Acicular γ-Fe2O3 particulate surface-coated with barium ferrite

In the past few years, barium ferrite (BF) particulates have undergone Intensive development in magnetic recording applications due to their high coercivity of up to 5000 Oe and the unique perpendicular recording characteristics. In general, BF particulates are hexagonal platelets. Recently, acicular BF particulates with coercivity of about 2000 Oe were made possible by reacting acicular a-FeOOH with coated BaCO₃. In this presentation, novel acicular γ-Fe₂O₃ particulates surface-coated will be disclosed. These particulates have coercivity of up to 2700 Oe and saturation magnetization of greater than 60 emu/g, and much improved thermal stability.