KR20100116780A - Method for forming ceramic fiber preform of ceramic composite - Google Patents

Abstract

PURPOSE: A shaping method of a ceramic composite material preform is provided to effectively form the 3D preform of a ceramic composite material with a simple process while maintaining the properties of ceramic fibers. CONSTITUTION: A shaping method of a ceramic composite material preform comprises the following steps: laminating ceramic fibers on a three-dimensional mold(1); impregnating the mold to a low-viscosity polymer(2); curing the polymer at the vacuum atmosphere(3); separating the preform from the mold(4); and coating carbon on the surface of the preform for carbonizing the polymer(5). The ceramic fibers are a woven simple fiber or a simple fiber.

Description

Method for shaping the preform of ceramic composites {Method for forming ceramic fiber preform of ceramic composite}

The present invention relates to a method of shaping a preform of a ceramic composite material, and more particularly, (1) laminating ceramic fibers on a mold; (2) impregnated with a polymer; (3) curing the polymer; And (4) demolding the preform from the mold; It relates to a method for producing a three-dimensional preform consisting of a ceramic composite material consisting of steps and to (5) carbonizing the polymer in addition to the method of coating carbon on the surface of the preform.

Composite materials consisting of carbon / carbon (C / C), carbon / silicon carbide (C / SiC) and silicon carbide / silicon carbide (SiC / SiC) use carbon (C) or silicon carbide (SiC) fibers as reinforcing fibers do. In addition, in order to manufacture a three-dimensional composite material, the fibers used are manufactured in the shape of the final product (preform), and then chemical vapor infiltration (CVI) or chemical vapor deposition (CVD), etc. The process of filling the matrix using the process of. In addition, in order to improve the mechanical properties of the composite material, a carbon coating film is generally formed on the fiber to form an interface between the fiber and the base material.

However, in order to maintain the shape of the preform in the manufacturing of the three-dimensional shape preform, a technique called stitching is used, which is not only difficult to manufacture a precise shape but also requires a lot of cost and time in the process. In addition, the carbon coating on the fiber is mainly used a chemical vapor deposition (CVD) method, which has the disadvantage of using a hazardous reaction gas and requires a separate CVD equipment.

In other words, the prior art has been made of a stitching process in which two-dimensional fibers are stitched together to form a ceramic composite preform having a three-dimensional structure and a process of recoating the same. In addition, the reinforcing fiber is filled in the three-dimensional mold and the reaction gas flows through the gas inlet formed in the mold to fill the base material. In other words, when manufacturing a three-dimensional structure of a complex shape, the process and costs are increased, such as the need to manufacture a mold for chemical vapor penetration (CVI). In addition, in ceramic composites, a carbon coating layer is usually formed between the matrix or matrix and the fiber to prevent crack propagation, thereby delaying or suppressing the breakdown of the material. To form such a coating layer, the preform is formed by chemical vapor deposition ( CVD) process.

However, this chemical vapor deposition (CVD) has the disadvantage of requiring a long process and requiring high manufacturing costs. In addition, the CVD process is mainly performed at a treatment temperature of 900, in which case there is a problem that the strength and properties of the ceramic fiber tend to be reduced by high temperature. Therefore, there is an urgent need for a technique for coating an interface at a lower temperature. In addition, a three-dimensional preform manufacturing process and a carbon coating layer forming process, which not only reduce the process time but also reduce the processing cost, are very necessary.

In addition, vaccum assisted resin transfer molding (VARTM) process is a representative process for manufacturing fiber reinforced plastics (FRP) by injecting polymers, minimizing hazards, and reducing costs and time on equipment and processes. It is one of the less expensive ways. The biggest advantage of the vacuum resin transition molding (VARTM) process is that the preform can be manufactured in any shape.

Accordingly, the present inventors have continued to develop a new manufacturing method for shaping the preform of the ceramic composite material, and as a result, laminating ceramic fibers on a three-dimensional mold, impregnating and curing the low viscosity polymer, and demolding the preform from the mold. Forming a three-dimensional preform made of a ceramic composite material and then carbonizing the polymer to coat carbon on the surface of the preform, thereby maintaining the properties of the ceramic fiber and making the three-dimensional ceramic composite material with a simple process and low cost. The present invention was successfully completed by confirming that the preform can be effectively produced.

It is an object of the present invention to provide a novel manufacturing method for shaping a preform composed of a ceramic composite material.

In order to achieve the above object, the present invention (1) laminated ceramic fibers on a three-dimensional mold; (2) impregnated with a low viscosity polymer; (3) curing the polymer in a vacuum atmosphere; And (4) demolding the preform from the mold; It provides a manufacturing method for shaping the preform of the ceramic composite material consisting of steps.

In addition, the present invention provides a manufacturing method of shaping the preform of the ceramic composite material in addition to the above step (5) the step of carbonizing the polymer.

Hereinafter, the present invention will be described in detail.

The present invention is directed to (1) laminating ceramic fibers on a mold; (2) impregnated with a polymer; (3) curing the polymer; And (4) demolding the preform from the mold; A method of manufacturing a ceramic composite material for shaping a preform in a step is provided.

In addition, the present invention (1) laminating ceramic fibers on a mold; (2) impregnated with a polymer; (3) curing the polymer; (4) demolding the preform from the mold; And (5) carbonizing the polymer; In the step of providing a ceramic composite material for coating the carbon on the surface of the preform.

In the step (1), it is preferable that the mold has a three-dimensional shape, and the ceramic fiber is preferably made of woven or short fibers, and the woven form is a single filament, a fiber bundle ( It is preferred that they be bundles, plain weaves, satin weaves, harness weaves or unidirectional fibers. In addition, the ceramic fibers are preferably laminated using an array of 1, 45 and 90 degrees or a combination thereof.

In the step (2), the polymer is preferably a low viscosity polymer that can be cured at room temperature or above room temperature, and the low viscosity polymer is preferably diluted with an organic solvent including acetone and alcohol. . In the step (5), it is preferable to carbonize in an inert atmosphere using a vacuum, nitrogen or argon gas. In addition, it is also preferable to adjust the thickness of the carbon coating by repeating each process in the steps (1) to (5).

The manufacturing method of the present invention is applied to the vacuum resin transition molding (VARTM; vaccum assisted resin transfer molding (VARTM) process) to minimize the risk and to reduce the cost and time of equipment and processes. In addition, the pyrolytic carbon remaining on the surface of the fiber carbonized in the manufacturing method of the present invention can be used as the interface between the fiber of the ceramic composite material and the base material.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Figure 1 schematically shows a manufacturing process of a ceramic composite material for reinforcing ceramic fibers along the entire process of forming a three-dimensional preform of the present invention. 1 (2) shows a polymer inlet, a vacuum inlet, a sealant and a vacuum bag. In addition, in Fig. 1 (3), the mold is heat-treated, and in Fig. 1 (4), the three-dimensional preform is demolded, and Fig. 4 (5) shows a process of carbonizing the fiber under an inert atmosphere.

Figure 2 shows the state of the fiber is not coated with any material on the ceramic fiber used in the present invention. Figure 3 shows a state in which the surface is surrounded by a low-viscosity polymer injected with a ceramic fiber coated with a polymer in the manufacturing process of the present invention to form a polymer film. Figure 4 shows a state in which the polymer on the ceramic fiber is carbonized in an inert atmosphere in the manufacturing process of the present invention and only carbon remains on the fiber surface.

As described above, the present invention provides a method for manufacturing a ceramic fiber comprising: (1) laminating ceramic fibers on a mold; (2) impregnated with a polymer; (3) curing the polymer; And (4) demolding the preform from the mold; It relates to a method for producing a three-dimensional preform consisting of a ceramic composite material consisting of steps and to carbon coating the surface of the preform in addition to the carbonization of the polymer (5). The method of shaping the preform of the ceramic fiber of the present invention is simpler to process and less expensive than the conventional method, and can effectively maintain the properties of the ceramic fiber by forming a coating layer in a low temperature region. It can overcome the limitations and can be widely used in the manufacture of various ceramic composite materials used in parts and materials industries such as aerospace and power plants. In fact, it is very useful to form the shape of the preform by the carbonization process only without expensive deterioration process without the expensive separate process of forming the interface coating layer between the base material and the fiber.

Hereinafter, the present invention will be described in more detail with reference to Examples.

However, the following examples are illustrative of the present invention, and the contents of the present invention are not limited by the following examples.

Example 1 Shaping of 3D Preforms Composed of Ceramic Composites

In the present invention, in order to shape a three-dimensional preform composed of a ceramic composite material, ceramic fibers were laminated on a three-dimensional mold prepared in advance, and a vacuum resin transition molding (VARTM) process was performed as follows. First, a vacuum sealant (vacuum sealant) to maintain a vacuum state is installed around the mold and a vacuum bag (vacuum bag) was attached to this sealant (vacuum sealant) to laminate the laminated fibers in a vacuum package. Then, a tube entering the inside of the vacuum bag and two tubes were installed, and a low viscosity polymer was injected while applying a vacuum through the tube. At this time, in order to facilitate the flow of the polymer was used a mat (mat) with high permeability on the laminated fibers. The low viscosity polymer was injected by adding a release film and a release agent to facilitate separation of the polymer during curing. In addition, after the injection of the polymer was completed, the polymer injection valve was closed, and the vacuum pressure was continuously increased. The polymer was cured under heating or room temperature, and the cured preform was demolded again in the 3D mold.

As a result, it was confirmed that the preform of the shaped ceramic composite material of the present invention can effectively maintain the shape of the preform even though it is manufactured by a simple process at low temperature.

Example 2 Shaping and Carbon Coating of Three-Dimensional Preforms Composed of Ceramic Composites

In the present invention, in order to shape a three-dimensional preform composed of a ceramic composite material, ceramic fibers were laminated on a three-dimensional mold prepared in advance, and a vacuum resin transition molding (VARTM) process was performed as follows. First, a vacuum sealant (vacuum sealant) to maintain a vacuum state is installed around the mold and a vacuum bag (vacuum bag) was attached to this sealant (vacuum sealant) to laminate the laminated fibers in a vacuum package. Then, a tube entering the inside of the vacuum bag and two tubes were installed, and a low viscosity polymer was injected while applying a vacuum through the tube. At this time, in order to facilitate the flow of the polymer was used a mat (mat) with high permeability on the laminated fibers. The low viscosity polymer was injected by adding a release film and a release agent to facilitate separation of the polymer during curing. In addition, after the injection of the polymer is completed, the polymer injection valve is closed, and the vacuum pressure is continuously increased, and the polymer is cured under heating or room temperature. Again, the cured preform was demolded in the three-dimensional mold, and the demolded polymer impregnated preform was heated in an inert atmosphere to carbonize the polymer applied to the fiber, leaving only carbon on the fiber surface.

As a result, although the preform of the shaped ceramic composite material of the present invention is manufactured in a simple process at low temperature, the shape of the preform can be effectively maintained only by the carbonization process without going through an expensive separate process of forming an interfacial coating layer between the base material and the ceramic fiber. I could confirm that there is.

Figure 1 schematically shows a manufacturing process of a ceramic composite material for reinforcing ceramic fibers along the entire process of forming a three-dimensional preform of the present invention.

Figure 2a shows the state of the fiber is not coated with any material on the ceramic fiber used in the present invention.

Figure 3 shows a state in which the surface is surrounded by a low-viscosity polymer injected with a ceramic fiber coated with a polymer in the manufacturing process of the present invention to form a polymer film.

Figure 4 shows a state in which the polymer on the ceramic fiber is carbonized in an inert atmosphere in the manufacturing process of the present invention and only carbon remains on the fiber surface.

Claims (7)

(1) laminating ceramic fibers on a three-dimensional mold; (2) impregnated with a low viscosity polymer; (3) curing the polymer in a vacuum atmosphere; And (4) demolding the preform from the mold; A manufacturing method for shaping the preform of the ceramic composite material consisting of steps. The method of claim 1, (5) in the step of carbonizing the polymer, the method of manufacturing a preform of a ceramic composite material, characterized in that it further comprises the step of coating carbon on the surface of the preform. The method of claim 1, In the step (1), the ceramic fiber is a woven fiber or a short fiber, the woven form is a single filament, a bundle of fibers, a plain weave, a satin weave , Harness weave or unidirectional (unidirectional) fiber manufacturing method for shaping the preform of the ceramic composite material. The method according to claim 1 or 3, In the step (1), the ceramic fiber is laminated using a 1, 45 and 90 degrees or a combination thereof, the manufacturing method of shaping the preform of the ceramic composite material. The method of claim 1, In the step (2), the polymer is a low viscosity polymer that can be cured at room temperature or above room temperature, and the low viscosity polymer is a preform of a ceramic composite material, which is used by diluting with an organic solvent including acetone and alcohol. Manufacturing method to shape. 3. The method of claim 2, In the step (5), the preform of the ceramic composite material for shaping the preform of the ceramic composite material, characterized in that the carbonized in an inert atmosphere using a vacuum, nitrogen or argon gas. The method according to claim 1 or 2, Repeating the steps in (1) to (5) to the manufacturing method for shaping the preform of the ceramic composite material, characterized in that to control the thickness of the carbon coating.

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