Quartz / quartz composite ceramic repair paste and preparation method thereof

Abstract

The present invention belongs to the technical field of ceramic post-processing, and specifically relates to a quartz / quartz composite ceramic repair paste and a preparation method thereof. The present invention precisely adjusts the ratio of raw materials such as methyltrimethoxysilane, DP-SiO2 nanopowder, and KH560 coupling agent to enable the components to work synergistically. The main bonding phase, methyltrimethoxysilane, provides basic bonding strength, while the reduced-efficiency DP-SiO2 nanopowder is evenly dispersed as a reinforcing phase. The KH560 coupling agent optimizes interfacial compatibility. The three cooperate with each other and are combined with a dual-curing treatment to make the matrix structure denser and the intermolecular force stronger. This reduces the amount of raw materials used while achieving a comprehensive improvement in the overall performance of the repair paste.

Description

Technical Field

[0001] The invention belongs to the technical field of ceramic post-processing, and particularly relates to a quartz / quartz composite ceramic repair paste and a preparation method thereof. Background Art

[0002] Quartz / quartz composite ceramics are new high temperature resistant materials made from high purity quartz fiber fabrics and silica sol through sol-gel process. They have a typical low thermal expansion coefficient (0.54×10 -6 Due to its high thermal conductivity (0.6-0.8 W / m·K), low dielectric constant (2.8-3.2), and excellent thermal shock stability (maintaining structural stability above 1200°C), it is widely used in the aerospace field. It is primarily used in the manufacture of components such as missile nose cones, satellite antenna covers, and communication windows for hypersonic vehicles. In recent years, the introduction of reinforcements such as Si3N4 fibers and Al2O3 fibers has further enhanced the material's overall strength to meet the extreme environmental demands of aerospace. However, due to its inherent brittleness, quartz / quartz composite ceramics are prone to damage such as scratches, chips, and chipping during production, assembly between products and antennas or metal compartments, circulation, and service. High-performance repair materials are urgently needed for repair.

[0003] Currently, conventional ceramic repair pastes generally suffer from poor mechanical properties, poor thixotropic properties, and insufficient durability. Furthermore, existing repair pastes have a single curing mechanism, often relying on a single hydrolysis reaction, resulting in weak interfacial bonding, high curing temperatures, and long curing times, further limiting their application. Therefore, developing a ceramic repair paste that combines high performance, low cost, long life, and simple curing conditions has become an urgent challenge for the industry. Summary of the Invention

[0004] The purpose of the present invention is to provide a quartz / quartz composite ceramic repair paste in view of the existing problems.

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

[0006] A method for preparing a quartz / quartz composite ceramic repair paste comprises the following steps:

[0007] S1. Add acidic silica sol into a three-necked flask, then add pure water, stir and mix well, and heat in a water bath to 50-60°C;

[0008] S2. After uniformly mixing anhydrous ethanol and a silane coupling agent, add the mixture to the three-necked flask in step S1, react at 50-60°C for 4-5 hours, and then increase the temperature to continue the reaction;

[0009] S3. Cool down to 25-30°C, mix methyltrimethoxysilane and silane coupling agent, add to a three-necked flask, and stir at room temperature;

[0010] S4. Pour the product obtained in step S3 into an open plastic bucket, add the pre-mixed DP-SiO2 nanopowder and triethyl borate, and disperse it using a high-speed disperser for 5 to 10 minutes;

[0011] S5. The paste obtained after dispersion is subjected to gradient solidification.

[0012] Furthermore, the mass ratio of the acidic silica sol to pure water in step S1 is (6-7):1;

[0013] The pH value of the acidic silica sol is 2-4, and the particle size is 8-80 nm.

[0014] Furthermore, the mass ratio of anhydrous ethanol to the silane coupling agent in step S2 is 1:(0.5~1);

[0015] The silane coupling agent is KH560;

[0016] The amount of anhydrous ethanol added is 10-12% of the total mass of acidic silica sol and pure water;

[0017] The temperature after heating is 85-95° C., and the reaction time is 2-3 h.

[0018] Furthermore, the mass ratio of methyltrimethoxysilane to the silane coupling agent in step S3 is (18-20):1;

[0019] The silane coupling agent is KH560;

[0020] The amount of methyltrimethoxysilane added is 1.2 to 1.3 times the mass of the acidic silica sol.

[0021] Furthermore, when the pre-mixed DP-SiO2 nanopowder and triethyl borate are mixed in step S4, the mass of the DP-SiO2 nanopowder is 10 to 12 times that of the triethyl borate;

[0022] The addition amount of DP-SiO2 nanopowder is 0.04~0.046 times the mass of acidic silica sol;

[0023] The high-speed disperser has a dispersing speed of 2500-3500 r / min.

[0024] Furthermore, the preparation of the DP-SiO2 nanopowder described in step S4 comprises the following steps:

[0025] (1) Disperse fumed silica powder in acidic silica sol, stir under ultrasonication for 20-30 min, and then place in a water bath at 60-70°C for 2-3 h to form a silanol activation layer.

[0026] (2) After uniformly mixing anhydrous ethanol and a silane coupling agent, add the mixture to the product of step (1), and reflux at 80-90°C for 4-5 hours under nitrogen protection to complete the grafting of epoxy groups;

[0027] (3) The product of step (2) is centrifuged and washed with ethanol for 3 to 4 times, and then vacuum-dried at a temperature of 60 to 80° C. to obtain DP-SiO 2 nanopowder.

[0028] Furthermore, the mass ratio of the fumed silica powder to the acidic silica sol in step (1) is 1:(0.3-0.4);

[0029] The pH value of the acidic silica sol is 2-3.

[0030] Furthermore, the mass ratio of anhydrous ethanol to the silane coupling agent in step (2) is 1:(0.5~1);

[0031] The silane coupling agent is KH560;

[0032] The added amount of the anhydrous ethanol is 0.4 to 0.5 times that of the fumed silica powder.

[0033] Furthermore, the gradient solidification in step S5 is divided into two stages:

[0034] The first stage: Si-OCH3 hydrolysis reaction at 45-55 °C for 0.5-1.5 h;

[0035] The second stage: heating to 85~95℃ and carrying out epoxy ring-opening polymerization for 1.5~2.5 hours.

[0036] Compared with the prior art, the present invention has the following advantages:

[0037] 1. This invention precisely adjusts the raw material ratios of methyltrimethoxysilane, DP-SiO2 nanopowder, and KH560 coupling agent to achieve synergistic effects. Methyltrimethoxysilane, the primary binder, provides foundational adhesion, while the reduced-volume, high-efficiency DP-SiO2 nanopowder is uniformly dispersed as a reinforcing phase. KH560 coupling agent optimizes interfacial compatibility. The three components work together, combined with a dual-curing process, to create a denser matrix structure and enhance intermolecular forces. This reduces raw material usage while improving the overall performance of the repair paste.

[0038] 2. The fumed silica of the present invention is first inorganically pre-coated with acidic silica sol to form a dense Si-O-Si network on the particle surface, effectively inhibiting the agglomeration of nanoparticles and improving dispersibility. Then, the KH560 coupling agent is organically grafted to orient the epoxy groups outward. When the repair paste contacts the quartz ceramic substrate, the epoxy groups can undergo ring-opening polymerization with the active groups on the substrate surface to form strong chemical bonds, achieving strong interfacial bonding between the nanoparticles and the substrate, thereby enhancing the mechanical properties of the repair paste.

[0039] 3. After dispersion in a high-speed disperser, the present invention performs a gradient curing process on the paste. In the first stage, the Si-OCH3 groups of methyltrimethoxysilane hydrolyze to form silanol groups (Si-OH), which initially build a matrix network through a condensation reaction. In the second stage, the epoxy groups grafted onto the DP-SiO2 surface undergo ring opening at high temperatures, undergoing polymerization reactions with silanol groups or other active groups, further cross-linking and curing. This dual curing process creates a denser matrix structure and strengthens intermolecular forces, thereby enhancing the overall strength, durability, and interfacial bonding of the repair paste. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a real picture of the repair paste;

[0041] Figure 2 Comparison pictures of the quartz / quartz composite ceramic antenna window before, during and after repair. DETAILED DESCRIPTION

[0042] In order to further explain the present invention, it is described below with reference to the following specific embodiments.

[0043] Example 1

[0044] A method for preparing a quartz / quartz composite ceramic repair paste comprises the following steps:

[0045] S1. Add acidic silica sol into a three-necked flask, then add pure water, stir and mix well, and heat in a water bath to 50°C;

[0046] The mass ratio of acidic silica sol to pure water is 6:1;

[0047] S2. After uniformly mixing anhydrous ethanol and silane coupling agent KH560 in a mass ratio of 1:0.5, add the mixture to the three-necked flask in step S1, react at 50°C for 4 h, then heat to 85°C and continue to react for 2 h;

[0048] The amount of anhydrous ethanol added is 10% of the total mass of acidic silica sol and pure water;

[0049] S3. Cool down to 25°C, mix methyltrimethoxysilane and silane coupling agent KH560 in a mass ratio of 18:1, add to a three-necked flask, and stir at room temperature;

[0050] The amount of methyltrimethoxysilane added is 1.2 times the mass of the acidic silica sol;

[0051] S4. Pour the product obtained in step S3 into an open plastic bucket, add pre-mixed DP-SiO2 nanopowder and triethyl borate (the mass of DP-SiO2 nanopowder is 10 times that of triethyl borate), and disperse it using a high-speed disperser at 2500 r / min for 5 min;

[0052] The amount of DP-SiO2 nanopowder added is 0.04 times the mass of acidic silica sol;

[0053] The preparation of the DP-SiO2 nanopowder comprises the following steps:

[0054] (1) Disperse fumed silica powder in acidic silica sol (pH = 2) at a mass ratio of fumed silica powder to acidic silica sol of 1:0.3. Stir under ultrasonication for 20 min and then place in a 60°C water bath for 2 h to form a silanol activation layer.

[0055] (2) After uniformly mixing anhydrous ethanol and silane coupling agent KH560 in a mass ratio of 1:0.5, the mixture was added to the product of step (1), and refluxed at 80°C for 4 h under nitrogen protection to complete the grafting of epoxy groups;

[0056] The amount of anhydrous ethanol added is 0.4 times that of the fumed silica powder;

[0057] (3) The product of step (2) was centrifuged and washed with ethanol three times, and then vacuum dried at 60°C to obtain a dual-phase coated nanopowder (DP-SiO2);

[0058] S5. The paste obtained after dispersion is subjected to gradient solidification;

[0059] The gradient curing is divided into two stages:

[0060] The first stage: Si-OCH3 hydrolysis reaction was carried out at 45 °C for 0.5 h;

[0061] The second stage: heating to 85 °C and carrying out epoxy ring-opening polymerization for 1.5 h.

[0062] Example 2

[0063] A method for preparing a quartz / quartz composite ceramic repair paste comprises the following steps:

[0064] S1. Add acidic silica sol into a three-necked flask, then add pure water, stir and mix well, and heat in a water bath to 55°C;

[0065] The mass ratio of acidic silica sol to pure water is 6.5:1;

[0066] S2. After uniformly mixing anhydrous ethanol and silane coupling agent KH560 in a mass ratio of 1:0.75, add the mixture to the three-necked flask in step S1, react at 55°C for 4.5 hours, then heat to 90°C and continue to react for 2.5 hours;

[0067] The amount of anhydrous ethanol added is 11% of the total mass of acidic silica sol and pure water;

[0068] S3. Cool down to 28°C, mix methyltrimethoxysilane and silane coupling agent KH560 at a mass ratio of 19:1, add to the three-necked flask, and stir at room temperature;

[0069] The amount of methyltrimethoxysilane added is 1.25 times the mass of the acidic silica sol;

[0070] S4. Pour the product obtained in step S3 into an open plastic bucket, add pre-mixed DP-SiO2 nanopowder and triethyl borate (the mass of DP-SiO2 nanopowder is 11 times that of triethyl borate), and disperse it using a high-speed disperser at 3000 r / min for 8 min;

[0071] The amount of DP-SiO2 nanopowder added is 0.043 times the mass of acidic silica sol;

[0072] The preparation of the DP-SiO2 nanopowder comprises the following steps:

[0073] (1) Disperse fumed silica powder in acidic silica sol (pH = 2.5) at a mass ratio of fumed silica powder to acidic silica sol of 1:0.35. Stir under ultrasonication for 25 min and then place in a 65°C water bath for 2.5 h to form a silanol activation layer.

[0074] (2) After uniformly mixing anhydrous ethanol and silane coupling agent KH560 in a mass ratio of 1:0.8, the mixture was added to the product of step (1), and refluxed at 85°C for 4.5 h under nitrogen protection to complete the grafting of epoxy groups;

[0075] The amount of anhydrous ethanol added is 0.45 times that of the fumed silica powder;

[0076] (3) The product of step (2) was centrifuged and washed with ethanol three times, and then vacuum dried at 70°C to obtain a dual-phase coated nanopowder (DP-SiO2);

[0077] S5. The paste obtained after dispersion is subjected to gradient solidification;

[0078] The gradient curing is divided into two stages:

[0079] The first stage: Si-OCH3 hydrolysis reaction was carried out at 50 °C for 1 h;

[0080] The second stage: heating to 90 °C and carrying out epoxy ring-opening polymerization for 2 h.

[0081] Example 3

[0082] A method for preparing a quartz / quartz composite ceramic repair paste comprises the following steps:

[0083] S1. Add acidic silica sol into a three-necked flask, then add pure water, stir and mix well, and heat in a water bath to 60°C;

[0084] The mass ratio of acidic silica sol to pure water is 7:1;

[0085] S2. After uniformly mixing anhydrous ethanol and silane coupling agent KH560 in a mass ratio of 1:1, add the mixture to the three-necked flask in step S1, react at 60°C for 5 h, then heat to 95°C and continue to react for 3 h;

[0086] The amount of anhydrous ethanol added is 12% of the total mass of acidic silica sol and pure water;

[0087] S3. Cool down to 30°C, mix methyltrimethoxysilane and silane coupling agent KH560 at a mass ratio of 20:1, add to a three-necked flask, and stir at room temperature;

[0088] The amount of methyltrimethoxysilane added is 1.3 times the mass of the acidic silica sol;

[0089] S4. Pour the product obtained in step S3 into an open plastic bucket, add pre-mixed DP-SiO2 nanopowder and triethyl borate (the mass of DP-SiO2 nanopowder is 12 times that of triethyl borate), and disperse it using a high-speed disperser at 3500 r / min for 10 min;

[0090] The amount of DP-SiO2 nanopowder added is 0.046 times the mass of acidic silica sol;

[0091] The preparation of the DP-SiO2 nanopowder comprises the following steps:

[0092] (1) Disperse fumed silica powder in acidic silica sol (pH = 3) with a mass ratio of fumed silica powder to acidic silica sol of 1:0.4. Stir under ultrasonication for 30 min and then place in a 70°C water bath for 3 h to form a silanol activation layer.

[0093] (2) After uniformly mixing anhydrous ethanol and silane coupling agent KH560 in a mass ratio of 1:1, the mixture was added to the product of step (1), and refluxed at 90°C for 5 h under nitrogen protection to complete the grafting of epoxy groups;

[0094] The amount of anhydrous ethanol added is 0.5 times that of the fumed silica powder;

[0095] (3) The product of step (2) was centrifuged and washed with ethanol four times, and then vacuum dried at 80°C to obtain a dual-phase coated nanopowder (DP-SiO2);

[0096] S5. The paste obtained after dispersion is subjected to gradient solidification;

[0097] The gradient curing is divided into two stages:

[0098] The first stage: Si-OCH3 hydrolysis reaction was carried out at 55 °C for 1.5 h;

[0099] The second stage: the temperature was raised to 95°C and the epoxy ring-opening polymerization reaction was carried out for 2.5 h.

[0100] Comparative Example 1

[0101] A method for preparing a quartz / quartz composite ceramic repair paste comprises the following steps:

[0102] S1. Add acidic silica sol into a three-necked flask, then add pure water, stir and mix well, and heat in a water bath to 55°C;

[0103] The mass ratio of acidic silica sol to pure water is 6.5:1;

[0104] S2. After uniformly mixing anhydrous ethanol and silane coupling agent KH560 in a mass ratio of 1:0.75, add the mixture to the three-necked flask in step S1, react at 55°C for 4.5 hours, then heat to 90°C and continue to react for 2.5 hours;

[0105] The amount of anhydrous ethanol added is 11% of the total mass of acidic silica sol and pure water;

[0106] S3. Cool down to 28°C, mix methyltrimethoxysilane and silane coupling agent KH560 at a mass ratio of 19:1, add to the three-necked flask, and stir at room temperature;

[0107] The amount of methyltrimethoxysilane added is 1.25 of the mass of the acidic silica sol;

[0108] S4. Pour the product obtained in step S3 into an open plastic bucket, add pre-mixed fumed silica powder and triethyl borate (the mass of fumed silica powder is 11 times that of triethyl borate), and disperse using a high-speed disperser at 3000 r / min for 8 min;

[0109] The amount of fumed silica powder added is 0.043 times the mass of the acidic silica sol;

[0110] S5. The paste obtained after dispersion is subjected to gradient solidification;

[0111] The gradient curing is divided into two stages:

[0112] The first stage: Si-OCH3 hydrolysis reaction was carried out at 50 °C for 1 h;

[0113] The second stage: heating to 90 °C and carrying out epoxy ring-opening polymerization for 2 h.

[0114] Comparative Example 2

[0115] A method for preparing a quartz / quartz composite ceramic repair paste comprises the following steps:

[0116] S1. Add acidic silica sol into a three-necked flask, then add pure water, stir and mix well, and heat in a water bath to 55°C;

[0117] The mass ratio of acidic silica sol to pure water is 6.5:1;

[0118] S2. After uniformly mixing anhydrous ethanol and silane coupling agent KH560 in a mass ratio of 1:0.75, add the mixture to the three-necked flask in step S1, react at 55°C for 4.5 hours, then heat to 90°C and continue to react for 2.5 hours;

[0119] The amount of anhydrous ethanol added is 11% of the total mass of acidic silica sol and pure water;

[0120] S3. Cool down to 28°C, mix methyltrimethoxysilane and silane coupling agent KH560 at a mass ratio of 19:1, add to the three-necked flask, and stir at room temperature;

[0121] The amount of methyltrimethoxysilane added is 1.25 of the mass of the acidic silica sol;

[0122] S4, pour the product obtained in step S3 into an open plastic bucket, add DP-SiO2 nanopowder, and disperse it using a high-speed disperser at 3000 r / min for 8 min;

[0123] The amount of DP-SiO2 nanopowder added is 0.043 times the mass of acidic silica sol;

[0124] The preparation of the DP-SiO2 nanopowder comprises the following steps:

[0125] (1) Disperse fumed silica powder in acidic silica sol (pH = 2.5) at a mass ratio of fumed silica powder to acidic silica sol of 1:0.35. Stir under ultrasonication for 25 min and then place in a 65°C water bath for 2.5 h to form a silanol activation layer.

[0126] (2) After uniformly mixing anhydrous ethanol and silane coupling agent KH560 in a mass ratio of 1:0.8, the mixture was added to the product of step (1), and refluxed at 85°C for 4.5 h under nitrogen protection to complete the grafting of epoxy groups;

[0127] The amount of anhydrous ethanol added is 0.45 times that of the fumed silica powder;

[0128] (3) The product of step (2) was centrifuged and washed with ethanol three times, and then vacuum dried at 70°C to obtain a dual-phase coated nanopowder (DP-SiO2);

[0129] S5. The paste obtained after dispersion is subjected to gradient solidification;

[0130] The gradient curing is divided into two stages:

[0131] The first stage: Si-OCH3 hydrolysis reaction was carried out at 50 °C for 1 h;

[0132] The second stage: heating to 90 °C and carrying out epoxy ring-opening polymerization for 2 h.

[0133] Comparative Example 3

[0134] A method for preparing a quartz / quartz composite ceramic repair paste comprises the following steps:

[0135] S1. Add acidic silica sol into a three-necked flask, then add pure water, stir and mix well, and heat in a water bath to 55°C;

[0136] The mass ratio of acidic silica sol to pure water is 6.5:1;

[0137] S2. After uniformly mixing anhydrous ethanol and silane coupling agent KH560 in a mass ratio of 1:0.75, add the mixture to the three-necked flask in step S1, react at 55°C for 4.5 hours, then heat to 90°C and continue to react for 2.5 hours;

[0138] The amount of anhydrous ethanol added is 11% of the total mass of acidic silica sol and pure water;

[0139] S3. Cool down to 28°C, mix methyltrimethoxysilane and silane coupling agent KH560 at a mass ratio of 19:1, add to the three-necked flask, and stir at room temperature;

[0140] The amount of methyltrimethoxysilane added is 1.25 of the mass of the acidic silica sol;

[0141] S4. Pour the product obtained in step S3 into an open plastic bucket, add pre-mixed DP-SiO2 nanopowder and triethyl borate (the mass of DP-SiO2 nanopowder is 11 times that of triethyl borate), and disperse it using a high-speed disperser at 3000 r / min for 8 min;

[0142] The amount of DP-SiO2 nanopowder added is 0.043 times the mass of acidic silica sol;

[0143] The preparation of the DP-SiO2 nanopowder comprises the following steps:

[0144] (1) Disperse fumed silica powder in acidic silica sol (pH = 2.5) at a mass ratio of fumed silica powder to acidic silica sol of 1:0.35. Stir under ultrasonication for 25 min and then place in a 65°C water bath for 2.5 h to form a silanol activation layer.

[0145] (2) After uniformly mixing anhydrous ethanol and silane coupling agent KH560 in a mass ratio of 1:0.8, the mixture was added to the product of step (1), and refluxed at 85°C for 4.5 h under nitrogen protection to complete the grafting of epoxy groups;

[0146] The amount of anhydrous ethanol added is 0.45 times that of the fumed silica powder;

[0147] (3) The product of step (2) was centrifuged and washed with ethanol three times, and then vacuum dried at 70°C to obtain a dual-phase coated nanopowder (DP-SiO2).

[0148] The repair paste prepared by the method of Example 2 was used to repair the quartz / quartz composite ceramic antenna window, and the performance was tested.

[0149] 1. Test methods and judgment criteria

[0150] Table 1 Test methods and judgment criteria

[0151] Serial number Experimental Project Test subjects Test performance Test method Judgment Criteria 1 Visual inspection (including repair products) Antenna Window Repair layer appearance According to the process documents, visual inspection The appearance is intact, without damage, etc. 2 Warm shock screening test (including repair products) Antenna Window Thermal shock resistance GJB150.5A-2009 The repair layer has no cracking, peeling, yellowing, etc. 3 High temperature storage test (including repaired products) Antenna Window High temperature resistance GJB150.3A-2009 The repair layer has no cracking, peeling, yellowing, etc. 4 Low temperature storage test (including repaired products) Antenna Window Low temperature resistance GJB150.4A-2009 The repair layer has no cracking, peeling, yellowing, etc.

[0152] The above test method was used to test 7 test pieces. The specifications and test contents of each test component are shown in Table 2 below.

[0153] Table 2 Test piece specifications and test contents

[0154]

[0155] 2. Test Results

[0156] The test results are shown in Table 3 below.

[0157] Table 3 Test results summary

[0158] Serial number Test items Test conditions Require Test subjects result in conclusion 1 Visual inspection (including repair products) \ The appearance is intact, without damage, etc. Antenna Window Appearance intact, no damage qualified 2 Warm shock screening test (including repair products) -55℃~+85℃, 30min for high and low temperature, 3min40s for switching time, 200 cycles After the test, the repair layer is intact and has no damage. Antenna Window After warm shock, the repair layer looks intact and has no damage qualified 3 High temperature storage test (including repaired products) 75℃，48h After the test, the repair layer is intact and has no damage. Antenna Window Appearance intact after high temperature storage qualified 4 Low temperature storage test (including repaired products) -55℃，48h After the test, the repair layer is intact and has no damage. Antenna Window Appearance intact after low temperature storage qualified

[0159] It can be seen from Table 3 above that the test pieces repaired with the repair paste of the present invention passed all tests and are suitable for repairing antenna windows.

[0160] The quartz composite ceramic repair pastes were prepared using the methods of Examples 1 to 3 and Comparative Examples 1 to 3, respectively. The quartz / quartz composite ceramic antenna windows (all the selected specimens had large scratches on the outer arc surface and were repaired as a whole) were repaired using the repair pastes, and performance tests were performed.

[0161] The comparison results are shown in Table 4 below.

[0162] Table 4 Comparison of repair results of the repair pastes of each embodiment and the comparative example

[0163] Visual inspection Warm shock screening test High temperature storage experiment Low temperature storage experiment Example 1 Appearance intact, no damage After warm shock, the repair layer looks intact and has no damage Appearance intact after high temperature storage Appearance intact after low temperature storage Example 2 Appearance intact, no damage After warm shock, the repair layer looks intact and has no damage Appearance intact after high temperature storage Appearance intact after low temperature storage Example 3 Appearance intact, no damage After warm shock, the repair layer looks intact and has no damage Appearance intact after high temperature storage Appearance intact after low temperature storage Comparative Example 1 Appearance intact, no damage The repair layer is slightly damaged after warm shock Slight damage to the appearance after high temperature storage Slight damage to the appearance after low temperature storage Comparative Example 2 Appearance intact, no damage After warm shock, the repair layer looks intact and has no damage Slight damage to the appearance after high temperature storage Appearance intact after low temperature storage Comparative Example 3 Appearance intact, no damage The repair layer is slightly damaged after warm shock Appearance intact after high temperature storage Slight damage to the appearance after low temperature storage

[0164] It can be seen from Table 4 above that the repair effects of Examples 1 to 3 are better than those of the comparative example. After the temperature shock test, the comparative example has a small amount of damage on the exterior.

[0165] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A method for preparing a quartz / quartz composite ceramic repair paste, characterized in that: The steps include: S1. Add acidic silica sol into a three-necked flask, then add pure water, stir and mix well, and heat in a water bath to 50-60°C; S2. After uniformly mixing anhydrous ethanol and a silane coupling agent, add the mixture to the three-necked flask in step S1, react at 50-60°C for 4-5 hours, and then increase the temperature to continue the reaction; S3. Cool down to 25-30°C, mix methyltrimethoxysilane and silane coupling agent, add to a three-necked flask, and stir at room temperature; S4. Pour the product obtained in step S3 into an open plastic bucket, add the pre-mixed DP-SiO2 nanopowder and triethyl borate, and disperse it using a high-speed disperser for 5 to 10 minutes; The preparation of the DP-SiO2 nanopowder comprises the following steps: (1) Disperse fumed silica powder in acidic silica sol, stir under ultrasonication for 20-30 min, and then place in a water bath at 60-70°C for 2-3 h to form a silanol activation layer. (2) After uniformly mixing anhydrous ethanol and a silane coupling agent, add the mixture to the product of step (1), and reflux at 80-90°C for 4-5 hours under nitrogen protection to complete the grafting of epoxy groups; The silane coupling agent is KH560; (3) centrifuging the product of step (2), washing it with ethanol for 3 to 4 times, and then vacuum drying it at a temperature of 60 to 80° C. to obtain DP-SiO2 nanopowder; S5. The paste obtained after dispersion is subjected to gradient solidification; The gradient curing is divided into two stages: The first stage: Si-OCH3 hydrolysis reaction at 45-55 °C for 0.5-1.5 h; The second stage: heating to 85~95℃ and carrying out epoxy ring-opening polymerization for 1.5~2.5 hours.

2. The method for preparing a quartz / quartz composite ceramic repair paste according to claim 1, characterized in that: The mass ratio of the acidic silica sol to pure water in step S1 is (6-7):1; The pH value of the acidic silica sol is 2-4, and the particle size is 8-80 nm.

3. The method for preparing a quartz / quartz composite ceramic repair paste according to claim 1, characterized in that: The mass ratio of anhydrous ethanol to silane coupling agent described in step S2 is 1:(0.5~1); The silane coupling agent is KH560; The amount of anhydrous ethanol added is 10-12% of the total mass of acidic silica sol and pure water; The temperature after heating is 85-95° C., and the reaction time is 2-3 h.

4. The method for preparing a quartz / quartz composite ceramic repair paste according to claim 1, characterized in that: The mass ratio of methyltrimethoxysilane to the silane coupling agent in step S3 is (18-20):1; The silane coupling agent is KH560; The amount of methyltrimethoxysilane added is 1.2 to 1.3 times the mass of the acidic silica sol.

5. The method for preparing a quartz / quartz composite ceramic repair paste according to claim 1, characterized in that: When the premixed DP-SiO2 nanopowder and triethyl borate are mixed in step S4, the mass of the DP-SiO2 nanopowder is 10 to 12 times that of the triethyl borate; The addition amount of DP-SiO2 nanopowder is 0.04~0.046 times the mass of acidic silica sol; The high-speed disperser has a dispersing speed of 2500-3500 r / min.

6. The method for preparing a quartz / quartz composite ceramic repair paste according to claim 1, characterized in that: The mass ratio of the fumed silica powder to the acidic silica sol in step (1) is 1:(0.3-0.4); The pH value of the acidic silica sol is 2-3.

7. The method for preparing a quartz / quartz composite ceramic repair paste according to claim 1, characterized in that: The mass ratio of anhydrous ethanol to silane coupling agent in step (2) is 1:(0.5~1); The added amount of the anhydrous ethanol is 0.4 to 0.5 times that of the fumed silica powder.

8. A quartz / quartz composite ceramic repair paste prepared by the method according to any one of claims 1 to 7.

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