Preparation And Characterization Of Ferrite Nanoparticles

At present, almost all cells defrost in warm water after rhagiocrine cells were froze by liquid nitrogen, it spends about one minute to defrost in 37-40℃ water. People have more and more realized the importance of defrost process through many years.In this paper, ferrite magnetic nanoparticles preparation technologies were studied. MeFe₂O₄ nanoparticles were synthesized by coprecipitation method and prepared Fe₃O₄ nanoparticles by the titration hydrolyzation method. To sure the Fe³+/Me²+=2, the aqueous mixture was added into a 6M NaOH solution drop-by-drop to form a precipitate. Adjust suit stir speed (about 3000r/min) and pH (11-13) value. After 30 minutes, the slurry was then placed in a boiling water bath and digested for two hours. After the digestion, the slurry was filtered and washed more than 10 times until the pH in the solution became neutral. Then got the brown powder was heat-treated at 100℃ for two hours, the suit treatment after cold was carried out and got the MeFe₂O₄ nanoparticles. At the same time, it studied by X-ray diffraction, TEM photographs, particle size analysis and magnetic properties test. Then analyzed every material results and selected the best one.In order the particles suspend in solution uniformly, it need to modify the surface of nanoparticles by surfactant. This test used sodium oleate surfactant to modify the surface of CoFe₂O₄ nanoparticles. Then compared the sedimentation time, particle size and zeta potential with the before modified one.CoFe₂O₄ nanoparticles suspension heating effect under the alternating magnetic field was studied in this paper. Vary CoFe₂O₄ nanoparticles suspension concentration were prepared, 0, 0.5, 1.0, 2.0, 4.0 mg/mL then measured the temperature changed with time in the certain alternating magnetic field. At the same time, measured 2 mg/mL CoFe₂O₄ nanoparticles suspension concentration temperature and time in differ alternating magnetic field.