High-temperature-resistant heat insulation tile and preparation method thereof

Abstract

The invention discloses a high-temperature-resistant thermal insulation tile and a preparation method thereof, and belongs to the technical field of preparation of high-performance thermal protection materials. The method comprises the following steps: mixing aluminum powder serving as a sintering aid with ceramic fibers, a normal-temperature binder, a dispersing agent and the like to prepare uniformly dispersed water-based slurry of the heat-insulating tile; pouring the heat-insulating tile slurry into a filtering tool for water filtering, forming a heat-insulating tile wet blank, and drying to obtain a heat-insulating tile dry blank; and transferring the heat-insulating tile dry blank into a muffle furnace for reactive sintering to obtain the high-temperature-resistant heat-insulating tile.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of high-performance thermal protection materials, and particularly relates to a high-temperature-resistant ceramic heat insulation tile and a preparation method thereof. BACKGROUND

[0002] Rigid ceramic heat insulation tiles are generally prepared by using ceramic fibers (such as quartz fibers, alumina fibers, etc.) as raw materials and boron compounds (such as boron nitride, boron carbide, etc.) as sintering aids through processes such as green body forming and high-temperature sintering. In the high-temperature sintering process, the boron compounds are oxidized to form molten boron oxide, which diffuses to the junctions of the ceramic fibers and reacts with the ceramic fibers to form a reinforced bonding bridge structure, providing the ceramic tile with the required mechanical properties. However, the melting and boiling points of boron oxide are relatively low, and it volatilizes at high temperatures (≥1200 ℃), which limits its application range. By controlling the content of boron oxide in the system, the temperature resistance of the ceramic heat insulation tile can be significantly improved. For example, compared with the AETB heat insulation tile developed by NASA AMES Research Center (68% quartz fiber + 12% borosilicate aluminum fiber + 20% alumina fiber), the BRI heat insulation tile developed by Boeing Company (67% quartz fiber + 32.75% alumina fiber + 0.25% boron carbide) significantly improves the temperature resistance of the heat insulation tile (the maximum temperature resistance can reach 1500 ℃) by replacing borosilicate aluminum with boron carbide and reducing the content of boron oxide, and has been widely used in the windward surface of X-37B. However, the boron-containing sintering aid system has a limited high-temperature resistance, and it is difficult to meet the high demand for reusability.

[0003] Therefore, there is an urgent need for a sintering aid solution that can replace boron compounds and significantly improve the high-temperature resistance and reusability of ceramic heat insulation tiles. SUMMARY

[0004] The present application aims to overcome the high-temperature resistance defects of existing boron-containing sintering aids and provide a ceramic heat insulation tile using aluminum powder as a sintering aid and a preparation method thereof, achieving the purposes of improving high-temperature resistance and enhancing reusability stability.

[0005] To achieve the above-mentioned purposes, the present application adopts the following technical solutions.

[0006] A preparation method of a high-temperature-resistant heat insulation tile, comprising the following steps: 1) Slurry preparation: heat-treat aluminum powder, then add ceramic fibers, heat-treated aluminum powder, room-temperature binder and dispersant into deionized water, stir uniformly to obtain a stable slurry; 2) Green body forming: pour the slurry into a filter tool, filter out the deionized water by vacuum suction filtration to obtain a heat insulation tile wet green body, and then obtain a heat insulation tile dry green body by drying. 3) high-temperature sintering: placing the ceramic tile green body in a muffle furnace for degreasing, reaction, and sintering to obtain a high-temperature-resistant ceramic heat-insulating tile.

[0007] Further, the heating pretreatment condition of the aluminum powder in step 1) is heat preservation at 300-600 ℃ for 6-72 h.

[0008] Further, the particle size of the pretreated aluminum powder in step 1) is 0.5-15 μm.

[0009] Further, the ceramic fiber in step 1) is quartz fiber and alumina fiber; the diameter of the ceramic fiber is 0.5-8 μm, and the length is 1-20 mm.

[0010] Further, the content of the quartz fiber, the alumina fiber, and the pretreated aluminum powder in step 1) ranges from 40 wt% to 98 wt%, from 0 wt% to 40 wt%, and from 2 wt% to 30 wt%, respectively.

[0011] Further, the dispersant in step 1) includes but is not limited to one or a combination of more than one of polyethylene glycol, polyammonium carboxylate, polyether-modified siloxane, polyacrylic acid / polyacrylate copolymer, sulfonate-acrylic acid copolymer, polyglycerol fatty acid ester, polyether phosphate / alkyl phosphate, etc.; the addition amount of the dispersant is 0.2-5 wt% relative to the mass of the aluminum powder.

[0012] Further, the room-temperature binder in step 1) is one of starch, sucrose, polyvinyl alcohol, dextrin, etc.; the addition amount of the room-temperature binder is not more than 15 wt% relative to the total mass of the solid phase in the slurry.

[0013] Further, the stirring rate in step 1) is 1000-4000 r / min, and the total stirring time is 30-130 min.

[0014] Further, the drying temperature in step 2) is not more than 100 ℃.

[0015] Further, the sintering temperature in step 3) is 1200-1700 ℃, and the sintering time is 1-10 h.

[0016] A high-temperature-resistant heat-insulating tile is prepared by the above preparation method.

[0017] The present application has the following beneficial effects.

[0018] ​The pretreatment process of the aluminum powder can prevent the reaction of the aluminum powder with water, so as to ensure the normal progress of the process and the structure and performance of the ceramic tile. In the slurry preparation process, the long stirring time required for the dispersion of the ceramic fiber and the temperature rise caused by the stirring can promote the reaction of the aluminum powder without pretreatment with water, thereby adversely affecting the structure and performance of the heat insulation tile, and even hindering the normal progress of the process. The heating and heat preservation of the aluminum powder can form an amorphous oxide layer on the surface of the aluminum powder, so as to prevent the reaction with water; and the optimization of the dispersant system can reduce the stirring time and prevent the temperature rise.

[0019] 2) The aluminum powder can replace the traditional sintering aid, so as to realize the synergistic improvement of the near-zero shrinkage, mechanical property and temperature resistance of the ceramic heat insulation tile. Based on the Kirkendall effect of the aluminum powder in the thermal oxidation process, the in-situ formation of the hollow structure, the outward growth of the aluminum oxide and the strengthening structure of the fine-grained bonding bridge, the reaction sintering porous ceramic is respectively endowed with the characteristics of high porosity, near-zero shrinkage and high strength. In the system of silicon oxide, aluminum oxide and the like, the molten aluminum can form a strong bonding bridge structure through the diffusion, oxidation and mullitization processes, so as to improve the mechanical property of the material; at the same time, the newly formed ceramic phase in the system has the properties of high temperature resistance and low thermal conductivity. DETAILED DESCRIPTION

[0020] In order to make the characteristics, advantages and effects of the technical solutions in the technical solutions of the present application more obvious and easy to understand, the following further detailed description is made in combination with the embodiments.

[0021] Embodiment 1: Preparation of a high-temperature-resistant heat insulation tile.

[0022] Slurry preparation: quartz fibers and aluminum oxide fibers with a diameter of 3 μm and a length of 15 mm were mixed in deionized water and stirred at a speed of 2000 r / min for 50 min. A water-based slurry with a solid content of 20 wt% containing pretreated 3 μm aluminum powder, starch and polyethylene glycol was added. Stirring was carried out at a speed of 2000 r / min for 20 min to obtain a ceramic tile slurry with a solid content of 0.2 wt%.

[0023] The mass ratio of the solid phase components, quartz fiber, aluminum oxide fiber and aluminum powder in the slurry is 70:20:10.

[0024] The aluminum powder pretreatment process is: heating at a rate of 1 ℃ / min to 450 ℃ and heat preservation for 36 h for surface passivation.

[0025] The water-based slurry of the aluminum powder, starch and polyethylene glycol, the starch addition amount is 8 wt% (relative to the total mass of the solid phase in the slurry), and the polyethylene glycol addition amount is 1 wt% (relative to the mass of the aluminum powder); stirring at a speed of 500 r / min for 15 min.

[0026] Green body forming: pour the slurry prepared in step 1) into a filter tool, and remove ionized water by vacuum suction filtration to obtain a thermal insulation tile wet green body; after placing the thermal insulation tile wet green body on a gypsum board for 48 h to absorb water, place it in an 80 ℃ oven until completely dried to obtain a thermal insulation tile dry green body.

[0027] High-temperature sintering: place the ceramic tile dry green body prepared in step 2) in a muffle furnace for degreasing, reaction and sintering, heat to 600 ℃ at a rate of 1 ℃ / min for 2 h for degreasing, and heat to 1550 ℃ at a rate of 2 ℃ / min for 4 h to obtain a high-temperature-resistant ceramic thermal insulation tile.

[0028] After testing, the prepared high-temperature-resistant thermal insulation tile has a density of 0.27 , a room temperature compressive strength of greater than 2.2 MPa, a room temperature thermal conductivity of less than 0.038 W / (m·K), and a linear shrinkage of less than 1% after being treated at 1500 ℃ for 1 h.

[0029] Example 2: Preparation of a high-temperature-resistant thermal insulation tile.

[0030] 1) Slurry preparation: mix quartz fibers and alumina fibers with a diameter of 3 μm and a length of 15 mm in deionized water, and stir at a speed of 2000 r / min for 55 min. Add a water-based slurry with a solid content of 25 wt% containing pretreated 1 μm aluminum powder, starch and polyethylene glycol; stir at a speed of 2000 r / min for 30 min to obtain a ceramic tile slurry with a solid content of 0.15 wt%.

[0031] The mass ratio of the solid phase components quartz fiber, alumina fiber and aluminum powder in the slurry is 80:5:15.

[0032] The aluminum powder pretreatment process is: heat to 400 ℃ at a rate of 0.5 ℃ / min for 48 h for surface passivation.

[0033] The water-based slurry of the aluminum powder, starch and polyethylene glycol, the starch addition amount is 10 wt% (relative to the total mass of the solid phase in the slurry), and the polyethylene glycol addition amount is 1.2 wt% (relative to the mass of the aluminum powder); stir at a speed of 500 r / min for 15 min.

[0034] 2) Green body forming: pour the slurry prepared in step 1) into a filter tool, and remove ionized water by vacuum suction filtration to obtain a thermal insulation tile wet green body; after placing the thermal insulation tile wet green body on a gypsum board for 48 h to absorb water, place it in an 80 ℃ oven until completely dried to obtain a thermal insulation tile dry green body.

[0035] 3) High-temperature sintering: the ceramic tile green body prepared in step 2) is placed in a muffle furnace for degreasing, reaction, and sintering, heated to 600 ℃ at a rate of 1 ℃ / min for 2 h for degreasing, and heated to 1600 ℃ at a rate of 2 ℃ / min for 2 h, to obtain a high-temperature-resistant ceramic heat-insulating tile.

[0036] The prepared high-temperature-resistant heat-insulating tile has a density of 0.21 , a room-temperature compressive strength of greater than 2.0 MPa, a room-temperature thermal conductivity of less than 0.032 W / (m·K), and a linear shrinkage of less than 1% after being treated at 1500 ℃ for 1 h.

[0037] Example 3: Preparation of a high-temperature-resistant heat-insulating tile.

[0038] 1) Preparation of a slurry: quartz fibers and alumina fibers with a diameter of 8 μm and a length of 20 mm are added to deionized water and mixed, and stirred at a speed of 3500 r / min for 20 min. A water-based slurry with a solid content of 20 wt% containing pretreated 15 μm aluminum powder, starch, and polyether-modified siloxane is added; stirring is performed at a speed of 3500 r / min for 30 min, to obtain a ceramic tile slurry with a solid content of 0.1 wt%.

[0039] The mass ratio of the solid-phase components in the slurry, namely the quartz fibers, the alumina fibers, and the aluminum powder, is 70:15:15.

[0040] The aluminum powder pretreatment process is surface passivation by heating to 550 ℃ at a rate of 0.5 ℃ / min for 12 h.

[0041] The water-based slurry of the aluminum powder, the starch, and the polyether-modified siloxane has a starch addition amount of 15 wt% (relative to the total mass of the solid phase in the slurry) and a polyether-modified siloxane addition amount of 0.8 wt% (relative to the mass of the aluminum powder); stirring is performed at a speed of 500 r / min for 15 min.

[0042] 2) Green body forming: the slurry prepared in step 1) is poured into a filter tool, and deionized water is filtered out by vacuum suction filtration, to obtain a heat-insulating tile wet green body; the heat-insulating tile wet green body is placed on a gypsum board to absorb water for 24 h, and then placed in a 70 ℃ oven until completely dried, to obtain a heat-insulating tile dry green body.

[0043] 3) High-temperature sintering: the ceramic tile green body prepared in step 2) is placed in a muffle furnace for degreasing, reaction, and sintering, heated to 600 ℃ at a rate of 1 ℃ / min for 2 h for degreasing, and heated to 1600 ℃ at a rate of 2 ℃ / min for 4 h, to obtain a high-temperature-resistant ceramic heat-insulating tile.

[0044] The prepared high-temperature-resistant heat-insulating tile has a density of 0.29 It has a room temperature compressive strength greater than 2.1 MPa, a room temperature thermal conductivity less than 0.045 W / (m∙K), and a linear shrinkage rate of less than 1% after treatment at 1500 ℃ for 1 h.

[0045] Example 4: Preparation of high-temperature resistant heat-insulating tiles.

[0046] 1) Slurry preparation: Quartz fibers with a diameter of 0.5 μm and a length of 1.5 mm and alumina fibers were added to deionized water and mixed, and stirred at 1500 r / min for 75 min. A water-based slurry with a solid content of 20 wt% containing pretreated 0.5 μm aluminum powder, dextrin, and polyglycerol fatty acid esters was added; and stirred at 1500 r / min for 45 min to obtain a ceramic tile slurry with a solid content of 0.15 wt%.

[0047] The mass ratio of the solid components quartz fiber, alumina fiber and aluminum powder in the slurry is 95:0:5.

[0048] The aluminum powder pretreatment process is as follows: the temperature is increased to 300℃ at a rate of 0.5℃ / min and held for 72 h for surface passivation.

[0049] The aqueous slurry of aluminum powder, dextrin, and polyglycerol fatty acid esters is prepared with dextrin added at 10 wt% (relative to the total solid mass in the slurry) and polyglycerol fatty acid esters added at 4 wt% (relative to the mass of aluminum powder); and stirred at 500 r / min for 15 min.

[0050] 2) Blank forming: Pour the slurry obtained in step 1) into a filter fixture, and remove the deionized water by vacuum filtration to obtain a wet blank of the heat insulation tile; place the wet blank of the heat insulation tile on a gypsum board to absorb moisture for 24 hours, and then place it in a 60 ℃ oven until it is completely dry to obtain a dry blank of the heat insulation tile.

[0051] 3) High-temperature sintering: The ceramic tile blank obtained in step 2) is placed in a muffle furnace for degreasing, reaction and sintering. The temperature is raised to 600 ℃ at a rate of 1℃ / min and held for 2 h for degreasing. The temperature is raised to 1250 ℃ at a rate of 2 ℃ / min and held for 8 h to obtain high-temperature resistant ceramic heat insulation tile.

[0052] The prepared high-temperature resistant heat-insulating tile has a density of 0.11, as tested. It has a room temperature compressive strength greater than 0.8 MPa, a room temperature thermal conductivity less than 0.025 W / (m∙K), and a linear shrinkage rate of less than 1% after treatment at 1200 ℃ for 1 h.

[0053] Example 5: Preparation of high-temperature resistant heat-insulating tiles.

[0054] 1) Slurry preparation: Quartz fibers with a diameter of 1 μm and a length of 3 mm and alumina fibers were added to deionized water and mixed, and stirred at 2000 r / min for 55 min. A water-based slurry with a solid content of 20 wt% containing pretreated 1 μm aluminum powder, starch and polycarboxylate ammonium salt was added; and stirred at 2000 r / min for 20 min to obtain a ceramic tile slurry with a solid content of 0.15 wt%.

[0055] The mass ratio of the solid components quartz fiber, alumina fiber and aluminum powder in the slurry is 45:30:25.

[0056] The aluminum powder pretreatment process is as follows: the temperature is increased to 300℃ at a rate of 0.5℃ / min and held for 72 h for surface passivation.

[0057] The aqueous slurry of aluminum powder, dextrin, and ammonium polycarboxylate was prepared with dextrin added at 12 wt% (relative to the total solid mass in the slurry) and ammonium polycarboxylate added at 0.3 wt% (relative to the mass of aluminum powder); and stirred at 400 r / min for 15 min.

[0058] 2) Blank forming: Pour the slurry obtained in step 1) into a filter fixture, and remove the deionized water by vacuum filtration to obtain a wet blank of the heat insulation tile; place the wet blank of the heat insulation tile on a gypsum board to absorb moisture for 48 hours, and then place it in a 60 ℃ oven until it is completely dry to obtain a dry blank of the heat insulation tile.

[0059] 3) High-temperature sintering: The ceramic tile blank obtained in step 2) is placed in a muffle furnace for degreasing, reaction and sintering. The temperature is raised to 600 ℃ at a rate of 1℃ / min and held for 2 h for degreasing. The temperature is raised to 1650 ℃ at a rate of 2 ℃ / min and held for 2 h to obtain high-temperature resistant ceramic heat insulation tile.

[0060] The prepared high-temperature resistant heat-insulating tile has a density of 0.32, as tested. It has a room temperature compressive strength greater than 3.1 MPa, a room temperature thermal conductivity less than 0.053 W / (m∙K), and a linear shrinkage rate of less than 1% after treatment at 1550 ℃ for 1 h.

[0061] Although the present invention has been disclosed above with reference to embodiments, it is not intended to limit the present invention. Appropriate modifications or equivalent substitutions made by those skilled in the art to the technical solutions of the present invention should be covered within the protection scope of the present invention, which is defined by the claims.

Claims

1. A method for preparing a high-temperature resistant heat-insulating tile, characterized in that, Includes the following steps: 1) Slurry preparation: The aluminum powder is pretreated by heating, and then the ceramic fiber, the pretreated aluminum powder, the room temperature binder and the dispersant are added to deionized water and stirred evenly to obtain a stable slurry. 2) Blank forming: The slurry is poured into a filter fixture, and deionized water is removed by vacuum filtration to obtain a wet blank of the heat insulation tile. After drying, a dry blank of the heat insulation tile is obtained. 3) High-temperature sintering: The dry ceramic tile blank is placed in a muffle furnace for degreasing, reaction and sintering to obtain high-temperature resistant ceramic heat insulation tile.

2. The preparation method according to claim 1, characterized in that, In step 1), the heating pretreatment conditions for aluminum powder are 300~600 ℃ for 6~72 h.

3. The preparation method according to claim 1 or 2, characterized in that, Median particle size of pretreated aluminum powder in step 1) The range is 0.5~15 μm.

4. The preparation method according to claim 1, characterized in that, In step 1), the ceramic fibers are quartz fibers and alumina fibers; the diameter of the ceramic fibers is 0.5~8 μm and the length is 1~20 mm.

5. The preparation method according to claim 4, characterized in that, In step 1), the contents of quartz fiber, alumina fiber and pretreated aluminum powder range from 40 to 98 wt%, 0 to 40 wt%, and 2 to 30 wt%, respectively.

6. The preparation method according to claim 1, characterized in that, The dispersant in step 1) includes one or more of the following: polyethylene glycol, polycarboxylic acid ammonium salt, polyether modified siloxane, polyacrylic acid / polyacrylate copolymer, sulfonate-acrylic acid copolymer, polyglycerol fatty acid ester, polyether phosphate ester / alkyl phosphate ester; the amount of dispersant added is 0.2~5 wt% relative to the mass of aluminum powder.

7. The preparation method according to claim 1, characterized in that, In step 1), the room temperature binder is one of starch, sucrose, polyvinyl alcohol, or dextrin; the amount of room temperature binder added is no more than 15 wt% relative to the total solid mass in the slurry.

8. The preparation method according to claim 1, characterized in that, In step 1), the stirring rate is 1000~4000 r / min and the total stirring time is 30~130 min; in step 2), the drying temperature does not exceed 100 ℃.

9. The preparation method according to claim 1, characterized in that, In step 3), the sintering temperature is 1200~1700 ℃ and the sintering time is 1~10 h.

10. A high-temperature resistant heat-insulating tile, characterized in that, It is prepared by the preparation method according to any one of claims 1-9.