The Research On Synthesis Of Compound Ferrite Nanoparticles Via Ultrasonic Wave-Assisted Aqueous Ball Milling Technology

In this paper, a series of Mn_xMg_1-xFe₂O₄?x=0.2, 0.5, 0.8? and Co-substituted Mn-Zn ferrites with the formula Co_xMn_0.8-x Zn_0.2Fe₂O₄?x=0, 0.2, 0.4, 0.6 and 0.8?have been successfully obtained by ultrasonic-assisted ball milling approach, while the Mn O2, Mg O, iron powder and Co3O4, Mn O2, Zn O, iron powder were used as raw materials, respectively, and the stainless steel balls were used as grinding balls. The experimental equipment was designed by the lab. For comparison, experiments using ball milling processing without ultrasonic wave and ultrasonic wave treatment without ball milling were carried out in the same device. The samples were taken out at different reaction times, the phase constitutions of the samples were analyzed by X-ray diffraction; the morphology and particle size of synthesized products were characterized by transmission electron microscopy; and the magnetic properties were measured by a vibrating sample magnetometer?VSM?.As the results, a series of Mn_xMg_1-xFe₂O₄?x=0.2, 0.5, 0.8? and Co-substituted Mn-Zn ferrites with the formula Co_xMn_0.8-x Zn_0.2Fe₂O₄?x=0, 0.2, 0.4, 0.6 and 0.8?have been successfully obtained by ultrasonic-assisted ball milling approach after 60 h.There was no need for the ferrites to sinter in further high temperature which means the process were quite simple and operational.In the comparison experiments using ball milling processing without ultrasonic wave and ultrasonic wave treatment without ball milling were carried out in the same device, in which there were no ferrites obtained. During the ultrasonic-assisted ball milling process, ultrasonic wave and ball milling coupled with each other dynamically and mechanically which lead to the friction, shear, impact, and compression.Therefore, the activation energy and chemical reaction incubation period decrease,while the specific surface area and internal stress increase as a result of ultrasonic-assisted ball milling. Obviously, the activation energy and powder activity provided by ball milling or ultrasonic radiation only are not enough to prepare the target nano-crystalline ferrite.The saturation magnetizations of the obtained Mn_xMg_1-xFe₂O₄?x=0.2,0.5,0.8?ferrites was 42.49emu/g ? 74.22emu/g ? 64.33emu/g, respectively, while the Co_xMn_0.8-x Zn_0.2Fe₂O₄?x=0,0.2,0.4,0.6,0.8? ferrites were 60.47emu/g?67.09emu/g?71.49emu/g ? 78.72emu/g ? 52.35emu/g, respectively, which means that differentcontents of additives have a significant impact on the magnetic properties of the ferrites. With the reaction time increased, the saturation magnetization increased from43.62emu/g to 67.09emu/g?Co0.2Mn0.6Zn0.2Fe2O4?. Narrow loops indicate low values of coercivity, which shows that the prepared samples can be demagnetized easily for electromagnetic applications.The initial slope of fluorescence cure for ultrasonic-assisted ball milling is significantly higher than that for ultrasonic wave or ball milling only, which indicates that the coupling effect of ultrasonic wave and ball milling can provide more activation energy for the chemical reaction. Comparing the results of ball milling or ultrasonic wave processing only, we can conclude that it is the coupling effect of ultrasonic wave and ball milling, which constantly refine the powders and continuously accelerate the reaction, contributing to the synthesis of ferrite nano-particles.