Research On Ferrites Preparation By Ultrasonic Solid-liquid Reactive Ball-milling

By using the technology of ultrasonic solid-liquid reactive ball milling,which was combining mechanochemistry with sonochemistry, mixed powders of ZnO andα-Fe₂O₃,Zn andα-Fe₂O₃,NiO andα-Fe₂O₃ were milled with ultrasonic waves and without ultrasonic waves in the distilled water solution.The milling products successfully prepared ZnFe₂O₄,NiFe₂O₄,which were sintered under 500⁸00℃.X-ray diffraction and TEM were employed to analyze the composition ,the gain size and microstructure of the products.The paper analyzed the impact of ultrasound on the gain size and the preparation of ZnFe₂O₄, NiFe₂O₄ in the way of solid-liquid reactive ball milling technology.The experimental results are as follows:1. ZnO andα-Fe₂O₃ mixed powders were milled in the ultrasonic solid-liquid reactive ball machine,from the contrast of the XRD pattern,we knew that there was no new phase formed during the milling process.milling with ultrasonic waves formed the solid solution in the 65th hours,which needed 80 hours under the milling without ultrasonic waves.Calculated by the Scherrer formula,the products of milling with ultrasonic had smaller grain size.2.Sintering the products of milling with ultrasonic and without ultrasonic at 600⁷50℃,products of milling with ultrasonic transformed to ZnFe₂O₄ completely at 700℃,which was 750℃milling without ultrasonic.The TEM images showed that the synthesized nano-particle size was 15²5nm.the particles size distribution and dispersion of milling with ultrasonic was better than without.Under the same sintering temperature, the more milling time ,the higher ZnFe₂O₄ percentage,the smaller crystallite size.3. Nanocrystalline zinc ferrite（ZnFe₂O₄） has been synthesized directly from Zn andα-Fe₂O₃ powders by solid-liquid mechanochemical reaction radiated by ultrasonic and without ultrasonic and low-temperature sintering. Compared with milling without ultrasonic waves,milling under ultrasonic waves has smaller products gain size.It was under 700℃,the products of ultrasonic milling transformed to ZnFe₂O₄ completely,which was 750℃under the milling without ultrasonic.4. Nanocrystalline nickel ferrite（NiFe₂O₄） has been synthesized directly from NiO andα-Fe₂O₃ powders by solid-liquid mechanochemical reaction radiated by ultrasonic and low-temperature sintering under 500⁸30℃. Compared with milling without ultrasonic waves,milling under ultrasonic waves has smaller products gain size.It was under 800℃,the products of ultrasonic milling transformed to NiFe₂O₄ completely,which was 830℃under the milling without ultrasonic.The XRD pattern showed that there was no new phase formation during the milling process.TEM analysis showed that the sintering products of ultrasonic milling was better in particles’size distribution and dispersion.