Ceramic product based on binder jet 3D printing and preparation method thereof

Abstract

The invention discloses a ceramic product based on binder jet 3D printing, which is prepared from the following components in parts by weight: 90 to 97 percent of composite powder and 3 to 10 parts of binder, the composite powder is prepared from 88 to 96.7 parts of composite powder and 0.3 to 2 parts of an adhesive; the composite powder comprises silicon carbide powder and carbon source powder; the adhesive is one of water, an organic solution and an inorganic solution. According to the ceramic product and the preparation method thereof, the carbon source powder is added into the silicon carbide powder, the carbon content in a green body can be increased without recarburization treatment in the subsequent process, and the density and performance of a sintered finished product are effectively improved; an adhesive is added into the composite powder, so that the flowability of the composite powder is reduced, and the mixing uniformity of the composite powder is improved; the green body is embedded in silicon particles for siliconizing reaction sintering, carbon and silicon react in the sintering process to expand the volume, gaps of the silicon carbide green body are filled, and the density of a ceramic finished product is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing, and in particular to a ceramic product based on binder jet 3D printing and a preparation method thereof. Background Art

[0002] Silicon carbide is an advanced engineering ceramic material with high hardness, high specific strength, high stability, high temperature resistance and corrosion resistance, which is widely used in aerospace, automobile engines and chemical industry. In traditional industries, the molding method of silicon carbide / carbon composite powder mainly relies on molding methods such as compression molding and slurry molding, which have problems such as low degree of personalization, internal defects of the molded green body and complex slurry configuration, which limits the manufacturing and application of high-performance silicon carbide ceramic products for large-sized special-shaped parts.

[0003] Binder jet 3D printing technology is fast, low cost, high powder adaptability, and high design freedom, and is suitable for the molding and manufacturing of large and special-shaped components. However, the silicon carbide green body of binder jet 3D printing currently needs to be carburized in the later stage, and the composite powder materials used in binder jet 3D printing still have problems such as uneven powder mixing and uneven powder distribution during the printing and spreading process. Summary of the invention

[0004] Based on this, in order to solve the above technical problems, the present invention provides a ceramic product based on binder jet 3D printing and a preparation method thereof.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A ceramic product based on binder jet 3D printing comprises, by weight: 90-97% of a composite powder and 3-10 parts of a binder; the composite powder comprises 88-96.7 parts of a composite powder and 0.3-2 parts of an adhesive; the composite powder comprises silicon carbide powder and carbon source powder; the adhesive comprises at least one of water, an organic solution and an inorganic solution.

[0007] In one embodiment, the carbon source powder is one or more of graphite, carbon fiber, carbon black, and asphalt.

[0008] In one embodiment, the ratio of the added amount of the silicon carbide powder to the added amount of the carbon source powder is 19-12:1-8.

[0009] In one embodiment, the particle size of the silicon carbide powder is 2 to 250 μm, and the particle size of the carbon source powder is 2 to 250 μm.

[0010] In one embodiment, the binder is one or more of furan resin, phenolic resin, PVA, and PVB.

[0011] In a second aspect, the present invention further discloses a preparation method, which is applied to any of the above-mentioned ceramic products based on binder jet 3D printing. The preparation method comprises the following steps:

[0012] Preparation of composite powder: uniformly mixing the silicon carbide powder and the carbon source powder to form the composite powder, and adding the adhesive into the composite powder and uniformly mixing;

[0013] Green body printing, adding the composite powder and the binder into a 3D printer, and jetting the binder through 3D printing to form the green body;

[0014] Reaction sintering, embedding the green body into silicon particles, and high-temperature reaction sintering to form the ceramic product.

[0015] In one embodiment, in the reaction sintering step, the particle size of the silicon particles is 0.5-8 mm, and the weight ratio of the silicon particles to the green body is 0.5-2:1.

[0016] In one embodiment, in the reaction sintering step, the sintering temperature is 1550-1700°C.

[0017] In one embodiment, in the step of preparing the composite powder, the mixing time of the silicon carbide powder and the carbon source powder is 0.5 to 5 hours; the mixing time of the composite powder and the adhesive is 1 to 60 minutes.

[0018] In one of the embodiments, in the green body printing step, the powder spreader parameters are set to a scraper plate angle of 70 to 140 degrees, a vibration frequency of 3000 to 4000 r / min, and a printing layer thickness of 0.1 to 0.3 mm.

[0019] Compared with the prior art, the method of the present invention has the following beneficial effects:

[0020] In the ceramic product based on binder jet 3D printing disclosed by the present invention, carbon source powder is added to silicon carbide powder, and the carbon content in the green body can be increased without subsequent carbon enrichment treatment, thereby effectively improving the density and performance of the sintered product, and obtaining high-quality large-sized silicon carbide ceramic products.

[0021] The ceramic product based on binder jet 3D printing disclosed in the present invention adds an adhesive to the composite powder to reduce the fluidity of the composite powder, improve the mixing uniformity of the composite powder, and significantly improve the problems of stratification or uneven particle distribution in the powder spreading process caused by differences in particle size, fluidity, density, etc. between silicon carbide powder and carbon source powder.

[0022] The ceramic product based on binder jet 3D printing disclosed by the present invention is that the green body is embedded in silicon particles and sintered by siliconization reaction. During the sintering process, the carbon and silicon react and expand in volume, filling the voids of the silicon carbide body and improving the density of the finished ceramic product. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] none DETAILED DESCRIPTION

[0024] For ease of understanding of the present invention, the present invention will be described more fully below with reference to relevant embodiments. Preferred embodiments of the present invention are provided in the embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thoroughly understood.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0026] One of the purposes of the present invention is to disclose a ceramic product based on binder jetting 3D printing, which comprises, by weight, 90-97% of a composite powder and 3-10 parts of a binder. The composite powder is spread on a printing base plate according to a set layer thickness by a 3D printer powder spreader, and the binder is sprayed onto the powder spreading surface by a print head, and the powder spreading and inkjet (binder) steps are circulated until the printing is completed, thereby completing the green body construction of the ceramic product.

[0027] Specifically, the composite powder may include 88 to 96.7 parts of composite powder and 0.3 to 2 parts of adhesive, wherein the composite powder includes silicon carbide powder and carbon source powder. The carbon source powder is preferably one or more of graphite, carbon fiber, carbon black, and asphalt. The ratio of the amount of silicon carbide powder to the carbon source powder added is preferably 19 to 12: 1 to 8, the particle size of the silicon carbide powder is preferably 2 to 250 μm, and the particle size of the carbon source powder is preferably 2 to 250 μm. In the ceramic product based on binder jet 3D printing disclosed in the present invention, carbon source powder is added to silicon carbide powder, which can improve the density and mechanical properties of the printed product on the one hand, and can improve the carbon content of the printed product on the other hand. At the same time, due to the differences in particle shape, fluidity and density between silicon carbide powder and carbon source powder, the mixed composite powder is difficult to meet the requirements of binder jet 3D printing, and there is uneven powder mixing, which aggravates the uneven distribution of powder during the printing powder spreading process, and seriously affects the quality of the printed green body. Therefore, the present invention adds an adhesive to the silicon carbide and carbon source composite powder, and uses the adhesive to evenly mix the silicon carbide powder and the carbon source powder through wet mechanical mixing to obtain a composite powder that meets the requirements of binder jetting 3D printing, which significantly improves the problem of stratification or uneven particle distribution during the powder spreading process caused by the large differences in particle shape, size, fluidity and density of the silicon carbide powder and the carbon source powder.

[0028] Furthermore, the adhesive can be selected from one or more of water, organic alkaline solution, organic acid solution, inorganic alkaline solution and inorganic acid solution, as long as it does not react with silicon carbide powder and carbon source powder. The binder can be one or more of furan resin, phenolic resin, phenolic modified furan resin, PVA and PVB.

[0029] One of the purposes of the present invention is to disclose a method for preparing a ceramic product based on binder jet 3D printing as described above, which may include the following steps:

[0030] S100, composite powder preparation

[0031] S110, mechanically mixing 2-250 μm silicon carbide powder and 2-250 μm carbon source powder at a weight ratio of 19-12:1-8 at room temperature for 0.5-5 hours to form a composite powder. A longer mixing time helps to improve the uniformity between the powders, but too long a mixing time may cause powder particle breakage or excessive energy consumption.

[0032] Directly doping carbon source particles into silicon carbide powder can increase the free carbon content of binder jet 3D printed silicon carbide green bodies, which helps to improve the density and mechanical properties of subsequent sintered products, thereby obtaining high-quality large-size silicon carbide ceramic products.

[0033] S120. Add an adhesive to the composite powder and mechanically mix for 1 to 60 minutes to form a composite powder. The addition of the adhesive can change the surface properties of the carbon source particles, making the interaction between the carbon source particles and the silicon carbide powder more stable, reducing the separation and local aggregation of particles, and improving the mixing uniformity; the addition of the adhesive can enhance the viscosity of the composite powder, reduce the fluidity of the composite powder, make the composite powder more easily adhere and agglomerate, and avoid uneven distribution of the carbon source powder and the silicon carbide powder due to differences in particle shape, size, fluidity, and density during the powder spreading process. At the same time, it can also prevent fine particles from raising dust during the printing process, reduce the risk of print head clogging during the printing process, and reduce the pollution of the environment by dust.

[0034] The present invention can evenly mix silicon carbide powder and carbon source powder with large differences in particle shape, size, fluidity, density, etc. through wet mechanical mixing. Compared with the conventional mixing process of using binders, additives, etc. to assist ball milling and then sequentially performing steps such as solidification, crushing, and re-screening, the wet mechanical mixing method of the present invention is simpler and more convenient to operate, and the mixing preparation cycle is greatly shortened, so that large-scale mixed powder preparation can be achieved.

[0035] In the present invention, the amount of adhesive added to 88-96.7 parts of the composite powder is 0.3-2 parts. This ratio can not only make the adhesive effectively improve the viscosity of the powder, but also avoid excessive wetting that causes the powder to be too wet or unable to flow, and avoid the difficulty of the subsequent powder spreader to put the powder, and the uneven density of the printed blank. In this sequence, the mechanical mixing equipment can be an inclined strong mixer, which can provide a strong shear force to help achieve a more uniform mixing between the powders.

[0036] S200, Green Printing

[0037] S210, adding the composite powder into the powder spreader of the binder jet 3D printer, adding the binder into the print head of the binder jet 3D printer, setting the printing program and printing parameters; the scraper plate angle is 70 to 140 degrees, the vibration frequency is 3000 to 4000 r / min, and the printing layer thickness is 0.1 to 0.3 mm.

[0038] S220, start the binder jetting 3D printer, the powder spreader evenly and flatly spreads a layer of composite powder on the printing base, and the print head sprays the binder onto the composite powder layer laid by the powder spreader according to the set path; after the printing platform descends by a printing layer thickness, the powder spreading, inkjet (binder), and workbench descending steps are repeated until the printing is completed, and the green body construction of the ceramic product is completed.

[0039] After printing, the density of the green body is ≥1.7g / cm 3 .

[0040] S300, Reaction Sintering

[0041] S310, embedding the green body into silicon particles, and placing the green body and the embedded silicon particles into a graphite high-temperature sintering furnace for reaction and sintering to form a final ceramic product. The particle size of the silicon particles is 0.5 to 8 mm, the weight ratio of the silicon particles to the green body is 0.5 to 2:1, and the sintering temperature is 1550 to 1700°C.

[0042] In the reaction sintering step, the ceramic products embedded in the silicon particles undergo siliconization reaction sintering. During the sintering process, the carbon and silicon react and expand in volume, filling the gaps between the particles in the green body and improving the density of the ceramic product. The density of the ceramic product after reaction sintering is ≥2.9g / cm 3 .

[0043] Embodiment 1

[0044] A ceramic product based on binder jet 3D printing includes, by weight: 79.9 parts of silicon carbide powder, 14.1 parts of graphite powder, 0.54 parts of sulfonic acid solution, and 5.46 parts of furan resin. In this embodiment, the silicon carbide powder is 60 to 150 μm, and the graphite powder is 30 to 120 μm.

[0045] The method for preparing a ceramic product based on binder jet 3D printing in this embodiment may include the following steps:

[0046] S100, composite powder preparation

[0047] 79.9 parts of silicon carbide powder and 14.1 parts of graphite powder were added to an inclined intensive mixer and mechanically mixed for 1 hour at room temperature; then 0.54 parts of sulfonic acid solution were added and mechanically mixed for 10 minutes to obtain a composite powder.

[0048] S200, Green Printing

[0049] The composite powder obtained in step S100 is added to the powder spreader of the binder jet 3D printer, the furan resin is added to the print head of the binder jet 3D printer, and the printing program and printing parameters are set; the binder jet 3D printer is started, the powder spreader evenly and flatly spreads a layer of composite powder on the printing base plate, and the print head sprays the furan resin onto the composite powder layer laid by the powder spreader according to the set path; after the printing platform descends by a printing layer thickness, the powder spreading, inkjet, and workbench descending steps are repeated until printing is completed, thereby completing the green body construction of the ceramic product of this embodiment.

[0050] In this embodiment, the scraper angle is 90 degrees, the vibration frequency is 3300r / min, the printing layer thickness is 0.2mm; the printed green density is 1.81g / cm 3 .

[0051] S300, Reaction Sintering

[0052] The green body printed in step S200 is embedded in silicon particles, and the green body and the embedded silicon particles are placed in a graphite high-temperature sintering furnace for reaction sintering to form the final ceramic product. The particle size of the silicon particles is 3 to 5 mm, the weight ratio of silicon particles to green body is 1.5:1, and the sintering temperature is 1650°C. After reaction sintering, the density of the ceramic product of this embodiment is 2.99 g / cm 3 .

[0053] Embodiment 2

[0054] A ceramic product based on binder jet 3D printing includes, by weight: 70 parts of silicon carbide powder, 23.4 parts of carbon fiber, 0.7 parts of organic fat solution, and 5.9 parts of phenolic resin. In this embodiment, the silicon carbide powder is 90-190 μm, and the carbon fiber is 120 mesh.

[0055] The method for preparing a ceramic product based on binder jet 3D printing in this embodiment may include the following steps:

[0056] S100, composite powder preparation

[0057] 70 parts of silicon carbide powder and 23.4 parts of carbon fiber were added to an inclined intensive mixer and mechanically mixed for 3 hours at room temperature; then 0.7 parts of organic fat solution were added and mechanically mixed for 25 minutes to obtain a composite powder.

[0058] S200, Green Printing

[0059] The composite powder obtained in step S100 is added to the powder spreader of the binder jet 3D printer, the phenolic resin is added to the print head of the binder jet 3D printer, and the printing program and printing parameters are set; the binder jet 3D printer is started, the powder spreader evenly and flatly spreads a layer of composite powder on the printing base plate, and the print head sprays furan resin onto the composite powder layer laid by the powder spreader according to the set path; after the printing platform descends by a printing layer thickness, the powder spreading, inkjet, and workbench descending steps are repeated until printing is completed, thereby completing the green body construction of the ceramic product of this embodiment.

[0060] In this embodiment, the scraper angle is 115 degrees, the vibration frequency is 3600r / min, the printing layer thickness is 0.25mm; the printed green density is 1.76g / cm 3 .

[0061] S300, Reaction Sintering

[0062] The green body printed in step S200 is embedded in silicon particles, and the green body and the embedded silicon particles are placed in a graphite high-temperature sintering furnace for reaction sintering to form the final ceramic product. The particle size of the silicon particles is 6 to 8 mm, the weight ratio of silicon particles to green body is 1.8:1, and the sintering temperature is 1650°C. After reaction sintering, the density of the ceramic product of this embodiment is 2.96 g / cm 3 .

[0063] Embodiment 3

[0064] A ceramic product based on binder jet 3D printing includes, by weight: 76.08 parts of silicon carbide powder, 19.02 parts of carbon black, 0.62 parts of toluenesulfonic acid solution, and 4.28 parts of furan resin. In this embodiment, the silicon carbide powder is 20 to 90 μm, and the carbon black is 5 to 30 μm.

[0065] The method for preparing a ceramic product based on binder jet 3D printing in this embodiment may include the following steps:

[0066] S100, composite powder preparation

[0067] 76.08 parts of silicon carbide powder and 19.02 parts of carbon black were added to an inclined intensive mixer and mechanically mixed for 4 hours at room temperature; then 0.62 parts of toluenesulfonic acid solution were added and mechanically mixed for 30 minutes to obtain a composite powder.

[0068] S200, Green Printing

[0069] The composite powder obtained in step S100 is added to the powder spreader of the binder jet 3D printer, the phenolic resin is added to the print head of the binder jet 3D printer, and the printing program and printing parameters are set; the binder jet 3D printer is started, the powder spreader evenly and flatly spreads a layer of composite powder on the printing base plate, and the print head sprays furan resin onto the composite powder layer laid by the powder spreader according to the set path; after the printing platform descends by a printing layer thickness, the powder spreading, inkjet, and workbench descending steps are repeated until printing is completed, thereby completing the green body construction of the ceramic product of this embodiment.

[0070] In this embodiment, the scraper angle is 130 degrees, the vibration frequency is 3800r / min, the printing layer thickness is 0.15mm, and the printed green density is 1.71g / cm 3 .

[0071] S300, Reaction Sintering

[0072] The green body printed in step S200 is embedded in silicon particles, and the green body and the embedded silicon particles are placed in a graphite high-temperature sintering furnace for reaction sintering to form the final ceramic product. The particle size of the silicon particles is 1 to 3 mm, the weight ratio of silicon particles to green body is 1.5:1, and the sintering temperature is 1700°C. After reaction sintering, the density of the ceramic product of this embodiment is 2.92 g / cm 3 .

[0073] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A ceramic product based on binder jet 3D printing, characterized in that: By weight, it comprises: 90-97% of composite powder and 3-10 parts of binder; The composite powder material comprises 88-96.7 parts of composite powder and 0.3-2 parts of adhesive; the composite powder comprises silicon carbide powder and carbon source powder; The adhesive includes at least one of water, an organic solution and an inorganic solution.

2. The ceramic product based on binder jet 3D printing according to claim 1, characterized in that: The carbon source powder is one or more of graphite, carbon fiber, carbon black and asphalt.

3. The ceramic product based on binder jet 3D printing according to claim 2, characterized in that: The ratio of the added amount of the silicon carbide powder to the added amount of the carbon source powder is 19-12:1-8.

4. The ceramic product based on binder jet 3D printing according to claim 3, characterized in that: The particle size of the silicon carbide powder is 2 to 250 μm, and the particle size of the carbon source powder is 2 to 250 μm.

5. The ceramic product based on binder jet 3D printing according to claim 1, characterized in that: The binder is one or more of furan resin, phenolic resin, PVA and PVB.

6. A preparation method, applied to the ceramic product based on binder jet 3D printing as claimed in any one of claims 1 to 5, characterized in that: The steps include: Preparation of composite powder: uniformly mixing the silicon carbide powder and the carbon source powder to form the composite powder, and adding the adhesive into the composite powder and uniformly mixing; Green body printing, adding the composite powder and the binder into a 3D printer, and jetting the binder through 3D printing to form the green body; Reaction sintering, embedding the green body into silicon particles, and high-temperature reaction sintering to form the ceramic product.

7. The preparation method according to claim 6, characterized in that: In the reaction sintering step, the particle size of the silicon particles is 0.5 to 8 mm, and the weight ratio of the silicon particles to the green body is 0.5 to 2:

1.

8. The preparation method according to claim 6, characterized in that: In the reaction sintering step, the sintering temperature is 1550-1700°C.

9. The preparation method according to claim 6, characterized in that: In the composite powder preparation step, the mixing time of the silicon carbide powder and the carbon source powder is 0.5 to 5 hours; the mixing time of the composite powder and the adhesive is 1 to 60 minutes.

10. The preparation method according to claim 6, characterized in that: In the green printing step, the powder spreader parameters are set to a scraper plate angle of 70 to 140 degrees, a vibration frequency of 3000 to 4000 r / min, and a printing layer thickness of 0.1 to 0.3 mm.