Effect of Fluoride or Chloride Ions on the Morphology of ZrO2 Thin Film Grown in Ethylene Glycol Electrolyte by Anodization (original) (raw)
Related papers
Synthesis of ZrO2 nanotubes in inorganic and organic electrolytes by anodic oxidation of zirconium
Journal of Solid State Electrochemistry, 2014
Present work reports on the results of the electrochemical growth of self-ordered zirconia nanotubes formed in aqueous Na 2 SO 4 +HF and nonaqueous electrolytes with glycerol addition. Anodization process was carried out in this inorganic water-based mixture with constant pH=2.5 and in the voltage range from 5 to 60 V. Similar experiments were repeated in an organic glycerol-based electrolyte with the voltage equal to 20 V and with variable glycerol concentration. All experiments were conducted at constant room temperature. The tube diameter dependence on the voltage of anodization process in an inorganic electrolyte was derived. It was found that when glycerol addition to water electrolyte was used, it takes more time to produce long zirconia nanotubes. However, they do not collapse as the similar structure of the same length formed in aqueous electrolyte.
Surface and Coatings Technology, 2017
The influence of K 2 CO 3 on the morphology of anodic zirconia (ZrO 2) nanotubes array were investigated by anodizing zirconium (Zr) foil at 60 V in fluorinated ethylene glycol (EG) electrolyte added to it varying amount of K 2 CO 3 : 0.5 vol.%, 1 vol.%, 2 vol.% and 3 vol.%. The adhesion of ZrO 2 on Zr is affected by the volume of K 2 CO 3 added whereby at lower volume, i.e. 0.5 vol.% and 1 vol.%, poor adhesion of anodic film was observed leading to the formation of loose ZrO 2 flakes. At higher 2 vol.% and 3 vol.% addition the adhesion was improved. All anodic films are comprised of nanotubes with length increases when more K 2 CO 3 was added in EG. Nanotubes grown in 3 vol.% K 2 CO 3 are 9.4 µm long with 48.8 nm outer diameter and 9.1 nm wall thickness. Reducing the applied potential to 20 V resulted in compact oxide and at 40 V, nanotubes with smaller diameter of < 50 nm were produced. Crystallization of the ZrO 2 nanotubes was achieved by annealing at 400 °C. The crystalline ZrO 2 nanotubes (mostly in monoclinic and tetragonal phasess) grown in 3 vol.% K 2 CO 3 exhibits the highest photocurrent density (0.12 mA/cm-2) and rapid methyl orange (MO) degradation under ultraviolet (UV) radiation. This is attributed to the good adhesion of ZrO 2 on Zr, longer length of the tubes and perhaps from the effect of adsorbed carbonate ions on the surface of the oxide.
Effect of Fluoride Media on the Stability of Anodic ZrO 2 Films
Corrosion, 1990
Stability of anodic Zr02 films on zirconium electrodes in sodium fluoride media was investigated using open-circuit impedance and potential measurements. The study indicates that the anodic oxide film comprises two layers; the extent of foreign ion incorporation during film growth in 1.0 N H2 SO4 is respons/bie for the difference in the physical nature of each of these layers. Furthermore, the extent of incorporation depends on both the initial formation CD and film thickness. The dissolution process follows a zero-order kinetic law.
Acta Chimica Slovenica, 2019
The present work reports on the morphologies and properties of anodized Zr in two different electrolytes. The Zr phosphates (α-ZP) obtained in the inorganic electrolyte containing H 3 PO 4 +NaF and zirconia (ZrO 2) nanostructures formed in the organic glycerol-based electrolyte were investigated by SEM, FT-IR and AFM. The surface analysis was completed by contact angles measurements. It was found that the type of electrolyte along with the applied voltage influence the structure of the sample and being more precise, the anodic oxidation in H 3 PO 4 electrolyte promotes the evolution of flaky structures and eventually of pores by increasing the applied voltage, while the anodizing performed in glycerol-based electrolyte results in the formation of nanoporous structures that evolve into nanotubes as the applied voltage grows. Based on experimental data a film forming mechanism for α-ZP and ZrO 2 was proposed and correlated to analyzed surface properties.
Synthesis of nanostructured zirconia by anodization at low potentials
Crystal Research and Technology, 2015
This work reports the synthesis of nanostructured ZrO 2 by anodization of zirconium electrodes at potentials well below the range of 10-50 V used as a standard procedure. Zirconium was first anodized in a 1M (NH 4) 2 SO 4 electrolyte and then further anodized in the presence of fluoride ions added to the electrolyte as NH 4 F. The maximum potential applied to zirconium during the whole process was 1 V with respect to an Ag/AgCl (sat.) reference electrode. Amorphous films of ZrO 2 consisting of nanopores and nanowire-like structures were produced with this low-potential methodology.
Anodic zirconia nanotubes: composition and growth mechanism
Electrochemistry Communications, 2010
The compositions of porous anodic films formed on zirconium in glycerol/fluoride electrolytes are examined prior to and following ageing in the electrolyte. The initial films are shown to contain significant amounts of fluorine, with an F:O atomic ratio between 1.0 and 2.5, dependent on the water content of the electrolyte. A three-layered film morphology is indicated, which is related to the migration rates of film species, incorporating a fluoride-rich layer at cell boundaries and bases, and outer layers compositionally differentiated by the presence of carbon species. Preferential loss of fluorine during ageing suggests degradation of the fluoride-rich material.
Effect of Aquo-Glycolic Media of Anodic Oxides on Zr-4 by AFM with Micro and Nanostructures.
International Journal of Engineering Sciences & Research Technology, 2013
The surface of zircaloy-4 anodized at a constant current density of 4mA.cm ethylene glycol at a potential 0-187V, was characterized by means of surface science technique AFM with micro and nanostructures. It was found that d homogeneous coverage on zr-4 surface modifying the topography. The incorporation of oxalate dianions from the electrolyte and ethylene glycol solvent to the surface during the anod oxide films grown with relatively high voltages, the oxide formed over the Zr rougher and protruded. Anodic oxide films were homogeneous and rough with nanosized grains. When the anodization voltage was 187 V the average roughness (Ra) of the anodic film reached 5.9nm, and the oxide formed changed abruptly to become as rough as that formed on non Abstract 4 anodized at a constant current density of 4mA.cm-2 in 0.05M ammonium oxalate and 187V, was characterized by means of surface science technique AFM with micro and nanostructures. It was found that during anodization by aquo-glycolic media the surface oxide grows with an in 4 surface modifying the topography. The incorporation of oxalate dianions from the electrolyte and ethylene glycol solvent to the surface during the anodizing process changes the topology. Anodized oxide films grown with relatively high voltages, the oxide formed over the Zr-4 in 0.05M AO+75%EG appeared rougher and protruded. Anodic oxide films were homogeneous and rough with nanosized grains. When the dization voltage was 187 V the average roughness (Ra) of the anodic film reached 5.9nm, and the oxide formed changed abruptly to become as rough as that formed on non-anodized in micro and nanometers. 4; Topology; Atomic force microscopy; Anodic zirconium oxide.
Electrochemistry Communications, 2010
Bioactive zirconium oxide nanotubular arrays on zirconium alloys are prepared electrochemically in fluoride and phosphate containing electrolyte. Geometric factors of the ZrO 2 nanotubular layers, particularly the pore diameter and thickness, are affected by the electrochemical conditions, including applied potential and anodization time. Under specific sets of conditions, highly ordered ZrO 2 nanotubular arrays are formed with diameters varying from 30 nm to 75 nm and lengths varying from 2 μm to 12 μm. XPS shows that the nanotubular layer contains a significant amount of phosphate species distributed almost homogeneously over the entire tubular length. The ZrO 2 nanotubular layer formed in fluoride and phosphate containing electrolyte highly enhances the formation of bioactive hydroxyapatite coating in simulated biological fluid (SBF).
Electrochimica Acta, 2007
We investigated the formation of self-organized zirconium titanate nanotubes by anodizing a Ti-35Zr alloy in 1 M (NH 4 ) 2 SO 4 + 0.1-2.0 wt.% NH 4 F electrolytes. The morphology and composition of the zirconium titanate nanotube are controlled by the applied electrochemical conditions. The outer diameter of nanotubes is controlled by the anodization potential in the range between 1 and 100 V (versus Ag/AgCl). Tubes with diameters from 14 to 470 nm can be grown. The nanotube length correlates with the anodic charge up to a length where significant dissolution of the nanotube layer is observed. The wall thickness, composition of the nanotubes and porosity of the nanotube layer are significantly affected by the fluoride ion concentration. The length limiting factor of the nanotube growth is found to be the diffusion of ionic species in the electrolyte.