Analyses Of Factors Affecting Nickel Ferrite Particles Synthesis In Ultrasound-assisted Aqueous Solution Ball Milling

The product can be directly synthesized by ultrasound-assisted aqueous solution ball milling, which can not be generated by ultrasound or ball milling. Therefore, ultrasound-assisted aqueous solution ball milling can indeed promote the reactions. The coupling effect is existed between ultrasound and ball milling. Different parameters have important effects on the reaction time and the product using ultrasound-assisted aqueous solution ball milling. Therefore, it's very important to determine optimal parameters. In this paper, ball milling experiments were conducted with and without ultrasound wave assistance in deionized water using NiCO₃·2Ni?OH?₂·4H₂O as raw materials. In the reaction process of NiFe₂O₄ prepared by ultrasound-assisted aqueous solution ball milling, some influencing factors including raw materials, ultrasonic frequency, ball to powder ratio and liquid level were changed. Samples were characterized by X-ray diffraction, fluorescence measurements and electroconductivity detections. The NiFe₂O₄ nanocrystals synthesized by ultrasound-assisted aqueous solution ball milling for 36h using NiCO₃·2Ni?OH?₂·4H₂O and Fe powder as raw materials were characterized by TEM and SAED. The coupling effect between ultrasound and ball milling is analyzed deeply. The influence mechanism of the reaction process affected by different influencing factors is discussed.1. Fluorescence intensity and electroconductivity were compared under the effection of ultrasound, ball milling, ultrasound-assisted ball milling for DI water. X-ray diffraction, fluorescence intensity and electroconductivity were compared under the effection of ultrasound, ball milling, ultrasound-assisted ball milling using NiCO₃·2Ni?OH?₂·4H₂O and Fe powder as raw materials. These results show that the quantities of hydroxyl radicals and ions generated by ultrasound-assisted aqueous solution ball milling are larger than those generated by ultrasound treatment or ball milling only processes. These increased quantities of hydroxyl radicals and ions will promote the reactions.2. Fluorescence intensity, electroconductivity and X-ray diffraction were compared of different raw materials Ni?CH3COO?2·4H₂O and Fe powder, NiO and Fe powder, NiCO₃·2Ni?OH?₂·4H₂O and Fe powder under the effection of ultrasound-assisted aqueous solution ball milling. We can conclude that in the process of ultrasound-assisted aqueous solution ball milling, the raw materials which are easily soluble in a liquid medium or whose bond energy is low will contribute to the generation of hydroxyl radicals and ions and promote the reactions.3. Fluorescence intensity, electroconductivity and X-ray diffraction were compared of different ultrasonic frequency 40KHz?28KHz?20KHz under the effection of ultrasound-assisted aqueous solution ball milling. These experiments illustrate that more hydroxyl radicals and ions will be generated in a short time with lower ultrasonic frequency, which will promote the reactions. These experiments illustrate that more hydroxyl radicals and ions will be generated in a short time with lower ultrasonic frequency, which will promote the reactions.4. Electroconductivity and X-ray diffraction were compared using the raw material NiCO₃·2Ni?OH?₂·4H₂O and Fe powder under the effection of ultrasound-assisted aqueous solution ball milling with different ball to powder ratios 10:1,100:1,200:1. Electroconductivity and X-ray diffraction were compared using the raw material NiCO₃·2Ni?OH?₂·4H₂O and Fe powder under the effection of ultrasound-assisted aqueous solution ball milling with different liquid levels 120mm, 80mm,40mm. These results show that raw materials will react sufficiently and quickly to synthesize the desired pure products with an optimal ball to powder ratio and an optimal liquid level.5. Based on the above experiments and analyses, in the process of single-phase NiFe₂O₄ synthesized by ultrasound-assisted aqueous solution ball milling, reactions will be sufficiently completed and the reaction speed will be the greatest when the raw materials are Ni?CH₃COO?2·4H₂O and Fe powder, the ultrasonic frequency is 20 KHz, the ball to powder ratio is 100:1 and the liquid level is 120 mm.