Point-by-point compositional analysis for atom probe tomography.

This new alternate approach to data processing for analyses that traditionally employed grid-based counting methods is necessary because it removes a user-imposed coordinate system that not only limits an analysis but also may introduce errors. We have modified the widely used "binomial" analysis for APT data by replacing grid-based counting with coordinate-independent nearest neighbour identification, improving the measurements and the statistics obtained, allowing quantitative analysis of smaller datasets, and datasets from non-dilute solid solutions. It also allows better visualisation of compositional fluctuations in the data.

Microstructure and electronic band structure of pulsed laser deposited iron fluoride thin film for battery electrodes.

Battery electrodes in thin-film form are free of the binders used with traditional powder electrodes and present an ideal platform to obtain basic insight to the evolution of the electrode-electrolyte interface passivation layer, the formation of secondary phases, and the structural underpinnings of reversibility. This is particularly relevant to the not yet fully understood conversion electrode materials, which possess enormous potential for providing transformative capacity improvements in next-generation lithium-ion batteries. However, this necessitates an understanding of the electronic charge transport properties and band structure of the thin films.

Influence of seeding and bath conditions in hydrothermal growth of very thin (∼20 nm) single-crystalline rutile TiO₂ nanorod films.

New seeding conditions have been examined for the hydrothermal growth of single-crystalline rutile TiO₂ nanorods. Rutile nanorods of ∼20 nm diameter are grown from seed layers consisting of either (A) TiO₂ or MnOOH nanocrystals deposited from suspension, or (B) a continuous sheet of TiO₂. These seed layers are more effective for seeding the growth of rutile nanorods compared to the use of bare F-SnO₂ substrates.

Laser deposited biocompatible Ca-P coatings on Ti-6Al-4V: microstructural evolution and thermal modeling.

A high intensity continuous wave diode pumped ytterbium laser source was used to deposit Ca-P coatings on a Ti-6Al-4V biocompatible alloy in order to generate a physically textured surface, enhancing osseointegration. Scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM) and energy dispersive spectroscopy (EDS) studies were coupled with X-ray and micro diffraction work to determine the structure, composition, and phases present in various zones of a sample prepared across the coating/substrate interaction zone. Three-dimensional thermal modeling was also carried out to determine the cooling rate and maximum temperature experienced by different regions of the substrate.

Laser surface modification for synthesis of textured bioactive and biocompatible Ca-P coatings on Ti-6Al-4V.

A textured calcium phosphate based bio-ceramic coating was synthesized by continuous wave Nd:YAG laser induced direct melting of hydroxyapatite precursor on Ti-6Al-4V substrate. Two different micro-textured patterns (100 μm and 200 μm line spacing) of Ca-P based phases were fabricated by this technique to understand the alignment and focal adhesion of the bone forming cells on these surfaces. X-ray diffraction studies of the coated samples indicated the presence of CaTiO₃, α-Ca₃(PO₄)₂, Ca(OH)₂, TiO₂ (anatase) and TiO₂ (rutile) phases as a result of the intermixing between the precursor and substrate material during laser processing.

Corrosion resistance and in vitro response of laser-deposited Ti-Nb-Zr-Ta alloys for orthopedic implant applications.

While direct metal deposition of metallic powders, via laser deposition, to form near-net shape orthopedic implants is an upcoming and highly promising technology, the corrosion resistance and biocompatibility of such novel metallic biomaterials is relatively unknown and warrants careful investigation. This article presents the results of some initial studies on the corrosion resistance and in vitro response of laser-deposited Ti-Nb-Zr-Ta alloys. These new generation beta titanium alloys are promising due to their low elastic modulus as well as due the fact that they comprise of completely biocompatible alloying elements.

Strengthening mechanisms in Ti-Nb-Zr-Ta and Ti-Mo-Zr-Fe orthopaedic alloys.

The microstructural evolution and attendant strengthening mechanisms in two novel orthopaedic alloy systems, Ti-Nb-Zr-Ta and Ti-Mo-Zr-Fe, have been compared and contrasted in this paper. Specifically, the alloy compositions considered are Ti-34Nb-9Zr-8Ta and Ti-13Mo-7Zr-3Fe. In the homogenized condition, both alloys exhibited a microstructure consisting primarily of a beta matrix with grain boundary alpha precipitates and a low-volume fraction of intra-granular alpha precipitates.