直接沉淀法制备纤维状纳米Al_2O_3

Preparation of Fibrous Nano-Alumina by Direct Precipitation

纳米Al2O3粒子的制备方法很多，但所制备的产物多为球形或不规则的粒状，呈纤雏状的纳米Al2O3粒子的报道不多．本文以Al2（SO4）3·18H2O和NaOH为原料，十二烷基苯磺酸钠（DBS）为表面活性剂，通过控制反应温度为65℃，Al2（SO4）3初始浓度为0．5mol／L，以直接沉淀法先合成纤维状氧化铝的前驱体，然后在1000℃下煅烧2h得到直径为5～10nm，长为60～120nm，分散良好的γ-Al2O3短纤维，通过TEM，XRD等检测手段对各阶段产物的表征和分析，详细讨论了洗滤方式，反应温度，Al2O3 初始浓度对前驱体产物粒径形貌的影响，以及煅烧温度对最后产物形态和晶型的调整。

Various methods are available to synthesize alumina nanoparticles, but the product shape obtained via these methods is almost spherical or irregular, and the preparation of fibrous nano-alumina has seldom been reported. In this paper, direct precipitation method that selects Al2（SO4）3·18H2O and NaOH as raw materials, and dodecyl benzene sulfonate （DBS） as surfactant was used to prepare nano-alumina. The fibrous nanosized Al2O3 precursor was firstly synthesized by controlling the reaction temperature at 60--70℃, and the initial reaction concentration of A12（SO4）3 was about 0.5 mol/L, etc. After calcining at 1 000℃ for 3 h, the well dispersed fibrous nano-alumina with 5-- 10 nm in width and 60-- 100 nm in length was attained. Through observing and analysing with transmission electron microscope （TEM） and X-ray diffraction （XRD）, the influences of the filter washing, the reaction temperature and the initial reactant concentration on the size and morphology of precursor were systematically examined, and the shape and crystal phase of final product affected by the calcination temperature were investigated.