Effect of high sintering temperature on the cobalt ferrite synthesized via co-precipitation method

Magnetic particle is one of the main elements used in magnetorheological (MR) materials. In this study, the magnetic cobalt ferrite nanoparticles are successfully synthesized via co-precipitation method at different sintering temperatures. The nanoparticles are prepared in neutral condition (pH 7) at different temperatures of 900, 1000 °C for 8 h, individually. The properties of cobalt ferrite related to phase analysis, microstructure and magnetic properties were characterized by particle size analyzer (PSA), field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and vibrating sample magnetometer (VSM). The result showed that the size of cobalt ferrite powders are 16.72, 17.76 and 37.29 nm correspond to different temperatures of 900, 1000 and 1100 °C, respectively. This indicated that the higher sintering temperature induced to the synthesized cobalt ferrite, greater size of the nanoparticles will be obtained. Meanwhile, the micrograph of cobalt ferrite powders poses a polygonal shape with all exhibit the face centered cubic (FCC) structure. In the meantime, the magnetic saturation, Ms increased with the size of nanoparticles increased from 28.95 to 38.85 emu/g, simultaneously correspond to increasing in the sintering temperatures. The results underlined that the sintering temperature did affect and alter the size of CoFe2O4 nanoparticles that resulted in magnetic properties enhancement