Carbonyl Iron Suspension With Core–Shell Structured Fe3O4@SiO2 Nanoparticle Additives and its Magnetorheological Property

Magnetic Fe
₃
O
₄
@SiO
₂
nanoparticles were initially synthesized by a sol-gel process and introduced to a soft magnetic carbonyl iron particle-based magnetorheological (MR) fluid to improve its MR properties and dispersion stability. Structure and properties of the core-shell Fe
₃
O
₄
@SiO
₂
nanoparticles were characterized, showing that they are soft magnetic. MR characteristics of two MR fluid systems with and without Fe
₃
O
₄
@SiO
₂
additives were investigated and compared under different magnetic field strengths using a rotational rheometer, exhibiting typical MR behaviors. Dispersion stability of the MR fluid was also characterized by an optical analyzer system of Turbiscan.