Self-organized anodization of copper in 0.1 M Na2CO3 electrolyte was studied in order to obtain nanostructured oxide surface on the metal substrate. Linear sweep voltammetry (LSV) revealed that the most suitable voltage range for anodic film formation is from 3 to 31 V. In this range (except between 3 and 7 V), the oxide is formed as nanorods, with the diameter of the anodically grown nanostructures increasing with the applied voltage. The smallest diameter of the nanorods was found to be 28 ± 9 nm (15 V), while the greatest diameter was 109 ± 15 nm (30 V). X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and Raman spectroscopy pointed out that the nanorods consist of crystalline CuO (tenorite) and Cu2O (cuprite), and amorphous Cu(OH)2. Moreover, the greater the anodizing voltage, the greater the CuO content versus Cu2O. The formed nanostructured materials may find applications in photocatalysis and catalytic electrochemical reduction of carbon dioxide into light hydrocarbons.@en

The anodization of commercially pure Ti alloy (99.5 wt %) and two biomedical titanium alloys, Ti6Al7Nb and Ti6Al4V, was performed, and the resulting anodic oxides were studied. The biomedical alloys were made by Laser Engineered Net Shaping. The glycol-based and glycerol-based electrolytes with 0.3 M ammonium fluoride and 2 wt % of deionized water content were tested. It was found that electrolyte type as well as the chemical composition of the base substrate affected the final morphology and chemical composition of the anodic oxide formed. A higher current density, ionic mobility, and oxide growth rate were obtained in glycol-based electrolyte as compared to those obtained in glycerol-based electrolyte for all tested alloys. A self-organized nanotubular and nanoporous morphology of the anodic oxide in both types of electrolyte was obtained. In each electrolyte, the alloy susceptibility to oxidation increased in the following order: Ti6Al4V < Ti 99.5% < Ti6Al7Nb, which can be correlated to the oxidation susceptibility of the base titanium alloy. It was observed that the more impurities/alloying elements in the substrate, the lower the pore diameters of anodic oxide. There was a higher observed incorporation of electrolyte species into the anodic oxide matrix in the glycerol-based electrolyte compared with that in glycol-based electrolyte@en

The effect of the separation between electrodes on the main output parameters of the anodic aluminum oxide structure, namely the pore size, the cell size, the thickness and the regularity ratio was investigated. Pure aluminum foils were anodized in 0.3 M oxalic acid at different combinations of electrode separations (1.5, 3 and 6 cm), anodization voltages (30, 45 and 60 V) and temperatures (10, 20 and 30 °C). Whereas cell size and thickness appeared to be independent on the electrode separation, minor effects emerged for the pore size and significant effects emerged for the regularity ratio. The latter decreased with electrode separation at the lowest anodization voltage, but increased for the other voltages, especially at intermediate value of 45 V. For the temperature series, the regularity ratio decreased with separation at highest and, mostly, lowest temperature, while increased at intermediate temperature. Therefore, in addition to the major fabrication parameters of anodization voltage, current density, temperature and electrolyte concentration, it appears that the electrode separation may also cause relevant effects on the pattern quality, which should be taken into account for careful control of this nanofabrication process.@en