Atom probe is a powerful technique for studying the composition of nano-precipitates, but their morphology within the reconstructed data is distorted due to the so-called local magnification effect. A new technique has been developed to mitigate this limitation by characterizing the distribution of the surrounding matrix atoms, rather than those contained within the nano-precipitates themselves. A comprehensive chemical analysis enables further information on size and chemistry to be obtained. The method enables new insight into the morphology and chemistry of niobium carbonitride nano-precipitates within ferrite for a series of Nb-microalloyed ultra-thin cast strip steels. The results are supported by complementary high-resolution transmission electron microscopy.
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http://dx.doi.org/10.1017/S1431927614012872 | DOI Listing |
ACS Appl Nano Mater
May 2024
Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, U.K.
Nanostructured niobium-titanium carbonitrides, (Nb,Ti)CN, with the cubic-rock salt structure are prepared without the use of reactive gases via thermal treatment (700-1200 °C) under nitrogen of mixtures of guanidine carbonate and ammonium niobate (V) oxalate hydrate, with addition of ammonium titanyl oxalate monohydrate as a titanium source. The bulk structure and chemical composition of the materials are characterized using powder X-ray diffraction (XRD) and powder neutron diffraction, elemental homogeneity is studied using energy dispersive spectroscopy (EDS) mapping using transmission electron microscopy (TEM), and surface chemical analysis is examined using X-ray photoelectron spectroscopy (XPS). Nanoscale crystallites of between 10 and 50 nm are observed by TEM, where EDS reveals the homogeneity of metal distribution for the mixed-metal materials.
View Article and Find Full Text PDFMaterials (Basel)
January 2024
Scientific and Technical Complex «New Technologies and Materials», Peter the Great St. Petersburg Polytechnic University, 195251 St. Petersburg, Russia.
One of the most popular methods for ranking duplex stainless steels (DSSs) and predicting their corrosion properties is the calculation of the pitting resistance equivalent number (PREN). However, since DSSs are two-phase materials with a significant fraction of secondary phases and precipitates, the application of the PREN can be highly limited. This article attempted to use a new approach to describe the corrosion resistance of these steels.
View Article and Find Full Text PDFSmall
February 2024
GBA Branch of Aerospace Information Research Institute, Chinese Academy of Sciences, and Guangdong Provincial Key Laboratory of Terahertz Quantum Electromagnetics, Guangzhou, Guangdong, 510700, China.
The use of photothermal therapy (PTT) with the near-infrared II region (NIR-II: 1000-1700 nm) is expected to be a powerful cancer treatment strategy. It retains the noninvasive nature and excellent temporal and spatial controllability of the traditional PTT, and offers significant advantages in terms of tissue penetration depth, background noise, and the maximum permissible exposure standards for skin. MXenes, transition-metal carbides, nitrides, and carbonitrides are emerging inorganic nanomaterials with natural biocompatibility, wide spectral absorption, and a high photothermal conversion efficiency.
View Article and Find Full Text PDFACS Appl Mater Interfaces
July 2021
Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States.
Recent developments in quantum materials hold promise for revolutionizing energy and information technologies. The use of soft matter self-assembly, for example, by employing block copolymers (BCPs) as structure directing or templating agents, offers facile pathways toward quantum metamaterials with highly tunable mesostructures via scalable solution processing. Here, we report the preparation of patternable mesoporous niobium carbonitride-type thin film superconductors through spin-coating of a hybrid solution containing an amphiphilic BCP swollen by niobia sol precursors and subsequent thermal processing in combination with photolithography.
View Article and Find Full Text PDFAdv Mater
July 2021
Materials Science & Engineering Department, Cornell University, Ithaca, NY, 14853, USA.
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