Magnetic ultrafine cobalt particles prepared by solution chemical reduction method

Coblat particles have been prepared by solution chemical reduction method in non-alcohol solution,using hydrazine hydrate as reducing agent and potassium sodium tartrate as complexing agent.X-ray diffraction(XRD) analysis indicateed that the Co particles prepared have close-packed hexagonal structure(hcp).Transmission electron microscope(TEM) and vibrating sample magnetometer(VSM) analysis indicated that the nanosized subround Co particles were prepared.The average particle diameter increases with increasing the temperature,concentration ratio of CoSO4·7H2O to seignette sol and the pH value.The specific saturation magnetization increases as the pH value increasing.The advantage of this method is that the press is simple and reduction reaction is easy to be controlled,and the Co particles can be changed in a wide range of mean particle size.