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Composite densification method of SiC-based composite material precursors at different states through dipping cracking

A composite material, impregnation cracking technology, applied in the aviation field, can solve the problems of long preparation cycle, small molecular weight, difficult to fill large pores, etc., achieve the effect of shortening the preparation cycle and increasing the densification speed

Active Publication Date: 2019-01-11
PLA NO 5719 FACTORY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The impregnation efficiency is low, and the volatilization of xylene will produce a large number of small pores, which are suitable for filling the large pores in the preform, resulting in a long preparation cycle
There is also the use of liquid polycarbosilane as a precursor for direct impregnation. This impregnation liquid has a small molecular weight and low viscosity. The impregnation liquid is suitable for filling small pores in the preform, and it is difficult to fill large pores, resulting in a long preparation cycle.
In summary, only a single solid or liquid polycarbosilane is used as a precursor, resulting in a long preparation period for impregnation and cracking, and it is necessary to develop a short-cycle densification process

Method used

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  • Composite densification method of SiC-based composite material precursors at different states through dipping cracking
  • Composite densification method of SiC-based composite material precursors at different states through dipping cracking
  • Composite densification method of SiC-based composite material precursors at different states through dipping cracking

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Take 1 piece of SiCf / SiC composite material prefabricated body, use 2.5D weaving, initial density is 1.2g / cm 3 , The specification is 150mm×150mm×20mm. The immersion lysis was carried out according to the method provided by the present invention. The process is divided into the following two stages:

[0026] (1) The process of the first stage is:

[0027] Step 1: First prepare solid polycarbosilane and xylene, weigh the polycarbosilane and xylene in a mass ratio of 1:1.2, put them into a container and stir for 23 minutes with a magnetic stirrer until uniform, and prepare the required impregnation liquid.

[0028] Step 2: Then put the SiC-based composite material preform into the impregnation barrel in the impregnation furnace. Body, keep the vacuum impregnation for 1.2h.

[0029] Then, argon gas is introduced to make the pressure in the impregnation furnace reach 5.3 MPa, and it is maintained for 2.2 hours, so that the impregnation liquid is immersed into the pores...

Embodiment 2

[0047]Take 1 piece of SiCf / SiC composite material prefabricated body, adopt 2.5D weaving, initial density is 1.25g / cm 3 , The specification is 150mm×150mm×20mm. The immersion lysis was carried out according to the method provided by the present invention. The process is divided into the following two stages:

[0048] (1) The process of the first stage is:

[0049] Step 1: First prepare solid polycarbosilane and xylene, weigh the polycarbosilane and xylene in a mass ratio of 1:1.5, put them into a container and stir for 25 minutes with a magnetic stirrer until uniform, and prepare the required impregnation liquid.

[0050] Step 2: Then put the SiC-based composite material preform into the impregnation barrel in the impregnation furnace, vacuum the impregnation furnace to 7kPa, and pump the impregnation solution prepared in step 1 into the impregnation barrel through the suction pipe to submerge the preform Body, keep the vacuum impregnation for 1.5h.

[0051] Then, argon g...

Embodiment 3

[0069] Take 1 piece of SiCf / SiC composite material prefabricated body, adopt 2.5D weaving, initial density is 1.25g / cm 3 , The specification is 150mm×150mm×20mm. The immersion lysis was carried out according to the method provided by the present invention. The process is divided into the following two stages:

[0070] (1) The process of the first stage is:

[0071] Step 1: First prepare solid polycarbosilane and xylene, weigh the polycarbosilane and xylene in a mass ratio of 1:1.2, put them into a container and stir for 23 minutes with a magnetic stirrer until uniform, and prepare the required impregnation liquid.

[0072] Step 2: Then put the SiC-based composite material preform into the impregnation barrel in the impregnation furnace. Body, keep the vacuum impregnation for 1.2h.

[0073] Then, argon gas is introduced to make the pressure in the impregnation furnace reach 5.3 MPa, and it is maintained for 2.2 hours, so that the impregnation liquid is immersed into the po...

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Abstract

The invention discloses a composite densification method of SiC-based composite material precursors at different states through dipping cracking. The composite densification method of SiC-based composite material precursors at different states through dipping cracking comprises two steps of dipping, wherein at a first stage, solid state polycarbosilane, which is capable of filling gaps among fiberbundles and solving problems of composite materials that pores are too large and filing is difficult, is adopted; at a second stage, liquid state polycarbosilane, which is capable of filling composite material small pores and accelerating densification speed, is adopted. The dipping cracking composite densification preparation period is reduced by more than 30% of conventional single densification technology period.

Description

technical field [0001] The invention belongs to the field of aviation technology, and in particular relates to a composite densification method for impregnating and cracking precursors of SiC-based composite materials in different states. Background technique [0002] SiC-based composite materials have excellent properties such as high-temperature strength, light weight, good corrosion resistance and wear resistance, and their high-temperature capabilities will improve engine performance, thrust-to-weight ratio and fuel consumption, and are ideal for high-temperature structural parts of long-life aero-engines Material. The preparation methods of SiC-based composite materials include chemical vapor infiltration method, reactive melt infiltration method, and precursor impregnation cracking method. However, the chemical vapor infiltration method has a long preparation cycle and is easy to form closed pores on the surface of the fiber, resulting in insufficient final density. H...

Claims

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Application Information

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IPC IPC(8): C04B35/573C04B35/622C04B35/80
CPCC04B35/806C04B35/573C04B35/622C04B2235/6562C04B2235/6567C04B2235/77
Inventor 郭双全黄璇璇姚改成司艳叶勇松刘俊伶
Owner PLA NO 5719 FACTORY