摘要
采用真空辅助凝胶注模和反应烧结法制备了面密度分别为9.35和11.7kg/m2,直径分别为200和500mm的两块超轻量化SiC反射镜,检测了反射镜的主要性能。结果显示:由于在真空环境下浇注,坯体没有宏观缺陷。材料中细小SiC颗粒的存在使材料具有相对较高的抗弯强度(335 MPa)和断裂韧性(4.5 MPa·m12)。此外,反射镜材料金相组织中未出现明显的SiC颗粒定向排列,具有较好的各向同性度:不同方向热膨胀系数差异小于3%,模量差异为1.3%。镜坯经过光学加工后面形误差(RMS值)为0.043λ(λ=632.8nm),表面粗糙度(Ra值)优于5nm。实验表明,真空辅助凝胶注模成型结合反应烧结工艺制备的超轻量化SiC反射镜各方面性能良好,适用于制备空间相机用反射镜。
Vacuum pressure assisted gel-casting and reaction sintering were applied to fabrication ofΦ200andΦ500mm ultra-lightweight SiC mirrors with the area densities of 9.17kg/m^2 and 10.8kg/m^2 respectively.The main properties of the SiC mirrors were tested.The results show that the green bodies of the SiC mirrors have no macroscopic defects due to its pouring in a vacuum environment.The mirror materials have high flexural strength（335MPa）and fracture toughness（4.5MPa·m^1/2）because of the fine SiC particles.The metallographic structures of the mirror materials do not show the directional alignment of SiC particles,which means the mirror materials possess a high isotropy ratio,in which the relative deviation of Coefficient of Thermal Expansion（CTE）is less than 3%,and the relative deviation of modulus reaches 1.3%.After polishing,the surface profile accuracy（RMS）of the mirror is 0.043λ（λ=632.8nm）,and the toughness is better than 5nm.These results demonstrate that the ultra-lightweight SiC mirrors fabricated by vacuum-assisted gel-casting and reaction sintering have excellent performance,and are suitable for fabrication of the mirrors of space cameras.
出处
《光学精密工程》
EI
CAS
CSCD
北大核心
2015年第8期2185-2191,共7页
Optics and Precision Engineering
基金
超轻RBSiC反射镜制备技术研究(No.Y2CXISS126)
关键词
光学制造
SIC
超轻量化反射镜
真空辅助凝胶注模
反应烧结
optical fabrication
silicon carbide
ultra-lightweight mirror
vacuum pressure assisted gel-casting
reaction sintering
