脉冲电磁场对草酸钴形貌的影响

Effects of pulsed electromagnetic field on morphology of cobalt oxalate powders

在脉冲电磁场(PEMF)作用下,采用常规沉淀方法制备了椭球形的草酸钴粉体。利用XRD以及SEM分别对产物的物相和形貌进行了表征;采用差分盒维法计算了草酸钴粉末团聚体的表面分形维数。结果表明:以氯化钴为原料、草酸铵为沉淀剂制备的产物为β-CoC2O4.2H2O;随着脉冲电压由200V增加到800V,草酸钴颗粒的形貌由棒状转变为椭球状,分形维数逐渐增大;脉冲电压大于800V时,草酸钴的形貌又向棒状转变,分形维数开始减小;以草酸钴为前躯体制备的Co粉表现出很好的形貌继承性。

Spheroidic cobalt oxalate powders were prepared by conventional precipitation when a pulsed electromagnetic field （PEMF） was introduced. The phase structures of the products were characterized by means of X-ray powder diffraction （XRD）. SEM was used to observe the morphologies of obtained cobalt oxalate powders. The surface fractal dimensions of cobalt oxalate aggregate were calculated using Differential Box Counting （DBC） algorithm. The results indicate that the products prepared from ammonium oxalate and cobalt chloride give rise to the formation of β-CoC2O4 · 2H2O particles; with rise in PEMF voltage from 200V to 800V, the morphology of cobalt oxalate particles turns from rod-like to spheroidicity and an increase in surface fraetal dimensions occurs; PEMF voltage higher than 800V results in the morphology transition from spheroidicity to rod-like and a decrease of surface fractal dimensions. The morphology of cobalt powders prepared from cobalt oxalate is intensively influenced by the precursor.