Synthesis of Iron Oxide Pigment by Planetary Milling

Abstract

In the present work, nanostructured Fe2O3 powders was prepared by mechanical milling in high energy planetary ball mill for different milling time (0 minutes, 15 minutes, 30 minutes and 1 hour) and BPR (6:1 and 10:1). Particle size analysis was carried out to study the size reduction of particles as a function of milling time and BPR and it has been found that particle size decreases with increase in milling time and BPR. X-ray diffraction analysis was carried out to study the change in peak intensity and width of the peak with milling time. Scanning electron microscopy was done to get brief idea about the agglomeration behaviour of the nanostructured Fe2O3 powder and variation in reactivity of powder with change in BPR. The crystallite size and lattice strain was determined using Williamson-Hall method. The crystallite size of Fe2O3 powder changes from 445nm to 199nm in case of BPR 6:1 and from 445nm to 146nm in case of BPR 10:1 after 1 hour of milling. The lattice strain continuously increases with milling time in both cases. Zeta potential analysis of prepared iron oxide nanoparticle dispersed in double distilled water was done. It was observed to be higher when milled at BPR 10:1 than that at BPR 6:1 at pH4 of the solution because of uniform dispersion of the finer particles due to increase in surface energy of the particles. The surface plasmon resonance peak in absorption spectra of Fe2O3 nanoparticle (milled at BPR 10:1 for 1 hour) was observed by an absorption maximum at 430nm. Also the absorption peak was observed to shift to longer wavelength with decrease in crystallite size of the nanoparticle.