轻型碳化硅质反射镜坯体的制造工艺

Fabrication of silicon carbide lightweight mirror blank

研究了轻型碳化硅质反射镜坯体制造技术,讨论了制备工艺中的关键环节。提出了一种先进的消失模技术用于制备性能更加优异的背部半封闭式轻量化结构。针对制备大尺寸复杂形状陶瓷的难点,研究了SiC陶瓷素坯凝胶注模成型及成型过程中高固相含量低黏度SiC浆料的配置、浆料固化时间控制及大尺寸复杂形状SiC湿坯的液体干燥工艺等。测试分析了坯体烧结过程中素坯的热失重与差热曲线,制定了最佳的烧结工艺。通过对以上关键技术的研究,制备得到了不同形状与轻量化结构形式的单块轻型SiC坯体,最大尺寸为1 100mm×820mm。

Fabrication techniques of lightweight silicon carbide（SiC） mirror blank were researched and the key problems in the fabricating process were discussed.An advanced lost mould method was proposed to fabricate the excellent lightweight structure with a partly open-back.In consideration of the difficulty on fabricating SiC ceramics with larger sizes and complex shapes,the gelcasting for a SiC green body was studied and the ingredient of the SiC slurry with high solid phase and low viscosity,control of slurry time and the drying processing for the wed bland in the gelcasting were discussed.Thermogravimetic and Differential Thermal Analysis TG/DTA curves for the green body were analyzed,then the best sintering process was established.By the proposed technologies,RB-SiC mirror blanks with different shapes and lightweight constructions were prepared and the largest one is 1 100 mm×820 mm.