Analyses of factors affecting nickel ferrite nanoparticles synthesis in ultrasound-assisted aqueous solution ball milling

• Some influencing factors for ultrasound-assisted ball milling were investigated.
• The optimal parameters for ultrasound-assisted ball milling were determined.
• Ultrasound-assisted ball milling increases hydroxyl radicals and ions quantities.
• Hydroxyl radicals and ions were used to reflect the reaction speed.

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 results indicate that more hydroxyl radicals and ions can be generated under the coupling effect of ultrasonic and ball milling. The fluorescence measurements and electroconductivity detections also reflect the reaction speed, allowing for optimal parameters to be determined.