Quartz fiber-silica sol composite material slurry and preparation method thereof, and quartz ceramic preparation method

Abstract

The invention provides quartz fiber-silica sol composite material slurry and a preparation method thereof, 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 dispersant; wherein 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 mass of the quartz fiber, the silica sol, the photosensitive resin system and the dispersing agent. The problem that the viscosity of the ceramic slurry is too high due to excessive quartz fibers in the presence of quartz particles is avoided, and the silica sol is used for replacing the quartz particles, so that the addition amount of the quartz fibers is greatly increased, and the aim of toughening the ceramic is fulfilled.

Description

Technical Field

[0001] The invention belongs to the field of quartz ceramics, and relates to a quartz fiber-silica sol composite material slurry and a preparation method thereof, and a quartz ceramic preparation method. Background Art

[0002] Radar radome is a protective device for aircraft radar antennas, which has wave-transmitting, load-bearing and temperature-resistant properties. Quartz ceramics has become one of the main candidate materials for radomes due to its low thermal expansion coefficient, good thermal shock resistance, excellent dielectric properties and thermal shock resistance. However, the traditional quartz radome preparation often adopts the fiber weaving plus silica sol impregnation and sintering process. This process is time-consuming, technically demanding, labor-intensive and cannot manufacture complex structural parts such as honeycomb structures. Therefore, the ceramic photocuring molding process has become a boon for the preparation of quartz antenna covers.

[0003] However, the quartz ceramics prepared by photocuring are currently brittle and have low fracture toughness, which limits their application in actual production. In order to solve this problem, a common method is to add chopped fibers to the ceramic matrix, and hinder the expansion and further formation of cracks through fiber bridging, pull-out and fracture, as well as crack deflection, so as to achieve the purpose of toughening. Quartz fiber reinforced quartz ceramics not only retain the original characteristics of its ceramic matrix, but also effectively overcome the sensitivity of brittle ceramic materials to cracks. Quartz ceramics reinforced by quartz fibers not only have stable dielectric properties, but also have the effect of toughening and strengthening. However, the introduction of quartz fibers increases the viscosity of ceramic slurry. The higher the quartz fiber content, the greater the viscosity of the slurry. This makes it more difficult to flatten the scraper during photocuring 3D printing, and the sample is easy to fall off the forming table, affecting the success rate of printing. Therefore, in the process of preparing photocuring ceramic slurry, the quartz fiber content is generally only about 2wt.% to 6wt.%, and the toughening effect is poor. The highest flexural strength of fused quartz ceramics produced by 3D printing reported so far is 28.9 MPa, which is relatively poor. The fracture toughness of ordinary fused quartz ceramics is between 0.6 and 0.8 MPa·m 1 / 2 However, the fracture toughness of quartz fiber reinforced fused silica has not been reported. Summary of the invention

[0004] In order to solve the problems of the above-mentioned prior art, the present invention provides a quartz fiber-silica sol composite material slurry and a preparation method thereof and a quartz ceramic preparation method, which avoids the problem of high viscosity of the ceramic slurry caused by excessive quartz fibers in the presence of quartz particles, and utilizes silica sol instead of quartz particles to greatly increase the addition amount of quartz fibers, thereby achieving the purpose of ceramic toughening.

[0005] The present invention is achieved through the following technical solutions:

[0006] A quartz fiber-silica sol composite material slurry comprises: 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, the photosensitive resin system and the dispersant.

[0007] Preferably, the amount of the 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 resin monomer and the silica sol.

[0008] Preferably, the photosensitive resin system comprises 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 dipentaerythritol 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 2,4,6 (trimethylbenzoyl) diphenyl phosphine oxide and diaryl iodonium salt; the second photoinitiator is one or both of phenyl bis (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 the dispersant used is 3% to 5% of the mass of the quartz fiber.

[0013] The method for preparing the quartz fiber-silica sol composite material slurry comprises 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, and then adding a dispersant and homogenizing to obtain the quartz fiber-silica sol composite material slurry.

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

[0015] S1. Using the quartz fiber-silica sol composite material slurry as a raw material, a photocuring 3D printing method is used for molding to obtain a quartz ceramic green body;

[0016] S2, degreasing the quartz ceramic green body to obtain a degreased quartz part;

[0017] S3, decarburizing and shaping the degreased quartz parts, and impregnating them with silica sol in a vacuum environment, and then sintering them after drying to obtain quartz ceramics.

[0018] Preferably, the process conditions of the decarburization and shaping treatment in S3 are: under air atmosphere, the decarburization temperature is 500-600° C., the heating rate is 0.5-0.8° C. / min, and the holding time is 90min-180min.

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

[0020] The present invention proposes a new ceramic toughening idea that can significantly increase the content of quartz fiber, that is, using high-content quartz fiber and silica sol as the main slurry. Although the quartz fiber content is relatively high, the prepared quartz fiber-silica sol composite material slurry still has a low viscosity. -1 The viscosity at the shear rate is 8.75~15.36Pa·s, which is more conducive to photocuring 3D printing and has a high printing success rate. In addition to acting as a part of the ceramic matrix, the addition of silica sol can also play a role in regulating the curing depth because it does not participate in the cross-linking curing reaction. Too high a curing depth will affect the printing accuracy, and too low a curing depth will cause problems with the interlayer bonding. Generally, the curing depth suitable for printing is between 150 and 300μm. Fused quartz itself has high light transmittance and is easy to cure, resulting in a high curing depth. The addition of silica sol can reduce the curing depth. The curing depth of quartz fiber-silica sol composite material slurry is 200~300μm. High quartz fiber content can make the prepared sample have better fracture toughness, and the subsequent impregnation process can improve the overall flexural strength of the sample. The fracture toughness of the sample obtained from the slurry of the present invention is 3.8~5.1MPa·m 1 / 2 (far exceeding the fracture toughness of existing photocurable 3D printed quartz ceramics of 0.6-0.8MPa·m 1 / 2 ), and the bending strength is 31.7-45.3Mpa. Therefore, the present invention abandons the conventional idea of ​​using ceramic powder as the main body and chopped fibers as the additive phase, and regards the combination of quartz fiber and silica sol as the main body, thereby avoiding the problem of excessive viscosity caused by too much fiber, thereby greatly increasing the amount of quartz fiber added, and achieving the purpose of ceramic toughening through fiber bridging, pulling out and crack deflection.

[0021] The preparation method of quartz ceramics of the present invention uses the above-mentioned quartz fiber-silica sol composite material slurry as raw material and is prepared by a light-curing 3D printing method. As mentioned above, the present invention uses a high-content quartz fiber and a silica sol blend as the slurry body. The quartz fiber content is relatively high, which can make the prepared sample have better fracture toughness. At the same time, because the quartz powder is replaced by silica sol, the viscosity of the slurry obtained by the high-content quartz fiber is still reduced, which is convenient for light-curing 3D printing. In the case of a high-content quartz fiber, quartz ceramic products can still be successfully prepared, and the fracture toughness of the products can also be further improved. The method of the present invention further obtains ceramic samples with better performance by immersing in silica sol.

[0022] Furthermore, after the quartz ceramic green body of the present invention is degreased, it is decarburized and shaped at 500-600° C. This step is to remove the carbon residue produced by degreasing in an argon atmosphere, and to increase the strength of the sample by sintering at a certain temperature, in preparation for silica sol impregnation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 This is the degreasing curve of the quartz workpiece made by the light-curing molding technology in Example 1;

[0025] Figure 2 This is the sintering curve of the quartz product made by the photo-stereolithography technology in Example 1. DETAILED DESCRIPTION

[0026] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways 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 devices not specifically specified in the following embodiments are all conventional equipment or devices in the art.

[0028] It should be noted that the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices. Moreover, unless otherwise specified, the numbering of each method step is only a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or to define the scope of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the present invention without substantially changing the technical content.

[0029] The quartz fiber-silica sol composite material 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 both of 2,4,6 (trimethylbenzoyl) diphenyl phosphine oxide (TPO) and diaryl iodonium salts; the second photoinitiator is one or both of phenyl bis (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 the 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 the dispersant is 3% to 5% of the total solid mass. The total solid mass is the mass of the quartz fiber.

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

[0037] In some specific embodiments of the present invention, before preparing the slurry, a quartz fiber pretreatment step is also included: the quartz fiber is heated in deionized water at 90-100°C for 2-3 hours, and then dried in an oven at 60-80°C, and then the quartz fiber is placed at 400-500°C for 3-4 hours to remove the adhesive on the surface of the quartz fiber to obtain pure quartz fiber.

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

[0039] S1. Photocuring 3D printing: using the above-mentioned quartz fiber-silica sol composite material slurry as raw material, adopting DLP photocuring printing method to form, and obtaining quartz ceramic green body.

[0040] S2, green body degreasing: degreasing the quartz ceramic green body to obtain a degreased quartz part.

[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 process conditions of the degreasing treatment described in S2 are: under argon atmosphere, the maximum degreasing temperature is 600-800°C, the heating rate is 0.1-0.2°C / min, the insulation time is 90-180min, and the furnace is cooled.

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

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

[0045] In some specific embodiments of the present invention, the process conditions of the sintering treatment in S3 are: in an air environment, the sintering temperature is 900-1000°C, the heating rate is 0.5-1°C / min, the holding time is 120-180min, and the furnace is cooled. Sintering at a low temperature avoids cracks caused by the formation of cristobalite.

[0046] The technical solution of the present invention is described in detail below in conjunction with specific embodiments and drawings, and this embodiment does not limit the present invention.

[0047] Embodiment 1:

[0048] 1) Quartz fiber treatment: 15wt.% of the total mass of the slurry was added to a beaker, heated at 100°C for 2 hours, and 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 to obtain pure quartz fiber.

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

[0050] 3) Photocuring 3D printing: using the quartz ceramic photocuring slurry obtained in step 2) as a raw material, DLP photocuring printing method is used for molding to obtain a quartz ceramic green body.

[0051] 4) Degreasing of green body: Under argon atmosphere, heat to 200℃ at a rate of 0.1℃ / min, keep warm for 120min, then heat to 300℃ at a rate of 0.1℃ / min, keep warm for 120min, then heat to 380℃ at a rate of 0.1℃ / min, keep warm for 120min, then heat to 550℃ at a rate of 0.1℃ / min, keep warm for 120min, finally heat to 600℃ at a rate of 0.1℃ / min, cool with the furnace to complete degreasing.

[0052] 5) Silica sol impregnation sintering: In air atmosphere, the temperature was raised to 600°C at a rate of 0.5°C / min and kept for 120min to remove carbon residue; in a vacuum environment, the sample was completely immersed in silica sol for 3h, dried, and then heated to 600°C at a rate of 0.5°C / min in air atmosphere, kept for 180in, then heated to 1000°C at a rate of 1°C / min, kept for 180min, cooled with the furnace, and the impregnation sintering was repeated 4 times to obtain quartz ceramics with a flexural strength of 45.3MPa and a fracture toughness of 5.1MPa·m 1 / 2 .

[0053] Figure 1 and Figure 2 They are the debinding curve and sintering curve of Example 1 respectively.

[0054] Embodiment 2:

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

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

[0057] 3) Photocuring 3D printing: using the quartz ceramic photocuring slurry obtained in step 2) as a raw material, DLP photocuring printing method is used for molding to obtain a quartz ceramic green body.

[0058] 4) Degreasing of green body: Under argon atmosphere, heat to 220℃ at a rate of 0.1℃ / min, keep warm for 120min, then heat to 440℃ at a rate of 0.1℃ / min, keep warm for 120min, then heat to 550℃ at a rate of 0.1℃ / min, keep warm for 120min, then heat to 600℃ at a rate of 0.1℃ / min, finally heat to 700℃ at a rate of 0.2℃ / min, keep warm and cool in the furnace to complete degreasing.

[0059] 5) Silica sol impregnation sintering: In air atmosphere, the temperature was raised to 600°C at a rate of 0.6°C / min and kept for 120 minutes to remove carbon residue; in a vacuum environment, the sample was completely immersed in silica sol for 3 hours, and after drying, the temperature was raised to 700°C at a rate of 0.5°C / min in air atmosphere, kept for 150 minutes, and then raised to 950°C at a rate of 1°C / min, kept for 180 minutes, and cooled with the furnace. The impregnation sintering was repeated 4 times to obtain quartz ceramics with a flexural strength of 41.5MPa and a fracture toughness of 4.6MPa·m 1 / 2 .

[0060] Embodiment 3:

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

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

[0063] 3) Photocuring 3D printing: using the quartz ceramic photocuring slurry obtained in step 2) as a raw material, DLP photocuring printing method is used for molding to obtain a quartz ceramic green body.

[0064] 4) Degreasing of green body: Under argon atmosphere, heat to 200℃ at a rate of 0.2℃ / min, keep warm for 120min, then heat to 400℃ at a rate of 0.1℃ / min, keep warm for 120min, then heat to 550℃ at a rate of 0.1℃ / min, keep warm for 120min, then heat to 650℃ at a rate of 0.1℃ / min, finally heat to 800℃ at a rate of 0.2℃ / min, cool with the furnace to complete degreasing.

[0065] 5) Silica sol impregnation sintering: In air atmosphere, the temperature was raised to 600°C at a rate of 0.5°C / min and kept for 120 minutes to remove carbon residue; in a vacuum environment, the sample was completely immersed in silica sol for 3 hours, and after drying, the temperature was raised to 600°C at a rate of 0.8°C / min in air atmosphere, kept for 120 minutes, and then raised to 900°C at a rate of 1°C / min, kept for 150 minutes, and cooled with the furnace. The impregnation sintering was repeated 4 times to obtain quartz ceramics with a flexural strength of 31.7MPa and a fracture toughness of 4.3MPa·m 1 / 2 .

[0066] Embodiment 4:

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

[0068] 2) Preparation of photocurable slurry: vinyl resin, IBOMA and TMPTA in a mass ratio of 1:1:2 were mixed, and then 3 wt.% of the total mass of the resin as photoinitiator TPO and 819 (TPO and 819 mass ratio 1:1) were added respectively and mixed evenly; the pure quartz fiber in step 1), 45 wt.% of the total mass of the resin as silica sol and 3.5 wt.% of the total solid mass as dispersant BYK-9076 were added, and homogenized at a speed of 2000 r / min for 5 min using a homogenizer to obtain a quartz photocurable slurry, and the slurry single layer curing depth was 230 μm, 100 s -1 The viscosity at the shear rate is 8.75 Pa·s.

[0069] 3) Photocuring 3D printing: using the quartz ceramic photocuring slurry obtained in step 2) as a raw material, DLP photocuring printing method is used for molding to obtain a quartz ceramic green body.

[0070] 4) Degreasing of green body: Under argon atmosphere, heat to 150℃ at a rate of 0.1℃ / min, keep warm for 120min, then heat to 300℃ at a rate of 0.1℃ / min, keep warm for 120min, then heat to 450℃ at a rate of 0.1℃ / min, keep warm for 120min, then heat to 550℃ at a rate of 0.1℃ / min, keep warm for 120min, finally heat to 700℃ at a rate of 0.1℃ / min, cool with the furnace to complete degreasing.

[0071] 5) Silica sol impregnation sintering: In air atmosphere, the temperature was raised to 550°C at a rate of 0.5°C / min and kept for 120 minutes to remove carbon residue; in a vacuum environment, the sample was completely immersed in silica sol for 3 hours, and after drying, the temperature was raised to 550°C at a rate of 0.5°C / min in air atmosphere, kept for 120 minutes, and then raised to 1000°C at a rate of 1°C / min, kept for 120 minutes, and cooled with the furnace. The impregnation sintering was repeated for a total of 4 times to obtain quartz ceramics with a flexural strength of 39.7MPa and a fracture toughness of 3.8MPa·m 1 / 2 .

[0072] Embodiment 5:

[0073] 1) Quartz fiber treatment: 13 wt.% of the total mass of the slurry was added to a beaker, heated at 100°C for 2.5 hours, and 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 to obtain pure quartz fiber.

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

[0075] 3) Photocuring 3D printing: using the quartz ceramic photocuring slurry obtained in step 2) as a raw material, DLP photocuring printing method is used for molding to obtain a quartz ceramic green body.

[0076] 4) Degreasing of green body: Under argon atmosphere, heat to 180℃ at a rate of 0.1℃ / min, keep warm for 120min, then heat to 320℃ at a rate of 0.1℃ / min, keep warm for 120min, then heat to 440℃ at a rate of 0.1℃ / min, keep warm for 120min, then heat to 540℃ at a rate of 0.1℃ / min, keep warm for 120min, finally heat to 750℃ at a rate of 0.1℃ / min, cool with the furnace to complete degreasing.

[0077] 5) Silica sol impregnation sintering: In air atmosphere, the temperature was raised to 600°C at a rate of 0.8°C / min and kept for 120 minutes to remove carbon residue; in a vacuum environment, the sample was completely immersed in silica sol for 3 hours, and after drying, the temperature was raised to 600°C at a rate of 0.8°C / min in air atmosphere, kept for 150 minutes, and then raised to 950°C at a rate of 1°C / min, kept for 180 minutes, and cooled with the furnace. The impregnation sintering was repeated 4 times to obtain quartz ceramics with a flexural strength of 43.6MPa and a fracture toughness of 4.6MPa·m 1 / 2 .

[0078] Embodiment 6:

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

[0080] Embodiment 7:

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

[0082] Embodiment 8:

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

[0084] Embodiment 9:

[0085] The content of quartz fiber was replaced with 7wt.%, and the other parameters and processes remained unchanged. The photocurable slurry prepared in this way was -1 The viscosity at the shear rate is 5.38Pa·s, and the fracture toughness of the sintered sample is 3.9MPa·m 1 / 2 .

[0086] Comparative Example 1

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

[0088] The quartz photocuring slurry prepared in this comparative example 1 has a single-layer curing depth of 1138 μm and a curing time of 100 s. -1 The viscosity at a shear rate of 103.8Pa·s. When the silica sol is replaced with fused quartz powder, the viscosity of the fused quartz ceramic slurry increases rapidly with the addition of quartz fiber. The content of quartz fiber can only be controlled at a low level, otherwise it is difficult to successfully prepare the ceramic slurry; in addition, due to the increase in the single-layer solidification depth, there is an obvious over-curing phenomenon during the printing process, especially for the printing of complex structural parts, which has a greater impact on the molding accuracy, and the high slurry viscosity also has a great impact on the success rate of printing. The flexural strength of the prepared quartz ceramic is 27.3MPa, and the fracture toughness is 1.83MPa·m 1 / 2 , are significantly lower than Example 1.

[0089] By 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 condition, the viscosity of the photocurable slurry of the embodiment of the present invention is much lower than that of Comparative Example 1 using fused quartz powder. Therefore, when silica sol is used, a lower photocurable slurry viscosity can be obtained at a higher quartz fiber content.

Claims

1. A quartz fiber-silica sol composite material slurry, characterized in that: include: 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.

2. The quartz fiber-silica sol composite material slurry according to claim 1, characterized in that: The amount of the 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 resin monomer and the silica sol.

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

4. The quartz fiber-silica sol composite material 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 material slurry according to claim 3, characterized in that: 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 dipentaerythritol 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 material slurry according to claim 5, characterized in that: The photoinitiator comprises a first photoinitiator and a second photoinitiator; the first photoinitiator is one or both of 2,4,6 (trimethylbenzoyl) diphenylphosphine oxide and diaryl iodonium salt; the second photoinitiator is one or both of phenyl bis (2,4,6-trimethylbenzoyl) phosphine oxide and benzoin dimethyl ether.

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

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

9. A method for preparing quartz ceramics, characterized in that: include: S1. Using the quartz fiber-silica sol composite material slurry according to any one of claims 1 to 8 as a raw material, forming it by a light-curing 3D printing method to obtain a quartz ceramic green body; S2, degreasing the quartz ceramic green body to obtain a degreased quartz part; S3, decarburizing and shaping the degreased quartz parts, and impregnating them with silica sol in a vacuum environment, and then sintering them after drying to obtain quartz ceramics.

10. The method for preparing quartz ceramics according to claim 9, characterized in that: The process conditions of the decarburization and shaping treatment in S3 are: under air atmosphere, the decarburization temperature is 500-600°C, the heating rate is 0.5-0.8°C / min, and the insulation time is 90min-180min.

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