Monthly Archives: June 2013

Electrochemical deposition and characterization of nanocrystalline Fe-Ni coatings


Author/s: and
Posted on
Fig.1: Variation of metal contents in the deposit with applied c.d.

Nanocrystalline Fe-Ni coatings were electrodeposited on mild steel (MS) panels at different current densities (c.d.) from an acid sulphate electrolyte. The operating parameters were optimized for best appearance and performance of the coatings. Different techniques like Field Emission Gun Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray Analysis (EDXA), X-Ray Diffraction, potentiodynamic polarization scan and Electrochemical Impedance Spectroscopy (EIS) were employed to characterize the electrodeposited thin films. The electrodeposition process was found to be anomalous with 35% to 70% Fe, depending on the current densities (c.d.) employed for deposition. The properties of all coatings were found to show close dependency with c.d., phase structure and composition of the alloys. Corrosion behaviors were studied in 5% HCl and 5% KOH medium and corrosion parameters were reported. Experimental results are discussed by relating the composition, phase structure and grain size with corrosion performance of the coatings in both acid and alkaline medium.

To read the whole article please:
    

Realisation of regularly faceted three-dimensional metallic mesocrystals by electrodeposition


Author/s: , and
Posted on

Electrodeposition has recently been shown to successfully create three dimensional micro- or nanostructures. Here we demonstrate that highly faceted metallic architectures are readily achieved by appropriate electrodeposition conditions. Three dimensional silver and copper mes-ocrystals with different shapes and size are potentiostatically electrodeposited on highly oriented pyrolytic graphite (HOPG) from simple sulfate and nitrate baths, respectively. The electrodeposition potential plays the most important role in determining the shape and size of mesocrystals. For silver mesocrystals, individual crystals with a range of shapes and sizes are observed which are not influenced by steps in the HOPG substrate. However, when copper is electrodeposited at one distinct potential it tends to form either wires on step edges or particles on terraces. Upon application of a dual pulse potential technique, well defined highly faceted copper mesocrystals are produced.

To read the whole article please: