Dispersion control of Fe₂O₃ nanoparticles using a mixed type of mechanical and ultrasonic milling

α-Fe₂O₃ nanoparticles with controlled dispersion were obtained by using a mixed type of mechanical and ultrasonic milling with the addition of surfactant, in which particle refinement was done mechanically, and dispersion was done physically and chemically. The particle refinement and dispersion degree of the α-Fe₂O₃ were examined by TEM observation and analyses of turbidity as well as FT-IR spectra of the particle-dispersed solution. Smaller particle size and addition of 1% n-octyl alcohol surfactant make the dispersion effect better. This improved dispersion of the nanoparticles was attributable to increased adsorption of hydroxide ions on α-Fe₂O₃ nanoparticle surfaces as its area increased.