多孔不锈钢基体上多孔SiO2陶瓷膜的制备

Preparation of porous SiO_2 membranes on porous stainless steel supports

为了研究SiO2陶瓷在孔径1μm的多孔不锈钢基体上的成膜性能,利用正硅酸乙酯通过胶溶法制得SiO2溶胶,对其制备过程中氨水的添加量、胶溶温度和胶溶时间以及SiO2陶瓷膜层制备过程中溶胶的陈化时间、黏合剂种类、制膜液浓度和烧结温度进行了探讨。结果表明,溶胶制备时氨水的添加量为2.1 mol/mol,胶溶温度50℃,胶溶时间12 h;SiO2陶瓷膜层制备时溶胶的陈化时间为24 h,黏合剂为聚乙烯醇1750(PVA 1750),制膜液浓度为0.047 mol/L,烧结温度为850℃;该条件下可以制得连续的颗粒状斜方相SiO2晶体陶瓷膜。

In order to explore the membrane formation properties of silica membranes on porous stainless steelsupports with mean pore size of 1μm, tetraethyl orthosilicate （TEOS） was employed to prepare the silica sol via colloidal gel route of sol-gel inethod. The effects of the amount of ammonia, the peptization temperature and the peptization period on the sol properties were investigated. In addition, the effects of the aging period of the sol, the kind of binders, the concentration of the casting solution and sintering temperature on the morphologies and phases of the top membranes were also discussed. The results show that the optimal amount of ammonia is 2.1 mol/mol, the optimal peptization temperature is 50℃, and the optimal peptization period is 12 h. The optimal parameters for membrane preparation are as follows： the aging period of the sol 24 h, the binder PVA 1750, the concentration of the casting solution 0.047 mol/L and the sintering temperature 850℃. Under these conditions, pure tridymite phase of grain-like silica membranes can be obtained.