Preparation And Physical Property Of Co_xCu_1-xFe₂O₄ (X=0～1) Ionic Ferrofluids

In this paper, the method of Co_xCu_1-x)Fe₂O₄ ionic ferrofluids preparation(the method of Massart and the self-formed method) is opmisted. The physical property of ferrofluids is also studied.First, the Co_xCu_(1-x)Fe₂O₄ nanoparticles is prepared by coprecipitation method. On the basis of the resuld from previously studing for the preparetion of ionic ferrofluids, the ferrofluids of Co_xCu_(1-x)Fe₂O₄ is prepared..Bying experiment, the value of Q is confirmed. Without magnetic field, ferrofluids can be steadied for a long time.The stability of ionic ferrofluids relate the time process is presented.The stability is anaylsed in the theory.The component, crystal and shape of nano-particles is analyzed by XRD and TEM respectively, and obtain that the particle are nearly global. The particle size distribution of several kinds of ionic ferrofluids has been studied, calculated the average paticles' diameter. The paticles' diameter of different sample is different.The paticles' diameter of self-formed ferrofluids is smaller than the when the nanoparticles. The reason is that the particulate of ferrofluids is eroded by acid. Useing XPS we find the results are differert chemic substance. The density of ionic ferrofluids has also been measured, obtained the relationship between volume fraction and density.The density and viscosity of ferrofluids is also measured.By the experiment of conductance and the value of pH, the ferrofluids which is prepared just now would be steady for sometime.At room temperature,the magnetic property of nanoparticles prepared by coprecipitation method and Massart ferrofluids is measured, the rule of magnetization is obtained, the different theory of powder's and ferrofluids' superparamagnetism is analysed . The magnetic behavior of CuFe₂O₄ ferrofluids prepared by self-formed is also measured.Bying the experiment of the frozen and thawy ferrofluids, the magnetism of ferrofluids increase is found. And the experiment curve is approached to the Langevin theory curve .The transmitted ratio of light through ferrofluids film under stable magnetic field(light paralled with magentic field or light perpendicular to magentic field) is measured, related the transmitted ration with the movement of particle chains in the ferrofluid. Under the magnetic field, nanoparticles in the ferrofuids form magnetic chains, and under the gradient of magnetic field, the magnetic chain flock to the center. From the repulsion between parallel chains, the chains would radiate. Using this model, the reason of light transmission intensity's change can be explained.