用于珠光颜料的片状氧化铝制备

Preparation of Flaky Aluminum Oxide for Pearlescent Pigment

采用熔融盐法制备片状α-Al2O3,研究了硫酸盐、煅烧温度、添加剂(磷酸盐、二氧化钛)对片状α-Al2O3晶体形貌的影响。当氢氧化铝凝胶煅烧温度为900℃时,没加硫酸盐分解所得的氧化铝晶相为κ-Al2O3晶相,而加入硫酸盐的氧化铝晶相为α-Al2O3晶相,熔融盐降低了片状α-Al2O3的形成温度,促进κ-Al2O3向α-Al2O3晶型转变。煅烧温度由900℃上升到1200℃时,片状α-Al2O3的团聚程度降低,颗粒尺寸分布更加均匀。当煅烧温度在1200℃下、磷酸盐添加量为3%、二氧化钛添加量为2%时,所制得片状氧化铝分散均匀,径厚比较大,片状氧化铝平均粒径为5.225μm、厚度约400-500 nm。

α-alumina platelets were prepared by a molten salt synthesis method when Al2（SO4）3？18H2O was used as raw material. The effects of sulfates, heating temperature, additives such as Na3PO4？12H2O and TiO2 on the morphology ofα-Al2O3 were studied. When the heating temperature of aluminum hydroxide gel is 900℃, the synthesized Al2O3 without adding sulfates is mainlyκ-Al2O3;nevertheless, the synthesized Al2O3 with sulfates is mainlyα-Al2O3. So, sulfates reduce the synthesizing temperature of lfakyα-Al2O3 and promoteκ-Al2O3 toα-Al2O3 crystalline phase. When the heating temperature increases to 1200℃, most ofα-Al2O3 platelets are hexagonal in its morphology, the increase of heating temperature is beneifcial to improve the size distribution and overlapping. When the heating temperature is 1200℃, the addition of Na3PO4？12H2O reaches 4%and TiO2 reaches 2%, the lfakyα-Al2O3 is dispersed uniformly, the average particle size is 5.225μm, and the thickness of them is about 400-500 nm.