A quartz fiber-silica sol composite slurry, a method for preparing the same, and a method for preparing a quartz ceramic

Abstract

The application provides a quartz fiber-silica sol composite material slurry, a preparation method of the quartz fiber-silica sol composite material slurry and a quartz ceramic preparation method. The quartz fiber-silica sol composite material slurry comprises quartz fiber, silica sol, a photosensitive resin system and a dispersing agent. The mass of the quartz fiber is 5-15% of the total mass of the slurry. The total mass of the slurry is the sum of the masses of the quartz fiber, the silica sol, the photosensitive resin system and the dispersing agent. The application avoids the problem of high viscosity of ceramic slurry caused by excessive quartz fiber in the presence of quartz particles. The silica sol is used to replace the quartz particles, so that the addition amount of the quartz fiber is greatly increased, and the purpose of ceramic toughening is achieved.

Description

Technical Field

[0001] This invention belongs to the field of quartz ceramics, and relates to a quartz fiber-silica sol composite material slurry, its preparation method, and a method for preparing quartz ceramics. Background Technology

[0002] Radar radomes are protective devices for aircraft radar antennas, possessing properties of wave transmission, load-bearing capacity, and temperature resistance. Quartz ceramics, due to their low coefficient of thermal expansion, good thermal shock resistance, excellent dielectric properties, and thermal shock resistance, have become one of the main candidate materials for radome bodies. However, traditional quartz radome fabrication often employs a fiber weaving and silica sol impregnation sintering process. This process is time-consuming, technically demanding, labor-intensive, and cannot manufacture complex structural components such as honeycomb structures. Therefore, the photopolymerization molding process of ceramics has become a boon for the fabrication of quartz radome bodies.

[0003] However, currently, photopolymer-cured quartz ceramics exhibit high brittleness and low fracture toughness, limiting their application in practical production. To address this issue, a common method is to add short-cut fibers to the ceramic matrix. These fibers, through bridging, pull-out, and breakage, as well as crack deflection, hinder crack propagation and further formation, thus achieving toughening. Quartz fiber-reinforced quartz ceramics retain the original characteristics of the ceramic matrix while effectively overcoming the crack sensitivity of brittle ceramic materials. Quartz fiber-reinforced quartz ceramics not only have stable dielectric properties but also provide toughening and reinforcement. However, the introduction of quartz fibers increases the viscosity of the ceramic slurry; the higher the quartz fiber content, the greater the viscosity. This makes it more difficult for the squeegee to level the surface during photopolymer 3D printing, and the sample is prone to detaching from the printing platform, affecting the printing success rate. Therefore, in the preparation of photopolymer ceramic slurries, the quartz fiber content is generally only about 2wt.%~6wt.%, resulting in a relatively poor toughening effect. The highest reported flexural strength of fused silica ceramics prepared by 3D printing is 28.9 MPa, which is relatively poor. The fracture toughness of ordinary fused silica ceramics is between 0.6 and 0.8 MPa. m 1 / 2 The fracture toughness of quartz fiber reinforced fused silica has not been reported. Summary of the Invention

[0004] To address the problems of the prior art, this invention provides a quartz fiber-silica sol composite slurry and its preparation method, as well as a method for preparing quartz ceramics. This avoids the problem of excessively high viscosity in ceramic slurries caused by excessive quartz fibers in the presence of quartz particles. By using silica sol to replace quartz particles, the amount of quartz fibers added is significantly increased, thereby achieving the purpose of toughening ceramics.

[0005] This invention is achieved through the following technical solution:

[0006] A quartz fiber-silica sol composite slurry includes: quartz fiber, silica sol, a photosensitive resin system, and a dispersant; wherein the mass of the quartz fiber is 5% to 15% of the total mass of the slurry; and the total mass of the slurry is the sum of the masses of the quartz fiber, silica sol, photosensitive resin system, and dispersant.

[0007] Preferably, the amount of silica sol used is 30% to 50% of the total resin mass; the total resin mass is the sum of the masses of the prepolymer, resin monomers and silica sol.

[0008] Preferably, the photosensitive resin system includes a prepolymer, a resin monomer, and a photoinitiator.

[0009] Furthermore, the prepolymer is one or more of epoxy acrylate, polyurethane acrylate, polyester acrylate, polyether acrylate and vinyl resin.

[0010] Furthermore, the resin monomer includes a first resin monomer and a second resin monomer; the first resin monomer is one or more of 1,6-hexanediol diacrylate, isobornyl methacrylate, and pentaerythritol hexaacrylate; the second resin monomer is one or more of trimethylolpropane triacrylate, tripropylene glycol diacrylate, and pentaerythritol tetraacrylate.

[0011] Furthermore, the photoinitiator includes a first photoinitiator and a second photoinitiator; the first photoinitiator is one or both of diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide and diaryliodomonium salt; the second photoinitiator is one or both of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide and benzoin dimethyl ether.

[0012] Preferably, the dispersant is one or more of BYK-9076, BYK-9077 and AD-8098, and the amount of dispersant used is 3% to 5% of the mass of quartz fiber.

[0013] The method for preparing the quartz fiber-silica sol composite slurry involves mixing a prepolymer, resin monomer, and photoinitiator to obtain a photosensitive resin system; adding quartz fiber and silica sol to the photosensitive resin system; then adding a dispersant and homogenizing to obtain the quartz fiber-silica sol composite slurry.

[0014] A method for preparing quartz ceramics, comprising:

[0015] S1. Using the quartz fiber-silica sol composite material slurry as raw material, the quartz ceramic green body is formed by photopolymerization 3D printing method.

[0016] S2. Degrease the quartz ceramic green body to obtain a degreased quartz part;

[0017] S3. The quartz degreased parts are decarburized and shaped, and then impregnated with silica sol in a vacuum environment. After drying, they are sintered to obtain quartz ceramics.

[0018] Preferably, the decarburization and shaping process conditions described in S3 are as follows: under air atmosphere, the decarburization temperature is 500~600℃, the heating rate is 0.5~0.8℃ / min, and the holding time is 90min~180min.

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

[0020] This invention proposes a novel ceramic toughening approach that can significantly increase the quartz fiber content. Specifically, it uses a high-content blend of quartz fiber and silica sol as the main component of the slurry. Although the quartz fiber content is relatively high, the prepared quartz fiber-silica sol composite slurry still possesses low viscosity, achieving a viscosity within 100 seconds. -1 The viscosity at the shear rate is 8.75~15.36 Pa. This process facilitates photopolymerization 3D printing, resulting in a high success rate. Furthermore, the addition of silica sol, besides acting as part of the ceramic matrix, also helps regulate the curing depth because it does not participate in the cross-linking curing reaction. Excessive curing depth affects printing accuracy, while insufficient curing depth leads to interlayer bonding problems. Generally, a curing depth of 150-300 μm is suitable for printing. Fused silica has high light transmittance and is easily cured, resulting in a high curing depth. The addition of silica sol can reduce the curing depth; the curing depth of the quartz fiber-silica sol composite slurry is 200-300 μm. A high quartz fiber content allows the prepared sample to have better fracture toughness, and subsequent impregnation processes can improve the overall flexural strength of the sample. The fracture toughness of the samples obtained from the slurry of this invention is 3.8-5.1 MPa. m 1 / 2 (far exceeding the fracture toughness of existing photopolymer 3D printed quartz ceramics, which is 0.6~0.8 MPa) m 1 / 2 The flexural strength is 31.7~45.3 MPa. Therefore, this invention abandons the conventional approach of using ceramic powder as the main body and chopped fibers as the additive phase. Instead, it considers the combination of quartz fiber and silica sol as the main body, avoiding the problem of excessive viscosity caused by too many fibers. This significantly increases the amount of quartz fiber added, and achieves the purpose of toughening ceramics through fiber bridging, pull-out, and crack deflection.

[0021] This invention discloses a method for preparing quartz ceramics, using the aforementioned quartz fiber-silica sol composite slurry as raw material and employing a photopolymerization 3D printing method. As described above, this invention uses a high-content blend of quartz fiber and silica sol as the main body of the slurry. The high quartz fiber content allows the prepared samples to possess better fracture toughness. Simultaneously, because silica sol replaces quartz powder, the viscosity of the slurry obtained with a high quartz fiber content is still reduced, facilitating photopolymerization 3D printing. Even with a high quartz fiber content, quartz ceramic products can still be successfully prepared, and the fracture toughness of the products can be further improved. The method of this invention further involves impregnation in silica sol to obtain ceramic samples with even better performance.

[0022] Furthermore, after the quartz ceramic green body of the present invention is degreased, it is decarburized and shaped at 500~600℃. This step is to remove the carbon residue generated during degreasing under an argon atmosphere, and to improve the strength of the sample by sintering at a certain temperature, in preparation for silica sol impregnation. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 The degreasing curve of the quartz part produced by the photopolymerization molding technology in Example 1 is shown.

[0025] Figure 2 The sintering curve of the quartz part produced by the photocuring molding technology in Example 1 is shown. Detailed Implementation

[0026] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0027] It should be noted that the process equipment or apparatus not specifically mentioned in the following embodiments are all conventional equipment or apparatus in the art.

[0028] It should be noted that the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or apparatuses. Furthermore, unless otherwise stated, the numbering of each method step is merely a convenient tool for identifying each method step, and not intended to limit the order of the method steps or define the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0029] The quartz fiber-silica sol composite slurry of the present invention comprises: quartz fiber, silica sol, photosensitive resin system, and dispersant; wherein the mass of the quartz fiber is 5% to 15% of the total mass of the slurry. The total mass of the slurry is the sum of the masses of the quartz fiber, silica sol, photosensitive resin system, and dispersant.

[0030] In some specific embodiments of the present invention, the photosensitive resin system includes a prepolymer, a resin monomer, and a photoinitiator.

[0031] In some specific embodiments of the present invention, the prepolymer is one or more of epoxy acrylate (EA), polyurethane acrylate (PUA), polyester acrylate (PEA), polyether acrylate and vinyl resin.

[0032] In some specific embodiments of the present invention, the resin monomer includes a first resin monomer and a second resin monomer. The first resin monomer is one or more of 1,6-hexanediol diacrylate (HDDA), isobornyl methacrylate (IBOMA), and dipentaerythritol hexaacrylate (DPHA); the second resin monomer is one or more of trimethylolpropane triacrylate (TMPTA), tripropylene glycol diacrylate (TPGDA), and pentaerythritol tetraacrylate (PPTTA). The volume ratio of the prepolymer, the first resin monomer, and the second resin monomer is (3~5):(2~4):(2~4).

[0033] In some specific embodiments of the present invention, the photoinitiator includes a first photoinitiator and a second photoinitiator; the first photoinitiator is one or two of diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO) and diaryliodonium salt; the second photoinitiator is one or two of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (819) and benzoin dimethyl ether.

[0034] In some specific embodiments of the present invention, the mass ratio of the first photoinitiator to the second photoinitiator is 1:1, and the total amount of the first photoinitiator and the second photoinitiator is 1% to 5% of the total mass of the resin; the amount of silica sol is 30% to 50% of the total mass of the resin. The total mass of the resin is the sum of the masses of the prepolymer, the first resin monomer, the second resin monomer, and the silica sol.

[0035] In some specific embodiments of the present invention, the dispersant is one or more of BYK-9076, BYK-9077, and AD-8098, and the amount of dispersant used is 3% to 5% of the total solid mass. The total solid mass is the mass of quartz fiber.

[0036] The method for preparing the quartz fiber-silica sol composite slurry of the present invention involves mixing a prepolymer, a resin monomer, and a photoinitiator to obtain a photosensitive resin system; adding quartz fiber and silica sol to the photosensitive resin system; then adding a dispersant and homogenizing at a rotation speed of 1000-2000 r / min for 3-5 min to obtain the quartz fiber-silica sol composite slurry.

[0037] In some specific embodiments of the present invention, before preparing the slurry, a pretreatment step for quartz fibers is included: heating the quartz fibers in deionized water at 90~100℃ for 2~3 hours, drying them in an oven at 60~80℃, and then treating the quartz fibers at 400~500℃ for 3~4 hours to remove the adhesive on the surface of the quartz fibers and obtain pure quartz fibers.

[0038] The present invention also provides quartz ceramics prepared based on the aforementioned quartz fiber-silica sol composite slurry, the preparation method comprising:

[0039] S1. Photopolymerization 3D printing: Using the above-mentioned quartz fiber-silica sol composite material slurry as raw material, the quartz ceramic green body is formed by DLP photopolymerization printing method.

[0040] S2. Degreasing of green body: Degreasing is performed on the quartz ceramic green body to obtain degreased quartz parts.

[0041] S3. Silica sol impregnation and sintering: The degreased quartz parts are decarburized and shaped, and then impregnated with silica sol in a vacuum environment. After drying, they are sintered. The impregnation and sintering processes are repeated several times to obtain quartz ceramics.

[0042] In some specific embodiments of the present invention, the degreasing process conditions described in S2 are as follows: under an argon atmosphere, the maximum degreasing temperature is 600~800℃, the heating rate is 0.1~0.2℃ / min, the holding time is 90~180min, and the furnace is cooled.

[0043] In some specific embodiments of the present invention, the process conditions for the decarburization and shaping treatment described in S3 are as follows: under air atmosphere, the decarburization temperature is 500~600℃, the heating rate is 0.5~0.8℃ / min, and the holding time is 90~180min.

[0044] In some specific embodiments of the present invention, the process conditions for the silica sol impregnation treatment in S3 are as follows: the decarburized sample is completely immersed in silica sol and impregnated in a vacuum environment for 2 to 5 hours.

[0045] In some specific embodiments of the present invention, the sintering process conditions described in S3 are as follows: sintering temperature of 900~1000℃ in air environment, heating rate of 0.5~1℃ / min, holding time of 120~180min, and furnace cooling. Sintering at low temperature avoids cracking due to the formation of cristobalite.

[0046] The technical solution of the present invention will be described in detail below with reference to specific embodiments and accompanying drawings. These embodiments do not constitute a limitation on the present invention.

[0047] Example 1:

[0048] 1) Quartz fiber treatment: 15 wt.% of the total slurry mass of quartz fiber was added to a beaker and heated at 100°C for 2 hours, then dried in an oven at 80°C. Afterwards, the quartz fiber was placed in a muffle furnace at 500°C for 4 hours to remove the binder on the surface of the quartz fiber, obtaining pure quartz fiber.

[0049] 2) Preparation of photocurable slurry: PUA, IBOMA, and TPGDA were mixed in a mass ratio of 2:1:1. Then, 2.5 wt.% of the total resin mass of photoinitiator TPO and 819 (TPO and 819 mass ratio 1:1) were added and mixed evenly. Pure quartz fiber from step 1), 30 wt.% of the total resin mass of silica sol, and 4 wt.% of the total solid mass of dispersant BYK-9076 were added. The mixture was homogenized at 2000 r / min for 5 min to obtain quartz photocurable slurry. The curing depth of a single layer of the slurry was 300 μm, and the curing time was 100 s. -1 The viscosity at the shear rate is 15.36 Pa. s.

[0050] 3) Photopolymerization 3D printing: Using the quartz ceramic photopolymerization slurry obtained in step 2) as raw material, the quartz ceramic green body is formed by DLP photopolymerization printing method.

[0051] 4) Degreasing of green billets: Under an argon atmosphere, the temperature is increased to 200℃ at a rate of 0.1℃ / min and held for 120 min. Then, the temperature is increased to 300℃ at a rate of 0.1℃ / min and held for 120 min. Next, the temperature is increased to 380℃ at a rate of 0.1℃ / min and held for 120 min. Then, the temperature is increased to 550℃ at a rate of 0.1℃ / min and held for 120 min. Finally, the temperature is increased to 600℃ at a rate of 0.1℃ / min and cooled with the furnace to complete the degreasing process.

[0052] 5) Silica sol impregnation sintering: In an air atmosphere, the temperature was increased to 600℃ at a rate of 0.5℃ / min and held for 120 min to remove carbon residue. In a vacuum environment, the sample was completely immersed in silica sol for 3 h. After drying, in an air atmosphere, the temperature was increased to 600℃ at a rate of 0.5℃ / min and held for 180 min. Then, the temperature was increased to 1000℃ at a rate of 1℃ / min and held for 180 min. The sample was cooled in the furnace. This impregnation sintering process was repeated four times to obtain quartz ceramic with a flexural strength of 45.3 MPa and a fracture toughness of 5.1 MPa. m 1 / 2 .

[0053] Figure 1 and Figure 2 The degreasing curve and sintering curve of Example 1 are shown respectively.

[0054] Example 2:

[0055] 1) Quartz fiber treatment: 12 wt.% of the total slurry mass of quartz fiber was added to a beaker and heated at 100°C for 3 hours, then dried in an oven at 80°C. Afterwards, the quartz fiber was placed in a muffle furnace at 450°C for 4 hours to remove the binder on the surface of the quartz fiber, obtaining pure quartz fiber.

[0056] 2) Preparation of photocurable slurry: PEA, HDDA, and TMPTA were mixed in a mass ratio of 2:2:1. Then, 3 wt.% of the total resin mass of photoinitiator TPO and 819 (TPO and 819 mass ratio 1:1) were added and mixed evenly. The pure quartz fiber from step 1), 40 wt.% of the total resin mass of silica sol, and 4 wt.% of the total solids mass of dispersant BYK-9077 were added. The mixture was homogenized at 1500 r / min for 5 min to obtain a quartz photocurable slurry. The single-layer curing depth of the slurry was 245 μm, and the curing time was 100 s. -1 The viscosity at the shear rate is 11.28 Pa. s.

[0057] 3) Photopolymerization 3D printing: Using the quartz ceramic photopolymerization slurry obtained in step 2) as raw material, the quartz ceramic green body is formed by DLP photopolymerization printing method.

[0058] 4) Degreasing of green billets: Under an argon atmosphere, the temperature is increased to 220℃ at a rate of 0.1℃ / min and held for 120 min. Then, the temperature is increased to 440℃ at a rate of 0.1℃ / min and held for 120 min. Next, the temperature is increased to 550℃ at a rate of 0.1℃ / min and held for 120 min. Then, the temperature is increased to 600℃ at a rate of 0.1℃ / min. Finally, the temperature is increased to 700℃ at a rate of 0.2℃ / min, held, and cooled in the furnace to complete the degreasing process.

[0059] 5) Silica sol impregnation sintering: In an air atmosphere, the temperature was increased to 600℃ at a rate of 0.6℃ / min and held for 120 min to remove carbon residue. In a vacuum environment, the sample was completely immersed in silica sol for 3 h. After drying, in an air atmosphere, the temperature was increased to 700℃ at a rate of 0.5℃ / min and held for 150 min, then increased to 950℃ at a rate of 1℃ / min and held for 180 min. The sample was then cooled in the furnace. This impregnation sintering process was repeated four times to obtain quartz ceramic with a flexural strength of 41.5 MPa and a fracture toughness of 4.6 MPa. m 1 / 2 .

[0060] Example 3:

[0061] 1) Quartz fiber treatment: 10 wt.% of the total slurry mass of quartz fiber was added to a beaker and heated at 100°C for 3 hours, then dried in an oven at 80°C. Afterwards, the quartz fiber was placed in a muffle furnace at 400°C for 4 hours to remove the binder on the surface of the quartz fiber, obtaining pure quartz fiber.

[0062] 2) Preparation of photocurable slurry: EA, DPHA, and PPTTA were mixed in a mass ratio of 2:1:2. Then, 2.5 wt.% of the total resin mass of photoinitiator diaryliodonium salt and benzoin dimethyl ether (mass ratio of diaryliodonium salt to benzoin dimethyl ether 1:1) were added and mixed evenly. The pure quartz fiber from step 1), 50 wt.% of the total resin mass of silica sol, and 4.5 wt.% of the total solids mass of dispersant AD-8098 were added. The mixture was homogenized at 2000 r / min for 4 min to obtain a quartz photocurable slurry. The single-layer curing depth of the slurry was 210 μm, and the curing time was 100 s. -1 The viscosity at the shear rate is 9.58 Pa. s.

[0063] 3) Photopolymerization 3D printing: Using the quartz ceramic photopolymerization slurry obtained in step 2) as raw material, the quartz ceramic green body is formed by DLP photopolymerization printing method.

[0064] 4) Degreasing of green billets: Under an argon atmosphere, the temperature is increased to 200℃ at a rate of 0.2℃ / min and held for 120 min. Then, the temperature is increased to 400℃ at a rate of 0.1℃ / min and held for 120 min. Next, the temperature is increased to 550℃ at a rate of 0.1℃ / min and held for 120 min. Then, the temperature is increased to 650℃ at a rate of 0.1℃ / min. Finally, the temperature is increased to 800℃ at a rate of 0.2℃ / min and cooled with the furnace to complete the degreasing.

[0065] 5) Silica sol impregnation sintering: In an air atmosphere, the temperature was increased to 600℃ at a rate of 0.5℃ / min and held for 120 min to remove carbon residue. In a vacuum environment, the sample was completely immersed in silica sol for 3 h, dried, and then heated to 600℃ in an air atmosphere at a rate of 0.8℃ / min and held for 120 min. Then, the temperature was increased to 900℃ at a rate of 1℃ / min and held for 150 min. The sample was then cooled in the furnace. This impregnation sintering process was repeated four times to obtain quartz ceramic with a flexural strength of 31.7 MPa and a fracture toughness of 4.3 MPa. m 1 / 2 .

[0066] Example 4:

[0067] 1) Quartz fiber treatment: 9 wt.% of the total slurry mass of quartz fiber was added to a beaker and heated at 100°C for 3 hours, then dried in an oven at 80°C. Afterwards, the quartz fiber was placed in a muffle furnace at 500°C for 3 hours to remove the binder on the surface of the quartz fiber, obtaining pure quartz fiber.

[0068] 2) Preparation of photocurable slurry: Vinyl resin, IBOMA, and TMPTA were mixed in a mass ratio of 1:1:2. Then, 3 wt.% of photoinitiator TPO and 819 (TPO and 819 mass ratio 1:1) were added to the mixture and mixed thoroughly. Pure quartz fiber from step 1), 45 wt.% of silica sol, and 3.5 wt.% of dispersant BYK-9076 were added. The mixture was homogenized at 2000 r / min for 5 min to obtain a quartz photocurable slurry. The single-layer curing depth of the slurry was 230 μm, and the curing time was 100 s. -1 The viscosity at the shear rate is 8.75 Pa. s.

[0069] 3) Photopolymerization 3D printing: Using the quartz ceramic photopolymerization slurry obtained in step 2) as raw material, the quartz ceramic green body is formed by DLP photopolymerization printing method.

[0070] 4) Degreasing of green billets: Under an argon atmosphere, the temperature is increased to 150℃ at a rate of 0.1℃ / min and held for 120 min. Then, the temperature is increased to 300℃ at a rate of 0.1℃ / min and held for 120 min. Next, the temperature is increased to 450℃ at a rate of 0.1℃ / min and held for 120 min. Then, the temperature is increased to 550℃ at a rate of 0.1℃ / min and held for 120 min. Finally, the temperature is increased to 700℃ at a rate of 0.1℃ / min and cooled with the furnace to complete the degreasing process.

[0071] 5) Silica sol impregnation sintering: In an air atmosphere, the temperature was increased to 550℃ at a rate of 0.5℃ / min and held for 120 min to remove carbon residue. In a vacuum environment, the sample was completely immersed in silica sol for 3 h, dried, and then heated to 550℃ in an air atmosphere at a rate of 0.5℃ / min and held for 120 min. Then, the temperature was increased to 1000℃ at a rate of 1℃ / min and held for 120 min. The sample was cooled in the furnace, and the impregnation sintering was repeated four times to obtain quartz ceramic with a flexural strength of 39.7 MPa and a fracture toughness of 3.8 MPa. m 1 / 2 .

[0072] Example 5:

[0073] 1) Quartz fiber treatment: 13 wt.% of the total slurry mass of quartz fiber was added to a beaker and heated at 100°C for 2.5 hours, then dried in an oven at 80°C. The quartz fiber was then placed in a muffle furnace at 500°C for 4 hours to remove the binder on the surface of the quartz fiber, obtaining pure quartz fiber.

[0074] 2) Preparation of photocurable slurry: PEA, DPHA, and TPGDA were mixed in a mass ratio of 2:2:1. Then, 2.5 wt.% of the total resin mass of photoinitiator diaryliodonium salt and 819 (diaryliodonium salt and 819 mass ratio 1:1) were added and mixed evenly. Pure quartz fiber from step 1), 40 wt.% of the total resin mass of silica sol, and 5 wt.% of the total solid mass of dispersant BYK-9077 were added. The mixture was homogenized at 1500 r / min for 5 min to obtain quartz photocurable slurry. The single-layer curing depth of the slurry was 225 μm, and the curing time was 100 s. -1 The viscosity at the shear rate is 13.96 Pa. s.

[0075] 3) Photopolymerization 3D printing: Using the quartz ceramic photopolymerization slurry obtained in step 2) as raw material, the quartz ceramic green body is formed by DLP photopolymerization printing method.

[0076] 4) Degreasing of green billets: Under an argon atmosphere, the temperature is increased to 180℃ at a rate of 0.1℃ / min and held for 120 min. Then, the temperature is increased to 320℃ at a rate of 0.1℃ / min and held for 120 min. Next, the temperature is increased to 440℃ at a rate of 0.1℃ / min and held for 120 min. Then, the temperature is increased to 540℃ at a rate of 0.1℃ / min and held for 120 min. Finally, the temperature is increased to 750℃ at a rate of 0.1℃ / min and cooled with the furnace to complete the degreasing process.

[0077] 5) Silica sol impregnation sintering: In an air atmosphere, the temperature was increased to 600℃ at a rate of 0.8℃ / min and held for 120 min to remove carbon residue. In a vacuum environment, the sample was completely immersed in silica sol for 3 h. After drying, in an air atmosphere, the temperature was increased to 600℃ at a rate of 0.8℃ / min and held for 150 min, then increased to 950℃ at a rate of 1℃ / min and held for 180 min. The sample was then cooled in the furnace. This impregnation sintering process was repeated four times to obtain quartz ceramic with a flexural strength of 43.6 MPa and a fracture toughness of 4.6 MPa. m 1 / 2 .

[0078] Example 6:

[0079] Compared to Example 1, the quartz fiber content was replaced with 13 wt.%, while other parameters and processes remained unchanged. The photocurable slurry prepared in this way cured within 100 seconds. -1 The viscosity at the shear rate is 10.20 Pa. The fracture toughness of the final sintered sample was 4.9 MPa. m 1 / 2 .

[0080] Example 7:

[0081] Compared to Example 1, the quartz fiber content was replaced with 11 wt.%, while other parameters and processes remained unchanged. The photocurable slurry prepared in this way cured within 100 seconds. -1 The viscosity at the shear rate is 8.75 Pa. The fracture toughness of the final sintered sample was 4.8 MPa. m 1 / 2 .

[0082] Example 8:

[0083] Compared to Example 1, the quartz fiber content was replaced with 9 wt.%, while other parameters and processes remained unchanged. The photocurable slurry prepared in this way cured within 100 seconds. -1 The viscosity at the shear rate is 7.54 Pa. The fracture toughness of the final sintered sample was 4.2 MPa. m1 / 2 .

[0084] Example 9:

[0085] By replacing the quartz fiber content with 7 wt.%, while keeping other parameters and processes unchanged, the prepared photocurable slurry cured for 100 seconds... -1 The viscosity at the shear rate is 5.38 Pa. The fracture toughness of the final sintered sample was 3.9 MPa. m 1 / 2 .

[0086] Comparative Example 1

[0087] The difference from Example 1 is that the silica sol was replaced with fused silica powder, and the silica fiber content was reduced to 4 wt.%.

[0088] The quartz photocurable slurry prepared in Comparative Example 1 had a single-layer curing depth of 1138 μm and a curing time of 100 s. -1 The viscosity at the shear rate is 103.8 Pa. When silica sol is replaced with fused silica powder, the viscosity of the fused silica ceramic slurry increases rapidly with the addition of quartz fibers. The quartz fiber content must be controlled at a low level; otherwise, the ceramic slurry is difficult to prepare successfully. Furthermore, due to the increased single-layer curing depth, significant over-curing occurs during printing, especially for complex structures, which greatly affects molding accuracy. High slurry viscosity also significantly impacts printing success rate. The prepared quartz ceramic exhibits a flexural strength of 27.3 MPa and a fracture toughness of 1.83 MPa. m 1 / 2 The values ​​were all significantly lower than those in Example 1.

[0089] Comparing Example 1 with Examples 6-9 and Comparative Example 1, it can be seen that although the quartz fiber content in the method of the present invention has a certain influence on the viscosity of the photocurable slurry and the fracture toughness of the ceramic, under the same quartz fiber content, the viscosity of the photocurable slurry in the embodiments of the present invention is much lower than that in Comparative Example 1 which uses fused silica powder. Therefore, when using silica sol, a lower viscosity of the photocurable slurry can be obtained at a higher quartz fiber content.

Claims

1. A quartz fiber-silica sol composite slurry, characterized in that, include: The slurry comprises quartz fiber, silica sol, photosensitive resin system, and dispersant; wherein the mass of the quartz fiber is 5% to 15% of the total mass of the slurry; and the total mass of the slurry is the sum of the masses of the quartz fiber, silica sol, photosensitive resin system, and dispersant.

2. The quartz fiber-silica sol composite slurry according to claim 1, characterized in that, The amount of silica sol used is 30% to 50% of the total resin mass; the total resin mass is the sum of the masses of the prepolymer, resin monomers and silica sol.

3. The quartz fiber-silica sol composite slurry according to claim 1, characterized in that, The photosensitive resin system includes a prepolymer, a resin monomer, and a photoinitiator.

4. The quartz fiber-silica sol composite slurry according to claim 3, characterized in that, The prepolymer is one or more of epoxy acrylate, polyurethane acrylate, polyester acrylate, polyether acrylate and vinyl resin.

5. The quartz fiber-silica sol composite slurry according to claim 3, characterized in that, The resin monomers include a first resin monomer and a second resin monomer; the first resin monomer is one or more of 1,6-hexanediol diacrylate, isobornyl methacrylate, and pentaerythritol hexaacrylate; the second resin monomer is one or more of trimethylolpropane triacrylate, tripropylene glycol diacrylate, and pentaerythritol tetraacrylate.

6. The quartz fiber-silica sol composite slurry according to claim 5, characterized in that, The photoinitiator includes a first photoinitiator and a second photoinitiator; the first photoinitiator is one or both of diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide and diaryliodomonium salt; the second photoinitiator is one or both of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide and benzoin dimethyl ether.

7. The quartz fiber-silica sol composite slurry according to claim 1, wherein the dispersant is one or more of BYK-9076, BYK-9077 and AD-8098, and the amount of dispersant is 3% to 5% of the mass of quartz fiber.

8. A method for preparing the quartz fiber-silica sol composite slurry according to any one of claims 1 to 7, characterized in that, A photosensitive resin system is obtained by mixing prepolymer, resin monomer, and photoinitiator; quartz fiber and silica sol are added to the photosensitive resin system, then a dispersant is added and homogenized to obtain a quartz fiber-silica sol composite slurry.

9. A method for preparing quartz ceramics, characterized in that, include: S1. Using the quartz fiber-silica sol composite material slurry as described in any one of claims 1 to 8 as raw material, a photopolymerization 3D printing method is used to form a quartz ceramic green body; S2. Degrease the quartz ceramic green body to obtain a degreased quartz part; S3. The quartz degreased parts are decarburized and shaped, and then impregnated with silica sol in a vacuum environment. After drying, they are sintered to obtain quartz ceramics.

10. The method for preparing quartz ceramics according to claim 9, characterized in that, The decarburization and shaping process conditions described in S3 are as follows: under air atmosphere, the decarburization temperature is 500~600℃, the heating rate is 0.5~0.8℃ / min, and the holding time is 90min~180min.

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