Study On The Dispersion Of Ultrafine Nickel Powder Prepared By Ultrasonic And Dispersant In Liquid Reduction

Ultrafine nickel powder is widely used in many application domains such as chemical energy materials, hard alloys, high temperature alloys, catalysts, electromagnetic shielding materials and aerospace domains for its great volume effect, surface effect and good conductivity. On the other hand, liquid phase reduction method takes advantages of easily obtained raw materials, simple operation, high efficiency, good quality and appearance of products. While the superfine powder reunion brings serious problem for the preparation and production process. According to the above research, we prepared the ultrafine nickel powder using the ultrasound and ultrasound combined with the dispersant of decentralized manner among the liquid reduction mode. We characterized the properties of the powder with scanning electron microscopy (SEM)s X-ray diffraction (XRD)、laser particle size analysis and so on, and study its dispersion. The conclusions are:(1) For the ultrafine nickel powders prepared with different ultrasonic power, the energy increased with the increase of ultrasonic power, which accelerated the reaction rate. But at great ultrasonic power, the agglomeration was serious for the high temperature and high pressure among ultrasonic process. At small ultrasonic power, the reaction was uncompleted for which the particle diffusion was not sufficient. In this paper, the ultrafine nickel powder of1.19um average particle size was prepared with240W ultrasonic power and35minutes reaction time.(2) For the ultrafine nickel powder prepared using the intermittent time ultrasound, the powder particle size was reduced after the first increase with the increase of ultrasonic time. Compared with the powder under ultrasonic powder always, the ultrasonic time increased and the average particle size was smaller. The average particle size of nickel powder with the interval of ultrasonic preparation3minutes was0.82μm, which had a fine dispersion.(3) For the ultrafine nickel powder prepared with the intermittent time ultrasound and different content of dispersant PVP, the reaction time increased, the reduction rate and the average particle size increased first and then decreased with the increase of PVP content and reaction time. The particle size of the powder prepared with the PVP content was lwt.%was0.75μm under moderate reaction time and the dispersion was good.(4) For the ultrafine nickel powder prepared with the intermittent time ultrasound and different content of dispersant PEG, with the increase of the PEG content, the reaction time decreased, reduction rate increased and the average particle size decreased gradually. The average particle size of the powder prepared with PEG (1000) was0.26μm, which had a fine dispersion. The PEG dispersant was superior to PVP for the reaction time、average particle size and dispersion, while the powder morphology with PVP was better than the powder with the PEG.