Synthesis and characterization of Co-Ni compound with urchinlike micro/nam) structure

Particles with urchinlike micro/nano structure were synthesized by a facile homogeneous co-precipitation process via the direct reaction between cobalt salt, nickel salt and urea. By varying the reaction temperature, concentration of reactant and reactant ratio, the obtained precursors are well-defined urchinlike particles with many thorns radially grown on the surface. After subsequent heal treatment of the corresponding precursors in oxidation and reduction atmosphere, respectively, the final products with different morphologies were characterized by FE- SEM, TEM, XRD and VSM. The heat-treated products with good ferrimagnetism fairly maintain the morphology of their corresponding precursors in oxidation atmosphere. A possible mechanism for the growth of this urehinlike architecture is proposed. It is worth noting that in reduction atmosphere, the particles grow into porous micro/ nanospheres and exhibit preferable ferrimagnetism.