KMnO_(4)对空间探测用SiC反射镜加工性能影响规律

Effect of KMnO_(4) on the Processing Properties of SiC Mirror for Space Exploration

SiC陶瓷作为新一代具有优异综合性能的反射镜材料,已在空间相机反射镜中得到了广泛应用。在SiC光学加工后期,需要进行表面改性以降低表面粗糙度提升表面质量,这将直接影响SiC反射镜的加工精度和周期,因此,有必要对其优化改进加工工艺。本文引入KMnO_(4)添加剂,分析了参与反应的化学反应机理,强氧化性MnO_(4)^(-)在SiC试样表面发生化学反应,降低了金刚石微粉对SiC反射镜的磨削去量,实现了降低表面粗糙度的目的。通过工艺实验得以验证,系列金刚石微粉抛光Φ200 mm口径常压烧结SiC反射镜,添加KMnO_(4)后表面粗糙度相应减小,W7磨料达到了单独使用W3磨料抛光表面粗糙度的效果,W0.1磨料抛光后表面粗糙度S_(q)达到1.628 nm(4D,10×),优于抛光表面改性SiC超光滑表面质量。KMnO_(4)添加剂的引入实现了SiC反射镜高效、高精度光学加工的目的。

SiC ceramics,as a new generation of mirror materials with excellent comprehensive properties,have been widely used in space camera mirrors.However,in the late stage of SiC optical processing,polishing continues after surface modification to reduce the surface roughness and improve the surface quality,will directly affect the process accuracy and cycle of SiC mirror.Therefore,it is necessary to improve and optimize its optical processing technology.In this paper,KMnO_(4)additive is introduced to analyze the chemical reaction mechanism involved in the reaction.Strong oxidizing MnO_(4)^(-) reacts with the surface of the SiC sample,which reduces the grinding amount of diamond powder to SiC mirror and achieves the purpose of reducing the surface roughness.For the series of diamond powder polishing the 200 mm diameter atmospheric pressure sintered SiC sample,the surface roughness was correspondingly reduced with KMnO_(4)additive.It was interesting that W7 abrasive with KMnO_(4)additive polishing SiC surface reached the similar roughness effect of W3 abrasive.The obtained mirror roughness S_(q)(4D,10 times magnification)was 1.628 nm after being polished with W0.1 diamond powder and KMnO_(4)additive.The result was better than the polished super smooth surface quality of modified SiC.This realized the efficient and high-precision processing of SiC mirror with the introduction of KMnO_(4)additive.