Titanium foil

Fabrication of titania nanotube arrays via anodic oxidation of titanium foil in fluoride based solutions was first reported in 2001 by Gong and co-workers [58]. Further studies focused on precise control and extension of the nanotube morphology [21], length and pore size [22], and wall thickness [3]. Electrolyte composition plays a critical role in determining the resultant nanotube array architecture and, potentially, its chemical composition. Electrolyte composition determines both the rate of nanotube array formation, as well as the rate at which the resultant oxide is dissolved. In most cases, a fluoride ion containing electrolyte is needed for nanotube array formation. In an effort to shift the band gap of the titania... 

During anodization of titanium foil in a 2.5% HNO3 plus 1% HF water solution electrolyte, with or without addition of boric acid, the applied anodic potential was initially ramped from 0 to 20 V at a rate of 6 V/min the anodization potential was then held constant at 20 V for 4 h [102,103]. An initial ramp of the voltage was used because... 

During a double-sided anodization process, where both sides of the starting Titanium foil are exposed to the anodizing electrolyte, by starting with 1 mm thick Ti foil have obtained 2 mm thick nanotube array membrane, comprised of two 1 mm long nanotube arrays, see Fig. 5.15. 

Fig. 5.17 Real time observation of anodization behavior of a 400 nm Ti thin film anodized at lOV in the HF - aqueous electrolyte (acetic acid and 0.5 vol.% HF mixed in ratio of 1 7). Inset shows a typical current density versus time response observed for a titanium foil (with one face protected with polymer coating) anodized at the same potential and electrolyte.

Fig. 5.21 FE-SEM images of titanium foil sample anodized in DSMO and ethanol mixture solution (1 1) containing 4% HE at -h20 V (vs. Pt) for 70 h at room temperature (a) before and (b) after washing in dilute HE.

Titanium foils were potentiostatically anodized at 25V in an electrolyte of pH 3.5 containing 0.4M ammonium nitrate NH4NO3 and 0.07M HF acid with reference to Fig. 5.26, Sample A was removed after 17 s of anodization, while Sample B was anodized for 240 s. Sample C was anodized for 6 h at 20V in an electrolyte of pH... 

Fig. 5.43 Photocurrent density versus applied potential in 1 M KOH solution under UV (320 nm to 400 nm) illumination (96 mW/cm ). Anodic samples prepared as (a Titanium foil anodized at 20 V for 70 h in DSMO and ethanol mixture solution (1 1) containing 4% HF. (b) H2O-HF electrolyte at 20 V for 1 h. Both samples were annealed at 550°C 6 h in oxygen atmosphere prior to testing. Dark current for each sample is shown in (c).

Fig. 3 shows a conceptual example of the possibilities offered from structuring the surface of oxides in terms of array of Ti02 nanotubes which can be viewed as an ensemble of nanoreactors. The SEM image in the inset of Fig. 3 shows an example of the Ti02 nanostructures obtained in the case of anodic oxidation of titanium foils. ... 

Fig. 9 Rate of hydrogen generation from nanotube arrays films of different lengths annealed at 530 °C. Electrode area of 1 cm 100 mW/cm visible light. In the inset FESEM cross-sectional image of 2.8 um long Xi02 nanotube array prepared by anodic oxidation of a titanium foil in an electrolyte containing potassium fluoride (KF 0.1 M), sodium hydrogen sulfate (1 M), trisodium citrate (0.2 M) and sodium hydroxide. Elaborated from Grimes et...

In general, ion beams were scanned at more than 50 x 50 mm, and exited the vacuum chamber through the beam window made of a 30-pm-thick titanium foil. The irradiation sample was placed in the air at a distance of 10 cm from the beam window. In the case of Arabidopsis or tobacco seeds, for example, 100 3000 seeds were sandwiched between kapton films (7.5-pm thickness) to make a monolayer of the seeds for homogeneous irradiation. In the case of rice or barley seeds, the embryo side was kept facing toward ion beams, whereas for calli or explants in a petri dish, the lid of the petri dish was replaced with a kapton-film cover to decrease the loss of the energy of ion beams. Samples were irradiated for less than 3 min for all doses. 

The electron gun consists of a spiral-shaped tungsten cathode and a Wehnelt cylinder. These two components not only constitute the electrodes of the acceleration gap, but also form the optical assembly to control and shape the electron beam. Current signals are linear and have repetition frequency about 800 Hz. They are used to deflect the electron beam horizontally and vertically over the exit window plane. The scanner can be equipped by two cathodes for maximum output. Then, the width of the exit window is more than double that of a standard unit with a single cathode. The exit window containing the 12-15 prn-thick titanium foil is relatively large to assure an effective cooling of the foil. 

When Bandi and Kuhne studied the reduction of C02 to methanol at mixed Ru02 + Ti02 electrodes (ratio 3 1) produced by coating titanium foil [65], in a C02-saturated KHC03 solution at a current density of 5 mA cm 2, only minimal C02 reduction was observed. However, the addition of electrodeposited Cu led to faradaic efficiencies of up to 30% for methanol at potentials of approximately -0.972V (versus SCE). Trace amounts of formic acid and ethanol were also observed. In this case, the rate-limiting step was surmised to be the surface recombination of adsorbed hydrogen and C02 to yield adsorbed COOH". 

An example of recent achievement in this area is a flexible, thin film Cu(In,Ga)Se2 solar cell deposited on a titanium foil, which was combined with a TiC>2 photocatalyst layer and modified by a niobium-doped titanium oxide front electrode to function as a photoelectrochemical tandem cell/membrane for a direct light-driven hydrogen evolution from an aqueous solution [48], Under illumination with UV/vis light, the system produced up to 0.052 pLH2/scm2 (e.g. the hydrogen formation rate was approximately 7,250 pmol/h g relative to the amount of TiC>2 used). Several aspects of the operating principles of the photoelectrochemical devices, the materials requirements, main bottlenecks, and the various device concepts (in relation to H2... 

The collector is molded from a mixture of carbon and phenolic resin which incorporates an in-situ formed titanium foil shield on the anode side to prevent corrosion. Small laboratory-sized collectors have accumulated over 12,000 hours of operational evaluation to date. Figure 7 shows large-sized molded collectors with 21/2 ft 2 active area. 

A sample electrode was prepared by grinding the polymeric Step 2 product in a mortar with acetylene black and then adding polyvinybdene fluoride and mixing with DMF. The mixture was next printed on a titanium foil and heated for 3 hours at 80°C. 

Figure5. SEM images of Ti02 nanowires prepared by anodization of titanium foils at 80 V in ethylene glycol containing 0.25 wt.% NH4F for 5h (a) overview of nanowires on the entire Ti02 nanotube arrays, (b) nanowires results from the splitting of porous nanotubes, and (c) enlarged view of nanowires with a diameter of a few tens of nanometers [38],...

Figure 10. Appearance of a titanium foil of 100 pm in thickness (a) with cavitation erosion and a form of cavitation failure (b, x300) after 15-min period of ultrasonic treatment in the developed cavitation mode in an aluminum melt.

J. For an irradiation experiment it is necessary to extract a beam of deuterons from an accelerator. The projectile energy is 22 MeV D. For this purpose the beam is deflected and permitted to pass through a thin titanium foil (density 4.5 g cm . Assuming that (Bragg-Kleman rule), what is the... 

Radioactive tritium gas is adsorbed on nonradioactive metal foil, such as titanium foil. 

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