A preparation system and application of fiber-reinforced ceramic matrix composites

Abstract

This invention provides a system for preparing fiber-reinforced ceramic matrix composites, comprising: a pressure device, a precursor resin supply device, a hot pressing device, a vacuum membrane bag to be impregnated, a precursor resin collection device, and a vacuum pump; the pressure device and the precursor resin supply device are connected; the vacuum membrane bag to be impregnated is disposed inside the hot pressing device and is connected to the precursor resin supply device and the precursor resin collection device respectively through the hot pressing device; the outlet of the hot pressing device is connected to the inlet of the precursor resin collection device, and the outlet of the precursor resin collection device is connected to the vacuum pump. This application also provides an application of the preparation system. The preparation system provided by this application can achieve efficient preparation of fiber-reinforced ceramic matrix composites and improve impregnation efficiency; furthermore, the preparation system provided by this application can also prepare large-size, structurally complex composite materials.

Description

Technical Field

[0001] This invention relates to the field of fiber-reinforced ceramic matrix composites, and more particularly to a preparation system and application of fiber-reinforced ceramic matrix composites. Background Technology

[0002] Fiber-reinforced ceramic matrix composites have gained increasing attention from materials scientists in recent years due to their excellent properties, including high strength, high toughness, high temperature resistance, good corrosion resistance, and low density at high temperatures. Currently, there are many processes for preparing fiber-reinforced ceramic matrix composites, mainly including hot pressing, reaction sintering, direct melt oxidation, chemical vapor infiltration, sol-gel method, and precursor conversion method (PIP). Among these, the precursor conversion method, which uses a precursor organic polymer to convert into ceramic to prepare ceramic and ceramic matrix composites, is a relatively advanced and effective method with advantages such as simple process and low cost. A crucial process step in the preparation of fiber-reinforced ceramic matrix composite preforms using the precursor conversion method is the impregnation process. The quality of the impregnation process directly affects the densification of the fiber-reinforced ceramic matrix composite, thus affecting the material properties.

[0003] Traditional PIP (Polymer Impregnation) processes involve the evaporation of organic solvents and the escape of low-density hydrocarbons, ultimately resulting in more than ten PIP cycles and a long preparation cycle for composite materials. To meet the engineering application needs of fiber-reinforced ceramic matrix composites, shortening the manufacturing cycle and reducing production costs are essential for future development. Therefore, providing a novel system for PIP impregnation is of great significance for adjusting composite material processes. Summary of the Invention

[0004] The technical problem solved by this invention is to provide a preparation system for fiber-reinforced ceramic matrix composites. The preparation system provided by this application can realize the efficient preparation of fiber-reinforced ceramic matrix composites and improve the impregnation efficiency. Furthermore, the preparation system provided by this application can also prepare large-size and structurally complex composite materials.

[0005] In view of this, this application provides a preparation system for fiber-reinforced ceramic matrix composites, comprising: a pressure device, a precursor resin supply device, a hot pressing device, a vacuum membrane bag to be impregnated, a precursor resin collection device, and a vacuum pump.

[0006] The pressure device and the precursor resin supply device are connected;

[0007] The vacuum film bag to be impregnated is disposed inside the hot pressing device and is connected to the precursor resin supply device and the precursor resin collection device respectively through the hot pressing device;

[0008] The outlet of the hot pressing device is connected to the inlet of the precursor resin collecting device, and the outlet of the precursor resin collecting device is connected to the vacuum pump.

[0009] Preferably, the number of precursor resin supply devices is ≥1.

[0010] Preferably, the number of precursor resin supply devices and the number of precursor resin collection devices are the same.

[0011] Preferably, the number of vacuum film bags to be impregnated is the same as the number of precursor resin devices.

[0012] Preferably, the preparation system further includes a connecting component disposed between the hot pressing device, the precursor resin supply device, and the precursor resin collection device for connecting the three.

[0013] Preferably, the connecting component is a flange;

[0014] The flange consists of a large-hole side and a small-hole side. The large-hole side is connected to the hot-pressing device, and the first row of the small-hole side is connected to the precursor resin collecting device, and the second row is connected to the precursor resin supply device.

[0015] Preferably, the vacuum film bag to be impregnated consists of a first vacuum film bag and a second vacuum film bag fitted over the surface of the first vacuum film bag.

[0016] Preferably, the first vacuum film bag is provided with a first interface and a second interface, and the second vacuum film bag is provided with a third interface;

[0017] The first interface is connected to the precursor resin collection device through the first row of holes on one side of the flange, the second interface is connected to the precursor resin supply device through the second row of holes on one side of the flange, and the third interface is connected to the precursor resin collection device through the small holes on one side of the flange.

[0018] Preferably, the precursor resin supply device is further provided with a vacuum device to achieve vacuum treatment of the precursor resin.

[0019] This application also provides the application of the aforementioned preparation system in the PIP process of fiber-reinforced ceramic matrix composites.

[0020] This application provides a system for preparing fiber-reinforced composite materials, comprising a pressure device, a precursor resin supply device, a hot pressing device, a vacuum membrane bag to be impregnated, a precursor resin collection device, and a vacuum pump. The pressure device and the precursor resin supply device are connected; the vacuum membrane bag to be impregnated is disposed inside the hot pressing device and is connected to both the precursor resin supply device and the precursor resin collection device via the hot pressing device; the outlet of the hot pressing device is connected to the inlet of the precursor resin collection device; and the outlet of the precursor resin collection device is connected to the vacuum pump. In the preparation system provided in this application, the fiber precursor is placed in the vacuum membrane bag. Due to the variable and flexible structure of the vacuum membrane bag to be impregnated, composite materials with large dimensions and complex structures can be prepared. At the same time, the vacuum membrane bag to be impregnated is placed in the hot pressing system, which can heat and pressurize the precursor resin, overcome the flow resistance, and improve the flowability of the precursor resin in the fiber preform. This drives the precursor resin to flow into the fiber preform in the vacuum membrane bag to be impregnated. Meanwhile, the precursor resin impregnates the fiber preform under pressure without dead angles in the hot pressing device, so that the pressure acting on the normal line of each point on the surface of the vacuum membrane bag is the same, which greatly improves the impregnation efficiency and is conducive to the densification of the composite material. Attached Figure Description

[0021] Figure 1 A schematic diagram of the structure of the fiber-reinforced ceramic matrix composite material preparation system provided by the present invention;

[0022] Figure 2 A schematic diagram of the flange provided by the present invention;

[0023] Among them, 1 is a pressure device, 2 is a precursor resin supply device, 3 is a connecting component, 4 is a hot pressing device, 5 is a precursor resin collection device, and 6 is a vacuum pump. Detailed Implementation

[0024] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.

[0025] In view of the long preparation cycle of fiber-reinforced ceramic matrix composites in the prior art, this application provides a preparation system for fiber-reinforced ceramic matrix composites. This preparation system can improve impregnation efficiency, requiring only 5 to 8 PIP cycles to obtain dense fiber-reinforced ceramic matrix composites, and can prepare large-size and complex-shaped fiber-reinforced ceramic matrix composites. Furthermore, the fiber-reinforced ceramic matrix composites of this application are prepared in a hot pressing device, eliminating the need to move the composite material during the preparation process and ensuring the stability of the composite material's properties. Specifically, the embodiments of this invention disclose a preparation system for fiber-reinforced ceramic matrix composites, including: a pressure device, a precursor resin supply device, a hot pressing device, a vacuum membrane bag to be impregnated, a precursor resin collection device, and a vacuum pump.

[0026] The pressure device and the precursor resin supply device are connected;

[0027] The vacuum film bag to be impregnated is disposed inside the hot pressing device and is connected to the precursor resin supply device and the precursor resin collection device respectively through the hot pressing device;

[0028] The outlet of the hot pressing device is connected to the inlet of the precursor resin collecting device, and the outlet of the precursor resin collecting device is connected to the vacuum pump.

[0029] A schematic diagram of the preparation system provided in this application is shown below. Figure 1 As shown, 1 is a pressure device, 2 is a precursor resin supply device, 3 is a connecting component, 4 is a hot pressing device, 5 is a precursor resin collection device, and 6 is a vacuum pump.

[0030] Specifically, the vacuum membrane bag to be impregnated (not shown in the figure) is used to hold the fiber preform to be impregnated. The vacuum membrane bag is a vacuum film well-known to those skilled in the art, characterized by its flexibility, large size, and arbitrarily adjustable structure. Using the vacuum membrane bag as a sealing model for the fiber preform allows for complete encapsulation of the fiber preform, ensuring the precursor resin is subjected to normal forces without any blind spots, thus increasing the impregnation driving force and facilitating the fabrication of large-sized, structurally complex components. To ensure a sealing effect, the vacuum membrane bag to be impregnated consists of a first vacuum membrane bag and a second vacuum membrane bag fitted over the surface of the first vacuum membrane bag.

[0031] The vacuum film bag to be impregnated is placed inside the hot press device (4). In a specific embodiment, the hot press device (4) is a hot press tank. In addition to retaining all the functions of conventional hot press tanks in the prior art, such as heating and pressurization, it also needs to have a channel for the precursor resin to enter and a channel for the precursor resin to flow out. The channel for the precursor resin to enter is connected to the precursor resin supply device (2), and the channel for the precursor resin to flow out is connected to the precursor resin collection device (5). Therefore, the hot press tank should have a channel at a suitable position on the tank wall to achieve the above connection. The channel is connected to the vacuum film bag to be impregnated inside the hot press device (3) and the precursor resin supply device (2) and the precursor resin collection device (5) outside the hot press device (3) through the connecting component (3), specifically a flange. The flange is preferably set on the outer wall of the hot press device (3).

[0032] In some specific embodiments, three interfaces are reserved on the vacuum film bag to be impregnated. The first vacuum film bag has two interfaces and the second vacuum film bag has one interface. The two interfaces reserved on the first vacuum film bag are respectively connected to the precursor resin supply device (2) and the precursor resin collection device (5), and are used for the inflow of precursor resin and the vacuum treatment and outflow of the vacuum film bag to be impregnated. The one interface of the second vacuum film bag is connected to the precursor resin collection device (5). The vacuum pump connected to the precursor resin collection device (5) is used to realize the vacuum treatment of the vacuum film bag to be impregnated, so that the vacuum film bag to be impregnated is in a negative pressure state, which is conducive to the introduction of precursor resin.

[0033] In some specific embodiments, the connecting component (3) is specifically a flange, the structure of which is as follows: Figure 2 As shown, one side has a large hole and the other side has a small hole. The side with the large hole is connected to the hot pressing device (4), and the side with the small hole is divided into a first row and a second row distributed vertically. The first row is connected to the precursor resin collection device (5) through a hose, and the second row is connected to the precursor resin supply device (2) through a hose. The number of small holes can be changed by replacing the flange component.

[0034] In some specific embodiments, the number of precursor resin supply devices (2) is ≥1. On this basis, the number of precursor resin supply devices (2) and precursor resin collection devices (5) is the same. The precursor resin supply devices (2) are divided into multiple pipelines through connecting components (3) to connect to the interior of the hot pressing device (4) and to connect with the same number of vacuum membrane bags to be impregnated, thereby realizing the preparation of multiple fiber-reinforced ceramic matrix composite materials. For example, three precursor resin supply devices (2) are connected to three small holes at the lower end of the flange (3) via hoses. The corresponding small holes on the inner side of the flange (3) are also connected to one side of the vacuum film bag containing the fiber preform via hoses. The other side of the vacuum film bag is also connected to the three small holes at the upper inner side of the flange (3) via hoses. The three small holes at the upper outer side of the flange (3) are connected to the three precursor resin supply devices (5) via polyurethane hoses. All three precursor resin supply devices (5) are connected to the vacuum pump (6). The flange provides a multi-channel function, which can realize the simultaneous preparation of multiple fiber-reinforced ceramic matrix composites.

[0035] The preparation system provided in this application can simultaneously vacuum the fiber preforms in n vacuum membrane bags to be impregnated, control the injection of n precursor resins of the same or different types by switching ball valves, observe the resin overflow from the resin precursor collection device (5) outside the hot pressing device (4), execute the process setting program, and after impregnation, heat up and cure the resin, cool down and depressurize it, and demold the sample.

[0036] The aforementioned precursor resin supply device (2) is a storage container for precursor resin, used to supply precursor resin. In some specific embodiments, the precursor resin supply device (2) is equipped with a vacuum device. After the precursor resin is prepared, the precursor resin is evacuated to remove air from the precursor resin. The precursor resin supply device (2) is also connected to a pressure device (1) through a metal pipe to pressurize the precursor resin supply device (2) and introduce the precursor resin into the vacuum membrane bag to be impregnated in the hot pressing device (4) to impregnate the fiber preform. The pressure device can apply pressure with air, nitrogen, or other means, and this application does not impose any particular restrictions on this. In some specific embodiments, the precursor resin supply device (2) is also equipped with a heating control unit to heat the precursor resin with higher viscosity, reduce its viscosity, and improve its fluidity.

[0037] The aforementioned precursor resin collection device (5) is a container for collecting excess resin. It is connected to the vacuum membrane bag to be impregnated via a connecting component (3). The pipe material is a high-pressure resistant pipe, and there should be a valve switch in the pipe. The valve is opened during the vacuuming and the entry of the precursor resin solution, and closed when the entry process ends.

[0038] The outlet of the precursor resin collection device (5) is connected to the vacuum pump (6), and the vacuum pump (6) is used to perform vacuuming on the vacuum film bag to be impregnated.

[0039] This application also provides the application of the preparation system in the PIP process of fiber-reinforced ceramic matrix composites.

[0040] In some specific embodiments, the preparation method of the preparation system in the PIP process of fiber-reinforced ceramic matrix composites is as follows:

[0041] The fiber preform is placed in the vacuum bag film to be impregnated, the vacuum bag film to be impregnated is placed in the hot press device (4), and then the vacuum bag film to be impregnated is evacuated by the vacuum pump (6) so that the vacuum bag film to be impregnated is in a negative pressure state.

[0042] The precursor resin is placed in the precursor resin supply device (2), and the vacuum system of the precursor resin supply device (2) is turned on to evacuate the precursor resin.

[0043] The flow of precursor resin is controlled by the switch valve in the pipeline of the precursor resin supply device (2). First, the precursor resin is slowly introduced into the fiber preform by the vacuum negative pressure in the vacuum membrane bag to be impregnated. When the precursor resin flows into the precursor resin collection device (5) connected to the vacuum pump (6), the switch valve for the precursor resin to flow out is closed. Pressure is applied to the precursor resin supply device by the pressure device (1) so that the fiber preform in the vacuum membrane bag to be impregnated is in the precursor resin-rich medium. Then the entry channel of the precursor resin is closed to complete the first impregnation process. During the impregnation process, the pressurization program of the hot press device (4) is turned on for pressurized impregnation.

[0044] After pressure impregnation, the heating and curing program of the hot press device (4) is turned on to cure and crosslink the precursor; then pyrolysis is carried out in a high-temperature furnace; finally, the above impregnation-curing-pyrolysis process is repeated at least once, preferably 5 to 8 times.

[0045] In this application, the fiber preform is selected from fibers that have been needle-punched, sewn, or braided, and the fibers are selected from one or more of carbon fiber T300, carbon fiber T700, carbon fiber M40, and silicon carbide fiber; in some specific embodiments, the fiber preform can be a regular shape or an irregular shape. The precursor resin is selected from one of polycarbosilane, polysiloxane, polynitrosilane, and polyborosilicate.

[0046] Experimental results show that the Cf / SiC composite material prepared using the fiber-reinforced ceramic matrix composite preparation system provided in this application, preferably after 6 to 8 repeated impregnation-curing-pyrolysis cycles, has a density of 2.1 to 2.2 g / cm³. 3 The porosity is 5–8%; the prepared Cf / SiOC composite material preferably underwent 6–8 repeated impregnation-curing-pyrolysis processes, and the density of the composite material is 1.9–2.1 g / cm³. 3 The porosity is 5-8%.

[0047] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0048] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A system for preparing fiber-reinforced ceramic matrix composites, comprising: Pressure device, precursor resin supply device, hot pressing device, vacuum membrane bag to be impregnated, precursor resin collection device, and vacuum pump; The pressure device and the precursor resin supply device are connected; The vacuum film bag to be impregnated is disposed inside the hot pressing device and is connected to the precursor resin supply device and the precursor resin collection device respectively through the hot pressing device; the vacuum film bag to be impregnated is used to place the fiber preform to be impregnated, and it is a flexible vacuum film. The outlet of the hot pressing device is connected to the inlet of the precursor resin collecting device, and the outlet of the precursor resin collecting device is connected to the vacuum pump; The preparation system further includes a connecting component, which is disposed between the hot pressing device, the precursor resin supply device, and the precursor resin collection device for connecting the three; the connecting component is a flange. The flange consists of a large hole side and a small hole side. The large hole side is connected to the hot pressing device, and the first row of the small hole side is connected to the precursor resin collection device, and the second row is connected to the precursor resin supply device. The vacuum film bag to be impregnated consists of a first vacuum film bag and a second vacuum film bag sleeved on the surface of the first vacuum film bag. The first vacuum film bag is provided with a first interface and a second interface, and the second vacuum film bag is provided with a third interface. The first interface is connected to the precursor resin collection device through the first row of holes on one side of the flange, the second interface is connected to the precursor resin supply device through the second row of holes on one side of the flange, and the third interface is connected to the precursor resin collection device through the small holes on one side of the flange. A vacuum pump connected to the precursor resin collection device is used to perform vacuuming treatment on the vacuum film bag to be impregnated, so that the vacuum film bag to be impregnated is in a negative pressure state, which is conducive to the introduction of precursor resin.

2. The preparation system according to claim 1, characterized in that, The number of precursor resin supply devices is ≥1.

3. The preparation system according to claim 2, characterized in that, The number of precursor resin supply devices and the number of precursor resin collection devices are the same.

4. The preparation system according to claim 3, characterized in that, The number of vacuum membrane bags to be impregnated is the same as the number of precursor resin supply devices.

5. The preparation system according to claim 1, characterized in that, The precursor resin supply device is also equipped with a vacuum pumping device to perform vacuum treatment on the precursor resin.

6. The application of the preparation system according to any one of claims 1 to 5 in the PIP process of fiber-reinforced ceramic matrix composites.

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