 500℃ is 0.1℃ / min, and it is held at 500℃ for 2 hours; the heating rate from 500℃ to 900℃ is 0.5℃ / min, and it is held at 900℃ for 1 hour; the heating rate from 900℃ to 1200℃ is 0.5℃ / min, and it is held at 1200℃ for 1 hour; the heating rate from 1200℃ to the highest temperature is 2℃ / min, and it is held at the highest temperature for 3 hours; the cooling rate from the highest temperature to 600℃ is 3℃ / min, and it is naturally cooled from 600℃ to 50℃. The highest temperature is 1510℃. Finally, a dense sintered all-ceramic coated die material is obtained.

[0095] Example 2 This embodiment provides a ceramic coating die head, and the specific process is as follows: 1. Weigh 39.5 kg of zirconium oxychloride octahydrate (ZrOCl2·8H2O), 2.4 kg of yttrium chloride hexahydrate (YCl3·6H2O), and 4.02 kg of alumina (α-Al2O3). Add them to 60 kg of deionized water, stir thoroughly, and heat in a water bath to 90°C for hydrolysis reaction for 1 hour. After the mixed solution cools to room temperature, start adding 12 wt.% ammonia solution dropwise. Stir the mixture continuously during the ammonia addition. When the pH of the mixed solution reaches 9, stop adding ammonia solution and continue stirring for 1 hour to obtain a precipitated mixture.

[0096] 2. The obtained mixture was subjected to two vacuum filtrations and three centrifugations. The precipitate after the first filtration was added to 12wt% ammonia water, ultrasonically vibrated for 8 minutes, and then centrifuged for the first time. The precipitate after the first centrifugation was added to deionized water, ultrasonically vibrated for 8 minutes, and then centrifuged for the second time. The second centrifugation was repeated for the third centrifugation. The precipitate after the third centrifugation was added to anhydrous ethanol, ultrasonically vibrated for 8 minutes, and then filtered for the second time. The obtained precipitate was placed in an oven set to 100℃ and dried.

[0097] 3. The dried powder is placed in a corundum-mullite crucible and heated to 1000℃ in a furnace at a rate of 3℃ / min, and held for 1 hour. The pre-fired powder is then ground to a D50 of 0.6μm using a sand milling process. The wet-milled slurry is then ball-milled, with PVA and methylcellulose binder, PC67 dispersant, and tributyl phosphate defoamer added simultaneously. After mixing and ball-milling for 2 hours, spray granulation is performed (inlet air temperature 240℃, outlet air temperature 90℃) to obtain ceramic granulated powder with good flowability.

[0098] 4. The prepared ceramic granulation powder is loaded into the designated mold, sealed, and then hoisted into the cylinder of the isostatic pressing equipment for isostatic pressing molding. The isostatic pressing pressure is 250MPa, and the pressure is held for 10mins. After forming, the green blank is wire-cut and CNC machined according to the drawings, and finally put into a gas furnace for high-temperature sintering. The sintering temperature rise curve is as follows: the heating rate from room temperature to 250℃ is 0.05℃ / min, and it is held at 250℃ for 12 hours; the heating rate from 250℃ to 500℃ is 0.25℃ / min, and it is held at 500℃ for 3 hours; the heating rate from 500℃ to 900℃ is 1℃ / min, and it is held at 900℃ for 1 hour; the heating rate from 900℃ to 1200℃ is 0.5℃ / min, and it is held at 1200℃ for 1 hour; the heating rate from 1200℃ to the highest temperature is 1℃ / min, and it is held at the highest temperature for 4 hours; the cooling rate from the highest temperature to 600℃ is 2℃ / min, and it is naturally cooled from 600℃ to 50℃. The highest temperature is 1550℃. Finally, a dense sintered all-ceramic coated die material is obtained.

[0099] Example 3 This embodiment provides a ceramic coating die, and the preparation method flowchart is shown below. Figure 1 As shown, the specific process is as follows: 1. Weigh 41.1 kg of zirconium oxychloride octahydrate (ZrOCl2·8H2O), 1.7 kg of yttrium nitrate hexahydrate (Y(NO3)3·6H2O), 1.5 kg of cerium chloride hexahydrate (CeCl3·6H2O), and 3.06 kg of alumina (α-Al2O3) and add them to 80 kg of deionized water. Stir thoroughly and heat in a water bath to 90°C for 1 hour for hydrolysis. After the mixed solution cools to room temperature, start adding 15 wt% ammonia solution dropwise. Stir the mixture continuously during the ammonia addition. When the pH of the mixed solution reaches 9, stop adding ammonia solution and continue stirring for 1 hour to obtain a precipitated mixture.

[0100] 2. The obtained mixture was subjected to three vacuum filtrations and two centrifugations. The precipitate after the first filtration was added to ammonia water with a concentration of 15 wt.%, and ultrasonically vibrated for 10 min before being filtered a second time. The precipitate after the second filtration was added to deionized water, and ultrasonically vibrated for 10 min before being centrifuged a first time. The second centrifugation was performed by repeating the steps of the first centrifugation. The precipitate after the second centrifugation was added to anhydrous ethanol, and ultrasonically vibrated for 10 min before being filtered a third time. The obtained precipitate was mixed with water to prepare a slurry with a moisture content of 50 wt.% and then spray-dried (inlet air temperature: 220℃, outlet air temperature: 90℃).

[0101] 3. The spray-dried powder is placed in a corundum-mullite crucible and heated to 800℃ at a rate of 2℃ / min in a furnace, and held for 2 hours. The pre-fired powder is then finely ground to a D50 of 0.8μm using a sand milling process. The wet-milled slurry is then ball-milled, with PVA binder, PC67 dispersant, and tributyl phosphate defoamer added simultaneously. After mixing and ball-milling for 4 hours, it is then spray-granulated (inlet air temperature 220℃, outlet air temperature 90℃) to obtain ceramic granulated powder with good flowability.

[0102] 4. The prepared ceramic granulation powder is loaded into the designated mold, sealed, and then hoisted into the cylinder of the isostatic pressing equipment for isostatic pressing molding. The isostatic pressing pressure is 200MPa, and the pressure is held for 20mins. After forming, the green blank is wire-cut and CNC machined according to the drawings, and finally put into a gas furnace for high-temperature sintering. The sintering heating curve is as follows: the heating rate from room temperature to 250℃ is 0.02℃ / min, and it is held at 250℃ for 8 hours; the heating rate from 250℃ to 500℃ is 0.5℃ / min, and it is held at 500℃ for 3 hours; the heating rate from 500℃ to 900℃ is 1℃ / min, and it is held at 900℃ for 1 hour; the heating rate from 900℃ to 1200℃ is 0.5℃ / min, and it is held at 1200℃ for 1 hour; the heating rate from 1200℃ to the highest temperature is 2℃ / min, and it is held at the highest temperature for 6 hours; the cooling rate from the highest temperature to 600℃ is 3℃ / min, and it is naturally cooled from 600℃ to 50℃. The highest temperature is 1550℃. Finally, a dense sintered all-ceramic coated die material is obtained.

[0103] Example 4 This embodiment provides a ceramic coating die head, and the specific process is as follows: 1. Weigh 46.39 kg of zirconium oxychloride octahydrate (ZrOCl2·8H2O), 1.70 kg of yttrium nitrate hexahydrate (Y(NO3)3·6H2O), 3.54 kg of cerium chloride hexahydrate (CeCl3·6H2O), and 0.29 kg of aluminum nitrate nonahydrate (Al(NO3)3·9H2O) and add them to 60 kg of deionized water. Stir thoroughly and heat in a water bath to 60°C for 1 hour for hydrolysis. After the mixed solution cools to room temperature, start adding 12 wt.% ammonia solution dropwise. Stir the mixture continuously during the ammonia addition. When the pH of the mixed solution reaches 9, stop adding ammonia solution and continue stirring for 1 hour to obtain a precipitated mixture.

[0104] 2. The obtained mixture was subjected to four vacuum filtrations and one centrifugation. The precipitate after the first filtration was added to 12 wt.% ammonia water, ultrasonically vibrated for 10 mins, and then subjected to a second filtration. The precipitate after the second filtration was added to deionized water, ultrasonically vibrated for 10 mins, and then centrifuged. The precipitate after centrifugation was added to deionized water, ultrasonically vibrated for 10 mins, and then subjected to a third filtration. The precipitate after filtration was added to anhydrous ethanol, ultrasonically vibrated for 10 mins, and then subjected to a fourth filtration. The resulting precipitate was placed in an oven and dried at 120℃.

[0105] 3. The dried powder is placed in a corundum-mullite crucible and heated to 600℃ at a rate of 1℃ / min in a furnace, and held for 2 hours. The pre-fired powder is then finely ground to a D50 of 1.2μm using a sand milling process. The wet-milled slurry is then ball-milled, with PVA, acrylic emulsion binder, ammonium polyacrylate dispersant, and silicone emulsion defoamer added simultaneously. After mixing and ball-milling for 2 hours, spray granulation is performed (inlet air temperature 240℃, outlet air temperature 120℃) to obtain ceramic granulated powder with good flowability. An optical microscope image of this powder is shown below. Figure 2 As shown.

[0106] 4. The prepared ceramic granulation powder is loaded into the designated mold, sealed, and then hoisted into the cylinder of the isostatic pressing equipment for isostatic pressing molding. The isostatic pressing pressure is 250MPa, and the pressure is held for 5mins. After forming, the green blank is wire-cut and CNC machined according to the drawings, and finally put into a gas furnace for high-temperature sintering. The sintering temperature rise curve is as follows: the heating rate from room temperature to 250℃ is 0.05℃ / min, and it is held at 250℃ for 10 hours; the heating rate from 250℃ to 500℃ is 0.25℃ / min, and it is held at 500℃ for 2 hours; the heating rate from 500℃ to 900℃ is 1℃ / min, and it is held at 900℃ for 1 hour; the heating rate from 900℃ to 1200℃ is 0.5℃ / min, and it is held at 1200℃ for 1 hour; the heating rate from 1200℃ to 1600℃ is 2℃ / min, and it is held at 1600℃ for 5 hours; the cooling rate from 1600℃ to 600℃ is 2℃ / min, and it is naturally cooled from 600℃ to 50℃, finally obtaining a dense sintered all-ceramic coated die material.

[0107] Comparative Example 1 This comparative example provides a metal coating die head made of SUS630. The material is wire-cut and CNC machined according to the drawings to obtain a coating die head with the same dimensions as those in Examples 1-4.

[0108] Test Example 1 The all-ceramic coated die materials obtained in Examples 1-4 were cut and sampled for testing, specifically including density, apparent porosity, Vickers hardness, fracture toughness, and wear resistance.

[0109] The apparent porosity was tested according to GB / T 25995-2010; the Vickers hardness was tested according to GB / T16534-2009; the fracture toughness was tested according to GB / T 23806-2009; and the wear resistance was tested according to ASTM G105-2016. The data obtained are shown in Table 1 below.

[0110] Table 1

[0111] Test Example 2 The wear resistance of the materials from Example 1 and Comparative Example 1 was compared using the following specific test methods: Step 1: Process the ceramic material of Example 1 and the SUS630 material of Comparative Example 1 to the same size, and polish the surface to a uniform roughness; Step 2: Weigh the sample blocks before testing; Step 3: Fix the ceramic sample and the SUS630 sample onto the same multi-functional wear resistance tester. Use 400# oilstone as the grinding medium, set the weight of the weight to 200g, the speed to 60r / min, and the number of revolutions to 1000r, and start the synchronous wear test. Step 4: After the wear test is completed, remove the sample blocks and weigh them separately; Step 5: Subtract the mass after the test from the mass before the test to obtain the wear amount.

[0112] The obtained wear data are shown in Table 2 below.

[0113] Table 2

[0114] Test Example 3 Electrochemical corrosion tests were performed on the materials from Example 1 and Comparative Example 1: 1. Prepare sample blocks and observe the surface morphology before testing using an optical microscope. The ceramic surface morphology photograph obtained in Example 1 is shown below. Figure 3 As shown; Comparative Example 1: Surface morphology photograph of SUS630 material. Figure 4 As shown.

[0115] 2. Prepare NMP solution (positive electrode solvent) and CMC solution (negative electrode solvent) for lithium batteries respectively.

[0116] 3. Fill a beaker with an appropriate amount of NMP solution and immerse the SUS630 sample and ceramic sample in the NMP solution respectively. Use an electrochemical workstation to test their electrochemical corrosion performance in the lithium battery cathode solution.

[0117] 4. Fill a beaker with an appropriate amount of CMC solution and immerse the SUS630 sample and ceramic sample in the CMC solution respectively. Use an electrochemical workstation to test their electrochemical corrosion performance in the lithium battery negative electrode solution.

[0118] 5. After the test, clean the sample with water and observe the surface morphology using an optical microscope to compare the corrosion conditions. The ceramic surface corrosion morphology photograph is shown below. Figure 5 As shown; surface corrosion morphology photographs of SUS630 material are shown below. Figure 6 As shown.

[0119] from Figure 5 and Figure 6It can be seen that SUS630 exhibits corrosion points in both NMP and CMC solutions, among which... Figure 6 These are corrosion spots that appeared on SUS630 in CMC solution; the ceramic material did not show any corrosion in either NMP or CMC solution.

[0120] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a ceramic coating die, characterized in that, Includes the following steps: A. Add zirconium-containing compound, aluminum-containing compound and doping stabilizer to deionized water and stir until homogeneous. Then add alkaline solution to carry out hydrolysis precipitation reaction. After completion, adjust the pH of the system to ≥9 and continue stirring for 0.5-1h to obtain the mixture; B. Perform a first solid-liquid separation on the mixture; An alkaline solution is added to the precipitate obtained from the first solid-liquid separation for a first wash, and a second solid-liquid separation is performed after the washing is completed. Deionized water is added to the precipitate obtained from the second solid-liquid separation for a second washing, and a third solid-liquid separation is performed after the washing is completed. After the pH of the liquid obtained from the third solid-liquid separation is ≤7.0, ethanol is added to the precipitate obtained from the third solid-liquid separation for a third wash. After the wash is completed, a fourth solid-liquid separation is performed. Finally, the precipitate obtained from the fourth solid-liquid separation is dried to obtain the precursor powder. C. The precursor powder is pre-calcined, and the powder obtained after pre-calcination is wet-milled to obtain a slurry; the slurry is spray-granulated to obtain spherical powder. D. The spherical powder is loaded into a mold and isostatically pressed to obtain a green body; the green body is processed to obtain a ceramic coating die green body; finally, the ceramic coating die green body is sintered at high temperature to obtain the ceramic coating die.

2. The preparation method according to claim 1, characterized in that, In step D, the highest temperature for high-temperature sintering is 1480-1600℃; the temperature control curve for high-temperature sintering is as follows: The heating rate from room temperature to 250℃ is 0.01-0.1℃ / min, and the temperature is held at 250℃ for 5-12 hours. The heating rate from 250℃ to 500℃ is 0.1-0.5℃ / min, and the temperature is held at 500℃ for 1-5 hours. The heating rate from 500℃ to 900℃ is 0.5-1℃ / min, and the temperature is held at 900℃ for 0.5-2 hours. The heating rate from 900℃ to 1200℃ is 0.2-1℃ / min, and the temperature is held at 1200℃ for 0.5-2 hours. The heating rate from 1200℃ to the highest temperature is 0.5-3℃ / min, and the highest temperature is held for 3-6 hours. The cooling rate from the highest temperature to 600℃ is 1-3℃ / min, and the temperature is naturally cooled from 600℃ to 50℃.

3. The preparation method according to claim 1, characterized in that, In step B, the first solid-liquid separation, the second solid-liquid separation, the third solid-liquid separation, and the fourth solid-liquid separation each independently include vacuum filtration or centrifugation.

4. The preparation method according to claim 1, characterized in that, The second cleaning is performed ≥1 time until the pH of the liquid after the third solid-liquid separation is ≤7.

0.

5. The preparation method according to claim 1, characterized in that, In step B, the drying method includes baking or spray drying.

6. The preparation method according to claim 5, characterized in that, The drying temperature is 100-150℃.

7. The preparation method according to claim 5, characterized in that, The inlet air temperature of the spray dryer is 200-240℃, and the outlet air temperature is 80-120℃.

8. The preparation method according to any one of claims 1-7, characterized in that, In step A, the zirconium-containing compound includes at least one of zirconium oxide, zirconium oxychloride, zirconium chloride, and zirconium nitrate; The aluminum-containing compound includes at least one of α-Al₂O₃, aluminum nitrate, aluminum chloride, and hydrated aluminum oxide; The doping stabilizer includes at least one of yttrium oxide, yttrium nitrate, yttrium chloride, cerium oxide, cerium nitrate, and cerium chloride.

9. The preparation method according to any one of claims 1-7, characterized in that, In step A, the zirconium-containing compound comprises 78-96 parts by weight, the aluminum-containing compound comprises 0.2-20 parts by weight, and the doping stabilizer comprises 0.2-20 parts by weight.

10. The preparation method according to claim 1, characterized in that, The hydrolysis precipitation reaction is carried out at a temperature of 60-90℃ for 1-2 hours.

11. The preparation method according to claim 1, characterized in that, In steps A and B, the alkaline solution each independently includes ammonia.

12. The preparation method according to claim 11, characterized in that, The concentration of the ammonia water is 10-15 wt.%.

13. The preparation method according to any one of claims 1-7, characterized in that, In step C, the pre-firing temperature is 600-1100℃, and the temperature is maintained for 1-2 hours.

14. The preparation method according to any one of claims 1-7, characterized in that, In step C, the particle size D50 of the powder in the slurry is 0.5-1.2 μm.

15. The preparation method according to any one of claims 1-7, characterized in that, In step C, the wet milling method includes sand milling, planetary ball milling, or stirred milling.

16. The preparation method according to any one of claims 1-7, characterized in that, In step C, the spray granulation is performed after adding binder, dispersant and defoamer to the slurry.

17. The preparation method according to claim 16, characterized in that, The adhesive includes at least one of polyvinyl alcohol, polyacrylic acid emulsion, and methylcellulose.

18. The preparation method according to claim 16, characterized in that, The dispersant includes a polymeric ammonium salt.

19. The preparation method according to claim 18, characterized in that, The polymeric ammonium salt includes ammonium polyacrylate and / or PC67.

20. The preparation method according to claim 16, characterized in that, The defoamer includes at least one of tributyl phosphate, fatty acid, and silicone emulsion.

21. The preparation method according to any one of claims 1-7, characterized in that, In step C, the inlet temperature of the spray granulation is 200-240℃, and the outlet temperature is 80-120℃.

22. The preparation method according to any one of claims 1-7, characterized in that, In step D, the isostatic pressing pressure is 150-300 MPa, and the pressure is held for 5-30 minutes.

23. The preparation method according to any one of claims 1-7, characterized in that, In step D, the green blank is obtained by wire cutting or CNC machining.

24. A ceramic coating die head prepared by the preparation method according to any one of claims 1-23.

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