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Friday, 25 May 2012

Magnetic fluids and characterization

Magnetic fluids can be prepared from nanomagnetic materials. Synthesis conditions are methods are tiresome and require high end technological tools.  Copper ferrite particles can be prepared from copper oxide and iron oxide. These starting precursors are mixed in a mortar. For fine mixing, toluene can be added. Some 10 hours of mixing and subsequent sintering will yield fine copper ferrite particles. These particles are then cooled by pouring liquid nitrogen on it. Mixing using toluene is repeated for about one hour now. Sintering to 1200 K will yield ultrapure copper ferrite. This copper ferrite material is then ball milled for several hours keeping rpm of milling unit at its maximum (a minimum of 750 rpm for steel balls and 500 rpm for tungsten carbide balls). Now ultrafine nanoparticles of copper ferrite are ready. Mix oleic acid and kerosene with fine powder and make a paste. This paste you heat using oven at around 350 Kelvin for two hours.  Take the sample out from oven, mix kerosene again to make it a solution. This solution is ball milled keeping some low rpm (a maximum of 250 rpm for steel balls and 100 rpm for tungsten carbide balls). Now magnetic fluid is ready. We can undergo various characterization studies such as X-ray diffraction, neutron diffraction, electron diffraction, low energy ion scattering, scanning electron microscopy, transmission electron microscopy etc. on these magnetic fluids.