Electrophoretic deposition of CoFe2O4 films from aqueous suspensions

CoFe₂O₄ nano-particles with average size of ～40 nm were synthesized via the chemical coprecipitation method. PAMANH₄ was used as dispersant to improve the stability of aqueous suspensions. Zeta potential and sediment volumes were tested to study the effects of pH and dispersant amounts on the stability of suspensions. The most stable suspension was obtained when using 0.6 wt.% PAMANH₄ as dispersant at pH = 10. Conductivity results showed that thoroughly dispersed suspensions were formed after being ultrasonic agitated for 30 min. CoFe₂O₄ films on Al₂O₃/Pt substrates fabricated via EPD sintered at 1250 °C exhibited preferentially oriented structure. The XRD analyses showed (2 2 0) and (5 1 1) were the preferential orientations. Anisotropy was also observed in magnetic hysteresis loops. Stronger ferromagnetic effect was observed in the in-plane orientation, with saturation magnetization of ～290 emu/cm³.