超微Fe_3O_4粒子正在广泛地应用到磁流体和催化等领域。化学共沉淀法制备Fe_3O_4是将碱液滴入一定温度的Fe~(2+)、Fe~(3+)混合液中。反应式为Fe~(2+)+2Fe~(3+)+8OH~-=Fe_3O_4+4H_2O。本文研究了Fe_3O_4超微粒子的磁性、粒度与工艺条件的关系。 1 实验 配制一定浓度的FeCl_2和FeCl_3溶液,按一定比例混合并置于三颈瓶中恒温。搅拌后,缓 Ultrafine Fe_3O_4 particles are widely used in the field of magnetic fluids and catalysis. Fe_3O_4 prepared by chemical coprecipitation method is to drop alkali solution into Fe ~ (2 +) and Fe ~ (3+) mixture at a certain temperature. The reaction formula is Fe ~ (2 +) + 2Fe ~ (3 +) + 8OH ~ - = Fe_3O_4 + 4H_2O. In this paper, the relationship between magnetic and particle size of Fe_3O_4 ultrafine particles and technological conditions was studied. 1 Experimental Preparation of a certain concentration of FeCl_2 and FeCl_3 solution, according to a certain percentage mixed and placed in a three-necked flask thermostat. After mixing, slow