Abstract: Cobalt ferrite magnetic nano-powder was prepared by composite-hydroxide-mediate method, the preparing process was studied. The structure and magnetic properties of the samples are measured and analyzed by X-ray diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). The results showed that cobalt ferrite with uniform particle sizes in the range of 10～50 nm can be obtained using nitrates or acetates as raw materials. The synthesized nano-particles are small in sizes with uniform diameter, and have a good disperability. Their magnetic properties are middle saturation magnetization and high coercive force. The cobalt ferrite synthesized shows a better quality.

Key words: Cobalt ferrite magnetic nano-powder was prepared by composite-hydroxide-mediate method, the preparing process was studied. The structure and magnetic properties of the samples are measured and analyzed by X-ray diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). The results showed that cobalt ferrite with uniform particle sizes in the range of 10～50 nm can be obtained using nitrates or acetates as raw materials. The synthesized nano-particles are small in sizes with uniform diameter, and have a good disperability. Their magnetic properties are middle saturation magnetization and high coercive force. The cobalt ferrite synthesized shows a better quality.