Synthesis of 3BaO·2CoO·12Fe2O3 powder using chemical coprecipitation

Abstract The titration order effect on the 3BaO·2CoO·12Fe 2 O 3 (Co 2 Z) ferrite formation mechanism is obtained using the coprecipitation method. This process is investigated using thermogravimetry (TG), differential thermal analysis (DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM) and superconducting quantum interference device (SQUID) magnetometer. It was found that Co 2 Z phase prepared using coprecipitation was obtained by the reaction of two previous formed BaFe 12 O 19 (BaM) and Ba 2 Co 2 Fe 12 O 22 (Co 2 Y) phases. For the sample obtained using back titration, the BaM phase was obtained directly by reacting BaCO 3 and amorphous iron hydroxide with no α -Fe 2 O 3 and BaFe 2 O 4 formed as intermediates. However, owing to the existence of coarsened α -Fe 2 O 3 and BaFe 2 O 4 in the calcined sample obtained using direct titration, the crystallite size of the formed BaM for the sample obtained using direct titration was larger than that by back titration. Consequently, the reactivity of the formed BaM and Co 2 Y phases for the samples obtained using direct titration were lower than those by back titration due to the larger crystallite sizes, which led to the Co 2 Z phase formation temperature for the sample obtained by direct titration having a higher temperature than that by back titration.