| Abstract [eng] |
Valve metal anodizing is a widely applied and convenient process for obtaining ordered oxide nanomaterials with controllable properties. The anodizing conditions, such as anodizing voltage, type of electrolyte, concentration, and temperature, significantly influence the morphology and composition of the obtained coatings and films. Modifying anodic oxides with the products of electrochemical oxidation of electrolyte components can create additional opportunities for regulating the properties of materials. Therefore, searching for new electrolytes is a prospective area of investigation. In this study, we used the ammonium heptamolybdate and sodium metavanadate additives as corrosion inhibitors to prevent aluminum dissolution at the initial stages of aluminum anodizing in formic acid solutions, thus increasing film growth rate and thickness. The content of carbonaceous species was higher than in oxalic and tartaric anodic alumina films, and the anodizing voltage was lower than in tartaric acid solutions. FTIR, XPS, and Raman spectroscopy established that carbonaceous species were embedded in the anodic alumina as CO2 and CO molecules, carboxylate ions, and carbon species in the sp2 and sp3 states. For the first time, carbonaceous inclusions were extracted from the oxide matrix, and they were shown to exist as luminescent and biocompatible nanoparticles possessing an excitation-dependent emission behavior at 280–450 nm. |
