Materials Chemistry and Physics 124 (2010) 658–663 Contents lists available at ScienceDirect Materials Chemistry and Physics journal homepage: www.elsevier.com/locate/matchemphys Phase evolution in Fe 2 O 3 /MgO nanocomposite prepared via a simple precipitation method A. Azhari, M. Sharif Sh., F. Golestanifard ∗ , A. Saberi Centre of Excellence for Advanced Materials Processing, Iran University of Science and Technology, Narmak, Tehran, Iran article info Article history: Received 16 February 2010 Received in revised form 16 June 2010 Accepted 12 July 2010 Keywords: Nanocomposite MgFe2O4 spinel Precipitation route abstract Nanocomposite of MgO/Fe 2 O 3 was prepared via a simple precipitation route by which a dispersed system containing nano-MgO flakes and nano-Fe 2 O 3 particles was obtained. It seems that modification of the surface of nano-Fe 2 O 3 by controlling pH and the flaky habit of MgO grown from Mg(OH) 2 were the main criteria for high dispersion yield in the as-received nanocomposite system. Formation of magnesioferrite spinel in consequence of a solid state reaction at significantly low temperature of 600 ◦ C was revealed through phase evolution studies carried out by XRD and DSC analyses. The reaction studied at the interface of MgO–Fe 2 O 3 nanoparticles by STEM proved the formation of MgFe 2 O 4 spinel via a counter-diffusion process. © 2010 Elsevier B.V. All rights reserved. 1. Introduction The dependence of physical properties of materials on par- ticle size is a well-known phenomenon. Interest in this field has increased because materials with nanometer-sized particles (1–100 nm in one dimension) exhibit novel electronic, optical, mag- netic and chemical properties [1]. Therefore, many efforts have been made to set up new and appropriate preparation methods in terms of nanoproduct formation. Among these, nanocrystalline spinel ferrites such as magne- sioferrite spinel (MgFe 2 O 4 ) have been investigated intensively in recent years due to their potential applications in magnetic mate- rials [2–5], sensors, semi-conductors, catalysts [6], pigments [7] and refractories [8]. Routinely, these ferrites with the particle size higher than micrometers are synthesized by chemical reaction between mixed oxides, hydroxides, carbonates or precursors at elevated temperatures such as 1100 ◦ C with prolonged soaking time and uncontrolled particle size [6,9]. Other methods such as spray pyrolysis process and sol–gel are also reported to prepare Fe 2 O 3 /MgO nanocomposites (and consequently nanospinel) with emphasis on controlling particle size, morphology and sintering temperature for miscellaneous applications. All these procedures, however, suffer from complexity, toxicity and expensive starting materials required to be compatible with the method. ∗ Corresponding author. Fax: +98 21 77240291. E-mail addresses: golestanifard@iust.ac.ir, m.sharif1980@gmail.com (F. Golestanifard). In this regard, the nanocomposite synthesis methods which encourage formation of spinel phase at lower temperatures are superior to the other conventional methods in terms of low cost and simplicity. Magnesioferrite spinel as an essential phase in distinct fields is of high importance to be prepared at lower temperatures with higher purity in order to improve properties and satisfy the basic needs of different applications. Meanwhile, among all known methods, we have employed a simple precipitation route in order to obtain Fe 2 O 3 /MgO nanocom- posite. Although the product of the simple precipitation method is not as homogenous as that of advanced methods such as sol–gel in atomic scale, we have developed a Fe 2 O 3 /MgO nanocomposite with appreciable surface contact between MgO and Fe 2 O 3 parti- cles as the constituents of the product and hence, with a higher tendency to react and form spinel. Compared with other low-tech precipitation routes, the method which is employed in this study dedicates appreciable advan- tages such as low cost, simple preparation of composite in nanoscale homogeneity without sensitive and complicated con- trolling parameters as well as high potential to be produced in industrial scale. Furthermore, we have developed a method to pre- pare binary and tertiary oxide nanocomposites with noticeable surface contact between the components for applications in which particular properties such as sinterability and nanoscale homo- geneity are of high importance. In the present work, the Fe 2 O 3 /MgO nanocomposite prepared by the simple precipitation method is investigated thoroughly to follow formation and evolution of magnesioferrite spinel at lower temperatures with pronounced reduced soaking time. 0254-0584/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.matchemphys.2010.07.030