Influences of structure and composition on the photoelectrochemical behaviour of anodic films on Zr and Zr–20at.%Ti

Study on the correlation between microstructures and corrosion properties of novel ZrTiAlV alloys

In this work, microstructures and corrosion behaviors of novel ZrTiAl-χV (χ = 0, 1, 3, 5, 7 wt%) alloys have been investigated. Phase composition and microstructures of the specimens are characterized using X-ray diffraction, optical microscopy, scanning electron microscopy, and transmission electron microscopy. The results show that phase composition of the alloys change by α' → α″ → α″ + β → β as V is added gradually. Meanwhile, the mean size of the α' phase, α″ martensite and β phase decreases as V content increases. In order to test the corrosion performance of the specimens, potentiodynamic polarization tests in NaCl and HCl solutions and immersion tests in HCl solution are performed. Analysis of potentiodynamic potential curves indicates that corrosion potential increases and corrosion current density decreases with adding V content in the examined alloys. From the results of weight loss tests, it can be observed that the weight loss of the examined alloys decreases along with the increase of V content. In addition, when the content of V is added from 3 to 7 wt%, the metastable corrosion pits are replaced with the stable corrosion pits. The phase composition as well as the grain size can be identified as the main factor affecting the corrosion performance of the alloys.

Photoelectrochemical evidence of nitrogen incorporation during anodizing sputtering – deposited Al–Ta alloys

Anodic films were grown to 20 V on sputtering-deposited Al–Ta alloys in ammonium biborate and borate buffer solutions.

Photoelectrochemical scanning droplet cell microscopy (PE-SDCM)

Principles of localised photoelectrochemistry are summarised and an experimental approach is described that allows the performance of the most important photoelectrochemical experiments within a diameter of 100 μm. Various light sources, such as a continuum emitter with a monochromator, LEDs, and lasers are coupled into a multi-mode fibre to illuminate a small spot that is wetted by the electrolyte from a capillary. Reference electrode, counter electrode, and optical fibre are installed in the capillary system. The performance of this system is demonstrated by photocurrent measurements on n-doped Si and p-doped Si as model substrates. A thickness-graded aluminium thin film for partial shadowing on Si proves the applicability for material library investigations in combinatorial materials science. Further experiments demonstrate the possibility of electrical light chopping as well as impedance spectroscopy with subsequent Mott-Schottky analysis for the determination of charge-carrier concentration and type, flat-band potential, and inversion layer formation. Photoelectrochemical scanning droplet cell microscopy (PE-SDCM) is an extremely versatile tool for the screening of water splitting photoelectrodes, the characterisation of photocatalysts, and high throughput characterisation of microgram amounts of new solar cell materials.