2005 Volume 48 Issue 4 Pages 750-755
This study attempts to prepare Ni nano-magnetic fluid using the developed submerged arc nanoparticle synthesis system (SANSS). Using optimized process parameters, Ni nanoparticles having average diameter of 10 nm were be fabricated, and these Ni nanoparticles prepared by the SANSS has strong magnetic features. When the surfactant PVP-K30 is added to the prepared nanofluid, molecules of the surfactant adhere to the surface of the nanoparticles, enabling the nanoparticles to remain in steady suspension and good dispersion. The nanofluid thus obtained was magnetic and had good flow property. In contrast, Ni particles in nanofluid without surfactant added cannot maintain good dispersion and there is no interdependent motion between the particles and the fluid. Traditional magnetic fluids containing non-nanoscaled particles are non-Newtonian fluids with viscosity higher than that of pure fluids without particles, whereas magnetic fluids with well dispersed nanoparticles more closely resemble Newtonian fluids. The Ni nanoparticles fabricated by the SANSS has no residual magnetization or coercive force, thus showing superparamagnetism. Under the magnetic field effect, Ni nanoparticles will move in the direction of the magnetic field. Nanoparticles can resume steady suspension in the carrying liquid when the magnetic field is removed.