Alumina fiber reinforced one-way wet prepreg and preparation method thereof

Abstract

The invention discloses alumina fiber reinforced one-way wet prepreg and a preparation method thereof, and belongs to the technical field of fiber reinforced ceramic matrix composite materials. In order to solve the technical problems of low ceramic content, poor storage stability and the like of the existing prepreg, the one-way wet prepreg is prepared by mainly adopting a method of dipping a liquid ceramic precursor in glue and uniformly winding in a drafting state. According to the method, the prepreg can be uniformly sized, the surface is smooth and flat, the solid content is high, the storage stability is good, and various alumina fiber reinforced ceramic matrix composite materials can be obtained after the prepared prepreg is subjected to lamination mould pressing and high-temperature heat treatment.

Description

Technical Field

[0001] The invention relates to the technical field of fiber-reinforced ceramic-based composite materials, and in particular to an alumina fiber-reinforced unidirectional wet prepreg and a preparation method thereof. Background Art

[0002] At present, the preparation process of alumina fiber reinforced ceramic matrix composites is mostly to prepare preforms or green bodies through layer laying, three-dimensional weaving, winding and other processes, and then realize the densification preparation of ceramic matrix composites through sol-gel process and slurry brushing process. The preform prepared by the preform weaving process has normal fibers, so the composite material has high interlayer strength and excellent performance. However, since the commonly used reinforcing fibers are mostly brittle inorganic fibers, the weaving process mostly relies on manual work, the preparation cycle is long, the fiber utilization rate is low, and the production cost is high. The layer forming process is simple and the cost is relatively low, but the quality control is difficult in the process of producing large parts. The fiber winding technology has a high degree of mechanization, is easy to realize mechanization and automation, has high production efficiency, and can give full play to the high tensile strength of the fiber.

[0003] Drawing on the wet prepreg preparation process of resin-based composite materials, the process of using a unidirectional fiber winding machine to prepare unidirectional alumina fiber prepreg is easy to use, the fiber and matrix content can be precisely controlled, the structure can be designed according to the load-bearing requirements of the component, and it has the advantages of easy storage, simple operation, and suitability for industrial production. For example, in 2001, DLR of Germany prepared alumina fiber-reinforced ceramic-based composites with the brand WHIPOX series through the winding molding prepreg process. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] One object of the present invention is to provide an alumina fiber reinforced unidirectional wet prepreg, which has a high ceramic content and can be stably stored for 10 days under an environment of 25°C / 50%. After the unidirectional prepreg is laminated and molded and further subjected to high-temperature heat treatment, a variety of alumina fiber reinforced ceramic-based composite materials can be prepared. The prepreg is a key raw material for preparing fiber-reinforced ceramic-based composite materials and is of great significance for the efficient and low-cost preparation of oxide ceramic-based composite materials.

[0006] Another object of the present invention is to provide a novel method for preparing alumina fiber reinforced unidirectional wet prepregs, which has universal applicability and can meet the preparation requirements of alumina fiber reinforced unidirectional wet prepregs such as quartz, alumina, mullite, zirconia, aluminum phosphate, and yttrium aluminum garnet.

[0007] (II) In order to achieve the above-mentioned object, the present invention provides the following technical solutions:

[0008] A method for preparing an alumina fiber reinforced unidirectional wet prepreg comprises the following steps:

[0009] (1) pre-treating the alumina fiber to remove the sizing agent on the surface;

[0010] (2) immersing the desizing alumina fibers in a dipping tank of a liquid ceramic precursor under a drawing state, and making the dipping alumina fibers evenly wound on a circular drum with a release paper on the surface under a preset drawing speed and tension;

[0011] (3) After the alumina fiber is spread to a preset thickness, the outer surface of the drum is wrapped with release paper, and the two release papers and the fiber are cut along the axis of the drum. After being taken off the drum, the release paper with the fiber is unfolded and flattened to prepare the alumina fiber reinforced unidirectional wet prepreg.

[0012] Furthermore, in step (1), the alumina fiber is in the form of filaments or ribbons, the alumina content in the fiber is not less than 60%, the fiber line density is not less than 50tex, the twist is not more than 100 twists / meter, and the length is not less than 20 meters; preferably, the alumina content is greater than 70%, the fiber line density is greater than 150tex, and the length is greater than 100 meters of untwisted continuous alumina fiber filaments.

[0013] Furthermore, the components of the liquid ceramic precursor in step (2) include one or more elements of aluminum, silicon, zirconium, and yttrium. The liquid ceramic precursor is liquid at room temperature or under heating conditions. When heated to a temperature above 800°C in air or an oxidizing atmosphere, it produces an oxide ceramic composed of one or more of microcrystalline glass, quartz, alumina, mullite, aluminum phosphate, and zirconium oxide, and has a certain wettability and can infiltrate one or more combinations of inorganic metal polymer solutions, sols, slurries, etc. on the fiber surface.

[0014] Furthermore, the precursor used for the liquid ceramic precursor in step (2) includes one or more of silica sol, aluminum sol, mullite sol, and aluminum phosphate sol, or includes one or more of alumina powder slurry, zirconium oxide powder slurry, and silicon oxide powder slurry, wherein the ceramic yield in the precursor is not less than 45%.

[0015] Furthermore, in step (2), the fibers are evenly wound on a circular drum with a release paper on the surface, which means that the fibers are evenly wound on a circular drum at a fixed position and in a rotating state by adjusting the reciprocating speed of the wire holding device; or the alumina fibers after being impregnated are wound on a cylinder with a preset parallel motion speed and rotation speed through a fixed wire holding device, and the latter is preferred.

[0016] Furthermore, the reciprocating speed and parallel motion speed in step (2) refer to motion speeds that can prevent gaps and overlaps between fiber bundles.

[0017] Furthermore, in step (2), the diameter and length of the circular drum are not less than 10 cm; preferably, the length is 30 cm and the diameter is greater than 30 cm.

[0018] Furthermore, the traction speed and tension preset in step (2) are that the line speed is not less than 5 m / min, and the tension is not more than 15 N.

[0019] Furthermore, the preset thickness spread in step (3) is not less than 0.5 mm and not more than 50 mm; the preferred thickness range is between 2-10 mm.

[0020] An alumina fiber reinforced unidirectional wet prepreg is prepared by the above preparation method.

[0021] (III) Compared with the prior art, the present invention has at least the following beneficial effects:

[0022] (1) The alumina fiber unidirectional wet prepreg prepared by the present invention has uniform sizing, a smooth surface, and a high solid content, and can be stably stored for 10 days under an environment of 25°C / 50%.

[0023] (2) The present invention uses liquid ceramic precursors as the raw materials for the matrix of ceramic-based composite materials. Since the ceramic particles formed after the liquid precursors are pyrolyzed are small in size and have more through holes, it is convenient for further densification in the later stage. In addition, the types of liquid ceramic precursors are diverse, which enriches the types of ceramic matrices and can prepare fiber-reinforced ceramic-based composite materials of different types and properties.

[0024] (3) The unidirectional prepreg prepared by the present invention can be used to prepare a variety of alumina fiber-reinforced ceramic-based composite materials after lamination molding and further high-temperature heat treatment. It is a key raw material for preparing fiber-reinforced ceramic-based composite materials and is of great significance for the efficient and low-cost preparation of oxide ceramic-based composite materials.

[0025] (4) This process is universal and can meet the preparation of unidirectional wet prepregs such as alumina fiber reinforced quartz, alumina, mullite, zirconia, aluminum phosphate, and yttrium aluminum garnet.

[0026] (5) The process of the present invention is simple, the process cost is low, the production cycle is short, and it is easy to prepare on a large scale. DETAILED DESCRIPTION

[0027] 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.

[0028] Example 1

[0029] Commercially available 190tex untwisted alumina fibers with an alumina mass content of 85% are passed through a tubular furnace with a constant temperature zone length of 1m and a temperature of 900°C at a rate of 2m / min in a precursor state, and the sizing agent on the fiber surface is removed in an air atmosphere, and the fibers are bundled and rolled for standby use; the desizing alumina fibers are immersed in an aluminum sol with a ceramic yield of 48% in a drawing state, and the alumina fibers after the colloid impregnation are evenly wound on a circular drum with a release paper on the surface at a cross angle of 180° at a drawing speed of 15m / min and a winding tension of 10N; after the alumina fibers are spread to a thickness of 2mm, the release paper is wrapped on the outer surface of the drum, two release papers and the fibers are cut along the axial direction of the drum, and after being taken off the drum, the release paper with the fibers is unfolded and flattened to prepare an alumina fiber reinforced unidirectional wet prepreg.

[0030] The prepared prepreg is in a wet state, placed in a vacuum bag, evacuated and sealed, and after being placed at room temperature for 15 days, the two layers can still be bonded together, and an alumina fiber reinforced alumina-based composite material blank is prepared under hot pressing. After further sintering and densification treatment of the blank, an alumina fiber reinforced alumina-based composite material can be prepared.

[0031] Example 2

[0032] Commercially available 800tex untwisted alumina fibers with an alumina mass content of 72% are passed through a tubular furnace with a constant temperature zone length of 1m and a temperature of 800°C at a rate of 1m / min in a precursor state, and the sizing agent on the fiber surface is removed in an air atmosphere, and the fibers are bundled and rolled for standby use; the desizing alumina fibers are immersed in a mullite slurry with a ceramic yield of 55% in a drawing state, and the alumina fibers after the dip are evenly wound on a circular drum with a release paper on the surface at a cross angle of 180° at a drawing speed of 10m / min and a winding tension of 15N; after the alumina fibers are spread to a thickness of 3mm, the release paper is wrapped on the outer surface of the drum, two release papers and the fibers are cut along the axial direction of the drum, and after being taken off the drum, the release paper with the fibers is unfolded and flattened to prepare an alumina fiber reinforced unidirectional wet prepreg.

[0033] The prepared prepreg is in a wet state, placed in a vacuum bag, evacuated and sealed, and after being placed at room temperature for 7 days, the two layers can still be bonded together. An alumina fiber reinforced mullite-based composite material blank is prepared under hot pressing. After further sintering and densification treatment of the blank, an alumina fiber reinforced mullite-based composite material can be prepared.

[0034] Example 3

[0035] Commercially available 190tex untwisted alumina fibers with an alumina mass content of 99% are passed through a tubular furnace with a constant temperature zone length of 1m and a temperature of 850°C at a rate of 2m / min in the precursor state, and the sizing agent on the fiber surface is removed in an air atmosphere, and the fibers are bundled and rolled for use; the desizing alumina fibers are immersed in a 120°C dipping tank containing a polymer mullite precursor in a drafting state. The softening point of the precursor is 85°C, the ceramic yield is 45%, and the viscosity at 120°C is The resin-impregnated alumina fibers are uniformly wound on a circular drum with a release paper on the surface at a cross angle of 180° at a drawing speed of 15 m / min and a winding tension of 5 N. After the alumina fibers are spread to a thickness of 1 mm, the release paper is wrapped on the outer surface of the drum, and the two release papers and the fibers are quickly cut along the axial direction of the drum. After being taken off the drum, the release paper with the fibers is unfolded and flattened to prepare the alumina fiber-reinforced unidirectional wet prepreg.

[0036] The prepared prepreg is in a solid state, placed in a vacuum bag, evacuated and sealed. After being placed at room temperature for 2 months, it can still be bonded in two layers when heated to 150°C. An alumina fiber reinforced mullite-based composite material blank is prepared under hot pressing. After further sintering and densification treatment of the blank, an alumina fiber reinforced mullite-based composite material can be prepared.

[0037] 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 an alumina fiber reinforced unidirectional wet prepreg, characterized in that: The following steps are involved: (1) pre-treating the alumina fiber to remove the sizing agent on the surface; (2) immersing the desizing alumina fibers in a dipping tank of a liquid ceramic precursor under a drawing state, and making the dipping alumina fibers evenly wound on a circular drum with a release paper on the surface under a preset drawing speed and tension; (3) After the alumina fiber is spread to a preset thickness, the outer surface of the drum is wrapped with release paper, and the two release papers and the fiber are cut along the axis of the drum. After being taken off the drum, the release paper with the fiber is unfolded and flattened to prepare the alumina fiber reinforced unidirectional wet prepreg.

2. The preparation method according to claim 1, characterized in that In step (1), the alumina fiber is in the form of filament or ribbon, the alumina content in the fiber is not less than 60%, the fiber line density is not less than 50tex, the twist does not exceed 100 twists / meter, and the length is not less than 20 meters.

3. The preparation method according to claim 1, characterized in that: The components of the liquid ceramic precursor in step (2) include one or more elements of aluminum, silicon, zirconium, and yttrium; the liquid ceramic precursor is liquid at room temperature or in a heated state, and when heated to a temperature above 800°C in air or an oxidizing atmosphere, it produces an oxide ceramic composed of one or more of microcrystalline glass, quartz, alumina, mullite, aluminum phosphate, and zirconium oxide, and is one or more combinations of inorganic metal polymer solutions, sols, and slurries that can infiltrate the fiber surface.

4. The preparation method according to claim 1, characterized in that: The precursor used for the liquid ceramic precursor in step (2) includes one or more of silica sol, aluminum sol, mullite sol, and aluminum phosphate sol, or includes one or more of aluminum oxide powder slurry, zirconium oxide powder slurry, and silicon oxide powder slurry; the ceramic yield in the precursor is not less than 45%.

5. The preparation method according to claim 1, characterized in that: In step (2), the fibers are evenly wound on a circular drum with a release paper on the surface, which means that the fibers are evenly wound on a circular drum at a fixed position and in a rotating state by adjusting the reciprocating speed of the wire holding device; or the alumina fibers after being dipped in glue are wound on a cylinder with a preset parallel motion speed and rotation speed through a fixed wire holding device.

6. The preparation method according to claim 1, characterized in that: The reciprocating speed and parallel motion speed in step (2) refer to the motion speeds at which neither gaps nor overlaps are generated between the fiber bundles.

7. The preparation method according to claim 1, characterized in that: In step (2), the diameter and length of the circular drum are not less than 10 cm.

8. The preparation method according to claim 1, characterized in that: The preset pulling speed and tension in step (2) are that the linear speed is not less than 5 m / min and the tension is not more than 15 N.

9. The preparation method according to claim 1, characterized in that: The preset thickness spread in step (3) is not less than 0.5 mm and not more than 50 mm.

10. An alumina fiber reinforced unidirectional wet prepreg, characterized in that: The invention is prepared by the preparation method according to any one of claims 1 to 9.