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Multiple carbon and ceramic base composite material piston and preparation method and application thereof

A technology of composite materials and pistons, which is applied in the direction of pistons, cylindrical pistons, plungers, etc., can solve the problems of high thermal expansion coefficient of aluminum alloy pistons, difficulty in obtaining a large increase, and high density of cast steel pistons, so as to improve mechanical strength , good dimensional stability, and high mechanical strength at high temperature

Active Publication Date: 2017-07-25
BEIHANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Traditional piston materials are mainly cast iron, cast steel, aluminum alloy, etc. Cast iron has high quality, low specific strength, and poor toughness, and is mainly used to produce large and medium bore low and medium speed engine pistons; cast steel pistons have high density and high cost , the cylinder liner is severely worn; the most widely used aluminum alloy piston has a large thermal expansion coefficient, high temperature mechanical properties, and relatively low wear resistance.
At this stage, the traditional piston production technology is quite mature, but the defects of the material itself make the performance of the traditional piston to the extreme, and it is difficult to get a big improvement; moreover, the country pays more and more attention to environmental protection, the exhaust gas emission of the traditional piston, Low efficiency and other problems restrict its development

Method used

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  • Multiple carbon and ceramic base composite material piston and preparation method and application thereof
  • Multiple carbon and ceramic base composite material piston and preparation method and application thereof
  • Multiple carbon and ceramic base composite material piston and preparation method and application thereof

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preparation example Construction

[0031] The invention provides a method for preparing a composite material piston, comprising the following steps:

[0032] S1: The piston preform is prepared by carbon fiber or polyacrylonitrile-based pre-oxidized wire; the initial density of the piston preform is 0.45-0.6g / cm 3 , the piston prefabricated body is formed by three-dimensional needling or four-step three-dimensional weaving.

[0033] S2: Preliminary densification treatment of the piston preform by chemical vapor infiltration method and / or precursor impregnation cracking method, and further densification treatment of the obtained product by chemical vapor phase infiltration method to obtain a density of 1.74-2.0g / cm 3 Composite pistons;

[0034] Step S2 is specifically: using chemical vapor infiltration method to deposit interfacial phase on the surface of the piston preform, including using natural gas and hydrogen as reaction gases, the flow ratio of natural gas and hydrogen is 2:1-3:1, and the flow rate of nat...

Embodiment 1

[0041] Imported T700 carbon fiber is prepared by three-dimensional acupuncture method to obtain an initial density of 0.45g / cm 3 The piston prefab, the size of the prefab is The structure of the piston preform is as follows figure 2 shown. The interfacial phase is deposited on the surface of the piston preform by chemical vapor infiltration, including natural gas and hydrogen as reaction gases, wherein the flow ratio of natural gas and hydrogen is 2:1, and the flow rate of natural gas is 0.6m 3 / h, the pressure is 2kPa, the power is 20kw, the temperature is raised to 1070°C at a heating rate of 300°C / h and kept for 25h, and the thickness of the interface layer reaches 400nm after densification; then the obtained material is treated by the precursor impregnation cracking method, Including dissolving polycarbosilane in xylene at 25°C for 6 hours to obtain polycarbosilane xylene solution, the mass ratio of polycarbosilane and xylene is 1:3, placing the obtained material in an...

Embodiment 2

[0043] The domestic polyacrylonitrile-based pre-oxidized yarn was selected and prepared by four-step three-dimensional weaving to obtain an initial density of 0.6g / cm 3 The piston prefab, the size of the prefab is The structure of the piston preform is as follows figure 2 shown. Preliminary densification of the piston preform by chemical vapor infiltration method, including using natural gas and propane as the reaction gas and hydrogen as the carrier gas, wherein the flow ratio of natural gas and propane is 6:1, the infiltration pressure is 8kPa, and the temperature is 1100°C , the infiltration time is 60h, and the density is 1.2g / cm 3 Composite pistons made of composite materials, the preliminary densified products are preliminarily machined to form a piston embryonic structure; the piston embryonic structure is completely densified by chemical vapor infiltration, including natural gas and propane as reaction gases, and hydrogen as a carrier. Gas, wherein the flow ratio ...

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Abstract

The invention relates to a multiple carbon and ceramic base composite material piston and a preparation method and application thereof. The preparation method is as follows: using carbon fiber or polyacrylonitrile based preoxidized silk to prepare a piston preform; using a chemical vapor infiltration method and / or precursor infiltration and pyrolysis method for preliminary densifying of the piston perform, using the chemical vapor infiltration method for further densifying of the obtained product to obtain a composite piston with the density of 1.74-2.0g / cm<3>; machining the obtained composite piston into final size design to obtain the composite piston finished product. The piston mass and the thermal expansion coefficient of the piston are reduced, the mechanical strength of the piston is improved, heat loss is effectively reduced, and noise and hydrocarbon and nitrogen oxide emissions can be reduced to achieve energy saving and environmental protection.

Description

technical field [0001] The invention relates to the technical field of piston material and piston design and processing, in particular to a multi-component carbon and ceramic matrix composite material piston and its preparation method and application. Background technique [0002] The piston is a key component of the engine. During the working process, it not only bears the heat load generated by the gas, but also bears mechanical loads such as reciprocating inertia force and friction force. Therefore, the requirements for material properties are very high. In order to meet the development of the engine in the direction of high power, light weight, low energy consumption, low emission, etc., the piston material is required to have sufficient high temperature strength and thermal stability, and can withstand high temperature and high pressure working environment; low density, light weight, to ensure the minimum Inertial force; good thermal conductivity, sufficient heat dissip...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/80C04B35/83C04B35/571C04B41/87F16J1/00
CPCC04B35/571C04B35/806C04B35/83C04B41/009C04B41/5042C04B41/87C04B2235/483C04B2235/5248C04B2235/614C04B2235/616C04B2235/77C04B2235/96C04B2235/9607F16J1/001C04B41/5035C04B41/5031
Inventor 罗瑞盈龙文彪
Owner BEIHANG UNIV
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