Preparation method of zero-expansion LAS/SiC composite material

Abstract

Disclosed is a preparation method of a zero-expansion LAS/SiC composite material. The method comprises: firstly, preparing LAS powder via a powder sintering method; then adopting SiC powder with a matching diameter as a conditioning agent of the zero-expansion LAS/SiC composite material; calculating the ratio of LAS powder and SiC powder for macro-control of the thermal expansion coefficient of the composite material; and finally adopting a hot pressed sintering method and post-process treatment to prepare the zero-expansion LAS/SiC composite material. The composite material obtained in the invention is high in densification degree. A matrix is softened at a high temperature, so that densification is beneficial to perform. Further, the externally-applied pressure quickens the densification process, so that pores, which cannot be discharged in the absence of pressure, can be forced to be eliminated under the action of stress. Organization is homogenized; the pore ratio is reduced; and the strength of the composite material is improved.

Description

technical field [0001] The present invention relates to a method for preparing a composite material, in particular to a method for preparing a zero-expansion LAS / SiC composite material. The obtained composite material can be used for reflector lenses of astronomical telescopes, precision machinery-laser resonators, and navigation-laser gyroscopes instruments, radar radomes and other products. Background technique [0002] In the functional structures and components used in the fields of aerospace, mechanical engineering and precision instruments, the thermal expansion and contraction behavior of various materials due to temperature changes has a great impact on their service performance and reliability. For example, metal structures and components used in the aerospace field and space environment usually experience drastic changes in ambient temperature. The difference in coefficient of thermal expansion (CTE) between different materials will not only cause large internal st...

AI Technical Summary

Problems solved by technology

For example, metal structures and components used in the aerospace field and space environment usually experience drastic changes in ambient temperature. The difference in coefficient of thermal expansion (CTE) between different materials will not only cause large internal stress inside the structure and components, but also cause Changes in surface contact state and tribological design (such as changes in the original structure of holes, pins, keys, etc.), resulting in functional failure, and in severe cases, microcracks and structural damage to components; in information storage and transmission , the microstructure and shape changes of materials and devices caused by thermal expansion and contraction may cause information distortion and transmission failure; in addition, the accuracy of the shape and small changes in the size of components in precision systems such as micro-electromechanical systems are crucial to their functions , but because the service environment of components often faces large temperature changes, the thermal expansion or contraction properties of materials have a significant impact on the performance stability of components, system life and application range

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