根据空间应用项目需求, 采用等离子辅助电子束蒸发方法对RB-SiC基底进行了表面改性, 并对表面改性的性能和可靠性进行了相关评估.经测试, 改性后RB-SiC基底表面粗糙度(rms)降低到0.632 nm; 散射系数降低到2.81%, 500~1 000 nm范围的平均反射率提高到97.05%, 已经接近于抛光良好的微晶玻璃的水平; 改性涂层温度稳定性高, 与基底结合牢固; 加工后, 面形精度达到0.119λ(PV)和0.014λ(rms), λ=632.8 nm.评估结果表明, 这种SiC基底表面改性的工艺是可靠的, 其光学性能满足空间高质量光学系统的要求, 适宜空间环境应用.

Surface modification for the RB-SiC substrate is carried out using e-beam evaporation with plasma ion assisted. The performance and reliability are evaluated according to the demand for space projects. After the surface modification, the surface roughness of the RB-SiC substrate is reduced to 0.632 nm, the scattering coefficient is reduced to 2.81% and the average reflectance from 500 nm to 1 000 nm is raised to 97.05%,These data indicates that the modification process can get an obvious result close to that of the fine polished zerodur glass.And,the modification coating has a good temperature stability and a high adhesion to the RB-SiC substrate. The surface figure precision of 0.119λ(PV) and 0.014λ(rms),(λ=632.8 nm) is obtained after optical surfacing. The optical and physical evaluation shows that this technics for the surface modification is reliable.The optical performance of the RB-SiC surface after modification can meet the requirements of high quality optical system for space use.