جستجوی مقالات مرتبط با کلیدواژه "cathodic electrodeposition" در نشریات گروه "علوم پایه"

In this paper, oleic acid capped iron oxide nanoparticles (OA-IONPs) is prepared through a simple and efficient electrochemical synthetic route. OA-IONPs were synthesized from the Fe(III) nitrate (0.005 M) and 10 cc oleic acid dissolved in ethanol (96%) solution with applying 5 mA cm–2. The prepared IONPs were characterized by different techniques of XRD, FE-SEM, TEM, FT-IR, TGA, DLS and VSM. The OA layer on the surfaces of IONPs was confirmed by FT-IR, DLS and DSC-TGA analyses. The magnetic analysis by VSM revealed that the prepared OA-IONPs exhibit negligible Mr and Ce values at the condition of H→0, implicating their superparamagnetic nature.

In this research, a simple and efficient cathodic electrochemical deposition (CED) route wasdeveloped for the preparation of magnetite nanoparticles (NPs) in an aqueous media. Thesurface of magnetite NPs was also coated for the first time via an in situ procedure during theCED process. In this method, initially, the Fe3O4 NPs (with size ~10 nm) were prepared from theFe2+/Fe3+ chloride bath through CED process. Then, dextran as the coating agent was coatedon the surface of Fe3O4 NPs during the CED process. The prepared NPs were characterizedby different techniques such as XRD, FE-SEM, TEM, IR, TGA, DLS and VSM. The XRD resultsproved the pure magnetite i.e. Fe3O4 crystal phase of the prepared samples. Morphologicalobservations through FE-SEM and TEM revealed particle morphology with nano-sizes of 8nm and 12 nm for the naked and dextran coated NPs, respectively. The dextran coat on thesurfaces of NPs was confirmed by FT-IR and DSC-TGA analyses. The average hydrodynamicdiameters of 17 nm and 54 nm were measured from DLS analysis for the naked and dextrancoated NPs, respectively. The magnetic analysis by VSM revealed that prepared NPs havesuperparamagnetic behavior, i.e. Ms=82.3 emu g–1, magnetization Mr=0.71 emug–1 and Ce=2.3Oe for the naked NPs, and Ms=43.1 emu g–1, Mr=0.47 emu g–1 and Ce=0.81Oe for the dextrancoated NPs. These results implied that this electrochemical strategy can be recognized as aneffective preparation method of polymer coated Fe3O4 NPs.

Ultrafine M(OH)n (M=La, Gd, Ni and Co) nanoparticles were electrochemically deposited from an additive–free M(NO3)n (0.005 M) low-temperature bath on a steel substrate at the constant current density of 1 mA cm−2. Heat–treatment of the prepared M(OH)n nanoparticles at 700oC led to formation of the oxide nanoparticles. The morphologies, crystal structures and compositions of the prepared products were determined by means of scanning (SEM) and transmission (TEM) electron microscopy as well as X-ray diffraction (XRD) and FT-IR spectroscopy. The results showed that the prepared M(OH)n samples are composed of ultrafine particles with the size of about 5 nm. After heat–treatment, the obtained products were well–crystallized phases of oxide nanoparticles with a size of around 10 nm. It was concluded that low-temperature cathodic electrodeposition offers a facile and feasible way for the preparation of ultrafine particles of metal oxides and hydroxides.