Nanoparticles of ferrofluid Fe 3 O 4 synthetised by coprecipitation method used in microactuation process

Ferrofluids are a special category of smart nanomaterials in particular magnetically controllable nanofluids. These types of nanofluids are colloidal of magnetic nanoparticles such as Fe3O4 stably dispersed in a carrier liquid The ferrofluid with nanoparticles of Fe3O4 was synthesized by co-precipitation method using FeCl3x6H2O and FeSO4x7H2O in molar ratio Fe/Fe=1:2, dissolved in 300 ml water and treated with NaOH 10% and heated to 80C. The precipitate Fe3O4 was treated with HCl 0.1 n, such as peptizing agent. The precipitate of Fe3O4 was magnetic decantation, repeated washed and then dispersed in surfactant acid oleic and inglobed in transformer oil. The proportion nanoparticles Fe3O4/acid oleic/transformer oil was 5/10/85% vol. The purity of the preparated Fe3O4 nanoparticles powder was examined by X-ray diffraction. The XRD pattern exhibits the peaks corresponding to Fe3O4 cubic with a spinel structure confirmed from hkl Miller indices (220), (311), (400), (511) and (440) with a lattice constant a=b=c=8.3778 A. The medium crystallites size determined with Debye-Scherrer formula was 14 nm. The ferrofluid has o dielectric properties, thus, for the frequency 1KHz the relative permittivity was 6,15, the loss tangent was 1.0554 and the impedance was 2.25 x10Ω.