Synthesis and Characterizations of Fe3O4 Added with Al2O3 Nanoparticles via Sol-Gel Technique

Abstract

Abstract A single step sol-gel has been established as a new route for synthesizing AkCb-added Fe3O4 nanoparticles. In this work, the effects of Al2O3 composition towards the micro structure and magnetic properties of AkCb-added Fe3O4 samples were investigated. A series of Fe and Al nitrate mixture solutions were prepared by varying the Al nitrate composition from 2.0 wt. % to 10.0 wt. %. A dropwise of propylene oxide has dimed out the clear red mixture solution with a significant release of heat before turned into a gel. The gel was dried at 90 °C for 48 h in a ventilated oven which then pulverized into a powder by using mortar grinder. The powder was calcinated at 900 °C for 1 h in a normal furnace atmosphere. The XRD results revealed that the existence of polycrystalline Fe3O4 were completed at calcination temperature 900 °C. The SEM images of the Fe3O4 with 10.0 wt.% of Al2O3 samples showed a distinct nanoparticles micro structure due to the increased of Fe3O4 nucleation initiated by Al2O3 nanoparticles. The Vickers microhardness of the Al2O3 added Fe3O4 samples were significantly increased as the Al2O3 content was increased up to 10.0 wt.% attributed from good distribution of Al2O3 nanoparticles in the sample. Subsequently, the magnetic properties of Fe3O4 investigated by alternating gradient magnetometer, AGM was insignificantly reduced by the addition of Al2O3 nanoparticles. This work indicated that the sol-gel reaction is an effective method to achieve uniform distribution and high purity of AkCb-added Fe3O4 nanoparticles with optimum microhardness and ferromagnetic performances.