【作者】 苏周；

【导师】 叶红齐；

【作者基本信息】 中南大学 ， 化学工艺， 2004， 硕士

【摘要】 片状氧化铝粉体是一种新型无机精细化学品，它具有特殊的二维结构与优良的物理化学性能，在颜料、化妆品、填料及磨料等领域有着广泛的应用。本文在综合分析氧化铝的晶体生长习性、熔盐化学特性的基础上，对熔盐法制备片状氧化铝粉体进行了系统研究。通过改变熔盐的种类与用量、烧成制度及掺入添加剂与晶种，考察了外界物理化学条件对氧化铝晶体生长形貌的影响，并用电子显微镜与光学显微镜、差热—热重分析、激光粒度和遮盖率等对片状氧化铝进行了表征，同时探讨了片状氧化铝的精制条件。研究结果表明：当硫酸铝与混合硫酸盐熔盐（Na₂SO₄：K₂SO₄：2.4：1.6）的摩尔比为1：4，同时添加1wt％的二氧化钛、1wt％的二氧化硅和3wt％的磷酸三钠，在1200℃烧结处理5小时，可得到粒径为5～25μm，厚度为200～400nm，径厚比为30～60的片状α—Al₂O₃粉体。通过改变添加剂的用量，可对片状氧化铝的粒度及径厚比进行控制和调整。论文还对熔盐法合成片状氧化铝的晶体生长机理进行了探讨，这对于控制氧化铝粉体在熔盐中的晶体生长具有一定的指导意义。更多还原

【Abstract】 Flaky alumina is one of the new inorganic fine chemicals with special two-dimensional structure and excellent physicochemical prosperities, and is widely applied in pigments, cosmetics, fillers and abrasive. The powders were prepared by molten salt synthesis method, and the influence factors, such as molten salts, sintering conditions, additive and seed, were investigated. The flaky powders obtained were characterized by means of microscope, TG-DTA, laser sizer, covering power measurement, et al. It was found that flaky a-A12O3 powder with diameter of 5~25um, thickness of 200~400nm and aspect ratio of 30~ 60, could be synthesized at 1200℃ for 5 hours when the mole ratio of aluminum sulfide to mixture sulfate salts (Na2SO4:K2SO4:=:2.4:1.6) was 1:4, and the additive amounts of phosphate, titania and silica were 3wt%, lwt% and lwt% (based on alumina) respectively. The size and aspect ratio of the powder can be adjusted and controlled by changing the amount of additives. The crystal growth mechanism of flaky alumina was also studied, which is useful to control the crystal growth of alumina in molten salts.更多还原