Cf/C-SiC composite material for engine piston and preparation method thereof

Abstract

The invention relates to a preparation method of a Cf / C-SiC composite material for an engine piston. The Cf / C-SiC composite material is prepared by densifying a needle-punched carbon fiber preform to the density of 1.95-2.20 g / cm < 3 > through a chemical vapor infiltration (CVI) method, a slurry impregnation (SI) method and a fusion reaction siliconizing (RMI) method. The specific preparation method comprises the following steps: firstly, preparing a carbon fiber preform by adopting a relay type needling method, then preparing a low-density carbon / carbon (Cf / C) porous body by adopting a CVI (Chemical Vapor Infiltration) method, introducing a carbon nanofiller by adopting an SI (Scale Index) method after high-temperature heat treatment, adjusting the pore size and distribution of the Cf / C porous body, and then preparing the Cf / C-SiC composite material by adopting an RMI (Reactive Magnetic Index) method; finally, releasing residual thermal stress through a high-temperature heat treatment method, and preparing the high-reliability and low-damage-sensitivity Cf / C-SiC composite material for the engine piston. The prepared Cf / C-SiC composite material for the engine piston has the advantages of higher room-temperature and high-temperature mechanical strength, smaller thermal expansion coefficient, lower damage sensitivity and excellent self-lubricating property.

Description

technical field [0001] The invention belongs to the technical field of preparation of ceramic-based composite materials, and in particular relates to a preparation material of a composite material for engine pistons, a preparation method and application thereof. Background technique [0002] The piston is one of the most important parts in the engine, because it works under the conditions of high temperature, high pressure, corrosion, friction, high-speed movement, etc., it has high requirements on the performance of the material. The traditional engine piston materials generally have three types: cast iron, steel and aluminum alloy. The development direction of internal combustion engines with high speed and low energy consumption requires piston materials to have better high-temperature mechanical properties and lighter weight to meet performance requirements. Data show that the maximum explosion pressure of the cylinder internal combustion engine has exceeded 20MPa or ev...

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Problems solved by technology

But the C prepared by RMI method f The residual Si existing in the matrix of the / C-SiC composite material will expand in volume during the cooling process, and it is easy to generate cracks at the Si-SiC interface, which will reduce the mechanical properties of the material at room temperature and the reliability of long-term service. At the same time, the residual Si belongs to Brittle materials will increase the sensitivity of the material to crack damage, which greatly limits the further application of this material in the field of engine pistons

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