Anodizing of Hydrogenated Titanium and Zirconium Films

Magnetron-sputtered thin films of titanium and zirconium, with a thickness of 150 nm, were hydrogenated at atmospheric pressure and a temperature of 703 K, then anodized in boric, oxalic, and tartaric acid aqueous solutions, in potentiostatic, galvanostatic, potentiodynamic, and combined modes. A study of the thickness distribution of the elements in fully anodized hydrogenated zirconium samples, using Auger electron spectroscopy, indicates the formation of zirconia. The voltage- and current-time responses of hydrogenated titanium anodizing were investigated. In this work, fundamental possibility and some process features of anodizing hydrogenated metals were demonstrated. In the case of potentiodynamic anodizing at 0.6 M tartaric acid, the increase in titanium hydrogenation time, from 30 to 90 min, leads to a decrease in the charge of the oxidizing hydrogenated metal at an anodic voltage sweep rate of 0.2 V·s−1. An anodic voltage sweep rate in the range of 0.05–0.5 V·s−1, with a hydrogenation time of 60 min, increases the anodizing efficiency (charge reduction for the complete oxidation of the hydrogenated metal). The detected radical differences in the time responses and decreased efficiency of the anodic process during the anodizing of the hydrogenated thin films, compared to pure metals, are explained by the presence of hydrogen in the composition of the samples and the increased contribution of side processes, due to the possible features of the formed oxide morphologies.

Metal Ions Supported Porous Coatings by Using AC Plasma Electrolytic Oxidation Processing

Coatings enriched with zinc and copper as well as calcium or magnesium, fabricated on titanium substrate by Plasma Electrolytic Oxidation (PEO) under AC conditions (two cathodic voltages, i.e., −35 or −135 V, and anodic voltage of +400 V), were investigated. In all experiments, the electrolytes were based on concentrated orthophosphoric acid (85 wt%) and zinc, copper, calcium and/or magnesium nitrates. It was found that the introduced calcium and magnesium were in the ranges 5.0–5.4 at% and 5.6–6.5 at%, respectively, while the zinc and copper amounts were in the range of 0.3–0.6 at%. Additionally, it was noted that the metals of the block S (Ca and Mg) could be incorporated into the structure about 13 times more than metals of the transition group (Zn and Cu). The incorporated metals (from the electrolyte) into the top-layer of PEO phosphate coatings were on their first (Cu+) or second (Cu2+, Ca2+ and Mg2+) oxidation states. The crystalline phases (TiO and Ti3O) were detected only in coatings fabricated at cathodic voltage of −135 V. It has also been pointed that fabricated porous calcium–phosphate coatings enriched with biocompatible magnesium as well as with antibacterial zinc and copper are dedicated mainly to medical applications. However, their use for other applications (e.g., catalysis and photocatalysis) after additional functionalizations is not excluded.

Anodic performance of black phosphorus in magnesium-ion batteries: the significance of Mg–P bond-synergy

Mg-ion storage within a covalent P-anode optimizes the anodic voltage and reduces the Mg-diffusion barrier, thereby can overcome the bottleneck in Mg-battery technology.

The Synthesis and Structure of Anodized Titania Nanotubes for Energy Conversion Materials

Titania nanotubes (TiO2NTs) photoanodes were synthesized by anodization method. The electrolytes were the mixtures of ethylene glycol (EG), ammonium fluoride (0.3 wt % NH4F) and deionized water (2 Vol % H2O) with different concentrations of dopant Fe (NO3)3∙9H2O. A constant dc power supply at 50 V was used as anodic voltage. The samples were annealed at 450 °C for 2 hours. The resultant products were characterized by Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD) to determine their microstructure when TiO2NTs were doped with different amounts of Fe atoms. The diameters of TiO2NTs were about60-120 nm. The highest density of TiO2NTs was obtained when the nanotubes were doped with 0.01 M of Fe.

Synthesis and Characterization Anodized Titania Nanotubes for Enhancing Hydrogen Production

Pure and doped Titania nanotubes (TiO2 NTs) photoanodes were fabricated by means of anodization method. The anodization was carried out in electrolytes prepared by mixing ethylene glycol (EG), ammonium fluoride (0.3 wt % NH4F) and deionized water (2 Vol % H2O) with different concentrations of dopant Fe (NO3)3∙9H2O. A constant dc power supply of 50 V was used as anodic voltage. The samples were annealed at 450 °C for 2 hours. The resultant products were characterized by Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD) to determine their microstructures when TiO2 NTs were doped with different amounts of Fe atoms. The diameters of TiO2 NTs were about 60-120 nm. The highest density of TiO2 NTs was obtained when the nanotubes were doped with 0.01 M of Fe. The photocatalytic activity was examined without external applied potential. The maximum photocurrent density was 3.0 mA/cm2 under illumination of 100 mW/cm2.

Structure Changes of Coating on NiTi Alloy Prepared by Micro-Arc Oxidation in Na2SiO3 Electrolyte

Nickel titanium is a near-equiatomic intermetallic that possesses distinctive and desirable thermomechanical properties. Micro-arc oxidation (MAO) treatment of NiTi can effectively prevent the release of Ni ions from NiTi. In this paper, NiTi is treated with MAO method in Na2SiO3electrolyte. MAO process of NiTi in Na2SiO3electrolyte contains two stages: “growth period”, “jumped period”. During the process of MAO, Ni in NiTi is oxidized to Ni ion, and the Ni ions are dissociated in electrolyte. Ti was left in NiTi, which generate much Ti content appearing on the surface of the sample, and contribute to prerequisites for the reaction. After the applied voltage reaches a certain value, Na2SiO3electrolyte participate in the reaction and form insulating amorphous silicon oxide layer. With the increase of thickness of insulating layer on NiTi, the anodic voltage increase. When applied voltage excess certain threshold, discharge spark appear on the surface of NiTi.