空间望远镜用C/SiC镜面研制综述

综述了空间望远镜的主镜用高强度、高表面精度、低热膨胀系数的低温（约4K）用镜面的制备和检测过程.日本将Φ710mm的高强度反应烧结SiC材料已用于红外望远镜镜面.在短切炭纤维增强C/C复合材料毛坯的基础上进行液相硅渗透（LSI）而制备的C/SiC复合材料在光学镜面方面具有更大的优势.通过提高C/C复合材料毛坯中沥青基炭纤维体积分数及控制硅化速度,可有效地提高LSI-C/SiC复合材料的机械性能和表面光学精度;通过不同规格的炭纤维的混杂化,可使C/SiC复合材料热膨胀系数的各向异性降低至小于4％的差异.SiC、Si-SiC浆料涂层处理可有效地提高表面精度至2 nm rms的极高要求.

An overview on C/SiC composite mirror for space telescope

h is presented here that the fabrication and testing of space telescope mirrors, which have the characteristics of high strength, high surface precision and low coefficient of thermal expansion（CTE） at about 4K. The reaction sintered SiC ceramic has been produced as a Φ710mm infrared telescope mirror in Japan. Based on the chopped carbon fiber reinforced C/ C composite as a green body, the liquid silicon infiltration （LSI） derived C/SiC composites have an advantage in using as the optical mirrors. The mechanical properties and surface optical precision in LSI-C/SiC mirrors can be improved by higher pitch carbon fiber volume fraction in C/C composites green body and controlling siliconizing degree. The anisotropy of CTE in C/SiC can be decreased below 4% through hybridization of different specification carbon fibers. The SiC powder and Si-SiC powders slurry coating treatment can effectively improve the surface precision to the superior requirement of 2 nm rms.