The mass absorption coefficients of tungsten and tantalum were measured with soft x-ray photons from 1450 eV to 2350 eV using an undulator source. This region includes the M3, M4, and M5 absorption edges. X-ray absorption fine structure was calculated within a real-space multiple scattering formalism; the predicted structure was observed for tungsten and to a lesser degree tantalum as well. Separately, the effects of dynamic screening were observed as shown by an atomic calculation within the relativistic time-dependent local-density approximation. Dynamic screening effects influence the spectra at the 25 % level and are observed for both tungsten and tantalum. We applied these results to characterize spatially-resolved spectra of a tungsten integrated circuit interconnect obtained using a scanning transmission x-ray microscope. The results indicate tungsten fiducial markers were deposited into silica trenches with a depths of 50 % and 60 % of the markers' heights.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4844524 | PMC |
http://dx.doi.org/10.6028/jres.108.002 | DOI Listing |
Int Endod J
January 2025
Department of Restorative Dentistry-Endodontics, Piracicaba Dental School, Universidade Estadual de Campinas, Piracicaba, São Paulo, Brazil.
Aim: Calcium silicate-based cements have been widely used in dentistry mainly due to their physicochemical and biological properties. Commercially available materials use radiopacifiers containing metals (bismuth, tantalum, tungsten and/or zirconium). To investigate volumetric changes, in vivo biocompatibility and systemic migration from eight commercially available materials, including powder/liquid and 'ready-to-use' presentations.
View Article and Find Full Text PDFMaterials (Basel)
December 2024
State Key Laboratory of Precision Welding & Joining of Materials and Structures, Harbin Institute of Technology, 92 West Dazhi Street, Harbin 15001, China.
This investigation focuses on Selective Laser Melting (SLM)-fabricated thin-walled Ta10W alloy components. Given the inherent limitations of SLM in producing large-scale, complex components in a single operation, laser welding was investigated as a viable secondary processing method for component integration. The study addresses the critical issue of weldability in additively manufactured tantalum-tungsten alloys, which frequently exhibit internal defects due to process imperfections.
View Article and Find Full Text PDFJ Phys Chem Lett
July 2024
Department of Chemical and Biological Engineering, Drexel University, 3141 Chestnut Street, Philadelphia, Pennsylvania 19104, United States.
Catalysts for electrochemical ozone production (EOP) face inherent selectivity challenges stemming from thermodynamic constraints. This work establishes a design strategy for minimizing these limitations and inducing EOP activity in tin oxide, which is an intrinsically EOP-inactive material. We propose that selective ozone production using tin oxide catalysts can be broadly achieved by co-doping with two elements: first, n-type dopants to enhance electrical conductivity, and second, transition metal dopants that leach and homogeneously generate essential hydroperoxyl radical intermediates.
View Article and Find Full Text PDFMaterials (Basel)
May 2024
Thermodynamics and Kinetics Group, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
This study introduces an advanced computational method aimed at accelerating continuum-scale processes using crystal plasticity approaches to predict mechanical responses in cobalt-based superalloys. The framework integrates two levels, namely, sub-grain and homogenized, at the meso-scale through crystal plasticity finite element (CPFE) platforms. The model is applicable across a temperature range from room temperature up to 900 °C, accommodating various dislocation mechanisms in the microstructure.
View Article and Find Full Text PDFMaterials (Basel)
March 2024
Southwest Technology and Engineering Research Institute, Chongqing 400039, China.
Due to its inherent high hardness, strength, and plasticity, tantalum-tungsten (Ta-W) alloy poses a considerable challenge in machining, resulting in pronounced tool wear, diminished tool lifespan, and suboptimal surface quality. This study undertook experiments utilizing uncoated carbide tools, TiAlN-coated carbide tools, and AlTiN-coated carbide tools for machining Ta-2.5W alloy.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!