不同钴离子溶剂对钴粉形貌的影响

分别采用乙醇、乙二醇和丙三醇为钴离子溶剂,用水合肼在室温下还原钴盐制备钴粉,研究了不同钴离子溶剂对所制备钴粉形貌的影响及其机理。研究结果表明:所制备的钴粉均由FCC和HCP两相混合组成。以乙醇为钴离子溶剂,当钴离子的浓度足够低时(0.045 mol/L),出现树枝状的颗粒,其余钴离子浓度下,原生钴颗粒形貌为类球形。采用多元醇(乙二醇、丙三醇)为钴离子溶剂时,由于一定量的多元醇会聚集形成微反应器,有利于表面光滑的球形原生钴粉颗粒生成。乙醇的添加量通过影响晶核的形核、生长、扩散等过程来影响产物形貌。多元醇的添加量主要通过影响溶液的黏度和微反应器的完整性和数量等来影响产物的形貌。乙二醇的添加量在80 m L时,获得了均匀的、表面光滑的球形钴粉颗粒。

Influence of Different Kind Cobalt Ion Solvents on the Morphology of Cobalt Powder

Cobalt powder was prepared by hydrazine hydrate reducing cobalt salt method at room temperature by using ethanol,ethylene glycol and glycerin as the solvent of cobalt ion,respectively.The influence of cobalt ion solvent on the particle morphology of cobalt powder and its mechanism were investigated.The results showed that,the prepared cobalt powder consists of FCC and HCP crystalline phase.Using ethanol as cobalt ion solvent,the dendritic primary particles can be gained when the concentration of Co²⁺ ion is too low (0.045 mol/L),and the near-spherical primary particles of cobalt powder can be gained when the rest of concentration of Co²⁺ ion is used.When ethylene glycol or glycerin is used as cobalt ion solvent,smooth spherical primary particles can be obtained because of the effect of micro reactor formed by polyhydric alcohols.The way of the ethanol content influencing the morphology is by means of affecting the nucleation,growth and diffusion of the formed crystal nucleus.However,the way of the polyhydric alcohol content influencing the morphology is by means of affecting the viscosity of solution,as well as the integrity and the quantity of micro reactors.In the investigation,when the addition of ethylene glycol is 80 mL,the uniform and smooth spherical cobalt powders can be obtained.