Fe(x)Pt(100-x) nanoparticles of varying composition have been synthesized with various shapes and sizes using a high pressure synthesis method which allows control of synthesis conditions, in particular the reaction temperature. Tailoring the shapes and sizes of Fe(x)Pt(1-x) nanoparticles allows one to control a variety of properties that are relevant to the many potential applications of metallic nanoparticles. Shape and composition can be used to control catalytic activity and to achieve high packing density in self-assembled films. Variation of both nanoparticle size and shape has been achieved by using various different solvents. The solvents used in the nanoparticle synthesis can influence the product because they can play a role as surfactants. Using solvents of various types it has been possible to synthesize Fe(x)Pt(100-x) nanoparticles with a variety of shapes including spherical, rod-like, cubic, hexagonal and high aspect ratio wires. Control of nanoparticle shape opens the door to their being used in various technological applications for which spherical nanoparticles are ineffective.
In the integrated oxy-fuel combustion and turbine power generation system, turbine alloys are exposed to high temperature and an atmosphere comprised of steam, CO2 and O2. While surface and internal oxidation of the alloy takes place, the microstructure in the subsurface region also changes due to oxidation that results in the loss of the strengthening precipitates. In an earlier study of the oxidation of Inconel 939 Ni-based superalloy exposed to oxy-fuel combustion environment for up to 1000 hours, a high-temperature-oxidation-induced phase transformation in the sub-surface region was noticed and a two-phase region formed at the expense of strengthening γ' phase. While one of the two phases was identified as the Ni-matrix (γ solid solution, face-center-cubic) phase, the other product phase remained unidentified. In this study, the crystal structure of the unknown phase and its orientation relationship with the parent Ni-matrix phase was investigated through electron diffraction and high-resolution transmission electron microscopy. It was determined that the crystal structure of the unknown phase could be modeled as a ternary derivative of the ordered η-Ni3Ti phase (D024) structure with lattice parameters of a = 0.5092 nm and c = 0.8336 nm, α = 90º, β = 90º and γ = 120º. Highlights Oxidation products of the turbine material, Inconel 939 Ni-based superalloy, were studied in simulated oxy-fuel combustion conditions, focusing on the products of the decomposition the strengthening γ' precipitates. An oxidation-induced phase transformation occurred in the subsurface region. One of the two product phases was not included in the Ni database of ThermoCalc. Through systematic electron microscopy investigation, this unknown phase was determined (modeled) as a ternary derivative of the ordered η-Ni 3 Ti phase (D0 24 ) in Ni-Ti-Ta system. AbstractIn the integrated oxy-fuel combustion and turbine power generation system, turbine alloys are exposed to high temperature and an atmosphere comprised of steam, CO 2 and O 2 . While surface and internal oxidation of the alloy takes place, the microstructure in the subsurface region also changes due to oxidation that results in the loss of the Manuscript Click here to view linked References 2 strengthening precipitates. In an earlier study of the oxidation of Inconel 939 Ni-based superalloy exposed to oxy-fuel combustion environment for up to 1000 hours, a hightemperature-oxidation-induced phase transformation in the sub-surface region was noticed and a two-phase region formed at the expense of strengthening γ' phase. While one of the two phases was identified as the Ni-matrix (γ solid solution, face-center-cubic) phase, the other product phase remained unidentified. In this study, the crystal structure of the unknown phase and its orientation relationship with the parent Ni-matrix phase was investigated through electron diffraction and high-resolution transmission electron microscopy. It was determined that the crystal structure of the unknown phase could be model...
Particle shape and size are two of the most important characteristics of nanoparticulate catalysts that determined their activity and selectivity. In many studies, the shapes of nanoparticles are characterized using transmission electron micrographs obtained at a single nanoparticle orientation and thus, the shape determination is based on viewing a single cross-sectional profile of the nanoparticle. A full determination of particle shape should require viewing over a range of angles. In this work Pt nanoparticles with controlled shapes and sizes have been synthesized using a high pressure technique. Angle resolved transmission electron microscopy techniques (electron tomography) are necessary to view the crystals over a range of orientations and determine their three dimensional shapes. In this work, angle resolved TEM imaging of nanoparticles reveals information about the nanoparticle shape and orientation on substrates that cannot be determined from single cross-sectional TEM images. Angle resolved TEM imaging of nanoparticles will be very valuable in catalysis and in the fields where the shapes of nanoparticles play an important role.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.