Rapid synthesis of nano-magnetite by thermal plasma route and its magnetic properties

Abstract

ABSTRACTThermal plasma method has been used to process mild steel scrap for nanopowder synthesis by changing the operating current. The phase analysis of the product nanopowders was studied by X-ray diffraction and the chemical composition was studied by energy dispersive spectroscopy. The morphology, particle size and particle size distribution of the samples were investigated by field emission scanning electron microscope. In addition to the above, the magnetic properties of the samples were investigated by superconducting quantum interface device magnetometer and high temperature vibrating sample magnetometer (HTVSM). From this study, the results indicate that the processed nanopowders were magnetite and exhibit spherical morphology. The magnetic properties, such as, saturation magnetization (MS), coercivity (HC), and Curie temperature (Tc) were estimated. The M–H loops exhibited soft magnetism and samples corresponding to 60 and 70A showed the highest MS and HC, respectively. The Curie temperature was determined for the sample corresponding to 60A using HTVSM as 852 and 840 K from the heating and cooling curves, respectively. The outcome of the results suggests that thermal plasma is a contaminant-free process and is suitable for processing metal scrap.