Manganese ferrite ceramic as well as preparation method and application thereof

Abstract

The invention relates to manganese ferrite ceramic as well as a preparation method and application thereof, and the preparation method comprises the following steps: ball-milling and uniformly mixing a ceramic raw material and a solvent to obtain slurry; curing the slurry in a mold, demolding and drying to obtain a blank plate, or granulating the slurry, pressing in the mold, and demolding to obtain a blank plate; the blank plate is subjected to glue discharging treatment and then subjected to sintering treatment, the sintering temperature ranges from 1100 DEG C to 1300 DEG C, and the manganese ferrite ceramic is obtained; the ceramic raw material comprises the following components in parts by mass: 40-50 parts of manganese dioxide powder; 20 to 25 parts of ferric oxide powder; and 5-10 parts of aluminum oxide powder. According to the manganese ferrite ceramic prepared by the method, the surface resistivity is 106-109 omega / sq, the elastic modulus is greater than or equal to 50 GPa, and the porosity is 35-45%.

Description

TECHNICAL FIELD

[0001] The application relates to the field of antistatic materials, in particular to a manganese ferrite ceramic and a preparation method and application thereof. BACKGROUND

[0002] Static electricity is a common physical phenomenon, and electric charges tend to accumulate on the surface or inside of non-conductive objects. In recent years, with the rapid development of the electronic industry, the harm of static electricity is increasingly apparent. Especially under the background of the wide application of integrated circuits and high polymer materials, the discharge and induction phenomenon caused by static electricity accumulation not only damages equipment, but also may affect human health.

[0003] The surface resistivity or volume resistivity of the antistatic material should be within a certain range, and the static electricity dissipation rate is large, so as to achieve the purpose that static electricity is not easy to accumulate. Compared with the previous antistatic products such as epoxy and melamine, PVC antistatic paint, floor, antistatic rubber plate and other high polymer materials, the antistatic ceramic overcomes the shortcomings of easy aging, poor wear resistance, easy pollution, poor durability and fire resistance. At the same time, it also has the advantages of wear resistance and strong anti-pollution ability of ceramic tiles. At present, the preparation method of the antistatic ceramic mainly adds a large amount of conductive second phase in the traditional ceramic material. Although the existence of the second phase can change the electrical properties to a certain extent, the mechanical properties of the ceramic itself will be greatly reduced due to the existence of a large number of heterogeneous interfaces.

[0004] Therefore, it is of great significance to prepare an antistatic ceramic with strong mechanical properties. SUMMARY

[0005] The main purpose of the application is to provide a manganese ferrite ceramic and a preparation method and application thereof, and to solve the technical problem of how to prepare an antistatic ceramic with strong mechanical properties, so as to be more suitable for practical use.

[0006] The purpose of the application and the technical problem are realized by adopting the following technical scheme. According to the preparation method of the manganese ferrite ceramic, the steps include:

[0007] The ceramic raw material and the solvent are ball milled and uniformly mixed to obtain a slurry;

[0008] The slurry is solidified in a mold, and the green plate is obtained after demolding and drying, or the slurry is granulated and pressed in a mold, and the green plate is obtained after demolding;

[0009] The green plate is degreased and then sintered at a temperature of 1100-1300 DEG C to obtain the manganese ferrite ceramic;

[0010] The ceramic raw material includes, by mass:

[0011] Manganese dioxide powder 40-50 parts;

[0012] Ferric oxide powder 20-25 parts; and

[0013] Alumina powder 5-10 parts.

[0014] The object and technical problem of the present application can also be further achieved by the following technical measures.

[0015] Preferably, the method for preparing the manganese ferrite ceramic, wherein the solvent is one or more of water and alcohol; the size of the manganese dioxide powder is 3-5 μm; the size of the ferric oxide powder is 3-5 μm; and the size of the alumina powder is 2-3 μm.

[0016] Preferably, the method for preparing the manganese ferrite ceramic, the specific step of solidifying the slurry in the mold is:

[0017] adding a cross-linking monomer and a cross-linking agent into the slurry and mixing uniformly, adding an initiator and mixing uniformly, pouring into the mold, and waiting for the solidification to be completed;

[0018] the solvent is 8-20 parts;

[0019] the cross-linking monomer is 12-18 parts, and the cross-linking monomer is at least one of acrylamide, acrylic monomer, and acrylamide derivative monomer;

[0020] the cross-linking agent is 1.2-1.8 parts, and the cross-linking agent is at least one of a bis-acrylamide cross-linking agent and a bis-acrylate cross-linking agent.

[0021] Preferably, the method for preparing the manganese ferrite ceramic, the specific step of solidifying the slurry in the mold is:

[0022] adding a binder into the slurry and mixing uniformly, pouring into the mold, and waiting for the solidification to be completed;

[0023] the solvent is 8-20 parts;

[0024] the binder is 0.15-0.3 parts, and the binder is at least one of coal tar pitch, phenol formaldehyde resin, and cellulose ether.

[0025] Preferably, the method for preparing the manganese ferrite ceramic, the specific step of solidifying the slurry in the mold is:

[0026] drying the slurry and sieving to obtain a mixed powder;

[0027] spraying a plasticizer solution on the surface of the mixed powder to obtain wet powder particles;

[0028] The wet powder particles are sieved to obtain granulated particles;

[0029] The granulated particles are dried after being left to stand to obtain granulated powder;

[0030] The granulated powder is filled into a mold and then pressed;

[0031] The solvent is 50-85 parts;

[0032] The specific method of pressing is: pressurized to 20-30 MPa, and kept for 10-15 seconds; then continue to pressurize to 60-80 MPa, and kept for 60-180 seconds.

[0033] Preferably, the specific step of the preparation method of the ferrite ceramic is that the slurry is granulated and then pressed in a mold.

[0034] The molding agent is added to the slurry and mixed, and then dried and sieved to obtain dry granulation;

[0035] The dry granulation is poured into an elastic mold, vacuumized, sealed, and then isostatic pressed;

[0036] The solvent is 40-65 parts;

[0037] The molding agent is 1-2 parts;

[0038] The molding agent is at least one of glyceryl trioleate, menhaden oil, and polyethylene glycol octylphenyl ether;

[0039] The specific method of isostatic pressing is: the sealed elastic mold is placed in an isostatic press, pressurized to 100-150 MPa at a pressurization rate of 6-10 MPa / min, and kept for 10-20 min; then slowly depressurized at a rate of 2-4 MPa / min.

[0040] Preferably, the procedure of the degassing treatment in the preparation method of the ferrite ceramic is: increased to 450-460℃ at a temperature increasing rate of 3-4℃ / min, and then increased to 590-620℃ at a temperature increasing rate of 0.8-1℃ / min, and kept for 2-4 h;

[0041] The procedure of the sintering treatment is: increased to 840-870℃ at a temperature increasing rate of 4-5℃ / min, and then increased to 1100-1300℃ at a temperature increasing rate of 0.8-2℃ / min, and kept for 2-3 h.

[0042] Preferably, the preparation method of the ferrite ceramic further comprises adding a dispersant to the slurry; the dispersant is 1-8 parts; and the dispersant is at least one of sulfonated melamine, glyceryl trioleate, and polyester polyether modified phosphate ester.

[0043] The objective of this application and the solution to its technical problem are also achieved by the following technical solution. According to the manganese ferrite ceramic proposed in this application, the raw materials of the aforementioned manganese ferrite ceramic include:

[0044] 40 to 50 parts of manganese dioxide powder;

[0045] 20 to 25 parts of ferric oxide powder; and,

[0046] 5 to 10 parts of alumina powder;

[0047] The sintering temperature of the aforementioned manganese ferrite ceramic is 1100–1300℃;

[0048] The aforementioned manganese ferrite ceramic has a surface resistivity of 10. 6 ~10 9 Ω / sq, elastic modulus ≥50GPa, porosity 35%~45%.

[0049] The purpose of this application and the solution to its technical problems are also achieved by the following technical solutions. This application proposes the application of the aforementioned manganese ferrite ceramics in semiconductor preparation, precision instrument manufacturing, petrochemical, pharmaceutical, or printing fields.

[0050] By employing the above technical solution, the manganese ferrite ceramic, its preparation method, and its application, as described in this application, have at least the following advantages:

[0051] The method for preparing manganese ferrite ceramics proposed in this application uses manganese dioxide, ferric oxide, and alumina as main raw materials. A blank is prepared through processes such as gel casting, slip casting, dry pressing, and isostatic pressing. The blank is then sintered at 1100℃~1300℃ to allow the manganese ferrite to react with the ceramic powder, thus obtaining the manganese ferrite ceramic. Due to the special electrical conductivity of the manganese ferrite material system, this manganese ferrite ceramic possesses both high mechanical strength and low resistivity, thereby achieving the purpose of antistatic properties.

[0052] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, the preferred embodiments of this application are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0053] Figure 1 This is a scanning electron microscope image of the manganese ferrite ceramic in Example 1 of this application;

[0054] Figure 2 This is an optical photograph of the manganese ferrite ceramic in Example 1 of this application;

[0055] Figure 3This is a photograph of the manganese ferrite ceramic in Example 1 of this application after processing;

[0056] Figure 4 This is a scanning electron microscope image of the manganese ferrite ceramic in Embodiment 2 of this application;

[0057] Figure 5 This is a scanning electron microscope image of the manganese ferrite ceramic in Example 3 of this application;

[0058] Figure 6 This is a scanning electron microscope image of the manganese ferrite ceramic in Example 4 of this application. Detailed Implementation

[0059] To further illustrate the technical means and effects adopted by this application to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, provides a detailed description of the specific implementation methods, structures, features, and effects of a manganese ferrite ceramic, its preparation method, and its application based on this application. In the following description, different "embodiments" or "embodiments" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable manner.

[0060] This application discloses a method for preparing manganese ferrite ceramics, the steps of which include:

[0061] The ceramic raw materials and solvent are ball-milled and mixed to obtain a slurry;

[0062] The aforementioned slurry is solidified in a mold, and after demolding and drying, a blank plate is obtained; or the aforementioned slurry is granulated and then pressed in a mold, and after demolding, the aforementioned blank plate is obtained.

[0063] The aforementioned blank is subjected to debinding treatment and then sintering treatment at a temperature of 1100-1300℃ to obtain manganese ferrite ceramic.

[0064] By weight, the aforementioned ceramic raw materials include:

[0065] 40 to 50 parts of manganese dioxide powder;

[0066] 20 to 25 parts of ferric oxide powder; and,

[0067] 5 to 10 parts of alumina powder.

[0068] Specifically, manganese dioxide, ferric oxide, and aluminum oxide are ground and sieved separately to obtain manganese dioxide powder, ferric oxide powder, and aluminum oxide powder for later use. Preferably, the size of the manganese dioxide powder is 3-5 μm; the size of the ferric oxide powder is 3-5 μm; and the size of the aluminum oxide powder is 2-3 μm.

[0069] The ceramic raw materials are ball-milled and mixed with a solvent to obtain a slurry. The solvent can be one or more of water and alcohol. By mass, the aforementioned ceramic raw materials include: 40 to 50 parts of manganese dioxide powder; 20 to 25 parts of ferric oxide powder; and 5 to 10 parts of alumina powder.

[0070] Manganese dioxide powder is one of the main crystalline phase raw materials constituting the final manganese ferrite ceramic. It regulates porosity and microstructure. Under high-temperature conditions, it undergoes a solid-phase reaction with ferric oxide, with a content of 40 to 50 parts. When the content of manganese dioxide powder is less than 40 parts, it mainly leads to excessive porosity and deterioration of mechanical properties, most likely damaging the elastic modulus. At the same time, the porosity may also exceed the standard, forming impurity phases, resulting in poor densification and non-uniform structure. When the content of manganese dioxide powder is greater than 50 parts, it causes the material to deviate from a porous insulator towards a dense semiconductor, most likely damaging the surface resistivity and also causing uncontrolled porosity. Therefore, the content of manganese dioxide powder should be controlled between 40 and 50 parts.

[0071] The role of ferric oxide powder is to construct the ceramic framework, form the main crystalline phase, and regulate electromagnetic properties. Its content is 20 to 25 parts. When the ferric oxide powder content is less than 20 parts, the final manganese ferrite ceramic will be dense and semi-conductive, with surface resistivity exceeding practical application requirements. When the ferric oxide powder content is greater than 25 parts, an excessively porous insulating ceramic with insufficient mechanical strength will be produced. Therefore, the ferric oxide powder content should be controlled between 20 and 25 parts.

[0072] The role of alumina powder is to regulate and stabilize the microstructure, improve mechanical strength, and regulate electromagnetic properties. Its content is 5 to 10 parts. If the alumina powder content is less than 5 parts, it will not effectively function as a grain refiner and reinforcing phase; if the alumina powder content is greater than 10 parts, it will disrupt the continuity of the manganese ferrite matrix, leading to structural and functional failure of the material. Therefore, the alumina powder content is controlled between 5 and 10 parts.

[0073] Preferably, a dispersant is also added to the slurry. The function of the dispersant is to stably and uniformly disperse the ceramic powder (MnO2, Fe2O3, Al2O3) in the slurry, preventing particle agglomeration, thereby preparing a slurry with low viscosity, high solid content, and good flowability. The amount of dispersant added is 1 to 8 parts, and the dispersant is at least one of sulfonated melamine, trioleic acid glyceride, and polyester polyether modified phosphate ester. When the content of dispersant is less than 1 part, it leads to uneven dispersion; when the content of dispersant is greater than 8 parts, it will affect the subsequent preparation of the blank; therefore, the content of dispersant is controlled between 1 and 8 parts.

[0074] During the ball milling process, the grinding balls in the ball milling jar impact, squeeze, and shear the ceramic particles (MnO2, Fe2O3, Al2O3 particles) during their movement. With the help of the mechanical energy provided by the ball mill, the dispersant molecules are more quickly and evenly adsorbed onto the surface of the ceramic particles, forming a stable electrostatic repulsion layer and a steric hindrance layer, which effectively prevents agglomeration.

[0075] The aforementioned slurry can be formed into blanks using gel casting, slip casting, dry pressing, and isostatic pressing. The advantages of dry pressing are large-scale, low-cost, and high-efficiency production; isostatic pressing is suitable for producing ceramic products with high electrical performance requirements; slip casting and gel casting can form ceramic products with complex shapes.

[0076] Gel casting method:

[0077] Add crosslinking monomers and crosslinking agents to the aforementioned slurry, mix them evenly, add an initiator and mix well, pour into a mold to cure, and obtain a blank after demolding and drying.

[0078] Specifically, 8 to 20 parts of solvent, 12 to 18 parts of crosslinking monomer, 1.2 to 1.8 parts of crosslinking agent, and 1 to 8 parts of dispersant are mixed evenly. Then, 40 to 50 parts of manganese dioxide powder, 20 to 25 parts of ferric oxide powder, and 5 to 10 parts of alumina powder are added. The mixture is ball-milled for 3 to 5 hours to obtain a uniformly mixed slurry.

[0079] The slurry is sieved and then vacuum-treated. The sieve mesh size can be 80 mesh. Preferably, the amount of initiator added is 2.0–3.0‰ of the slurry mass. The initiator is added to the vacuum-treated slurry, stirred for 3–5 minutes, and then poured into a mold. After curing for 2–3 hours, it is placed in a constant temperature and humidity chamber for drying. The humidity is set to 95%, 90%, 85%, 80%, and 75%, with each humidity stage lasting 3–8 hours. After drying, a blank is obtained.

[0080] The solvent is water or alcohol. The solvent acts as a medium to dissolve the monomers, crosslinking agents, and dispersants, and suspend the ceramic powder; its content is 8 to 20 parts. When the solvent content is less than 8 parts, the slurry is difficult to mix evenly and easily clumps together; when the solvent content is greater than 20 parts, the slurry shrinks significantly during drying and is prone to cracking. Therefore, the solvent content is controlled between 8 and 20 parts.

[0081] Crosslinking monomers are the basic units that form the long-chain backbone of the polymer, and their content is 12 to 18 parts. When the content of crosslinking monomers is less than 12 parts, the mechanical strength of the green body is low, and it is difficult for the powder components to be effectively aggregated together; when the content of crosslinking monomers is greater than 18 parts, the green body is prone to cracking; therefore, the content of crosslinking monomers is controlled between 12 and 18 parts. Preferably, the crosslinking monomer is at least one of acrylamide, acrylic monomers, and acrylamide derivatives.

[0082] The crosslinking agent functions by linking linear monomer polymer chains into a large, insoluble three-dimensional network. This network acts like a "skeleton" within a mold, fixing the ceramic particles in situ, thereby imparting shape and strength to the green body. Its content is typically 1.2 to 1.8 parts. When the crosslinking agent content is less than 1.2 parts, the green body is prone to collapse and cracking; when the crosslinking agent content is greater than 1.8 parts, the green body is hard and brittle with poor toughness. Therefore, the crosslinking agent content is controlled between 1.2 and 1.8 parts. Preferably, the crosslinking agent is at least one of bisacrylamide crosslinking agents and bispropylene ester crosslinking agents.

[0083] Grouting method:

[0084] Add binder to the aforementioned slurry, mix well, pour into a mold to cure, and obtain a blank after demolding and drying.

[0085] Specifically, 8 to 20 parts of solvent and 1 to 8 parts of dispersant are mixed evenly, and 40 to 50 parts of manganese dioxide powder, 20 to 25 parts of ferric oxide powder and 5 to 10 parts of alumina powder are added. The mixture is ball-milled for 3 to 5 hours to obtain a uniformly mixed slurry.

[0086] The slurry is vacuum-treated, then 0.15 to 0.3 parts of binder are added and stirred for 3 minutes. The mixture is then poured into a pre-prepared mold. After 2 to 3 hours of curing, the slurry is demolded and then placed in a constant temperature and humidity chamber for drying. The humidity levels are varied from 95% to 75%, with each humidity stage lasting 3 to 8 hours, resulting in a blank. Preferably, the binder is at least one of coal tar pitch, phenolic resin, and cellulose ethers.

[0087] Dry pressing method:

[0088] The aforementioned slurry is dried and sieved to obtain a mixed powder; a plasticizer solution is sprayed onto the surface of the aforementioned mixed powder to obtain wet powder particles; the aforementioned wet powder particles are sieved to obtain granulated particles; the aforementioned granulated particles are allowed to stand and then dried to obtain granulated powder; the aforementioned granulated powder is filled into a mold and then pressed, and after demolding, a blank is obtained.

[0089] Specifically, 40 to 50 parts of manganese dioxide powder, 20 to 25 parts of ferric oxide powder, and 5 to 10 parts of alumina powder are mixed and transferred to a zirconia ball mill jar. Zirconia grinding balls and 50 to 85 parts of solvent are added, and the jar is fixed on a planetary ball mill at a speed of 600 rpm for 8 hours to obtain a slurry.

[0090] Pour the slurry quickly into a large enamel pan or glass tray, spread it evenly, and dry it at 80°C for 8 hours. Place the dried powder in a ceramic mortar and gently crush it with a pestle. Then sieve it through an 80-mesh standard sieve to obtain a preliminarily refined mixed powder.

[0091] The sieved powder is placed in a large plastic container, and the plasticizer solution is slowly and evenly sprayed into it using a small spray bottle. Simultaneously, the container is continuously shaken and agitated with the other hand to keep the powder in a "boiling" state, ensuring even distribution of the plasticizer solution. The moistened powder is immediately sieved through an 80-mesh sieve. The powder is gently squeezed by hand or a rubber plate to pass through the sieve, forming relatively uniform granules. The plasticizer can be one or more of polyvinyl alcohol, polyacrylates, cellulose aldehydes, and polyvinylpyrrolidone. Preferably, the plasticizer solution is a polyvinyl alcohol solution with a mass concentration of 4% to 8%. Polyvinyl alcohol is both a plasticizer and a lubricant; its molecular chains are soft and have excellent lubricity. When added to the powder, it forms a thin lubricating film on the surface of the powder particles, reducing internal friction, improving the overall uniformity of the green body, and reducing stress caused by pressing.

[0092] The granulated particles were aged at room temperature for 2 hours to allow the solvent and plasticizer to migrate more evenly within the particles. Then, they were spread thinly and dried in a 60°C oven for 1 hour to remove excess surface moisture while maintaining a certain degree of plasticity within the particles for easy pressing.

[0093] Take a small amount of zinc stearate powder and apply it evenly to the mold punch and cavity as a release agent. Weigh a certain amount of granulating powder (for a 90mm mold) and pour it into the mold cavity. To ensure even filling, use a scraper to level the powder.

[0094] Place the mold in the center of the press, and first apply pressure at a slow speed to 20-30 MPa, hold the pressure for 10-15 seconds, then continue to slowly apply pressure to the final pressure of 60-80 MPa, and hold the pressure at the final pressure for 60-180 seconds. After slowly releasing the pressure, remove the mold from the press, and carefully eject the billet from the mold to obtain the billet plate.

[0095] Isostatic pressing:

[0096] Add a molding agent to the aforementioned slurry, mix well, dry and sieve to obtain dry granulation; pour the aforementioned dry granulation into an elastic mold, vacuum and seal it, perform isostatic pressing, and obtain a blank after demolding.

[0097] Specifically, 40-50 parts of manganese dioxide powder, 20-25 parts of ferric oxide powder, and 5-10 parts of alumina powder are poured into a zirconia ball mill jar. Zirconia grinding balls, 40-65 parts of solvent, 1-2 parts of forming agent, and 1-8 parts of dispersant are added. The ball mill jar is sealed, and the mixture is ball-milled using a planetary mill for 8 hours to obtain a slurry. Preferably, the forming agent is at least one of polyethylene glycol, herring oil, and polyethylene glycol octylphenyl ether.

[0098] The slurry is dried into blocks at 85℃, crushed, and then dry-granulated through a 100-mesh vibrating screen. The granulated powder is slowly poured into an elastic mold while the mold is gently vibrated. The mold's sealing cap is placed on, but not fully tightened. The entire mold is connected to a vacuum port, and the vacuum pump is started to evacuate to -0.1 MPa and held for 10 minutes. After that, the sealing cap is tightened. The sealed mold is then placed smoothly into the high-pressure vessel of an isostatic press. The vessel lid is closed, and the pressure pump is started at a rate of 6–10 MPa / min, increasing the pressure to 100–150 MPa and holding it for 10–20 minutes. Then, the pressure is slowly released at a rate of 2–4 MPa / min, and the blank is removed.

[0099] The aforementioned blanks are subjected to a debinding process followed by sintering at 1100–1300℃ to obtain manganese ferrite ceramics. During the debinding process, the organic matter in the blanks undergoes fracture, oxidation, and carbonization at high temperatures. The main chain and side groups are oxidized into carbon dioxide and water, and nitrogen-containing groups are oxidized into nitrogen oxides. During the sintering process, manganese dioxide gradually loses oxygen atoms at high temperatures, transforming into active manganese tetroxide, which then reacts with ferric oxide to form manganese ferrite ceramics.

[0100] Preferably, the debinding process is as follows: heating to 450–460°C at a rate of 3–4°C / min, then heating to 590–620°C at a rate of 0.8–1°C / min, and holding at that temperature for 2–4 hours. The sintering process is as follows: heating to 840–870°C at a rate of 4–5°C / min, then heating to 1100–1300°C at a rate of 0.8–2°C / min, and holding at that temperature for 2–3 hours.

[0101] This application discloses a manganese ferrite ceramic, the raw materials of which include: 40-50 parts of manganese dioxide powder; 20-25 parts of ferric oxide powder; and 5-10 parts of alumina powder; the sintering temperature of the aforementioned manganese ferrite ceramic is 1100-1300℃; and the surface resistivity of the aforementioned manganese ferrite ceramic is 10 Ω·cm.6 ~10 9 Ω / sq, elastic modulus ≥50GPa, porosity 35%~45%.

[0102] The manganese ferrite ceramic and its preparation method proposed in this application use manganese dioxide, ferric oxide, and alumina as main raw materials. A blank is prepared through processes such as gel casting, slip casting, dry pressing, and isostatic pressing. The blank is then sintered at 1100℃~1300℃ to allow the manganese ferrite to react with the ceramic powder, thus obtaining the manganese ferrite ceramic. Due to the special electrical conductivity of the manganese ferrite material system, this manganese ferrite ceramic possesses both high mechanical strength and low resistivity, thereby achieving the purpose of antistatic properties.

[0103] This application proposes the application of the aforementioned manganese ferrite ceramics in semiconductor preparation, precision instrument manufacturing, petrochemical, pharmaceutical, or printing fields.

[0104] The present application will be further described below with reference to specific embodiments, but this should not be construed as a limitation on the scope of protection of the present application. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the present application are still within the scope of protection of the present application.

[0105] Unless otherwise specified, all materials and reagents mentioned below are commercially available products well known to those skilled in the art; unless otherwise specified, all methods described are methods known in the art. Unless otherwise defined, the technical or scientific terms used should have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains.

[0106] Example 1

[0107] This embodiment provides a manganese ferrite ceramic and a method for preparing manganese ferrite ceramic by gel casting.

[0108] Mix 18 parts deionized water, 3.5 parts acrylamide, 0.35 parts N,N-methylenebisacrylamide, and 3 parts sulfonated melamine, and stir for 30 minutes to fully dissolve the sulfonated melamine. Add 47 parts manganese dioxide, 22 parts ferric oxide, and 5.9 parts alumina powder to the solution, and ball mill for 3 hours to obtain a uniformly mixed slurry.

[0109] The slurry is vacuum-treated, then 0.25 parts of initiator are added and stirred for 3 minutes. It is then poured into a pre-prepared mold. After 3 hours of curing, the slurry is demolded and then placed in a constant temperature and humidity chamber for drying. The humidity changes to 95%, 90%, 85%, 80%, and 75%, and each humidity stage is maintained for 4 hours to obtain the blank.

[0110] The blank was placed in a muffle furnace for debinding. The debinding procedure was as follows: the temperature was increased to 450℃ at a heating rate of 3℃ / min, then increased to 600℃ at a heating rate of 0.8℃ / min, and held for 2 hours. Next, sintering was performed: the temperature was increased to 850℃ at a heating rate of 5℃ / min, then increased to 1100℃ at a heating rate of 0.8℃ / min, and held for 3 hours. This yielded a manganese ferrite ceramic with dimensions of 500mm × 500mm × 20mm. A scanning electron microscope image of the obtained manganese ferrite ceramic is shown below. Figure 1 Optical photographs Figure 2 See photos of the processing. Figure 3 .

[0111] Example 2

[0112] This embodiment provides a manganese ferrite ceramic and a method for preparing manganese ferrite ceramic by slip casting.

[0113] Mix 20 parts of deionized water and 5 parts of sulfonated melamine, stir for 30 minutes to fully dissolve the sulfonated melamine, then add 44 parts of manganese dioxide, 25 parts of ferric oxide, and 5.75 parts of alumina powder, and ball mill for 5 hours to obtain a uniformly mixed slurry.

[0114] The slurry is vacuum-treated, then 0.25 parts of binder are added and stirred for 3 minutes. The mixture is then poured into a pre-prepared mold. After 2 hours of curing, the slurry is demolded and then placed in a constant temperature and humidity chamber for drying. The humidity changes to 95%, 90%, 85%, 80%, and 75%, with each humidity stage lasting for 3 to 8 hours, to obtain the blank.

[0115] The blank was placed in a muffle furnace for debinding. The debinding procedure was as follows: the temperature was increased to 450℃ at a heating rate of 3℃ / min, then increased to 600℃ at a heating rate of 0.8℃ / min, and held for 2 hours. Next, sintering was performed: the temperature was increased to 850℃ at a heating rate of 5℃ / min, then increased to 1200℃ at a heating rate of 0.8℃ / min, and held for 3 hours. This yielded a manganese ferrite ceramic with dimensions of 500mm × 500mm × 18mm. A scanning electron microscope image of the obtained manganese ferrite ceramic is shown below. Figure 4 .

[0116] Example 3

[0117] This embodiment provides a manganese ferrite ceramic and a method for preparing manganese ferrite ceramic by dry pressing.

[0118] Pour 45 parts of manganese dioxide powder, 23 parts of ferric oxide powder, and 8 parts of aluminum oxide powder into a large polyethylene bottle, and shake or roll by hand for 10 to 15 minutes to perform preliminary dry mixing, so that the powders of different colors are macroscopically uniform.

[0119] Transfer the preliminarily mixed powder to a clean zirconia ball mill jar, add zirconia grinding balls and alcohol, with a grinding ball:powder:alcohol mass ratio of 2:1:0.8, seal the ball mill jar, fix it on a planetary ball mill, rotate at 600 rpm, and mill for 8 hours.

[0120] The ball-milled slurry is quickly poured into a large enamel pan or glass tray, spread evenly, and dried at 80°C for 8 hours. The dried powder is then placed in a ceramic mortar and gently crushed with a pestle. Finally, it is sieved through an 80-mesh standard sieve to obtain a preliminarily refined mixed powder.

[0121] Place the sieved powder into a large plastic container. Using a small spray bottle, slowly and evenly spray a 5-part polyvinyl alcohol solution into the container with one hand. Simultaneously, shake and agitate the container with the other hand to keep the powder in a "boiling" state, ensuring the polyvinyl alcohol solution is evenly distributed. Immediately sieve the moistened powder through an 80-mesh sieve. Gently squeeze the powder with your hand or a rubber plate to force it through the sieve, forming relatively uniform granules.

[0122] The granulated granules were aged at room temperature for 2 hours to allow moisture and binder to migrate more evenly within the granules. Then, they were spread thinly and dried in a 60°C oven for 1 hour to remove excess surface moisture while maintaining a certain degree of plasticity within the granules for easy pressing, thus obtaining granulated powder.

[0123] Take a small amount of zinc stearate powder and apply it evenly to the die and cavity of the mold as a release agent. Pour the granulating powder into the mold cavity (mold Φ90mm). To ensure uniform filling, use a scraper to level it.

[0124] Place the mold in the center of the press, and first apply pressure at a slow speed to 20-30 MPa, hold the pressure for 10-15 seconds, then continue to slowly apply pressure to the final pressure of 60-80 MPa, and hold the pressure for 60 seconds. After slowly releasing the pressure, remove the mold from the press, and carefully eject the billet from the mold to obtain the billet plate.

[0125] The blank was placed in a muffle furnace for debinding. The debinding procedure was as follows: the temperature was increased to 450℃ at a heating rate of 3℃ / min, then increased to 590℃ at a heating rate of 0.8℃ / min, and held for 4 hours. Next, sintering was performed: the temperature was increased to 840℃ at a heating rate of 4℃ / min, then increased to 1200℃ at a heating rate of 0.8℃ / min, and held for 3 hours. This yielded a manganese ferrite ceramic with dimensions of Φ90mm × 11mm. A scanning electron microscope image of the obtained manganese ferrite ceramic is shown below. Figure 5 .

[0126] Example 4

[0127] This embodiment provides a method for preparing manganese ferrite ceramics by isostatic pressing.

[0128] Weigh out 48 parts of manganese dioxide, 22 parts of ferric oxide, and 9 parts of aluminum oxide. Pour all the weighed powders into a zirconia ball mill jar, add zirconia grinding balls (ball-to-powder mass ratio 2:1), 48 parts of anhydrous ethanol, 1 part of trioleic acid glyceride, and 2 parts of polyethylene glycol. Seal the ball mill jar and ball mill for 8 hours using a planetary mill.

[0129] The slurry is dried into blocks at 85°C, crushed, and then dry granulated through a 100-mesh vibrating screen.

[0130] Slowly pour the granulated powder into the elastic mold while gently vibrating it. Cover the mold with the sealing cap, but do not tighten it completely. Connect the entire mold to the vacuum port, start the vacuum pump, evacuate to -0.1 MPa, and maintain this pressure for 10 minutes. Then tighten the sealing cap.

[0131] Place the sealed mold steadily into the high-pressure vessel of the isostatic press, close the vessel lid, start the pressure pump, pressurize at a rate of 8 MPa / min, raise the pressure to 100 MPa, and hold the pressure for 20 minutes. Then slowly depressurize at a rate of 2 MPa / min and remove the billet.

[0132] The blank was placed in a muffle furnace for debinding. The debinding procedure was as follows: the temperature was increased to 460℃ at a rate of 4℃ / min, then increased to 620℃ at a rate of 1℃ / min, and held for 2 hours. Next, sintering was performed: the temperature was increased to 870℃ at a rate of 5℃ / min, then increased to 1300℃ at a rate of 2℃ / min, and held for 2 hours to obtain manganese ferrite ceramic with dimensions of Φ90mm × 10mm. Scanning electron microscope images of the obtained manganese ferrite ceramic are shown below. Figure 6 .

[0133] The manganese ferrite ceramics obtained in Examples 1-4 were subjected to physical property testing, including surface resistivity, elastic modulus, and porosity. The results are shown in Table 1. The surface resistivity was tested according to GB / T 31838; the elastic modulus was tested according to GB / T 10700; and the porosity was tested according to GB / T 21650.

[0134] Table 1. Test results of manganese ferrite ceramics in Examples 1-4

[0135] Surface resistivity / Ω / sq Elastic modulus / GPa Porosity / % Example 1 3.98*10 9 ]] 50.96 41.6 Example 2 4.88*10 8 ]]> 52.33 43.1 Example 3 2.66*10 6 ]]> 51.23 42.9 Example 4 1.08*10 8 ]]> 51.11 36.6

[0136] The technical features in the claims and / or specification of this application can be combined, and the combination is not limited to the combinations obtained through reference in the claims. Technical solutions obtained by combining the technical features in the claims and / or specification are also within the scope of protection of this application.

[0137] The above description is merely a preferred embodiment of this application and is not intended to limit this application in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application shall still fall within the scope of the technical solution of this application.

Claims

1. A method for preparing manganese ferrite ceramics, characterized in that, The steps include: The ceramic raw materials and solvent are ball-milled and mixed to obtain a slurry; The slurry is solidified in a mold, and after demolding and drying, a blank is obtained; or the slurry is granulated and then pressed in a mold, and after demolding, the blank is obtained. The blank is subjected to debinding treatment and then sintering treatment at a temperature of 1100-1300℃ to obtain manganese ferrite ceramic. By weight, the ceramic raw material comprises: 40 to 50 parts of manganese dioxide powder; 20 to 25 parts of ferric oxide powder; and, 5 to 10 parts of alumina powder.

2. The preparation method according to claim 1, characterized in that, The solvent is one or more of water and alcohol; The size of manganese dioxide powder is 3–5 μm; The size of ferric oxide powder is 3–5 μm; The size of the alumina powder is 2-3 μm.

3. The preparation method according to claim 1, characterized in that, The specific steps for solidifying the slurry in the mold are as follows: Add crosslinking monomers and crosslinking agents to the slurry and mix evenly. Add initiator and mix evenly. Pour into a mold and wait for curing to complete. The solvent is 8 to 20 parts; The crosslinking monomer is 12 to 18 parts, and the crosslinking monomer is at least one of acrylamide, acrylic monomers and acrylamide derivatives. The crosslinking agent is 1.2 to 1.8 parts, and the crosslinking agent is at least one of bisacrylamide crosslinking agents and bispropylene ester crosslinking agents.

4. The preparation method according to claim 1, characterized in that, The specific steps for solidifying the slurry in the mold are as follows: Add binder to the slurry and mix well. Pour the mixture into a mold and wait for it to cure. The solvent is 8 to 20 parts; The binder is 0.15 to 0.3 parts, and the binder is at least one of coal tar pitch, phenolic resin and cellulose ether.

5. The preparation method according to claim 1, characterized in that, The specific steps for granulating the slurry and then pressing it in a mold are as follows: The slurry is dried and then sieved to obtain a mixed powder; A plasticizer solution is sprayed onto the surface of the mixed powder to obtain wet powder particles; The wet powder particles are sieved to obtain granulated particles; The granulated particles are allowed to stand and then dried to obtain granulated powder; After filling the mold with the granulated powder, it is pressed. The solvent is 50 to 85 parts; The specific method for compression is as follows: pressurize to 20-30 MPa and hold for 10-15 seconds; then continue to pressurize to 60-80 MPa and hold for 60-180 seconds.

6. The preparation method according to claim 1, characterized in that, The specific steps for granulating the slurry and then pressing it in a mold are as follows: A molding agent is added to the slurry, mixed well, dried, and then sieved to obtain dry granulation. The dry granulation process is poured into an elastic mold, vacuumed and then sealed, and then subjected to isostatic pressing. The solvent is 40 to 65 parts; The molding agent is 1 to 2 parts; The molding agent is at least one of trioleic acid glyceride, herring oil and polyethylene glycol octylphenyl ether; The specific method of isostatic pressing is as follows: the sealed elastic mold is placed into an isostatic press, and the pressure is increased to 100-150 MPa at a rate of 6-10 MPa / min, and the pressure is maintained for 10-20 minutes; then the pressure is slowly released at a rate of 2-4 MPa / min.

7. The preparation method according to claim 1, characterized in that, The procedure for the glue removal process is as follows: raise the temperature to 450-460°C at a heating rate of 3-4°C / min, then raise it to 590-620°C at a heating rate of 0.8-1°C / min, and hold it at that temperature for 2-4 hours. The sintering process is as follows: the temperature is increased to 840-870℃ at a heating rate of 4-5℃ / min, and then increased to 1100-1300℃ at a heating rate of 0.8-2℃ / min, and held for 2-3 hours.

8. The preparation method according to claim 1, characterized in that, The slurry also contains a dispersant; The dispersant is 1 to 8 parts; The dispersant is at least one of sulfonated melamine, trioleic acid glyceride, and polyester polyether modified phosphate ester.

9. A manganese ferrite ceramic, characterized in that, The raw materials for the manganese ferrite ceramic include: 40 to 50 parts of manganese dioxide powder; 20 to 25 parts of ferric oxide powder; and, 5 to 10 parts of alumina powder; The sintering temperature of the manganese ferrite ceramic is 1100–1300℃; The surface resistivity of the manganese ferrite ceramic is 10. 6 ~10 9 Ω / sq, elastic modulus ≥50GPa, porosity 35%~45%.

10. The application of the manganese ferrite ceramic of claim 9 in semiconductor preparation, precision instrument manufacturing, petrochemical field, pharmaceutical field or printing field.

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