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Process for producing compact silicon/silicon carbide coating of optics reflection mirror

A technology of silicon carbide coatings and mirrors, which is applied in optics, coatings, optical components, etc., can solve the problems of surface roughness difficult to achieve high-resolution mirrors, SiC materials are difficult to complete, and low bonding strength, etc., to achieve shortening The effect of short preparation cycle and processing cycle and high bonding strength

Inactive Publication Date: 2008-07-16
NAT UNIV OF DEFENSE TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, there are some insurmountable problems in the preparation of high-resolution mirrors by traditional single-layer SiC and its composite materials: 1. Density. SiC materials prepared by traditional processes are difficult to be completely dense. Surface roughness is difficult to meet the requirements of high-resolution mirrors
2. Manufacturability. Since SiC belongs to the covalent bond structure, it needs to be sintered at high temperature (greater than 1800°C) or with additives, so its manufacturability is poor
CVD SiC dense coating can provide excellent optical processing characteristics, however, the coating prepared by this process has low bonding strength with the body (not purely chemical bonding) and stress due to thermal expansion coefficient mismatch

Method used

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  • Process for producing compact silicon/silicon carbide coating of optics reflection mirror
  • Process for producing compact silicon/silicon carbide coating of optics reflection mirror

Examples

Experimental program
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Effect test

Embodiment 1

[0018] The pre-coating formula is 40wt% of silicon powder, 15wt% of silicon carbide powder, 35wt% of carbon powder and 10wt% of polyvinyl alcohol, then add water ball mill with the same weight as the total weight of the above formula and mix it into mud, and then use the method of manual brushing Coating the surface of the mirror substrate preform made of C / C material to obtain a pre-coating, and then sintering the pre-coated C / C preform in a vacuum sintering furnace, process parameters: in the furnace The vacuum degree is less than 500Pa, the sintering temperature is 1600°C, and the temperature is kept for 4 hours to obtain a product coated with a dense silicon / silicon carbide coating (Si / SiC).

Embodiment 2

[0020] The pre-coating formula is 35wt% of silicon powder, 10wt% of silicon carbide powder, 45wt% of carbon powder and 10wt% of phenolic resin, and then add acetone ball mill with the same weight as the total weight of the above formula to make a slurry, and then make it on the C / SiC material The surface of the reflector substrate prefabricated part is brushed to obtain a precoat, and then placed in a vacuum sintering furnace for reaction to obtain a product coated with a dense silicon / silicon carbide coating (Si / SiC), and the sintering process parameters are the same as in Example 1 .

[0021] It can be seen from Figure 1 and Figure 2 that the surface roughness of the reaction sintered Si / SiC coating after polishing is less than 1.5nm, which meets the optical application requirements of the mirror.

[0022] From the comparison of the thermal expansion coefficients of the reaction sintered Si / SiC coating and the C / SiC substrate shown in Figure 3, it can be seen that the therma...

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Abstract

The invention relates to a preparation method of a dense silicon / silicon carbide coating used in optical reflecting mirror., in which the micron scale graphite (carbon) powder, the silicon carbide, the silicon powder, an organic additive and a solvent are blended into a slurry, and prepared into an optical pre-coating layer on a prefabricated member (C / C material or C / SiC material) of the matrix of the reflecting mirror through manual brushing, and finally the dense silicon / silicon carbide coating used in optical reflecting mirror is prepared through reactive sintering. The silicon / silicon carbide coating prepared by the invention has outstanding optical machining properties with a material density at about 2.60g / cm<3>, Si-C chemical bonding with a high bonding strength being formed between the coating and the matrix, a nearly identical thermal expansion factor. No intension exists between the coating and a billet body; the surface roughness of the coating is smaller than 1.5nm after chemical processing, so the coating is applicable to the reflective layer of the optical reflecting mirror.

Description

technical field [0001] The invention belongs to a preparation process of a high-resolution optical mirror, in particular to a preparation method of an optical mirror coating. Background technique [0002] The space optical system plays the role of reconnaissance, detection and information collection in space vehicles. With the rapid development of satellite remote sensing technology, users have higher and higher requirements for the ground resolution of remote sensors. Future space optical systems require good imaging quality in a wide range of electromagnetic bands, which range from ultraviolet, visible light, infrared, and even extended to x-rays and gamma-rays. In order to work in such a wide range of electromagnetic wavelengths, only total reflection or catadioptric optical systems can meet the application requirements. Therefore, space optical systems mostly use reflective designs. The key component in the reflective optical system is the reflector, in addition to meet...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B05D7/24B05D3/00G02B1/10
Inventor 张长瑞曹英斌刘荣军张彬
Owner NAT UNIV OF DEFENSE TECH
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