Fiber-reinforced ceramic-based composite material with sandwich structure and preparation method of fiber-reinforced ceramic-based composite material

Abstract

The invention discloses a fiber-reinforced ceramic-based composite material with a sandwich structure and a preparation method of the fiber-reinforced ceramic-based composite material, and belongs to the technical field of fiber-reinforced ceramic-based composite materials. In order to solve the problems that an existing sandwich structure ceramic-based composite material is insufficient in light weight and high-temperature resistance and high in preparation cost, the sandwich structure material is prepared by mainly adopting a method of taking inorganic fibers as a framework and filling and bonding a liquid ceramic precursor through a pressing and laminating process. The invention can realize light weight, high strength, high temperature resistance, oxidation resistance and corrosion resistance of the material, is suitable for extreme high temperature environment, and has the advantages of simple process, low cost and short production period.

Description

Technical Field

[0001] The invention relates to the technical field of fiber-reinforced ceramic-based composite materials, and in particular to a fiber-reinforced ceramic-based composite material with a sandwich structure and a preparation method thereof. Background Art

[0002] With the development of aerospace technology, aerospace vehicles have put forward higher requirements on the heat protection and weight reduction performance of materials. 2f The structural density of SiO2 ceramic matrix composite materials is relatively high, and the heat insulation effect is difficult to meet the new design requirements. Therefore, a new lightweight heat-resistant structure must be developed to meet the urgent demand for heat-resistant materials for new carriers. The sandwich structure not only has the advantages of light weight, high strength, and good bending resistance, but also has a special heat transfer path that makes it have a better heat-resistant effect.

[0003] Currently, mature sandwich structure materials mostly use glass fiber and quartz fiber reinforced composite materials as skins, and aramid paper honeycombs and PMI foam as core materials. This material system can meet performance requirements at room temperature and below 300°C. However, when the temperature is higher than 300°C, aramid, PMI and other organic matter decompose, and the sandwich structure is destroyed, thus limiting its application scenarios at high temperatures. The all-ceramic sandwich structure is based on inorganic fibers as the skeleton and is filled with a ceramic matrix. While inheriting the advantages of traditional honeycomb materials such as lightweight and high strength, it also has the characteristics of high temperature resistance, oxidation resistance, and corrosion resistance.

[0004] Due to the poor toughness of inorganic fibers, it is difficult to prepare honeycomb structures like aramid fibers. Although the weaving of honeycomb structures can be achieved through the long fiber three-dimensional weaving process, the weaving preparation cycle is long, the fiber utilization rate is low, and the production cost is high. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] One object of the present invention is to provide a fully ceramic sandwich structure fiber-reinforced ceramic matrix composite material, which has an inorganic fiber skeleton and is filled with a ceramic matrix. While inheriting the advantages of traditional honeycomb materials such as lightweight and high strength, it also has the characteristics of high temperature resistance, oxidation resistance and corrosion resistance.

[0007] Another object of the present invention is to provide a low-cost preparation process to address the defects or shortcomings in the existing weaving process for preparing sandwich structure ceramic matrix composite materials, which can greatly reduce the production cost of sandwich structure fiber-reinforced ceramic matrix composite materials.

[0008] (II) In order to achieve the above-mentioned object, the present invention provides the following technical solutions:

[0009] A method for preparing a fiber-reinforced ceramic matrix composite material of a sandwich structure comprises the following steps:

[0010] (1) Inorganic fibers are used as reinforcements and are immersed in a dipping tank containing a liquid ceramic precursor, and a flat paper made of a fiber-reinforced composite material is prepared through a drying process and a flattening process, and the semi-dried flat paper is pressed through a corrugated mold or a corrugated roller to become a corrugated paper;

[0011] (2) After the surface of the corrugated paper is soaked with an inorganic adhesive having a bonding function, the corrugated paper is placed face to face with the flat paper and pressure is applied to make the wave crest of the corrugated paper and the flat paper bond together to form the smallest sandwich structure unit, and according to the required thickness of the sandwich structure material, the required number of the smallest sandwich structure units are bonded together to prepare a composite material blank of the sandwich structure;

[0012] (3) The composite material blank is heat treated and then mechanically processed to prepare a fiber-reinforced ceramic matrix composite material with a sandwich structure.

[0013] Furthermore, the inorganic fiber in step (1) is inorganic fiber paper prepared from inorganic fiber bulk with a diameter of 3-100 microns or fiber cloth woven from inorganic fiber filaments; the types of inorganic fiber paper or fiber cloth include one or more of glass fiber, basalt fiber, quartz fiber, alumina fiber, mullite fiber, zirconia fiber, carbon fiber, silicon carbide fiber, and silicon nitride fiber.

[0014] Furthermore, the liquid ceramic precursor in step (1) is in liquid state at room temperature or under heating state, has wettability to the fiber surface, and when heated to a temperature above 800°C in air or an oxidizing atmosphere, produces oxide ceramics composed of one or more of microcrystalline glass, quartz, alumina, mullite, aluminum phosphate, and zirconium oxide; when heated to a temperature above 600°C in an inert atmosphere, produces carbide ceramics composed of one or more of silicon carbide, graphite carbon, boron carbide, and zirconium carbide; the liquid ceramic precursor is preferably a combination of one or more of a fusible inorganic metal polymer, a non-fusible but soluble inorganic metal polymer solution, a sol, and a slurry.

[0015] Furthermore, the liquid ceramic precursor in step (1) includes one or more combinations of polyaluminoxane colloid, alumina sol, silica sol, mullite sol, zirconium sol, and slurry containing alumina powder.

[0016] Furthermore, in step (1), the liquid ceramic precursor comprises one or more combinations of polycarbosilane powder slurry, tetraethyl orthosilicate powder slurry, and silicon carbide powder slurry.

[0017] Furthermore, the drying process in step (1) is: by adjusting the drying temperature or partial drying temperature during the drying process, the solvent in the fiber paper or fiber cloth after dipping is completely or partially removed; preferably, if the liquid ceramic precursor is a polymer precursor, the drying temperature is 40-60°C higher than its softening point, or the partial drying temperature is 10-40°C higher than its softening point; if the liquid ceramic precursor is a water-soluble sol, the drying temperature is 80-200°C, or the partial drying temperature is 50-80°C; if the liquid ceramic precursor is an organic solvent sol, the drying temperature is 1-50°C higher than its boiling point, or the partial drying temperature is 1-30°C lower than its boiling point.

[0018] Furthermore, in step (1), the flattening process is to press the fiber paper or fiber cloth with an uneven surface after drying through a laminating machine, so that the fiber paper or fiber cloth becomes flat and its firmness is increased. The preferred pressing force is between 0.5-3 MPa.

[0019] Furthermore, the inorganic binder with bonding function in step (2) refers to the ability to bond ceramic materials, and the binder will be transformed into a ceramic phase after high-temperature treatment, so that the bonded ceramic material still has a high bonding force and is in a bonded state. The preferred inorganic binder is one or more of dihydrogen aluminum phosphate, aluminum phosphate, chromium aluminum phosphate and their water-soluble solutions.

[0020] Furthermore, the heat treatment in step (3) is to heat the composite body to a high temperature in air or an inert gas to remove or partially remove the non-ceramic phase components in the body so that the composite material is completely in a ceramic phase; preferably, if the composite body is an oxide ceramic material, the heat treatment temperature in air is higher than 800°C; if the composite body is a carbide ceramic material, the heat treatment temperature in an inert gas is not lower than 1300°C.

[0021] A fiber-reinforced ceramic-based composite material with a sandwich structure is prepared by the above preparation method. The fiber-reinforced ceramic-based composite material is a sandwich structure, the skeleton of the sandwich is an inorganic fiber-reinforced ceramic-based composite material, and the ceramic matrix is ​​in a glassy state, a ceramic phase or a crystalline phase.

[0022] (III) Compared with the prior art, the present invention has at least the following beneficial effects:

[0023] (1) The fiber-reinforced ceramic matrix composite material of the sandwich structure prepared by the present invention and its preparation process, the material is based on inorganic fiber as the skeleton and filled with a ceramic matrix, while inheriting the advantages of traditional honeycomb materials such as lightweight and high strength, it also has the characteristics of high temperature resistance, oxidation resistance and corrosion resistance, with a bursting strength of 100kPa, an edge compression strength of 500N / m, and a gram weight of 90-160g / m 2, can be used as thermal insulation material and structural material and is widely used in extreme high temperature environments.

[0024] (2) The process of the present invention is simple, the process cost is low, and the production cycle is short. Compared with the existing weaving process, it can greatly reduce the process cost of the composite material and facilitate large-scale preparation. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a preparation flow chart of fiber reinforced ceramic matrix composites with sandwich structure.

[0026] Figure 2 This is a real photo of corrugated alumina fiber corrugated paper;

[0027] Figure 3 This is a real photo of the alumina fiber reinforced ceramic matrix composite material with a sandwich structure. DETAILED DESCRIPTION

[0028] In order to make the various technical features and advantages or technical effects in the above technical solutions of the present invention more obvious and easy to understand, they are described in detail below in conjunction with embodiments.

[0029] This embodiment specifically discloses a method for preparing a fiber-reinforced ceramic matrix composite material with a sandwich structure. The preparation process is as follows: Figure 1 As shown, the specific steps include:

[0030] (1) Alumina fiber paper is prepared from alumina fiber loose cotton with a diameter of 3-100 microns. As a reinforcement, it is impregnated in a dipping tank containing a liquid ceramic precursor. The liquid ceramic precursor includes polyaluminoxane glue and polycarbosilane powder slurry, which is liquid at room temperature and has wettability on the fiber surface. By adjusting the drying temperature during the drying process (higher than the softening point by 50°C), the solvent in the fiber paper after dipping is completely removed, and then the fiber paper with an uneven surface after drying is pressed by a laminating machine (pressing force is greater than 1MPa), so that the fiber paper or fiber cloth becomes flat and the firmness is increased, thereby preparing a flat paper made of fiber-reinforced composite material. The semi-dried flat paper is pressed by a corrugated mold or a corrugated pressing roller to become a corrugated paper with a corrugated structure, such as Figure 2 shown.

[0031] (2) The surface of the corrugated paper is soaked with an inorganic binder, aluminum dihydrogen phosphate, and then the corrugated paper is placed face to face with the flat paper, and pressure is applied to bond the wave crest of the corrugated paper to the flat paper to form the smallest sandwich structure unit. According to the required thickness of the sandwich structure material, the required number of minimum sandwich structure units are bonded together to prepare a composite material blank of the sandwich structure.

[0032] (3) The composite body is heated to 900°C in an inert gas for heat treatment to remove the non-ceramic phase components in the body and make the composite material completely ceramic. Then, after mechanical processing, an alumina fiber reinforced ceramic matrix composite material with a sandwich structure is prepared, such as Figure 3 shown.

[0033] Although the present invention has been disclosed as above by way of embodiments, it is not intended to limit the present invention. Appropriate modifications or equivalent substitutions of the technical solutions of the present invention made by ordinary technicians in the field should all be included in the protection scope of the present invention. The protection scope of the present invention shall be based on what is defined in the claims.

Claims

1. A method for preparing a fiber-reinforced ceramic matrix composite material with a sandwich structure, characterized in that: The following steps are involved: (1) Inorganic fibers are used as reinforcements and are immersed in a dipping tank containing a liquid ceramic precursor, and a flat paper made of a fiber-reinforced composite material is prepared through a drying process and a flattening process, and the semi-dried flat paper is pressed through a corrugated mold or a corrugated roller to become a corrugated paper; (2) After the surface of the corrugated paper is soaked with an inorganic adhesive having a bonding function, the corrugated paper is placed face to face with the flat paper and pressure is applied to make the wave crest of the corrugated paper and the flat paper bond together to form the smallest sandwich structure unit, and according to the required thickness of the sandwich structure material, the required number of the smallest sandwich structure units are bonded together to prepare a composite material blank of the sandwich structure; (3) The composite material blank is heat treated and then mechanically processed to prepare a fiber-reinforced ceramic matrix composite material with a sandwich structure.

2. The preparation method according to claim 1, characterized in that The inorganic fiber in step (1) is inorganic fiber paper prepared from inorganic fiber loose cotton with a diameter of 3-100 microns or fiber cloth woven from inorganic fiber filaments; the types of inorganic fiber paper or fiber cloth include one or more of glass fiber, basalt fiber, quartz fiber, alumina fiber, mullite fiber, zirconia fiber, carbon fiber, silicon carbide fiber, and silicon nitride fiber.

3. The preparation method according to claim 1, characterized in that: The liquid ceramic precursor in step (1) is in liquid state at room temperature or under heating state, has wettability to the fiber surface, and when heated to a temperature above 800°C in air or an oxidizing atmosphere, produces oxide ceramics composed of one or more of microcrystalline glass, quartz, alumina, mullite, aluminum phosphate, and zirconium oxide; when heated to a temperature above 600°C in an inert atmosphere, produces carbide ceramics composed of one or more of silicon carbide, graphite carbon, boron carbide, and zirconium carbide; the liquid ceramic precursor is a combination of one or more of a fusible inorganic metal polymer, a non-fusible but soluble inorganic metal polymer solution, a sol, and a slurry.

4. The preparation method according to claim 1 or 3, characterized in that: In step (1), the liquid ceramic precursor includes one or more combinations of polyaluminoxane colloid, alumina sol, silica sol, mullite sol, zirconium sol, and slurry containing alumina powder.

5. The preparation method according to claim 1 or 3, characterized in that: In step (1), the liquid ceramic precursor includes one or more combinations of polycarbosilane powder slurry, tetraethyl orthosilicate powder slurry, and silicon carbide powder slurry.

6. The preparation method according to claim 1, characterized in that: The drying process in step (1) is as follows: by adjusting the drying temperature or partial drying temperature during the drying process, the solvent in the fiber paper or fiber cloth after dipping is completely or partially removed; if the liquid ceramic precursor is a polymer precursor, the drying temperature is 40-60°C higher than its softening point, or the partial drying temperature is 10-40°C higher than its softening point; if the liquid ceramic precursor is a water-soluble sol, the drying temperature is 80-200°C, or the partial drying temperature is 50-80°C; if the liquid ceramic precursor is an organic solvent sol, the drying temperature is 1-50°C higher than its boiling point, or the partial drying temperature is 1-30°C lower than its boiling point.

7. The preparation method according to claim 1, characterized in that: The flattening process in step (1) is to press the fiber paper or fiber cloth with an uneven surface after drying through a laminating machine to make the fiber paper or fiber cloth flat, and the pressing force is 0.5-3MPa.

8. The preparation method according to claim 1, characterized in that: The inorganic binder having a bonding function in step (2) is one or more of aluminum dihydrogen phosphate, aluminum phosphate, aluminum chromium phosphate and their water-soluble solutions.

9. The preparation method according to claim 1, characterized in that: The heat treatment in step (3) is to heat the composite body to a high temperature in air or an inert gas to remove or partially remove the non-ceramic phase components in the body so that the composite material is completely in a ceramic phase; if the composite body is an oxide ceramic material, the heat treatment temperature in air is higher than 800°C; if the composite body is a carbide ceramic material, the heat treatment temperature in an inert gas is not lower than 1300°C.

10. A fiber-reinforced ceramic matrix composite material with a sandwich structure, characterized in that: The fiber-reinforced ceramic-based composite material is prepared by the preparation method according to any one of claims 1 to 9, and has a sandwich structure, the skeleton of the sandwich is an inorganic fiber-reinforced ceramic-based composite material, and the ceramic matrix is ​​in a glassy state, a ceramic phase or a crystalline phase.

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