A high-stable dual-phase colloidal ceramic ink material, a preparation method and application thereof

Abstract

The application discloses a kind of high-stability two-phase colloidal ceramic ink material and preparation method and application thereof, the two-phase colloidal ceramic ink material is composed of ceramic colloidal suspension, polymer colloidal suspension, additive, the ceramic colloidal suspension is composed of ceramic, solvent, dispersing agent, binder;The polymer colloidal suspension is composed of water, surfactant, rheological modifier, colloidal stabilizer.The two-phase colloidal ceramic ink material provided in the application, ceramic powder colloidal suspension and polymer colloid two phases mutually adsorb and combine, and by surfactant adjust the wetting of polymer colloid on the surface of ceramic particle and the thickness and area of adsorption layer, form the micro colloidal structure of ceramic particle wrapped by polymer colloid and have excellent stability, can be stably stored at normal temperature for 3 months and above without the change of rheological property, and can be consistently formed process condition stable printing after 3 months.

Description

Technical Field

[0001] This invention belongs to the field of 3D printing technology, specifically relating to a highly stable biphase colloidal ceramic ink material, its preparation method, and its application. Background Technology

[0002] Traditional ceramic forming relies on mold manufacturing, which suffers from long production cycles, high manufacturing costs, and limited forming accuracy, making it difficult to create complex and intricate structures. The inherent high brittleness and hardness of ceramics further complicate their processing and fabrication. Therefore, there is an urgent need to develop ceramic 3D printing technology to address these issues. Ceramic 3D printing, using ceramic inks or slurries as raw materials, primarily employs stereolithography (SLA) and direct inkwriting (DIW) technologies.

[0003] Direct-write printing technology, utilizing computer-aided design and precision mechanics, precisely controls the deposition of ceramic ink to fabricate complex three-dimensional structures layer by layer. Compared to other 3D printing technologies, direct-write printing exhibits several significant advantages: 1) it eliminates the need for ultraviolet light and laser radiation; 2) it requires no heating and can be formed at room temperature; and 3) it can achieve highly dense sintered bodies during the sintering process. However, this technology also has significant limitations, such as: 1) printing specific structures typically requires ceramic inks with specific properties to meet their extrusion molding requirements; and 2) the preparation and rheological property control of direct-write ceramic ink materials are complex. Existing ceramic inks generally suffer from poor stability and difficulty in effectively controlling rheological properties, leading to slow extrusion speeds, extrusion difficulties, nozzle clogging, extrusion expansion, and discontinuities. This results in breaks or gaps in the direct-write structure, making it impossible to print large and complex intricate ceramic structures. Therefore, developing ceramic ink materials with high stability and easily controllable rheological properties, along with their preparation methods, is of great significance for 3D printing ceramics. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the first objective of this invention is to provide a highly stable biphase colloidal ceramic ink material. The biphase colloidal ceramic ink material provided by this invention has high stability and can be stably stored at room temperature for more than 3-6 months. It can meet the requirements of continuous extrusion molding, has good printability and formability, and can stably print various large ceramic components and complex and delicate microscale three-dimensional structures. Moreover, the printed ceramic structures have high density and excellent mechanical properties.

[0005] The second objective of this invention is to provide a method for preparing a highly stable two-phase colloidal ceramic ink material.

[0006] The third objective of this invention is to provide an application of a highly stable two-phase colloidal ceramic ink material.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] This invention discloses a highly stable biphase colloidal ceramic ink material, comprising a ceramic colloidal suspension, a polymer colloidal suspension, and additives. The ceramic colloidal suspension comprises ceramic, solvent, dispersant, and binder; the polymer colloidal suspension comprises water, surfactant, rheology modifier, and colloidal stabilizer. In the biphase colloidal ceramic ink material, the mass ratio of ceramic colloidal suspension: polymer colloidal suspension: additives is 40-95: 2-20: 0.001-10.

[0009] The biphase colloidal ceramic ink material provided by this invention is composed of a ceramic colloidal suspension, a polymer colloidal suspension, and additives. The ceramic powder colloidal suspension and the polymer colloidal suspension adsorb and bind to each other. The polyelectrolyte coated on the surface of the ceramic powder particles attracts the polymer colloidal particles through electrostatic attraction and hydrogen bonding and other forces. The surfactant adjusts the wetting of the polymer colloidal particles on the surface of the ceramic particles and the thickness and area of ​​the adsorption layer, forming a uniform micro-colloidal structure of ceramic particles wrapped by polymer colloidal particles. It has good stability and high green body mechanical strength, and has excellent stability. It can be stably stored at room temperature for 3 months or more without changes in rheological properties, and can be stably printed under consistent molding process conditions after 3 months.

[0010] However, in the biphasic colloidal ceramic ink material, the proportions of each component need to be controlled within the range of this invention; otherwise, it will result in complete flow or agglomeration, leading to poor rheological properties and making direct writing printing impossible.

[0011] In a preferred embodiment, the mass ratio of the biphasic colloidal ceramic ink material is: ceramic colloidal suspension: polymer colloidal suspension: additives = 80-95: 5-20: 0.001-1.

[0012] In a further preferred embodiment, the mass ratio of ceramic colloidal suspension to polymer colloidal suspension in the biphasic colloidal ceramic ink material is 85-94:5-13. Maintaining the mass ratio of ceramic colloidal suspension to polymer colloidal suspension within this range results in the most stable biphasic colloidal ceramic ink material. Furthermore, additives are incorporated into the biphasic colloidal ceramic ink material to fine-tune its rheological properties and wetting characteristics. Even a small amount of additive is sufficient; typically, about two drops are enough.

[0013] In a preferred embodiment, the ceramic in the ceramic colloidal suspension is selected from at least one of zirconium oxide, titanium dioxide, alumina, hydroxyapatite, silicon carbide, silicon nitride, and boron nitride.

[0014] As can be seen, ceramics have a wide range of compatibility in this invention. This is because the formation mechanism of the biphase colloidal ceramic ink material of this invention is to regulate the mixing, adsorption and binding state of the polymer colloidal suspension and the ceramic particle colloidal suspension, as well as the spreading of the polymer on the surface of the ceramic particles, thereby regulating the microstructure and rheological properties of the ceramic ink. Therefore, in terms of its mechanism of action, this invention can obtain a uniformly dispersed and stable biphase colloidal ceramic ink material by preparing colloidal suspensions of different ceramic powders and matching them with different polymer colloidal suspensions.

[0015] In a preferred embodiment, the solid content of the ceramic is 42.0-62.0 vol.%.

[0016] In a preferred embodiment, the ceramic comprises ceramic powder with a particle size of 0.1-30.0 μm, preferably 0.1-3 μm.

[0017] In a further preferred embodiment, the ceramic powder is composed of ceramic powder A with a particle size of 0.1-0.3 μm, ceramic powder B with a particle size of 0.6-1.5 μm, and ceramic powder C with a particle size of 1-3 μm, wherein the mass ratio of ceramic powder A: ceramic powder B: ceramic powder C is 1-3:3-6:1-6.

[0018] By optimizing the particle size of the ceramic particles, small ceramic particles can be fully filled into large particles, forming a more compact suspension structure and flow state. This significantly improves the solid content and flowability of the prepared ceramic colloidal suspension, resulting in ceramic ink materials with superior performance. This allows the two-phase colloidal ceramic ink materials to be stably stored at room temperature for up to 6 months.

[0019] In a preferred embodiment, the ceramic further comprises ceramic fibers, wherein the amount of ceramic fibers added is 0.01-15% of the mass of the ceramic powder, preferably 0.01-1%, the length of the ceramic fibers is 0.01-100 mm, and the diameter of the ceramic fibers is 0.01-10 mm. The inventors have discovered that adding a small amount of ceramic fibers can further improve the stability of the two-phase colloidal ceramic ink material.

[0020] In a preferred embodiment, the solvent is selected from at least one of deionized water, anhydrous ethanol, and acetone.

[0021] In a preferred embodiment, the dispersant is selected from inorganic or organic dispersants. The inorganic dispersant is selected from at least one of silicates and alkali metal phosphates, preferably at least one of water glass, sodium tripolyphosphate, sodium hexametaphosphate, and sodium pyrophosphate. The organic dispersant is selected from at least one of triethylhexylphosphonic acid, sodium dodecyl sulfate, methylpentanol, cellulose derivatives, polyacrylamide, glucon, polyethylene glycol fatty acid, polyacrylic acid, polyvinyl acid, citric acid, ammonium polyacrylate, tetramethylammonium hydroxide, sodium polycarboxylate, and polyacetylimide.

[0022] In a further preferred embodiment, the dispersant is selected from at least one of polyacrylic acid, tetramethylammonium hydroxide, and polyvinyl acid.

[0023] In a preferred embodiment, the amount of dispersant added is 0.1-10.0% of the mass of the ceramic powder, preferably 1-2%.

[0024] In a preferred embodiment, the adhesive is selected from at least one of polyvinyl alcohol, polyethylene oxide, methylcellulose, carboxymethylcellulose, cellulose, hydroxyethylcellulose, gum arabic, epoxy resin, waterborne polyurethane resin, phenolic resin, and carbomer.

[0025] In a further preferred embodiment, the adhesive is selected from at least one of phenolic resin, gum arabic, methylcellulose, carboxymethylcellulose, epoxy resin, and carbomer.

[0026] In a preferred embodiment, the amount of binder added is 0.01-20.0% of the mass of the ceramic powder, preferably 3-10%.

[0027] In a preferred embodiment, the sum of the mass fractions of the surfactant, rheology modifier, and colloidal stabilizer in the polymer colloidal suspension is 0.01-35.0 wt.%.

[0028] In a preferred embodiment, the surfactant is selected from at least one of stearic acid, oleic acid, lauric acid, sulfates, sulfonates, lecithin, amino acid type, betaine type, alkyl glucoside, fatty acid glycerides, and polyols.

[0029] Further preferred, the sulfated oil, fatty alcohol sulfate, or at least one of the following: R is a fatty hydrocarbon chain with 12 to 18 carbons; even more preferably, at least one of the following: sulfated castor oil, sodium dodecyl sulfate, SDS, or sodium lauryl sulfate.

[0030] In a further preferred embodiment, the sulfonate is selected from at least one of aliphatic sulfonates, alkylaryl sulfonates, and alkylnaphthalene sulfonates.

[0031] In a further preferred embodiment, the alkyl glucoside is selected from at least one of cocoyl glucoside, lauryl glucoside, and cetearyl glucoside.

[0032] In a further preferred embodiment, the fatty acid glyceride is a monostearate with an HLB of 3 to 43.

[0033] In a further preferred embodiment, the polyol is selected from at least one of sucrose esters with an HLB of 5 to 13, fatty acid sorbitan, and polysorbate esterifying agents.

[0034] More preferably, the surfactant is selected from at least one of stearic acid, sodium lauryl sulfate, alkyl aryl sulfonates, glyceryl monostearate, and sulfated castor oil.

[0035] In a preferred embodiment, the surfactant in the polymer colloidal suspension has a mass fraction of 0.001-15.0%, preferably 0.01-0.6%.

[0036] In a preferred embodiment, the rheology modifier is selected from at least one of natural resins, synthetic resins, natural heteropolysaccharides, organic acid-modified heteropolysaccharides, magnesium aluminum silicate, sodium magnesium silicate, xanthan gum, guar gum, pectin, acrylic polymers, ethylene glycol polymers, and crosslinked acrylic resins.

[0037] In a further preferred embodiment, the rheology modifier is selected from at least one of xanthan gum, guar gum, pectin, acrylic polymers, ethylene polymers, and crosslinked acrylic resins.

[0038] In a preferred embodiment, the mass fraction of the rheology modifier in the polymer colloidal suspension is 0.01-20.0%, preferably 0.02-10%, and more preferably 0.3-2%.

[0039] In a preferred embodiment, the colloidal stabilizer is selected from at least one of phosphate esters, phosphate compounds, collagen, gelatin, ammonium compounds, linear, branched or cyclic polyols, polyamines, polythiol compounds, sugar compounds, polyaminocarboxylic acids, polyvinylpyrrolidone, cyclodextrin, diatomaceous earth, ε-caprolactam and polyhydroxy polycarboxylic acids.

[0040] In a further preferred embodiment, the colloidal stabilizer is selected from at least one of polysaccharides, starch, glycylglycerol, α-N-benzoylDL-alanine, phenylalanine, asparagine, collagen, gelatin, alanine, aminosulfonic acid, polyvinylpyrrolidone, cyclodextrin, diatomaceous earth, and ε-caprolactam.

[0041] More preferably, the colloidal stabilizer is selected from at least one of cyclodextrin, polyvinylpyrrolidone, polysaccharides, gelatin, and collagen.

[0042] In a preferred embodiment, the mass fraction of the colloidal stabilizer in the polymer colloidal suspension is 0.01-20.0%, preferably 0.01-5%, and more preferably 0.5-5%.

[0043] In a preferred embodiment, the auxiliary agent is selected from at least one of ethylene glycol, glycerin, silicone oil, ethanol, acetone, OP, and n-octanol.

[0044] This invention also provides a method for preparing a highly stable biphase colloidal ceramic ink material. A dispersant and a binder are added to a solvent, and then a ceramic ball is added and milled to obtain a ceramic colloidal suspension. A surfactant, a rheology modifier, and a colloidal stabilizer are added to water, and the mixture is allowed to stand for aging to obtain a polymer colloidal suspension. The ceramic colloidal suspension and the polymer colloidal suspension are then mixed, and an additive is added. After mixing and standing, the mixture is allowed to stand to obtain the biphase colloidal ceramic ink material.

[0045] The preparation method of the present invention prepares ceramic colloidal suspension and polymer colloidal suspension respectively, and then adds additives after the ceramic ink is prepared to fine-tune its rheological properties and wettability, so as to obtain a two-phase colloidal ceramic ink material with good stability and excellent rheological properties.

[0046] The inventors discovered that only by separately preparing a ceramic colloidal suspension and a polymer colloidal suspension using the preparation method of this invention, and then mixing them, can the biphase colloidal ceramic ink material required by this invention be obtained. This is because the degree of dispersion and mixing resulting from directly adding ceramic powder to an organic colloid is completely different from that resulting from combining a ceramic powder suspension in a colloidal state with another polymer colloidal suspension. Furthermore, this leads to differences in the microstructure of the ceramic powder and polymer colloidal combination. Therefore, by separately controlling the properties of the two colloidal phases, the microstructure and rheological properties of the ceramic ink material can be controlled, allowing for convenient and free control of ink component parameters and ceramic ink properties. Specifically, at the microscopic level, the preparation method of this invention enables the adsorption and binding of the ceramic powder colloid and polymer colloidal phases. The polyelectrolyte coated on the surface of the ceramic particles attracts the polymer colloidal phase through electrostatic attraction and hydrogen bonding, and the surfactant adjusts the wetting and adsorption layer thickness and area of ​​the polymer colloidal layer on the ceramic particle surface, resulting in a more uniform microcolloid structure of ceramic particles encapsulated by polymer colloidal material.

[0047] Therefore, if the method of this invention is not adopted, but all materials are directly mixed to disperse and mix the ceramic powder in the organic phase, there will be a lack of control over the structure of the mixed ink, and it will not be able to control the microstructure. Moreover, firstly, it will lead to uneven composition; secondly, it will cause insufficient mixing; thirdly, it will be difficult to achieve the component design and rheological properties adjustment and control of the ceramic ink material; and fourthly, it is easy to cause subsequent debinding and sintering problems due to the addition of too much organic colloidal phase.

[0048] In a preferred embodiment, the ball mill rotates at a speed of 80-300 rpm and the milling time is 4-72 hours.

[0049] In a further preferred embodiment, during ball milling, zirconia balls with a diameter of 5-20 mm are used as the grinding medium, and the ball-to-material ratio is 1-2:1. By using zirconia balls of the aforementioned diameter as the grinding medium and controlling the ball-to-material ratio and milling speed within the range specified in this invention, the resulting ceramic colloidal suspension exhibits good and stable dispersion.

[0050] In a preferred embodiment, the static aging time is 4-72 hours.

[0051] In a preferred embodiment, the mixing method is one of ball milling, vibration, ultrasonication, or shearing.

[0052] In a preferred embodiment, the settling time is 4-72 hours. After settling, a biphase colloidal ceramic ink material with a highly stable network structure formed by the cross-linking of a polymer colloidal suspension and ceramic particles is formed.

[0053] This invention also provides an application of a highly stable biphase colloidal ceramic ink material, which is used in the preparation of ceramic materials by direct writing.

[0054] In a preferred embodiment, the process of preparing ceramic materials by direct writing is as follows: placing the biphasic colloidal ceramic ink material in the syringe of a 3D direct writing device, obtaining a ceramic blank by direct writing at room temperature through layer-by-layer stacking according to the ceramic structure model, and then sintering the ceramic blank to obtain the ceramic material.

[0055] In actual operation, the model program of the 3D direct writing device and the path code of the ceramic structure model output by CAM are set. The three-dimensional ceramic blank can be obtained by printing at room temperature by layering. Then the ceramic blank is dried at room temperature and sintered at high temperature to obtain the desired ceramic component.

[0056] In a preferred embodiment, the diameter of the nozzle ranges from 60 nm to 2000 μm.

[0057] In a preferred embodiment, the sintering temperature is 800-2300℃, the heating rate is 5-15℃ / min, and the holding time is 0.5-72h.

[0058] The sintering method can be atmospheric pressure sintering, high temperature vacuum sintering, or atmosphere sintering.

[0059] The beneficial effects of this invention are as follows:

[0060] Compared to existing technologies, this biphase colloidal ceramic ink material consists of two colloidal suspensions: a ceramic colloidal suspension and a polymer colloidal suspension. It possesses a skeletal structure composed of ceramic particles and a three-dimensional network structure formed by polymer materials, resulting in a ceramic green body with high mechanical strength and excellent structural performance. The colloidal stabilizer added to the polymer colloidal suspension maintains constant viscosity in room temperature aqueous solution, exhibiting good dispersibility and binding force. It is a powerful oil / water and water / oil emulsifier, and its excellent emulsifying ability serves as a protective colloid for liquid-dispersed ceramic colloidal suspensions. Within a certain concentration range, it acts as a lyophilic colloid, delaying or preventing the aggregation or settling of hydrophobic ceramic particles, thereby improving the stability of the ceramic suspension. Simultaneously, when combined with an appropriate surfactant, it stabilizes the ceramic colloidal particles while forming a stable hydration film layer on the surface of the ceramic particles, resulting in ceramic particles and ink materials with excellent surface wettability. This prevents nozzle clogging during extrusion molding, meeting the requirements for stable printing. Through the above combination, a highly stable biphase colloidal ceramic ink material is obtained.

[0061] Taking cyclodextrin colloids as an example, they are cone-shaped molecules composed of 6, 7, 8, or more D-glucan units linked by α-1,4 glycosidic bonds. Since the hydroxyl groups of each glucose unit constituting cyclodextrin are located on the outer surface of the cone-shaped molecule's cavity, and the inner surface of the cyclodextrin molecule's cavity contains only glycosidic oxygen atoms and hydrogen atoms covering them, the entire cyclodextrin molecule possesses amphiphilic properties: lipophilic inside the cavity and hydrophilic outside. Its unique molecular structure allows some ceramic particles to enter the hydrophobic cavity of the cyclodextrin molecule, forming inclusion complexes and receiving specific protection, thus enhancing the ceramic suspension's heat resistance and resistance to chemical changes, and improving the stability of the ceramic particles.

[0062] Compared to existing technologies, the preparation method of this invention omits steps such as pH adjustment, addition of antiphase polyelectrolytes and salt ions, which are required in other direct-write ceramic ink material preparation techniques. The rheological properties of the ceramic ink are controlled through the combined design of ceramic colloidal suspensions and polymer colloidal suspensions in the ceramic ink components. This avoids the process of inducing the ceramic suspension to transition from a fluid state to a gel state, as is common in existing technologies, and significantly reduces the formation of large ceramic particles during the gel transition. Simultaneously, the polymer colloidal suspension in this invention possesses excellent film-forming properties, hygroscopicity, and strong adhesiveness. Its chemical structure, such as the amine structure in polyvinylpyrrolidone or the "cone-shaped" molecules in cyclodextrin, can complex with many polar functional groups. When used in conjunction with other natural or synthetic polymers or organic compounds added to the ceramic colloidal suspension, it can effectively regulate hygroscopicity and flexibility, flexibly adjusting the rheological properties of the ceramic ink material. Therefore, by changing different component designs, a wide range of continuous and stable control over rheological properties can be achieved.

[0063] The preparation process of the high-stability ceramic ink material in this patent is simple, easy to operate and implement, and the preparation conditions are mild with no special requirements, making it easy for large-scale industrial application. The prepared ceramic ink material is easy to extrude, does not clog nozzles, has stable performance, and can continuously and stably print structural parts. During the molding process, the ceramic ink material of this invention has the following characteristics: 1) Shearing in the middle for 10-80 seconds -1 1) At high speeds, the ceramic ink has very low viscosity, within the range of 0.1-50.0 Pa·s, ensuring smooth passage through the nozzle without clogging; 2) It solidifies rapidly without shearing, and the solidified linear fluid has good elasticity and strength, maintaining its original shape even without support; 3) It has a high solid content, preventing cracking or deformation of the molded structure due to shrinkage during drying and sintering; 4) Due to the addition of various rheology modifiers and polymers in this invention, a cross-linked ceramic gel network structure is formed together with the ceramic powder. The addition of these modifiers and polymers gives the prepared ceramic ink microstructure good stability and high green body mechanical strength, and excellent stability. It can be stably stored at room temperature for 3 months or more without changes in rheological properties, and can be stably printed under consistent molding process conditions after 2 months; 5) The ceramic ink of this invention has excellent printability, uniform ink material properties, smooth extrusion, high density of the molded structure, and excellent mechanical properties. Tests have shown that the ceramic ink material prepared using this patented method can be stably preserved for more than 3 months, and in the preferred embodiment for more than 6 months. It can stably print various large ceramic components and complex and delicate microscale three-dimensional structures. Attached Figure Description

[0064] Figure 1 This is a schematic diagram of the process of direct writing to form a silicon carbide ceramic structure according to the present invention;

[0065] Figure 2 This is a diagram of the complex structure of silicon carbide ceramic directly written according to the present invention;

[0066] Figure 3 This is a schematic diagram showing the viscosity of silicon carbide ceramic ink as a function of shear rate in Embodiment 1 of the present invention;

[0067] Figure 4 This is a schematic diagram showing the change of the elastic modulus of silicon carbide ceramic with oscillation pressure in Embodiment 1 of the present invention;

[0068] Figure 5 This is a microstructure diagram of the silicon carbide ceramic ink of the present invention. Detailed Implementation

[0069] The following examples use silicon carbide ceramic powder as a typical example. Other ceramic powders, such as alumina, zirconium oxide, and hydroxyapatite, are implemented with reference to the method in this patent.

[0070] Example 1

[0071] The formulation design of silicon carbide two-phase colloidal ceramic ink is as follows:

[0072] In the silicon carbide ceramic colloidal suspension: the silicon carbide solid phase content is 46.0 vol.%, the particle size is 0.1-3 μm, the solvent is water, the dispersant is polyacrylic acid, which is 2.0% of the dry powder mass, and the binder is phenolic resin, which is added at 3.0% of the dry powder mass.

[0073] In the polymer colloidal suspension: the rheology modifier is xanthan gum, with a mass fraction of 0.5%; the colloidal stabilizer is cyclodextrin, with a mass fraction of 1.0%; and the surfactant is stearic acid, with a mass fraction of 0.01%.

[0074] The preparation process of the ceramic colloidal suspension is as follows: silicon carbide, deionized water, polyacrylic acid, and phenolic resin are mixed to form a slurry; the mixture is then ball-milled at 100 rpm for 12 hours to achieve uniform mixing, resulting in a ceramic colloidal suspension with a solid content of 46.0 vol.%. To obtain a well-dispersed and stable suspension, high-purity zirconia balls with a diameter of 5-20 mm are used as the grinding medium, with a ball-to-material ratio of 1.1:1.

[0075] The preparation process of the polymer colloidal suspension is as follows: weigh the above-mentioned amounts of surfactant, rheology modifier and colloidal stabilizer in aqueous solution, dissolve and mix them according to the required amount and stir for 4 hours to prepare a polymer colloidal suspension with specific rheological properties and surface wettability, and let it stand for 12 hours before use.

[0076] Subsequently, the prepared polymer colloidal suspension and the well-dispersed ceramic colloidal suspension were mixed at a mass ratio of 90:10 and shaken well. Two drops of n-octanol were added, and the mixture was ball-milled again. After standing for 12 hours, a biphase colloidal silicon carbide ceramic ink material with a highly stable network structure formed by cross-linking of polymer colloidal suspension and ceramic particles was formed.

[0077] The biphase colloidal silicon carbide ceramic ink material prepared above exhibits a high efficiency of 10s. -1 The viscosity at the shear rate is 1 Pa·s, exhibiting good shear-thinning behavior and excellent viscoelasticity, with an elastic modulus as low as 10. 4Pa, exhibiting excellent shape retention, can stably and smoothly pass through the nozzle while maintaining its three-dimensional shape. The 3D direct-writing ceramic ink is loaded into the nozzle barrel of a 3D direct-writing device with a nozzle diameter of 210 μm. After setting the program for the 3D direct-writing device, a three-dimensional structure can be obtained by printing in air in a layer-by-layer manner. The obtained silicon carbide ceramic green body is heated to 2150℃ at a programmed temperature rise of 10℃ / min and held for 6 hours to obtain silicon carbide ceramic structural parts. The mechanical strengths of the silicon carbide green body and the sintered body are 10.3 MPa and 151.2 MPa, respectively, exhibiting high 3D printing mechanical strength. The prepared ink material can be stably stored at room temperature for about 3 months.

[0078] Example 2

[0079] The formulation of silicon carbide biphase colloidal ceramic ink is designed as follows: In the silicon carbide ceramic colloidal suspension, the preferred solid phase content is 47.0 vol.%, with a particle size of 0.1-3 μm; the solvent is water; the dispersant is tetramethylammonium hydroxide, accounting for 1.4% of the dry powder mass; and the binder is methylcellulose, added at 2.0% of the dry powder mass.

[0080] In the polymer colloidal suspension: the rheology modifier is an acrylic polymer with a mass fraction of 0.5%, the colloidal stabilizer is polyvinylpyrrolidone with a mass fraction of 0.5%, and the surfactant is sodium lauryl sulfate with a mass fraction of 0.02%. The preparation process of the ceramic colloidal suspension is as follows: silicon carbide particles, deionized water, tetramethylammonium hydroxide, and methylcellulose are mixed to form a slurry; the mixture is ball-milled at 200 rpm for 8 hours to obtain a ceramic colloidal suspension with a solid content of 47.0 vol.%. To obtain a well-dispersed and stable suspension, high-purity zirconia balls with a diameter of 5-20 mm are used as the grinding medium, with a ball-to-material ratio of 1:1. The preparation process of the polymer colloidal suspension is as follows: the above-mentioned amounts of surfactant, rheology modifier, and colloidal stabilizer are weighed in an aqueous solution, dissolved and mixed according to the required amounts, and stirred for 6 hours to prepare a polymer colloidal suspension with specific rheological properties and surface wettability. After standing and aging for 8 hours, it is ready for use. Subsequently, the prepared polymer colloidal suspension and the well-dispersed ceramic colloidal suspension were mixed and shaken at a mass ratio of 94:5, and 2 drops of n-octanol were added. The mixture was then ball-milled again and allowed to stand for 16 hours to form a biphase colloidal silicon carbide ceramic ink material with a highly stable network structure formed by cross-linking of polymer colloidal suspension and ceramic particles.

[0081] It in 10s -1 The viscosity at the shear rate is 0.5 Pa·s, exhibiting good shear-thinning behavior and excellent viscoelasticity, with an elastic modulus as high as 10. 5Pa exhibits excellent shape retention, allowing it to pass stably and smoothly through the nozzle while maintaining its three-dimensional shape. The 3D direct-writing ceramic ink is loaded into the nozzle barrel of a 3D direct-writing device with a nozzle diameter of 160 μm. After setting the program for the 3D direct-writing device, a three-dimensional structure is obtained by printing in air in a layer-by-layer manner. The obtained silicon carbide ceramic green body is heated to 2100℃ at a programmed temperature rise of 10℃ / min and held for 8 hours to obtain a silicon carbide ceramic structural part. The mechanical strengths of the silicon carbide green body and the sintered body are 12.6 MPa and 140.1 MPa, respectively, exhibiting high mechanical strength for 3D printing. The prepared ink material can be stably stored at room temperature for approximately 4 months.

[0082] Example 3

[0083] The formulation of silicon carbide biphase colloidal ceramic ink is designed as follows: In the silicon carbide ceramic colloidal suspension, the preferred content of silicon carbide solid phase is 52.0 vol.%, with a particle size of 3 μm; the solvent is water; the dispersant is polyvinyl acid, accounting for 2.5% of the dry powder mass; and the binder is polyvinyl alcohol, added at 6.0% of the dry powder mass.

[0084] In the polymer colloidal suspension: the rheology modifier is pectin with a mass fraction of 0.3%, the colloidal stabilizer is polysaccharide with a mass fraction of 1.5%, and the surfactant is alkyl aryl sulfonate with a mass fraction of 0.03%.

[0085] The preparation process of the ceramic colloidal suspension is as follows: silicon carbide particles, deionized water, polyvinyl acid, and polyvinyl alcohol are mixed to form a slurry; the mixture is then ball-milled at 150 rpm for 10 hours to achieve uniform mixing, resulting in a ceramic colloidal suspension with a solid content of 52.0 vol.%. To obtain a well-dispersed and stable suspension, high-purity zirconia balls with a diameter of 5-20 mm are used as the grinding medium, with a ball-to-particle ratio of 1.2:1.

[0086] The preparation process of the polymer colloidal suspension is as follows: The surfactant, rheology modifier, and colloidal stabilizer of the above-mentioned amounts are weighed into an aqueous solution, dissolved and mixed according to the required amounts, and stirred for 8 hours to prepare a polymer colloidal suspension with specific rheological properties and surface wettability. After standing and aging for 24 hours, it is ready for use. Subsequently, the prepared polymer colloidal suspension is mixed with the well-dispersed ceramic colloidal suspension at a mass ratio of 85:13, shaken well, and 2 drops of n-octanol are added. The mixture is then ball-milled again until homogeneous. After standing and aging for 18 hours, a highly stable network structure of biphase colloidal silicon carbide ceramic ink material with cross-linked polymer colloidal suspension and ceramic particles is formed.

[0087] It in 10s -1 The viscosity at the shear rate is 1.5 Pa·s, exhibiting good shear-thinning behavior and excellent viscoelasticity with an elastic modulus as high as 10. 4The 3D direct-writing ceramic ink exhibits excellent shape retention, allowing it to pass smoothly through the nozzle and maintain its three-dimensional shape. The ink is loaded into the nozzle barrel of a 3D direct-writing device with a nozzle diameter of 300 μm. After setting the program for the 3D direct-writing device, a three-dimensional structure is obtained by printing in air layer by layer. The resulting silicon carbide ceramic green body is heated to 2000℃ at a programmed temperature increase of 10℃ / min and held for 4 hours to obtain a silicon carbide ceramic structural part. The mechanical strengths of the silicon carbide green body and the sintered body are 15.2 MPa and 170.2 MPa, respectively, exhibiting high mechanical strength for 3D printing. The prepared ink material can be stably stored at room temperature for approximately 3 months.

[0088] Example 4

[0089] The formulation of silicon carbide biphase colloidal ceramic ink is as follows: Silicon carbide ceramic colloidal suspension: silicon carbide solid phase content range of 50.0 vol.%, particle size of 0.6 μm, solvent is water, dispersant is tetramethylammonium hydroxide at 1.4% of the dry powder mass, and binder is carboxymethyl cellulose at 1.0% of the ceramic particle mass.

[0090] In the polymer colloidal suspension, the rheology modifier is guar gum with a mass fraction of 2.0%, the surfactant is glyceryl monostearate with a mass fraction of 0.5%, and the colloidal stabilizer is gelatin with a mass fraction of 3.0%.

[0091] The preparation process of the dual-phase colloidal silicon carbide ceramic ink material is shown in Example 3. After obtaining the ink material, it is ultrasonically vibrated for 6 hours before use. The prepared ink material can be stably stored at room temperature for about 3 months. Its stability within 10 seconds... -1 The viscosity at the shear rate is 3.0 Pa·s, exhibiting good shear-thinning behavior and excellent viscoelasticity with an elastic modulus as high as 10. 4 Pa, possessing excellent shape retention, can smoothly pass through the nozzle and maintain its three-dimensional shape. The 3D direct-writing ceramic ink is loaded into the nozzle of the 3D direct-writing device, with a nozzle diameter of 300 μm. After setting the program for the 3D direct-writing device, a three-dimensional structure can be obtained by printing in air in a layer-by-layer manner. The obtained silicon carbide ceramic green body is heated to 2100℃ at a programmed temperature rise of 10℃ / min and held for 5 hours to obtain silicon carbide ceramic structural parts. The mechanical strengths of the silicon carbide green body and the sintered body are 8.4 MPa and 132.6 MPa, respectively, exhibiting high mechanical strength for 3D printing.

[0092] Example 5

[0093] The silicon carbide ceramic ink formulation is as follows: silicon carbide solid content preferably ranges from 50.0 vol.%, particle size is 0.6 μm, solvent is water, dispersant is tetramethylammonium hydroxide at 1.4% of the dry powder mass, and binder is carboxymethyl cellulose at 10.0% of the dry powder mass.

[0094] In the polymeric colloidal suspension, the rheology modifier was ethylene glycol polymer (1.2% by mass), the colloidal stabilizer was collagen (5.0% by mass), and the surfactant was sulfated castor oil (0.6% by mass).

[0095] The preparation process of the dual-phase colloidal silicon carbide ceramic ink material is shown in Example 3.

[0096] The prepared ink material can be stably stored at room temperature for about two months. Its stability is within 10 seconds. -1 The viscosity at the shear rate is 8.0 Pa·s, exhibiting good shear-thinning behavior and excellent viscoelasticity with an elastic modulus as high as 10. 6 Pa, possessing excellent shape retention, can smoothly pass through the nozzle and maintain its three-dimensional shape. The 3D direct-writing ceramic ink is loaded into the nozzle of the 3D direct-writing device, with a nozzle diameter of 210μm. After setting the program for the 3D direct-writing device, a three-dimensional structure can be obtained by printing in air in a layer-by-layer manner. The obtained silicon carbide ceramic green body is heated to 1950℃ at a programmed temperature rise of 10℃ / min and held for 6 hours to obtain silicon carbide ceramic structural parts. The mechanical strengths of the silicon carbide green body and the sintered body are 15.8MPa and 120.6MPa, respectively, exhibiting high mechanical strength for 3D printing.

[0097] Example 6

[0098] The formulation design of the silicon carbide dual-phase colloidal ceramic ink is the same as in Example 2, except that the silicon carbide ceramic particles were optimized for particle size matching in this example. Specifically, the silicon carbide ceramic particles used in this example consist of silicon carbide ceramic particles A with a particle size of 0.3 μm, silicon carbide ceramic particles B with a particle size of 0.6 μm, and silicon carbide ceramic particles C with a particle size of 1 μm. The mass ratio of ceramic particles A: ceramic particles B: ceramic particles C is 2:6:2. The design of other components and the preparation process parameters are the same as in Example 2. The ink material obtained in this example has a 10s... -1 The viscosity at the shear rate is 0.33 Pa·s, exhibiting good shear-thinning behavior and excellent viscoelasticity, with an elastic modulus as high as 10. 5Pa, possessing excellent shape retention, can stably and smoothly pass through the nozzle while maintaining its three-dimensional shape. The 3D direct-writing ceramic ink is loaded into the nozzle barrel of a 3D direct-writing device with a nozzle diameter of 160 μm. After setting the program for the 3D direct-writing device, a three-dimensional structure can be obtained by printing in air in a layer-by-layer manner. The obtained silicon carbide ceramic green body is heated to 2100℃ at a programmed temperature rise of 10℃ / min and held for 8 hours to obtain silicon carbide ceramic structural parts. The mechanical strengths of the silicon carbide green body and the sintered body are 22.5 MPa and 180.6 MPa, respectively, exhibiting high 3D printing mechanical strength. The prepared ink material can be stably stored at room temperature for about 5 months. In this embodiment, by matching the particle size of ceramic particles, the fluidity of the ceramic suspension can be improved, resulting in a ceramic ink material that is more easily shear-thinned. At the same time, it can significantly improve the mechanical properties and strength of the formed structure.

[0099] Example 7

[0100] The formulation design of the silicon carbide dual-phase colloidal ceramic ink is the same as in Example 2, except that it also includes the addition of silicon carbide ceramic fibers. The fibers are 10 mm long and 0.1 mm in diameter, and the addition amount is 0.05% of the dry powder mass. Other component designs and process parameters are the same as in Example 2. The ink material obtained in this example... -1 The viscosity at the shear rate is 1.21 Pa·s, exhibiting good shear-thinning behavior and excellent viscoelasticity, with an elastic modulus as high as 10. 5 Pa, possessing excellent shape retention, can stably and smoothly pass through the nozzle while maintaining its three-dimensional shape. The 3D direct-writing ceramic ink is loaded into the nozzle barrel of a 3D direct-writing device with a nozzle diameter of 160 μm. After setting the program for the 3D direct-writing device, a three-dimensional structure can be obtained by printing in air in a layer-by-layer manner. The obtained silicon carbide ceramic green body is heated to 2100℃ at a programmed temperature rise of 10℃ / min and held for 8 hours to obtain silicon carbide ceramic structural parts. The mechanical strengths of the silicon carbide green body and the sintered body are 25.5 MPa and 196.6 MPa, respectively, exhibiting high 3D printing mechanical strength. The prepared ink material can be stably stored at room temperature for about 6 months. In this embodiment, the addition of silicon carbide ceramic fibers can significantly improve the stability of the ceramic ink material and enhance and toughen the mechanical properties such as toughness and strength of the printed ceramic structure.

[0101] Comparative Example 1

[0102] 1μm silicon carbide particles, deionized water, zinc acetate, and ammonium polyacrylate are mixed in a slurry. The solid content ranges from 48.0 vol.%, the ammonium polyacrylate is 0.8 wt.% of the dry silicon carbide powder content, and the zinc acetate is 0.05% of the ink mass. The mixture is then ball-milled at 100-140 rpm for 12-24 hours. After milling, the mixture is ultrasonically vibrated for 1-12 hours to obtain 3D direct-writing ceramic ink. This 3D direct-writing ceramic ink is loaded into the nozzle of a 3D direct-writing device with a nozzle diameter of 210 μm. The 3D direct-writing device program is set, and printing is performed in the air using a layer-by-layer stacking method to obtain three-dimensional structures. Although this ink has good viscoelasticity and can form three-dimensional structures through the nozzle, nozzle clogging occurs after a period of printing, resulting in unstable and continuous printing. The stability of the prepared ink material is less than 1 hour, making it unsuitable for printing large components.

[0103] Comparative Example 2

[0104] The formulation of silicon carbide ceramic ink is as follows: silicon carbide solid content preferably ranges from 47.0 vol.%, particle size is 0.1-3 μm, solvent is water, dispersant is tetramethylammonium hydroxide, accounting for 1.4% of the dry powder mass, binder is methylcellulose, rheology modifier is acrylic polymer, mass fraction is 0.5%, colloidal stabilizer is polyvinylpyrrolidone, mass fraction is 0.5%, and surfactant is sodium lauryl sulfate, mass fraction is 0.02%. The preparation process of the ceramic colloidal suspension is as follows: silicon carbide particles, deionized water, tetramethylammonium hydroxide, methylcellulose, and all the above materials are mixed together to form a slurry, preparing a ceramic ink material with a solid content of 47.0 vol.%. To ensure good dispersion of the ceramic mixture, high-purity zirconia balls with a diameter of 5-20 mm are used as the grinding medium, with a ball-to-particle ratio of 1:1. The mixture is ball-milled at 200 rpm for 8 hours to achieve uniform mixing. Finally, 2 drops of n-octanol are added, and the mixture is ball-milled again to achieve uniform mixing. After standing for 16 hours, the ceramic ink material is formed. During the preparation process, the ceramic suspension has poor dispersibility, and most of it aggregates and settles at the bottom, making it difficult to flow and disperse. As a result, the final ceramic ink material clumps together and cannot be smoothly extruded and written directly.

Claims

1. A highly stable two-phase colloidal ceramic ink material, characterized in that: The biphase colloidal ceramic ink material is composed of a ceramic colloidal suspension, a polymer colloidal suspension, and additives. The ceramic colloidal suspension is composed of ceramics, a solvent, a dispersant, and a binder. The polymer colloidal suspension is composed of water, a surfactant, a rheology modifier, and a colloidal stabilizer. In the biphase colloidal ceramic ink material, by mass, the ratio of ceramic colloidal suspension: polymer colloidal suspension: additives is 40-95: 2-20: 0.001-10. The preparation method of the dual-phase colloidal ceramic ink material is as follows: Dispersant and binder are added to solvent, and then ceramic ball milling is performed to obtain ceramic colloidal suspension. Surfactant, rheology modifier and colloidal stabilizer are added to water and allowed to stand for aging to obtain polymer colloidal suspension. Then the ceramic colloidal suspension and polymer colloidal suspension are mixed and additives are added. After mixing and standing, the biphasic colloidal ceramic ink material is obtained.

2. The highly stable dual-phase colloidal ceramic ink material according to claim 1, characterized in that: In the ceramic colloidal suspension, the ceramic is selected from at least one of zirconium oxide, titanium dioxide, alumina, hydroxyapatite, silicon carbide, silicon nitride, and boron nitride. The solid content of the ceramic is 42.0-62.0 vol.%; The ceramic comprises ceramic powder with a particle size of 0.1-30.0 µm.

3. The highly stable two-phase colloidal ceramic ink material according to claim 2, characterized in that: The ceramic powder is composed of ceramic powder A with a particle size of 0.1-0.3μm, ceramic powder B with a particle size of 0.6-1.5μm, and ceramic powder C with a particle size of 1-3μm, wherein the mass ratio of ceramic powder A: ceramic powder B: ceramic powder C is 1-3: 3-6: 1-6. The ceramic also includes ceramic fibers, the amount of which is 0.01-15% of the ceramic powder mass, the length of which is 0.01-100 mm, and the diameter of which is 0.01-10 mm.

4. The highly stable two-phase colloidal ceramic ink material according to claim 2, characterized in that: The solvent is selected from at least one of deionized water, anhydrous ethanol, and acetone; The dispersant is selected from inorganic dispersants or organic dispersants, wherein the inorganic dispersant is selected from at least one of silicates and alkali metal phosphates, and the organic dispersant is selected from at least one of triethylhexylphosphonic acid, sodium dodecyl sulfate, methylpentanol, cellulose derivatives, polyacrylamide, glucon, fatty acid polyethylene glycol esters, polyacrylic acid, polyvinyl acid, citric acid, ammonium polyacrylate, tetramethylammonium hydroxide, sodium polycarboxylate, and polyacetylimide. The amount of the dispersant added is 0.1-10.0% of the mass of the ceramic powder; The adhesive is selected from at least one of polyvinyl alcohol, polyethylene oxide, methylcellulose, carboxymethylcellulose, cellulose, hydroxyethylcellulose, gum arabic, epoxy resin, waterborne polyurethane resin, phenolic resin and carbomer; The amount of binder added is 0.01-20.0% of the mass of the ceramic powder.

5. A highly stable two-phase colloidal ceramic ink material according to claim 1 or 2, characterized in that: The sum of the mass fractions of the surfactant, rheology modifier, and colloidal stabilizer in the polymer colloidal suspension is 0.01-35.0 wt.%. The surfactant is selected from at least one of stearic acid, oleic acid, lauric acid, sulfate, sulfonate, lecithin, amino acid type, betaine type, alkyl glucoside, fatty acid glycerides and polyols; The sulfate is selected from at least one of sulfated oil and fatty alcohol sulfate esters; the sulfonate is selected from at least one of aliphatic sulfonates, alkyl aryl sulfonates, and alkyl naphthalene sulfonates; and the alkyl glucoside is selected from at least one of cocoyl glucoside, lauryl glucoside, and cetearyl glucoside. The fatty acid glyceride is a monostearate with an HLB value of 3-43. The polyol is selected from at least one of sucrose esters with an HLB of 5-13, fatty acid sorbitan, and polysorbate esterifying agents. In the polymer colloidal suspension, the mass fraction of the surfactant is 0.001-15.0%. The rheology modifier is selected from at least one of the following: natural resin, natural heteropolysaccharide, organic acid-modified heteropolysaccharide, magnesium aluminum silicate, sodium magnesium silicate, acrylic polymer, and ethylene glycol polymer. In the polymer colloidal suspension, the mass fraction of the rheology modifier is 0.01-20.0%. The colloidal stabilizer is selected from at least one of the following: phosphoric acid compounds, collagen, gelatin, ammonium compounds, linear, branched, or cyclic polyols, linear, branched, or cyclic polyamines, linear, branched, or cyclic polythiol compounds, sugar compounds, polyaminocarboxylic acids, polyvinylpyrrolidone, diatomaceous earth, and ε-caprolactam. In the polymer colloidal suspension, the mass fraction of the colloidal stabilizer is 0.01-20.0%.

6. The highly stable dual-phase colloidal ceramic ink material according to claim 1, characterized in that: The auxiliary agent is selected from at least one of ethylene glycol, glycerin, silicone oil, ethanol, acetone, OP, and n-octanol.

7. The highly stable two-phase colloidal ceramic ink material according to claim 1, characterized in that: The ball mill rotates at 80-300 rpm and the milling time is 4-72 hours. During the ball milling process, zirconia balls with a diameter of 5-20 mm are used as the grinding media, and the ball-to-material ratio is 1-2:

1. The static aging time is 4-72 hours. The mixing method is one of ball milling, vibration, ultrasonication, or shearing. The settling time is 4-72 hours.

8. The application of the highly stable two-phase colloidal ceramic ink material according to any one of claims 1-7, characterized in that: The biphase colloidal ceramic ink material is applied to the preparation of ceramic materials using direct writing.

9. The application of the highly stable two-phase colloidal ceramic ink material according to claim 8, characterized in that: The process of preparing ceramic materials by direct writing is as follows: the two-phase colloidal ceramic ink material is placed in the syringe of the 3D direct writing equipment, and a ceramic blank is obtained by direct writing at room temperature by layering according to the ceramic structure model. Then the ceramic blank is sintered to obtain the ceramic material. The nozzle diameter ranges from 60 nm to 2000 μm; The sintering temperature is 800-2300℃, the heating rate is 5-15℃ / min, and the holding time is 0.5-72h.

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