S. Pratapa, L. Susanti, Y.A.S. Insany, Z. Alfiati, B. Hartono, Mashuri, Ahmad Taufiq, Abdullah Fuad, Triwikantoro, M.A. Baqiya, S. Purwaningsih, E. Yahya, Darminto
Simple coprecipitation method has been used to produce nanoparticles of MgO (magnesia), MgOAl2O3 (spinel), Y2O3 (yttria) and Fe3O4 (ferrite). The raw materials were, in respective, magnesium powder, magnesium and aluminium powders, ytrria powder, and natural sand. The coprecipitation included the use of suitable acid and base to dissolve the powders or sand and to produce precipitates, as well as the use of water to wash and purify the precipitates, and drying at relatively low temperatures, namely lower than 100°C, followed by heating at 450°C, 750°C, 600°C and 200°C to produce magnesia, spinel, yttria and ferrite nanopowders, respectively. X-ray diffractometry was used to characterise the purity and nanocrystallinity of the final powders. It was found qualitatively that the powders were of high purity. Further line-broadening analysis using single-line and Rietveld-based softwares was performed to reveal the nanocrystallinity of the powders. Different line breadth values were found for the powders, indicating different crystallite sizes. It was also found that, particularly for spinel and yttria, the diffraction peaks exhibited 'longer' tails, indicating broader crystallite size distribution. The average crystallite size for the powders ranged from 3 to 70 nm. The results could then be used as 'fingerprints' for nanocrystallinity using x-ray diffractometry. The XRD crystallite sizes for yttria and ferrite nanocrystals are in fair agreement with their counterparts from electron microscopy observation. © 2010 American Institute of Physics.
Department of Physics, Institute of Technology Sepuluh November (ITS), Surabaya 60111, Jl. Arief Rahman Hakim, Indonesia; Department of Physics, State University of Malang, Malang 60111, Jl. Surabaya, Indonesia
