为了满足空间用大口径、复杂轻量化结构RB-SiC基底反射镜对高性能表面质量的需求,针对RB-SiC基底的特性,提出了改进表面改性工艺的方法。采用高能量考夫曼离子源辅助,预先对基底进行碳化和加镀C缓冲层,并制备Si改性涂层的方法对RB-SiC基底进行了表面改性。测试结果表明:与单纯霍尔离子源辅助方法相比,该工艺方法制备的Si改性涂层生长得更加致密、均匀,抛光特性良好;改性抛光后表面粗糙度(rms)降低到0.635 nm,达到了S-SiC基底的水平;改性后RB-SiC基底的反射率明显提高,达到了抛光良好的微晶玻璃的水平。结果表明,该工艺方法是提高RB-SiC基底表面改性效果的一种合理有效的方法。

A improved technological process to the surface modification of a RB-SiC substrate mirror was proposed according to the material special properties of the large scale and complicated light weighted RB-SiC materials for space projects. Using a high energy Kaufman ion source for the Ion Beam Aided Deposition(IBAD),the substrate was pre-carbonized and coated by a carbon buffer layer. Then,a Si layer was coated upon the buffer layer for surface modification,and the properties of the sample were tested. In comparison to the process simply using a Hall ion source for the IBAD,the coating has a more compact and uniform structure and a better property in polishing. After surface modification,the surface roughness(rms) of the substrate is reduced to 0.635 nm which is the same as that of the S-SiC substrate,also the surface reflectance is obviously enhanced to that of the fine polished zerodur glass. The conclusion can be drawn that this technological process of surface modification for the RB-SiC mirror is quite reasonable and effective.