Surface modification of SiC mirror by IARE method

摘要

A method to prepare high quality SiC coating at low temperature using large aperture E-beam evaporation PVD equipment with ion assistance was developed for the surface modification of SiC mirror for space projects .This method was called Ion Assisted Reactive Evaporation (IARE). The modified SiC coating was prepared using CH_4 and Si with Kaufman ion source by IARE at 300°C and it had met the requirements of applications. The SiC coating prepared by this method was amorphous. It was dense, homogeneous and easy to be polished. The surface modification of a SiC mirror was carried out using SiC coating by this method and achieved a fine surface modification effect. The surface roughness (rms) of the SiC substrate was reduced to 0.862nm, the scattering coefficient was reduced to 2.79% and the reflectance coated with Ag film was improved simultaneously after the surface modification. The effect of surface modification using SiC coating was close to that of using Si coating. It can be drawn that this technological method to preparation SiC coating for the surface modification of SiC mirror is reasonable and effective.