【摘要】 采用正硅酸乙酯溶胶-凝胶法制备纳米SiO2,并与氯化铈溶液混合,用氨水沉淀法制备了SiO2-CeO2复合氧化物。利用XRD、SEM等手段对其物相类型、外观形貌、颗粒大小、表面电位等物理性能进行了表征,测定了它们对3种光学玻璃的抛光速率。结果表明:合成复合氧化物具有立方萤石型结构,由Sherrer方程计算的晶粒DXRD(200)小于100nm甚至10nm。随着SiO2复配量的增加和煅烧温度的降低,晶粒度减小,比表面增大;激光粒度分析仪测定的中位粒径D50在2￣3μm之间,且随SiO2复配量的增加呈增大趋势,但随煅烧温度的变化在800℃时出现极小值,而此时的ζ电位的负值最大,对3种玻璃的抛光速率也最大。证明抛光速率与表面电位及相应的悬浮性、颗粒大小有直接关系。随着SiO2复配量的增加,复合氧化物的ζ电位负值及对3种玻璃的抛光速率均增大。因此,在CeO2中复配SiO2是提高抛光速率的有效方法,此时,最佳的煅烧温度为800℃。更多还原

【Abstract】 SiO2-CeO2 mixed oxides were prepared by precipitating cerium ion with ammonia from solution containing cerium chloride and nano-silica, which was prepared by means of sol-gel method using ethyl-orthosilicate as raw material. Their crystalline phase type, morphology, crystalline size, particle size and ζ potential were characterized, and the polishing rate was determined. The synthesized mixed oxides were nanocrystalline ceria with cubic fluorite structure,the calculated average crystalline sizes based on the half peak width and Sherrer formula were less than 100 nm, even lower than 10 nm. With the increase of mass ratio of SiO2 to CeO2 and the decrease of calcination temperature, the crystalline size decreased, however, the specific surface area and the particle sizes determined by laser scattering method, which ranged from 2 000 to 3 000 nm, increased. The dependence of calcination temperature on the zeta potential, particle size and polishing rate for three glasses all showed peak value at around 800 ℃. These facts demonstrate that there exists a direct relation between polishing rate and particle zeta potential as well as the corresponding physical properties such as particle size and suspension stability. On the other hand, the negative zeta potential and the polishing rate for three glasses were all increased with the increase in the addition amount of SiO2 in the mixed oxide. Therefore, doping SiO2 with CeO2 is an effective route to enhance polishing rate, and the best calcining temperature lies around 800 ℃.更多还原