A heat-resistant ceramic fiber composite gate plate and a preparation method and application thereof

Abstract

The application relates to the technical field of industrial furnace system, solves the problems of structural failure and performance decline caused by the mismatch of thermal expansion coefficients and the uneven temperature field which cannot be fundamentally solved by the existing means, and particularly relates to a heat-resistant ceramic fiber composite damper and a preparation method thereof, which is prepared by medium-temperature solidification sintering of a pre-oxidized iron-chromium-aluminum alloy framework and a ceramic matrix filled in the framework at 800-1000 DEG C, wherein the ceramic matrix is composed of polycrystalline alumina fiber, Y2O3 stabilizer, nano zirconium oxide particles and an acid aluminum phosphate solution. The composite damper has excellent high-temperature structural stability, thermal shock resistance and temperature uniformity, is suitable for a high-temperature industrial environment above 1200 DEG C, and the service life is significantly improved.

Description

Technical Field

[0001] This application relates to the field of industrial furnace and kiln materials, and more specifically, it relates to a heat-resistant ceramic fiber composite gate and its preparation method. Background Technology

[0002] Currently, gate valves used in high-temperature industrial applications are mostly made of heat-resistant cast steel or composite gate valves combining zirconium-containing ceramic fibers with stainless steel plates. Compared to heat-resistant cast steel, composite gate valves achieve better thermal shock resistance, mechanical strength, and service life due to their increased bulk density and the addition of coatings. However, the combination of metal and ceramics faces two major challenges: mismatched coefficients of thermal expansion and the "cold core" effect.

[0003] In related technologies, composite gates combining zirconium-containing ceramic fibers and stainless steel plates have a huge difference in the coefficients of thermal expansion between the metal skeleton and the ceramic fiber module. This leads to interfacial shear stress during repeated thermal cycling, which can easily cause material peeling or cracking. The metal skeleton becomes a heat source at high temperatures, resulting in uneven temperature distribution inside the gate, additional thermal stress, and may reduce the strength of the metal.

[0004] Therefore, some companies have attempted to alleviate the above problems by improving material formulations or surface treating the metal skeleton. However, these methods have failed to fundamentally solve the structural failures caused by the mismatch in thermal expansion coefficients and the performance degradation caused by uneven temperature fields. Based on this, this application provides a heat-resistant ceramic fiber composite gate, its preparation method, and its application. Summary of the Invention

[0005] To address the aforementioned technical problems, this application provides a heat-resistant ceramic fiber composite gate, its preparation method, and its application. This method can overcome the technical barriers to combining metal and ceramic while maintaining the comprehensive performance of the materials, thereby achieving a longer service life and higher reliability.

[0006] In a first aspect, this application provides a heat-resistant ceramic fiber composite gate, which adopts the following technical solution:

[0007] A heat-resistant ceramic fiber composite gate is made by sintering a pre-oxidized iron-chromium-aluminum alloy skeleton and a ceramic matrix filled in the skeleton at a medium temperature of 800-1000℃.

[0008] The iron-chromium-aluminum alloy skeleton has a grid-like, porous, or corrugated structure.

[0009] The ceramic matrix is ​​composed of polycrystalline alumina fibers, Y2O3 stabilizer, nano-zirconia particles, and an aqueous solution of acidic aluminum phosphate.

[0010] Preferably, the weight ratio of the pre-oxidized iron-chromium-aluminum alloy skeleton to the ceramic matrix is ​​1:(3-5).

[0011] Preferably, the grade of the iron-chromium-aluminum alloy skeleton is 0Cr25Al5;

[0012] The pre-oxidation treatment conditions are: heating at 700-900℃ in air for 1-2 hours.

[0013] Preferably, the ceramic matrix is ​​composed of the following components by weight percentage:

[0014] The ingredients are 80-90 wt% polycrystalline alumina fiber, 1-3 wt% Y2O3 stabilizer, 3-5 wt% nano-zirconia particles, and the balance being an aqueous solution of acidic aluminum phosphate.

[0015] Preferably, the polycrystalline alumina fiber is α-Al2O3 with an Al2O3 content of ≥99.5% and a fiber diameter of 7-12μm.

[0016] Preferably, the aqueous solution of the acidic aluminum phosphate is a 30-50% aluminum dihydrogen phosphate solution.

[0017] Secondly, this application provides a method for preparing a heat-resistant ceramic fiber composite gate, which adopts the following technical solution:

[0018] A method for preparing a heat-resistant ceramic fiber composite gate includes the following steps:

[0019] a) Pre-oxidize the iron-chromium-aluminum alloy skeleton;

[0020] b) Mix polycrystalline alumina fibers, Y2O3 stabilizer, nano-zirconia particles and an aqueous solution of acidic aluminum phosphate in the corresponding weight ratio to prepare a ceramic slurry;

[0021] c) Pour the ceramic slurry obtained in b) into the alloy skeleton in a), and after shaping, perform medium-temperature curing and sintering at 800-1000℃ for 2-4 hours to obtain the heat-resistant ceramic fiber composite gate.

[0022] Thirdly, this application provides a heat-resistant ceramic fiber composite gate, or the application of the heat-resistant ceramic fiber composite gate obtained by the above process in carbon flue gates or high-temperature industrial furnace systems, characterized in that it is suitable for long-term application in high-temperature industrial environments above 1200℃.

[0023] In summary, this application has the following beneficial effects:

[0024] 1. The heat-resistant ceramic fiber composite gate in this application achieves a synergistic effect of macroscopic mechanical support and micro-crack suppression through the composite structure of pre-oxidized iron-chromium-aluminum alloy skeleton and multi-scale toughened ceramic matrix, thereby ensuring its excellent structural stability, thermal shock resistance and mechanical strength in high-temperature environments above 1200℃.

[0025] 2. The heat-resistant ceramic fiber composite gate obtained by the preparation method in this application benefits from the precise process control of pre-oxidation, slurry filling and medium-temperature curing sintering. The resulting product has stable and uniform performance, good high-temperature toughness and durability, excellent long-term stability, and significant industrialization value and application prospects.

[0026] 3. The heat-resistant ceramic fiber composite gate in this application can effectively meet the application needs of systems such as carbon flues and high-temperature industrial furnaces under extreme thermal cycling conditions compared with traditional refractory bricks or single ceramic materials. Its superior comprehensive performance, long-term applicability and universality are significantly better than traditional materials, effectively extending the service life of equipment and reducing maintenance costs. Detailed Implementation

[0027] The following detailed description of this application is based on the embodiments. Except for some specifications that are explicitly limited, the raw materials used in this application are all commercially available common materials.

[0028] Preparation Example 1

[0029] A ferrochrome-aluminum alloy frame, grade 0Cr25Al5, is specifically a grid-like steel square frame with dimensions of 600×600×10mm, divided into 3600 units, each unit being 10×10×10mm.

[0030] Preparation Example 2

[0031] A ferrochrome-aluminum alloy frame, grade 0Cr25Al5, is specifically a grid-like steel square frame with dimensions of 600×600×10mm, divided into 3600 units, each unit being 10×10×10mm.

[0032] The pre-oxidation treatment conditions are: heating at 900°C for 1 hour in an air atmosphere.

[0033] Preparation Example 3

[0034] A ferrochrome-aluminum alloy frame, grade 0Cr25Al5, is specifically a grid-like steel square frame with dimensions of 600×600×10mm, divided into 36 units, each unit being 100×100×10mm.

[0035] The pre-oxidation treatment conditions are: heating at 700°C for 2 hours in an air atmosphere.

[0036] Preparation Examples 4-8

[0037] A ceramic matrix comprising the following components by weight percentage (per 100 kg):

[0038] Table: Components and their weights (kg) in Preparation Examples 4-8

[0039] Preparation Example Components 4 5 6 7 8 Polycrystalline alumina fiber 80 80 80 85 90 Y2O3 stabilizer 1 2 3 2 1 nano-zirconia particles 3 4 5 4 3 Aqueous solution of aluminum phosphate 16 14 12 9 6

[0040] The polycrystalline alumina fiber is α-Al2O3 with an Al2O3 content of ≥99.5% and a fiber diameter of 7-12μm. The aqueous solution of acidic aluminum phosphate is a 50% aluminum dihydrogen phosphate solution.

[0041] Performance testing

[0042] The gate plate prepared in the embodiment was selected as the test object, and its high-temperature durability, thermal shock performance, thermal conductivity and interfacial bonding strength were tested respectively. The specific test methods and conditions are as follows:

[0043] 1) High-temperature durability test: Place the gate to be tested in a furnace at 1200℃ for 1000 hours, observe the structural integrity and record the results;

[0044] 2) Thermal shock performance test: The gate to be tested is cyclically subjected to 100 cycles between 1200℃ and room temperature, and the cracks and spalling of the gate are recorded.

[0045] 3) Thermal conductivity test: The thermal diffusivity from room temperature to 1200℃ was measured using the laser scintillation method;

[0046] 4) Interface bonding strength: The metal-ceramic interface strength is measured by shear test.

[0047] Example

[0048] Example 1

[0049] A heat-resistant ceramic fiber composite gate is prepared by the following steps:

[0050] a) The pre-oxidized iron-chromium-aluminum alloy skeleton was prepared by Preparation Example 1;

[0051] b) Mix the ceramic matrix obtained in Preparation Example 4 evenly;

[0052] c) Pour the ceramic matrix obtained in b) into the alloy skeleton in a) at a weight ratio of 1:3. After shaping, perform medium-temperature curing and sintering at 800℃ for 4 hours to obtain the heat-resistant ceramic fiber composite gate.

[0053] Example 2

[0054] A heat-resistant ceramic fiber composite gate differs from Example 1 in that it is prepared using the following steps:

[0055] a) The pre-oxidized iron-chromium-aluminum alloy skeleton was prepared by Example 2;

[0056] b) Mix the ceramic matrix obtained in Preparation Example 4 evenly;

[0057] c) Pour the ceramic matrix obtained in b) into the alloy skeleton in a) at a weight ratio of 1:3. After shaping, perform medium-temperature curing and sintering at 800℃ for 4 hours to obtain the heat-resistant ceramic fiber composite gate.

[0058] Example 3

[0059] A heat-resistant ceramic fiber composite gate differs from Example 1 in that it is prepared using the following steps:

[0060] a) The pre-oxidized iron-chromium-aluminum alloy skeleton was prepared by Example 3;

[0061] b) Mix the ceramic matrix obtained in Preparation Example 4 evenly;

[0062] c) Pour the ceramic matrix obtained in b) into the alloy skeleton in a) at a weight ratio of 1:3. After shaping, perform medium-temperature curing and sintering at 800℃ for 4 hours to obtain the heat-resistant ceramic fiber composite gate.

[0063] Example 4

[0064] A heat-resistant ceramic fiber composite gate differs from Example 1 in that it is prepared using the following steps:

[0065] a) The pre-oxidized iron-chromium-aluminum alloy skeleton was prepared by Preparation Example 1;

[0066] b) Mix the ceramic matrix obtained in Preparation Example 5 evenly;

[0067] c) Pour the ceramic matrix obtained in b) into the alloy skeleton in a) at a weight ratio of 1:3. After shaping, perform medium-temperature curing and sintering at 800℃ for 4 hours to obtain the heat-resistant ceramic fiber composite gate.

[0068] Example 5

[0069] A heat-resistant ceramic fiber composite gate differs from Example 1 in that it is prepared using the following steps:

[0070] a) The pre-oxidized iron-chromium-aluminum alloy skeleton was prepared by Preparation Example 1;

[0071] b) Mix the ceramic matrix obtained in Preparation Example 6 evenly;

[0072] c) Pour the ceramic matrix obtained in b) into the alloy skeleton in a) at a weight ratio of 1:3. After shaping, perform medium-temperature curing and sintering at 800℃ for 4 hours to obtain the heat-resistant ceramic fiber composite gate.

[0073] Example 6

[0074] A heat-resistant ceramic fiber composite gate differs from Example 1 in that it is prepared using the following steps:

[0075] a) The pre-oxidized iron-chromium-aluminum alloy skeleton was prepared by Preparation Example 1;

[0076] b) Mix the ceramic matrix obtained in Preparation Example 7 evenly;

[0077] c) Pour the ceramic matrix obtained in b) into the alloy skeleton in a) at a weight ratio of 1:3. After shaping, perform medium-temperature curing and sintering at 800℃ for 4 hours to obtain the heat-resistant ceramic fiber composite gate.

[0078] Example 7

[0079] A heat-resistant ceramic fiber composite gate differs from Example 1 in that it is prepared using the following steps:

[0080] a) The pre-oxidized iron-chromium-aluminum alloy skeleton was prepared by Preparation Example 1;

[0081] b) Mix the ceramic matrix obtained in Preparation Example 8 evenly;

[0082] c) Pour the ceramic matrix obtained in b) into the alloy skeleton in a) at a weight ratio of 1:3. After shaping, perform medium-temperature curing and sintering at 800℃ for 4 hours to obtain the heat-resistant ceramic fiber composite gate.

[0083] Comparative Example 1

[0084] A heat-resistant ceramic fiber composite gate differs from Example 1 in that:

[0085] The ceramic matrix was replaced by an equal amount of zirconium-containing ceramic fibers, and an additional 5% of the total amount of zirconium-containing ceramic fibers was added with HC-1601 binder, purchased from Huachuan, with all other conditions being the same.

[0086] Comparative Example 2

[0087] A heat-resistant ceramic fiber composite gate differs from Example 1 in that the iron-chromium-aluminum alloy skeleton is not pre-oxidized, while all other conditions are the same.

[0088] The heat-resistant ceramic fiber composite gates prepared in Examples 1-7 and Comparative Examples 1-2 were selected as test objects, and their high-temperature durability, thermal shock performance, thermal conductivity and interfacial bonding strength were tested respectively. The test results are recorded in the table below.

[0089] Table: Performance test results of Examples 1-7 and Comparative Examples 1-2

[0090] Test Project Group High temperature durability 1000h Post-thermal shock cycle state Thermal conductivity W / m·K Interfacial bonding strength (MPa) Example 1 No cracks or peeling intact 1.8 12.5 Example 2 No cracks or peeling intact 1.8 12.7 Example 3 No cracks or peeling intact 1.9 13.0 Example 4 No cracks or peeling intact 2.1 12.5 Example 5 No cracks or peeling intact 2.4 12.5 Example 6 No cracks or peeling intact 2.2 12.2 Example 7 No cracks or peeling intact 2.0 12.0 Comparative Example 1 minor cracks Edge peeling 1.6 9.2 Comparative Example 2 minor cracks Edge peeling 1.8 10.1

[0091] As can be seen from the table above, the heat-resistant ceramic fiber composite gates prepared in Examples 1-5 all exhibit excellent high-temperature structural stability, thermal shock resistance, and temperature uniformity, making them suitable for high-temperature industrial environments above 1200℃. Compared with Comparative Examples 1-2, their performance is significantly improved, as detailed below:

[0092] Regarding its high-temperature durability: no cracks or peeling were observed after 1000 hours;

[0093] Its condition after thermal shock cycling is basically intact, with no defects such as peeling or cracking.

[0094] Its thermal conductivity is as high as 1.8-2.4 W / m·K, which is about 0-11% higher than that of comparative examples 1-2, demonstrating its excellent heat dissipation and high temperature resistance.

[0095] Its interfacial bonding strength is as high as 12.2-13.0MPa, which is about 21-40% higher than that of comparative examples 1-2. It can be seen that it has excellent bonding ability and is not prone to defects caused by the mismatch of thermal expansion coefficients and the "cold core" effect due to the combination of metal and ceramic.

[0096] In summary, based on the data, we can conclude that it has the following advantages:

[0097] 1) Excellent high-temperature structural stability:

[0098] Both high-purity polycrystalline alumina fibers and pre-oxidized alloy skeletons can withstand high temperatures above 1200℃ for a long time without softening or melting. The addition of water-based solutions of nano-zirconia, Y2O3 and acidic aluminum phosphate further stabilizes the high-temperature phase composition of the ceramic matrix.

[0099] 2) Excellent thermal shock resistance (thermal shock stability):

[0100] This is one of the most prominent advantages of this application. When the gate plate is rapidly cooled or heated, huge thermal stress will be generated inside. The metal skeleton of this application has good plasticity and thermal conductivity, which can buffer some of the thermal stress. In addition, the multi-scale toughening mechanism (fiber toughening, phase transformation toughening) in the ceramic matrix can effectively suppress the propagation of microcracks caused by thermal stress and prevent the material from suddenly fracturing. That is, the metal and ceramic interfaces are firmly bonded, avoiding cracking at the interface due to the difference in thermal expansion coefficients.

[0101] 3) Significantly improved temperature uniformity:

[0102] Composite gates made by sintering a pre-oxidized iron-chromium-aluminum alloy skeleton and a ceramic matrix filled in the skeleton at medium temperature of 800-1000℃ have good overall heat insulation performance, which can reduce heat loss inside the furnace and kiln. At the same time, it makes the temperature field distribution of the gate itself and the surrounding area more uniform, reduces damage caused by local overheating, and is conducive to process stability and energy saving.

[0103] 4) Long service life:

[0104] The combined effect of all the above advantages (high temperature stability, thermal shock resistance, corrosion resistance, and uniform temperature) means that the speed at which cracks are generated and propagated in the gate plate is greatly reduced under harsh high-temperature cyclic conditions, and the risk of spalling and breakage is significantly reduced. Therefore, its service life is significantly improved compared with traditional refractory brick gate plates or pure ceramic gate plates, thereby improving the operating efficiency and economic benefits of industrial furnaces and kilns.

[0105] Based on the various data, the possible reasons are as follows:

[0106] The core principle of this heat-resistant ceramic fiber composite gate is the combination of rigidity and flexibility and multi-scale synergistic toughening. Through the composite of a metal skeleton and a ceramic matrix, it cleverly solves the problems of brittleness, poor thermal shock stability, and insufficient overall strength of traditional refractory materials at high temperatures. Specifically:

[0107] 1) The role of "reinforcing steel" – a pre-oxidized iron-chromium-aluminum alloy skeleton:

[0108] Mechanical support: The mesh, porous or corrugated structure provides macroscopic skeletal support for the entire gate, giving the material excellent overall mechanical strength and resistance to deformation, overcoming the shortcomings of pure ceramic materials that are brittle and easy to break.

[0109] The criticality of pre-oxidation treatment: Pre-oxidation of 0Cr25Al5 alloy in air at 700-900℃ is to pre-form a dense and robust mixed oxide film of Cr2O3 and Al2O3 on its surface. This film has two important functions:

[0110] Preventing continuous oxidation at high temperatures: This prevents oxygen from continuing to corrode the interior of the alloy during subsequent high-temperature use, greatly extending the service life of the skeleton itself.

[0111] Improved interfacial bonding: This oxide film, being an oxide as well as the ceramic substrate, has better chemical compatibility and can significantly improve the interfacial bonding strength between the metal skeleton and the ceramic substrate, preventing interfacial delamination due to differences in thermal expansion coefficients during thermal cycling.

[0112] 2) The role of "concrete" – multifunctional ceramic matrix:

[0113] High-temperature resistant main structure: Polycrystalline alumina fiber (α-Al2O3, ≥99.5%) is the main body of the matrix. Its melting point is extremely high (>2000℃), which provides the matrix with high-temperature structural stability and corrosion resistance in environments above 1200℃.

[0114] Micro- and nano-scale toughening:

[0115] Polycrystalline alumina fibers form a three-dimensional network in the matrix, which plays a role in fiber pull-out, bridging and deflection of micron-scale cracks, consumes fracture energy and greatly improves the fracture toughness of the material.

[0116] The added nano-zirconia (ZrO2) particles are the core technology. When the material is subjected to stress, ZrO2 undergoes a martensitic phase transformation (from tetragonal phase to monoclinic phase). This process is accompanied by a volume expansion of about 3-5%, which generates compressive stress on the surrounding microcracks and effectively inhibits crack propagation.

[0117] Stabilization treatment: Y2O3, as a stabilizer, can stabilize the high-temperature tetragonal phase of zirconia to room temperature, ensuring that the nano-zirconia particles can undergo phase transformation when needed during service, thereby exerting a toughening effect instead of spontaneously fracturing.

[0118] Low-temperature sintering and bonding: Acidic aluminum phosphate aqueous solution (aluminum dihydrogen phosphate) is an inorganic binder that dehydrates and condenses during the medium-temperature (800-1000℃) curing and sintering process to form an AlPO4 glass phase with good bonding strength. It enables the ceramic components to be cured at a relatively low temperature, avoiding fiber damage and excessive energy consumption caused by high-temperature sintering. At the same time, it also has a certain degree of heat resistance.

[0119] 3) Principle of synergistic effect:

[0120] The combination of a metallic framework (macroscopic toughness) and a ceramic matrix (micro-nano-scale toughness) allows stress to be effectively dispersed and absorbed at multiple levels, from macroscopic to microscopic, when the material is subjected to thermal or mechanical stress. A detailed analysis follows:

[0121] Macroscopic stress is borne by a tough metal skeleton; microscopic cracks are effectively prevented from propagating into the ceramic matrix by alumina fibers and zirconia particles undergoing phase transformation; good interfacial bonding between the metal and ceramic ensures that stress can be effectively transferred between the two.

[0122] Example 8

[0123] A heat-resistant ceramic fiber composite gate differs from Example 1 in that it is prepared using the following steps:

[0124] a) The pre-oxidized iron-chromium-aluminum alloy skeleton was prepared by Preparation Example 1;

[0125] b) Mix the ceramic matrix obtained in Preparation Example 4 evenly;

[0126] c) Pour the ceramic matrix obtained in b) into the alloy skeleton in a) at a weight ratio of 1:4. After shaping, perform medium-temperature curing and sintering at 800℃ for 4 hours to obtain the heat-resistant ceramic fiber composite gate.

[0127] Example 9

[0128] A heat-resistant ceramic fiber composite gate differs from Example 1 in that it is prepared using the following steps:

[0129] a) The pre-oxidized iron-chromium-aluminum alloy skeleton was prepared by Preparation Example 1;

[0130] b) Mix the ceramic matrix obtained in Preparation Example 4 evenly;

[0131] c) Pour the ceramic matrix obtained in b) into the alloy skeleton in a) at a weight ratio of 1:5. After shaping, perform medium-temperature curing and sintering at 800℃ for 4 hours to obtain the heat-resistant ceramic fiber composite gate.

[0132] Example 10

[0133] A heat-resistant ceramic fiber composite gate differs from Example 1 in that it is prepared using the following steps:

[0134] a) The pre-oxidized iron-chromium-aluminum alloy skeleton was prepared by Preparation Example 1;

[0135] b) Mix the ceramic matrix obtained in Preparation Example 4 evenly;

[0136] c) Pour the ceramic matrix obtained in b) into the alloy skeleton in a) at a weight ratio of 1:1. After shaping, perform medium-temperature curing and sintering at 800℃ for 4 hours to obtain the heat-resistant ceramic fiber composite gate.

[0137] The heat-resistant ceramic fiber composite gates prepared in Examples 8-10 above were selected as test objects, and their high-temperature durability, thermal shock performance, thermal conductivity and interfacial bonding strength were tested respectively. The test results are recorded in the table below.

[0138] Table: Performance Test Results of Examples 8-10

[0139] Test Project Group High temperature durability 1000h Post-thermal shock cycle state Thermal conductivity W / m·K Interfacial bonding strength (MPa) Example 8 No cracks or peeling intact 1.9 12.5 Example 9 No cracks or peeling intact 2.0 12.3 Example 10 No cracks or peeling intact 1.8 11.1

[0140] As can be seen from the table above, the heat-resistant ceramic fiber composite gates prepared in Examples 8-10 still possess excellent high-temperature structural stability, thermal shock resistance, and temperature uniformity, making them suitable for high-temperature industrial environments above 1200℃. Compared to Example 1, their various properties have changed to varying degrees, as detailed below:

[0141] Regarding its high-temperature durability: no cracks or peeling were observed after 1000 hours;

[0142] Its condition after thermal shock cycling is basically intact, with no defects such as peeling or cracking.

[0143] Its thermal conductivity is as high as 1.8-2.0 W / m·K, which is not significantly different from that of Example 1. However, based on the basic principle, it can be known that the higher the amount of ceramic matrix used, the higher its thermal conductivity will be. But if the amount is too high, it will affect the interfacial bonding strength.

[0144] Its interfacial bonding strength is as high as 11.1-12.5 MPa, which is not significantly different from that of Example 1, and still has excellent bonding ability. It can be seen that the preferred weight ratio of the pre-oxidized iron-chromium-aluminum alloy skeleton and the ceramic matrix is ​​1:(3-5), and there is no significant performance fluctuation within this range.

[0145] It should also be noted that the heat-resistant ceramic fiber composite gate in this application is only a typical example of Embodiment 1. Within the preferred range, those skilled in the art can adjust its operating temperature and other conditions according to actual operation, and its various performance changes can be expected, so they will not be elaborated further.

[0146] The above are all modifications that can be made to this embodiment without contributing any inventive step, or solutions that clearly constitute technical teaching, after reading this specification. However, as long as they are within the scope of the claims of this application, they should be protected by patent law.

Claims

1. A heat-resistant ceramic fiber composite gate, characterized in that, It is made by sintering a pre-oxidized iron-chromium-aluminum alloy skeleton and a ceramic matrix filled in the skeleton at a medium temperature of 800-1000℃; The weight ratio of the pre-oxidized iron-chromium-aluminum alloy skeleton to the ceramic matrix is ​​1:(3-5); The iron-chromium-aluminum alloy skeleton has a grid-like, porous, or corrugated structure. The grade of the iron-chromium-aluminum alloy skeleton is 0Cr25Al5; The pre-oxidation treatment conditions are: heating at 700-900℃ in air for 1-2 hours; The ceramic matrix is ​​composed of the following components by weight percentage: Polycrystalline alumina fiber 80-90wt%, Y2O3 stabilizer 1-3wt%, nano-zirconia particles 3-5wt%, and aqueous solution of acidic aluminum phosphate as the balance; The polycrystalline alumina fiber is α-Al2O3 with an Al2O3 content of ≥99.5% and a fiber diameter of 7-12 μm.

2. The heat-resistant ceramic fiber composite gate according to claim 1, characterized in that, The aqueous solution of the acidic aluminum phosphate is a 30-50% aluminum dihydrogen phosphate solution.

3. The method for preparing the heat-resistant ceramic fiber composite gate according to any one of claims 1-2, characterized in that, Includes the following steps: a) Pre-oxidize the iron-chromium-aluminum alloy skeleton; b) Mix polycrystalline alumina fibers, Y2O3 stabilizer, nano-zirconia particles and an aqueous solution of acidic aluminum phosphate in the corresponding weight ratio to prepare a ceramic slurry; c) Pour the ceramic slurry obtained in b) into the alloy skeleton in a), and after shaping, perform medium-temperature curing and sintering at 800-1000℃ for 2-4 hours to obtain the heat-resistant ceramic fiber composite gate.

4. The application of the heat-resistant ceramic fiber composite gate as described in claim 1 or the heat-resistant ceramic fiber composite gate obtained in claim 3 in carbon flue gates or high-temperature industrial furnace systems, characterized in that, It is suitable for long-term use in high-temperature industrial environments above 1200℃.