Preparation method of silicon carbide composite film of reflector used in space

Abstract

The invention provides a preparation method of a silicon carbide composite film of a reflector used in space, and the method is characterized in that the polished reaction sintering silicon carbide substrate is placed in a deposition chamber, a silicon carbide whisker film is deposited at first: one path of gas is mixed gas of methyl silicochloroform and hydrogen from a vaporization kettle, wherein the pressure in the vaporization kettle can be controlled at 0.2 - 0.3 MPa, the total flow of mixed gas can be controlled at 200 - 300 ml / minutes, methyltrichlorosilane is sent to the deposition chamber by hydrogen through a bubbling method, the other path of gas is argon with flow of 800 - 900ml / minutes, a process of low pressure chemical vapor deposition is employed, wherein the deposition pressure in the deposition chamber is 6 - 7 kPa, the deposition temperature is 1100 - 1150 DEG C; redepositing a silicon carbide particle film: the total flow of hydrogen and methyl silicochloroform can be modified to 300 - 400 ml / minutes, the air flow rate of argon is modified to 500 - 600 ml / minutes, the deposition pressure in the deposition chamber is 3 - 5 kPa; finally, a process of polishing is performed and the silicon carbide composite film can be obtained on the substrate. According to the invention, the residual thermal stress between the substrate and the silicon carbide composite film is small, and associativity is good, and the method of the invention is beneficial to preparation of large size silicon carbide reflectors.

Description

technical field [0001] The invention provides a method for preparing a silicon carbide composite film for space mirrors, belonging to the technical field of ceramic preparation. Background technique [0002] People's exploration of space has promoted the development and research of the auxiliary observation system, and the performance and stability of the lens in the auxiliary observation system directly affect the use of the system. Harsh environments such as high vacuum, weightlessness and high-energy radiation in space make people put forward high requirements on the performance of lens materials. Due to the advantages of cost and large size, the main task of mirror design is to reduce weight. Mirrors can be designed to consist of smooth and dense membranes and lightweight mirror bodies. Lightweight structures include reduced structural thickness, porous structures and foam structures. Porous structures can be achieved by drilling blind holes, honeycomb structures and ...

AI Technical Summary

Problems solved by technology

The patent "High reflection film of silicon carbide mirror in the visible light band and its preparation method" adopts the method of magnetron sputtering to prepare a high reflection film with a 4-layer structure, which consists of a silicon film dense layer, a transition layer, an Ag reflective layer, SiO 2 The composition of the protective layer is complicated, the high temperature resistance of Ag is poor, and the process is complicated