Preparation and performance of silicon-oil-based Fe₃O₄-Co nano-composite magnetic fluid

According to low specific saturation magnetization and heat transfer of traditional Fe₃O₄ magnetic fluid, cobalt nanoparticles were prepared by direct current arc plasma evaporation device and then added into silicon-oil-based Fe₃O₄ magnetic fluid. The specific saturation magnetization, density, viscosity, and tribological properties under different cobalt nanoparticles amounts were studied. The results indicate that the density and viscosity of nano-composite magnetic fluid all increase gradually when the mass ratio of Co to Fe₃O₄ is improved from 1/3 to 6/3, and the specific saturation magnetization increases greatly. When the mass ratio of Co to Fe₃O₄ equals 2, the specific saturation magnetization increases from 0.43 A·m²/kg to 2.91 A·m²/kg. And moreover, the nano-composite magnetic fluid can also improve the tribological properties obviously. The composite magnetic fluid can also improve the sealing performance of the mechanical seals with repairing effect.