A ceramic insulation tile sintering auxiliary material and its preparation method and use method

Abstract

The present invention discloses a ceramic insulation tile sintering aid, its preparation method, and its use, belonging to the technical field of thermal protection material manufacturing. The invention prepares two different modified ceramic fiber felts and two different modified ceramic fiber cloths, lays them together to form a laminated structure, and sews the layers together with ceramic sewing thread to produce the ceramic insulation tile sintering aid. Using this ceramic insulation tile sintering aid in insulation tiles can solve the problems of boron oxide escape and adhesion to the backing plate during the sintering process of rigid ceramic insulation tiles.

Description

Technical Field

[0001] The invention provides a ceramic insulation tile sintering auxiliary material and a preparation method and a use method thereof, belonging to the technical field of heat protection material manufacturing. Background Art

[0002] Rigid ceramic insulation tiles are a traditional thermal protection material in the aerospace field. They are made of ceramic fibers and sintering aids as the main raw materials, and are prepared through processes such as fiber pulping, filtration forming, drying, and sintering. Among them, the sintering process is to place the dried insulation tile blanks in a muffle furnace and gradually heat them to above 1000°C. During the heating process, the sintering aids represented by boron nitride are gradually oxidized to boron oxide and sinter with ceramic fibers represented by quartz fibers, forming a new ceramic phase on the surface of the ceramic fibers and connecting adjacent ceramic fibers together, thereby completing the sintering and obtaining high-strength rigid ceramic insulation tiles. However, due to the evaporation and escape of boron oxide during sintering, the sintering strength of the insulation tiles will be reduced and the strength will be uneven. In addition, due to the sintering reaction between boron oxide and quartz fibers, the sintered insulation tiles are easily adhered to the glass of the sintering pad and are difficult to remove, causing product damage. To address this problem, it is necessary to invent a ceramic insulation tile sintering aid and a method of using the same to achieve non-adhesive and uniform sintering of the insulation tile. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for preparing a ceramic insulation tile sintering auxiliary material to solve the problems of boron oxide escape and adhesion to the backing plate during the sintering process of rigid ceramic insulation tiles.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A method for preparing a ceramic insulation tile sintering auxiliary material comprises the following steps:

[0006] 1) Preparation of modified ceramic fiber felt A: The ceramic fiber felt A is immersed in a water-soluble polymer solution for a period of time, removed, and then transferred to a hollow platform and allowed to stand until no more water-soluble polymer solution drips, and then transferred to an oven for complete drying;

[0007] 2) Preparation of modified ceramic fiber felt B: boron nitride is added to a water-soluble polymer aqueous solution and stirred evenly, followed by immersion of ceramic fiber felt B for a period of time. The impregnated ceramic fiber felt B is then removed and transferred to a hollow platform for standing until no more water-soluble polymer solution drips, and then transferred to an oven for complete drying.

[0008] 3) Preparation of modified ceramic fiber cloth C: Ceramic fiber cloth C is immersed in a water-soluble polymer solution for a period of time, removed, and then transferred to a hollow platform and allowed to stand until no more water-soluble polymer solution drips, and then transferred to an oven for complete drying;

[0009] 4) Preparation of modified ceramic fiber cloth D: Ceramic fiber cloth D is immersed in a water-soluble polymer solution for a period of time, removed, and then transferred to a hollow platform and allowed to stand until no more water-soluble polymer solution drips, and then transferred to an oven for complete drying;

[0010] 5) Fiber lamination step: sequentially lay a layer of modified ceramic fiber felt A, a layer of modified ceramic fiber felt B, two layers of modified ceramic fiber cloth C, and a layer of modified ceramic fiber cloth D to form a laminated structure. The layers are sewn together with ceramic sewing thread to obtain a ceramic insulation tile sintering aid.

[0011] Furthermore, the ceramic fiber felt A in step 1) comprises quartz fiber, alumina fiber and mullite fiber, and the total mass ratio of the alumina fiber to the mullite fiber is not less than 70%.

[0012] Furthermore, the water-soluble polymer solution in step 1) is a polyacrylamide aqueous solution with a concentration of 1% to 5%, and the immersion time is 1 to 10 minutes.

[0013] Furthermore, the oven temperature in step 1) is 60-100°C.

[0014] Furthermore, the water-soluble polymer solution in step 2) is a polyacrylamide aqueous solution with a concentration of 5% to 10%; the mass ratio of the boron nitride to the polymer solute in the water-soluble polymer solution is 1:1.

[0015] Furthermore, the ceramic fiber felt B in step 2) contains alumina fibers, and the mass ratio of the alumina fibers is not less than 90%.

[0016] Furthermore, in step 2), the ceramic fiber felt B is immersed for 10 to 30 minutes.

[0017] Furthermore, the oven temperature in step 2) is 60-100°C.

[0018] Furthermore, the ceramic fiber cloth C in step 3) contains alumina fibers, and the mass ratio of the alumina fibers is not less than 90%.

[0019] Furthermore, the water-soluble polymer solution in step 3) is a polyacrylamide aqueous solution with a concentration of 1% to 5%, and the immersion time is 1 to 10 minutes.

[0020] Furthermore, the oven temperature in step 3) is 60-100°C.

[0021] Furthermore, the ceramic fiber cloth D in step 4) comprises alumina fiber and quartz fiber, the mass ratio of the alumina fiber is not less than 30%, and the mass ratio of the quartz fiber is not less than 60%.

[0022] Furthermore, the water-soluble polymer solution in step 4) is a polyacrylamide aqueous solution with a concentration of 1% to 5%, and the immersion time is 1 to 10 minutes.

[0023] Furthermore, the oven temperature in step 4) is 60-100°C.

[0024] Furthermore, in step 5), the thickness of the modified ceramic fiber felt A is 0.5-1.0 mm, the thickness of the modified ceramic fiber felt B is 1.0-2.0 mm, the thickness of each layer of the modified ceramic fiber cloth C is 0.3-0.5 mm, and the thickness of the modified ceramic fiber cloth D is 0.1-0.3 mm.

[0025] A ceramic insulation tile sintering auxiliary material is prepared by the above preparation method.

[0026] A method for using a ceramic insulation tile sintering auxiliary material comprises the following steps:

[0027] Before the insulation tile blank is sintered, the ceramic insulation tile sintering auxiliary material is wrapped on the surface of the insulation tile blank to be sintered, and the modified ceramic fiber felt A is in contact with the insulation tile blank. After the wrapping is completed, sintering is carried out according to the original temperature program.

[0028] The beneficial effects achieved by the present invention are as follows:

[0029] 1) The modified ceramic fiber felt A, as the layer in contact with the insulation tile, has good high-temperature resistance and does not react with boron oxide, ensuring that it will not adhere to the ceramic insulation tile during the sintering process, thereby ensuring the integrity of the insulation tile sintering process; the use of polyacrylamide aqueous solution to coat and modify the ceramic fiber felt A can improve the fiber connectivity and stiffness of the ceramic fiber felt A, and effectively improve the problems of low strength, easy powder loss, and difficult transfer of the ceramic fiber felt A due to the presence of more alumina fibers; during the sintering process, the polyacrylamide in the modified ceramic fiber felt A decomposes at high temperature, and the loose and breathable structure of the fiber felt A can ensure the smooth penetration of boron oxide vapor.

[0030] 2) The boron nitride is carried by polyacrylamide in the modified ceramic fiber felt B, which can ensure the stable fixation between the boron nitride powder and the fiber felt, avoiding the scattering problem of boron nitride. It can also form a boron oxide vapor barrier to avoid the loss of boron oxide in the insulation tile. The use of polyacrylamide aqueous solution to coat the ceramic fiber felt B can improve the problems of low strength, easy powder loss, and difficult transfer of the ceramic fiber felt B.

[0031] 3) The purpose of modifying ceramic fiber cloth C is to minimize the leakage of boron oxide vapor and to protect the cloth from corrosion. Using a polyacrylamide aqueous solution to coat ceramic fiber cloth C can improve its low strength and easy powder shedding.

[0032] 4) The purpose of modified ceramic fiber cloth D is to provide maximum strength to the laminated structure as the outermost layer. The reaction between the quartz fibers and the boron oxide captures small amounts of escaping boron oxide vapor, thereby protecting the muffle furnace from boron oxide corrosion. The low alumina fiber content and high quartz fiber content ensure that the ceramic fiber cloth has both high strength and high temperature resistance. DETAILED DESCRIPTION

[0033] In order to make the various technical features and advantages or technical effects of the above technical solutions of the present invention more obvious and easy to understand, they are described in detail below in conjunction with embodiments.

[0034] Example 1

[0035] A method for preparing a ceramic insulation tile sintering auxiliary material comprises the following steps:

[0036] 1) Preparation of modified ceramic fiber felt A: The ceramic fiber felt A was immersed in a 1% polyacrylamide aqueous solution for 10 minutes, then removed and transferred to a hollow platform for standing until no more polymer solution dripped, and then transferred to a 60°C oven until completely dried.

[0037] Furthermore, the ceramic fiber felt A is a mixture of quartz fiber, alumina fiber and mullite fiber, wherein the total mass content of the alumina fiber and the mullite fiber is not less than 70%.

[0038] 2) Preparation steps of modified ceramic fiber felt B: Boron nitride was added to a 5% polyacrylamide aqueous solution at a mass ratio of 1:1 between boron nitride and polyacrylamide solids and stirred evenly, and then ceramic fiber felt B was placed in it and immersed for 30 minutes. The impregnated ceramic fiber felt B was then removed and transferred to a hollow platform for standing until no more polymer solution dripped, and then transferred to a 100°C oven until completely dried.

[0039] Furthermore, the mass content of alumina fibers in the ceramic fiber felt B is not less than 90%.

[0040] 3) Preparation of modified ceramic fiber cloth C: Ceramic fiber cloth C was immersed in a 1% polyacrylamide aqueous solution for 10 minutes, removed, and then transferred to a hollow platform and allowed to stand until no more polymer solution dripped. It was then transferred to a 60°C oven and completely dried.

[0041] Furthermore, the mass content of alumina fibers in the ceramic fiber cloth C is not less than 90%.

[0042] 4) Preparation of modified ceramic fiber cloth D: Ceramic fiber cloth D is immersed in a 5% aqueous polyacrylamide solution for 10 minutes, removed, and then transferred to a hollow platform and allowed to stand until no more polymer solution drips. The cloth is then transferred to a 60°C oven and dried completely. Furthermore, the weight content of alumina fiber in the ceramic fiber cloth D is not less than 30%, and the weight content of quartz fiber is not less than 60%.

[0043] 5) Fiber lamination step: sequentially lay a layer of modified ceramic fiber felt A with a thickness of 0.5 mm, a layer of modified ceramic fiber felt B with a thickness of 1.0 mm, two layers of modified ceramic fiber cloth C with a thickness of 0.5 mm each, and a layer of modified ceramic fiber cloth D with a thickness of 0.3 mm. The layers are sewn together with ceramic sewing thread to obtain a ceramic insulation tile sintering aid.

[0044] After experimental testing, the prepared rigid ceramic insulation tile sintering auxiliary material was used to sinter quartz fiber ceramic insulation tiles at a sintering temperature of 1100°C. After sintering, the sintering auxiliary material was intact and there was no adhesion between the insulation tiles. The compressive strength of the edge area and the compressive strength of the center area of the obtained insulation tile blank fluctuated by less than 5%, and the strength uniformity was good.

[0045] Example 2

[0046] A method for preparing a ceramic insulation tile sintering auxiliary material comprises the following steps:

[0047] 1) Preparation of modified ceramic fiber felt A: The ceramic fiber felt A was immersed in a 5% polyacrylamide aqueous solution for 1 minute, then removed and transferred to a hollow platform for standing until no more polymer solution dripped, and then transferred to a 100° C. oven until completely dried.

[0048] Furthermore, the ceramic fiber felt A is a mixture of quartz fiber, alumina fiber and mullite fiber, wherein the total mass content of the alumina fiber and the mullite fiber is not less than 70%.

[0049] 2) Preparation steps of modified ceramic fiber felt B: According to a mass ratio of 1:1 between boron nitride and polyacrylamide solids, boron nitride was added to a 10% polyacrylamide aqueous solution and stirred evenly, and then ceramic fiber felt B was placed in it and immersed for 10 minutes. The impregnated ceramic fiber felt B was then removed and transferred to a hollow platform for standing until no more polymer solution dripped, and then transferred to a 60°C oven until completely dried.

[0050] Furthermore, the mass content of alumina fibers in the ceramic fiber felt B is not less than 90%.

[0051] 3) Preparation of modified ceramic fiber cloth C: Ceramic fiber cloth C was immersed in a 5% polyacrylamide aqueous solution for 1 minute, removed, and then transferred to a hollow platform and allowed to stand until no more polymer solution dripped. It was then transferred to a 100°C oven until completely dried.

[0052] Furthermore, the mass content of alumina fibers in the ceramic fiber cloth C is not less than 90%.

[0053] 4) Preparation of modified ceramic fiber cloth D: Ceramic fiber cloth D is immersed in a 1% aqueous polyacrylamide solution for 1 minute, removed, and then transferred to a hollow platform and allowed to stand until no more polymer solution drips. The cloth is then placed in an oven at 100°C until completely dried. Furthermore, the weight content of alumina fiber in the ceramic fiber cloth D is not less than 30%, and the weight content of quartz fiber is not less than 60%.

[0054] 5) Fiber lamination step: sequentially lay a layer of modified ceramic fiber felt A with a thickness of 1.0 mm, a layer of modified ceramic fiber felt B with a thickness of 2.0 mm, two layers of modified ceramic fiber cloth C with a thickness of 0.3 mm each, and a layer of modified ceramic fiber cloth D with a thickness of 0.1 mm. The layers are sewn together with ceramic sewing thread to obtain a ceramic insulation tile sintering aid.

[0055] After experimental testing, the prepared rigid ceramic insulation tile sintering auxiliary material was used to sinter quartz fiber and alumina fiber dual fiber ceramic insulation tiles at a sintering temperature of 1300°C. After sintering, the sintering auxiliary material was intact and there was no adhesion between the insulation tile and the insulation tile. The compressive strength of the edge area and the compressive strength of the center area of the obtained insulation tile blank fluctuated by less than 5%, and the strength uniformity was good.

[0056] Example 3

[0057] A method for preparing a ceramic insulation tile sintering auxiliary material comprises the following steps:

[0058] 1) Preparation steps of modified ceramic fiber felt A: Ceramic fiber felt A is immersed in a 3% polyacrylamide aqueous solution for 5 minutes, then removed and transferred to a hollow platform for standing until no more polymer solution drips, and then transferred to an 80°C oven until completely dried.

[0059] Furthermore, the ceramic fiber felt A is a mixture of quartz fiber, alumina fiber and mullite fiber, wherein the total mass content of the alumina fiber and the mullite fiber is not less than 70%.

[0060] 2) Preparation steps of modified ceramic fiber felt B: According to a mass ratio of 1:1 between boron nitride and polyacrylamide solids, boron nitride was added to a 7% polyacrylamide aqueous solution and stirred evenly, and then ceramic fiber felt B was placed in it and immersed for 20 minutes. The impregnated ceramic fiber felt B was then removed and transferred to a hollow platform for standing until no more polymer solution dripped, and then transferred to an 80°C oven until completely dried.

[0061] Furthermore, the mass content of alumina fibers in the ceramic fiber felt B is not less than 90%.

[0062] 3) Preparation of modified ceramic fiber cloth C: Ceramic fiber cloth C was immersed in a 3% polyacrylamide aqueous solution for 6 minutes, removed, and then transferred to a hollow platform and allowed to stand until no more polymer solution dripped. It was then transferred to an 80°C oven until completely dried.

[0063] Furthermore, the mass content of alumina fibers in the ceramic fiber cloth C is not less than 90%.

[0064] 4) Preparation of modified ceramic fiber cloth D: Ceramic fiber cloth D is immersed in a 3% aqueous polyacrylamide solution for 6 minutes, removed, and then transferred to a hollow platform and allowed to stand until no more polymer solution drips. The cloth is then placed in an 80°C oven until completely dried. Furthermore, the weight content of alumina fiber in the ceramic fiber cloth D is not less than 30%, and the weight content of quartz fiber is not less than 60%.

[0065] 5) Fiber lamination step: sequentially lay a layer of modified ceramic fiber felt A with a thickness of 0.8 mm, a layer of modified ceramic fiber felt B with a thickness of 1.5 mm, two layers of modified ceramic fiber cloth C with a thickness of 0.4 mm each, and a layer of modified ceramic fiber cloth D with a thickness of 0.2 mm. The layers are sewn together with ceramic sewing thread to obtain a ceramic insulation tile sintering aid.

[0066] After experimental testing, the prepared rigid ceramic insulation tile sintering auxiliary material was used to sinter quartz fiber and mullite fiber dual fiber ceramic insulation tiles at a sintering temperature of 1200°C. After sintering, the sintering auxiliary material was intact and there was no adhesion between the insulation tile and the insulation tile. The compressive strength of the edge area and the compressive strength of the center area of the obtained insulation tile blank fluctuated by less than 5%, and the strength uniformity was good.

[0067] Comparative Example 1

[0068] Without using sintering aids, the quartz fiber ceramic insulation tile used in Example 1 was sintered by the same procedure at a sintering temperature of 1100°C. After sintering, the bottom of the insulation tile was bonded to the silicon carbide pad in the muffle furnace; the edge strength of the obtained insulation tile blank was lower than the strength of the center area, the compressive strength fluctuated by more than 15%, and the strength uniformity was poor.

[0069] Although the present invention has been disclosed as above by way of embodiments, they are not intended to limit the present invention. Any appropriate modification or equivalent substitution of the technical solution of the present invention by a person skilled in the art should be included in the protection scope of the present invention. The protection scope of the present invention shall be based on that defined in the claims.

Claims

1. A method for preparing a ceramic insulation tile sintering auxiliary material, characterized in that: The following steps are involved: 1) Preparation of modified ceramic fiber felt A: immersing the ceramic fiber felt A in a water-soluble polymer solution for a period of time, removing the felt, transferring the felt to a hollow platform, and allowing the felt to stand until no more water-soluble polymer solution drips, followed by transferring the felt to an oven for complete drying; the ceramic fiber felt A comprises quartz fiber, alumina fiber, and mullite fiber, with the total weight ratio of the alumina fiber to the mullite fiber being no less than 70%; 2) Preparation of modified ceramic fiber felt B: adding boron nitride to a water-soluble polymer aqueous solution and stirring uniformly, then placing ceramic fiber felt B in the solution and immersing for a period of time, then removing the impregnated ceramic fiber felt B, transferring it to a hollow platform, and allowing it to stand until no more water-soluble polymer solution drips, and then transferring it to an oven for complete drying; the ceramic fiber felt B comprises alumina fibers, the mass ratio of which is not less than 90%; 3) Preparation of modified ceramic fiber cloth C: immersing the ceramic fiber cloth C in a water-soluble polymer solution for a period of time, removing the cloth, transferring the cloth to a hollowed-out platform, and allowing the cloth to stand until no more water-soluble polymer solution drips, followed by drying the cloth in an oven. The ceramic fiber cloth C comprises alumina fibers, with the weight ratio of the alumina fibers being not less than 90%. 4) Preparation of modified ceramic fiber cloth D: immersing the ceramic fiber cloth D in a water-soluble polymer solution for a period of time, removing the cloth, transferring the cloth to a hollow platform, and allowing the cloth to stand until no more water-soluble polymer solution drips, followed by drying the cloth in an oven. The ceramic fiber cloth D comprises alumina fibers and quartz fibers, with the alumina fibers comprising not less than 30% by weight and the quartz fibers comprising not less than 60% by weight. 5) Fiber lamination step: sequentially lay a layer of modified ceramic fiber felt A, a layer of modified ceramic fiber felt B, two layers of modified ceramic fiber cloth C, and a layer of modified ceramic fiber cloth D to form a laminated structure. The layers are sewn together with ceramic sewing thread to obtain a ceramic insulation tile sintering aid.

2. The preparation method according to claim 1, wherein In step 1), the water-soluble polymer solution is a polyacrylamide aqueous solution with a concentration of 1% to 5%, and the immersion time is 1 to 10 minutes; the oven temperature is 60 to 100°C.

3. The preparation method according to claim 1, wherein The ceramic fiber felt B in step 2) is immersed for 10 to 30 minutes.

4. The preparation method according to claim 1, wherein In step 2), the water-soluble polymer solution is a polyacrylamide aqueous solution with a concentration of 5% to 10%; the mass ratio of the boron nitride to the polymer solute in the water-soluble polymer solution is 1:1; and the oven temperature is 60 to 100°C.

5. The preparation method according to claim 1, wherein In step 3), the water-soluble polymer solution is a polyacrylamide aqueous solution with a concentration of 1% to 5%, and the immersion time is 1 to 10 minutes; the oven temperature is 60 to 100°C.

6. The preparation method according to claim 1, wherein In step 4), the water-soluble polymer solution is a polyacrylamide aqueous solution with a concentration of 1% to 5%, and the immersion time is 1 to 10 minutes; the oven temperature is 60 to 100°C.

7. The preparation method according to claim 1, wherein In step 5), the thickness of the modified ceramic fiber felt A is 0.5-1.0 mm, the thickness of the modified ceramic fiber felt B is 1.0-2.0 mm, the thickness of each layer of the modified ceramic fiber cloth C is 0.3-0.5 mm, and the thickness of the modified ceramic fiber cloth D is 0.1-0.3 mm.

8. A ceramic insulation tile sintering auxiliary material, characterized in that: The ceramic insulation tile sintering auxiliary material is prepared by the preparation method of any one of claims 1 to 7.

9. A method for using a ceramic insulation tile sintering auxiliary material, characterized in that: The following steps are involved: Before the thermal insulation tile blank is sintered, the ceramic thermal insulation tile sintering auxiliary prepared by the preparation method of a ceramic thermal insulation tile sintering auxiliary according to any one of claims 1 to 7 is wrapped on the surface of the thermal insulation tile blank to be sintered, and the modified ceramic fiber felt A is in contact with the thermal insulation tile blank. After wrapping is completed, sintering is carried out according to the original temperature program.