Structural and electronic properties, oxidation and aging effect of electrochemically (EC) synthesized magnetite nanopowders (NPs) are studied by means of X-ray diffraction (XRD), X-ray absorption fine structure (XAFS) and X-ray magnetic circular

Structural, magnetic and electrical properties of iron oxide nano-sized powders synthesised electrochemically under various conditions are presented. The influence of the temperature and current density of synthesis on particular powder characteristics is established. Possibilities for co-existence of various phases and their impact on powder properties, as well as feasible paths of phase relaxation and transition during non-isothermal heating are investigated, too. In this way, optimal procedures for the preparation and stabilisation of iron oxides nano-sized powders of different characteristics are evaluated.

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Magnetic iron oxide nano-powders were synthesised electrochemically, using a low-carbon steel electrode immersed in a NaCl aqueous solution, at constant temperature of the electrolyte, pH and current density. In the second step, portions of the starting admixture were boiled at ~360 K during two hours and autoclaved at various temperatures. Both the starting powder and the treated ones were examined by a standard XRD method, then uniaxially pressed into pellets under 400 MPa, and their electric and magnetic behavior during non isothermal heating was analyzed

Investigation of properties of electrochemically synthesized iron oxide nano-powdersKey words. Electrochemical synthesis, Fe oxides, morphology, nano-powders, properties, structure. SummaryNano-sized powders of iron oxides have been synthesized electrochemically at temperatures in the range of 295-361 K, and current densities in the range of 200-1000 mA dm −2 . The structure and morphology of the powders were investigated by X-ray diffraction and scanning electron and transmission electron microscopy techniques. Their infrared absorption spectra, specific heat C p (T) and magnetic susceptibility χ(T) temperature dependences are also determined. The obtained powders consist of two phases, each possessing distinguished characteristics: the one formed of large plates and the other of whiskers. By appropriate adjustment of the synthesis conditions, it is possible to change features and relative abundances of the two phases, and that way to control morphology and other powder properties. Relaxation and transformation of the phases under external influences was also investigated, and the optimal procedure for preparation and stabilization of iron oxide nano-sized powders with desired characteristics was established.