scholarly journals In Situ Ternary Boride: Effects on Densification Process and Mechanical Properties of WC-Co Composite Coating

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1995
Author(s):  
Junfeng Bao ◽  
Yueguang Yu ◽  
Bowen Liu ◽  
Chengchang Jia ◽  
Chao Wu
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Bonding Strength ◽  
Dark Field ◽  
Flame Spraying ◽  
Composite Powders ◽  
X Ray ◽  
Transmission Electron ◽  
Ternary Boride

New coatings resistant to corrosion in high-temperature molten zinc aluminum were prepared by supersonic flame spraying of various composite powders. These composite powders were prepared by mixing, granulation, and heat treatment of various proportions of Mo–B4C powder and WC and Co powder. X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF–STEM), energy dispersive X-ray spectroscopy (EDS), and mechanical analysis were used to study the effects of Mo–B4C on the microstructure, phase, porosity, bonding strength, and elastic modulus of the composite powder and coating. Results show that the addition of an appropriate quantity of Mo–B4C reacts with Co to form ternary borides CoMo2B2 and CoMoB. Ternary boride forms a perfect continuous interface, improving the mechanical properties and corrosion resistance property of the coating. When the amount of Mo–B4C added was 35.2%, the mechanical properties of the prepared coating reached optimal values: minimum porosity of 0.31 ± 0.15%, coating bonding strength of 77.81 ± 1.77 MPa, nanoindentation hardness of 20.12 ± 1.85 GPa, Young’s modulus of 281.52 ± 30.22 GPa, and fracture toughness of 6.38 ± 0.45 MPa·m1/2.

Phase Transformations in Ti-7w/oMo-3w/oMe Alloy

1974 ◽  
Vol 32 ◽  
pp. 514-515
Author(s):  
S. Fujishiro
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Tensile Strength ◽  
Mechanical Processing ◽  
Ray Method ◽  
X Ray ◽  
Transmission Electron ◽  
Water Quench ◽  
Alpha Beta

The mechanical properties of three titanium alloys (Ti-7Mo-3Al, Ti-7Mo- 3Cu and Ti-7Mo-3Ta) were evaluated as function of: 1) Solutionizing in the beta field and aging, 2) Thermal Mechanical Processing in the beta field and aging, 3) Solutionizing in the alpha + beta field and aging. The samples were isothermally aged in the temperature range 300° to 700*C for 4 to 24 hours, followed by a water quench. Transmission electron microscopy and X-ray method were used to identify the phase formed. All three alloys solutionized at 1050°C (beta field) transformed to martensitic alpha (alpha prime) upon being water quenched. Despite this heavily strained alpha prime, which is characterized by microtwins the tensile strength of the as-quenched alloys is relatively low and the elongation is as high as 30%.

scholarly journals Synthesis of nickel/gallium nanoalloys using a dual-source approach in 1-alkyl-3-methylimidazole ionic liquids

2019 ◽  
Vol 10 ◽  
pp. 1754-1767
Author(s):  
Ilka Simon ◽  
Julius Hornung ◽  
Juri Barthel ◽  
Jörg Thomas ◽  
Maik Finze ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Dark Field ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Annular Dark Field ◽  
Dual Source ◽  
Induced Decomposition

NiGa is a catalyst for the semihydrogenation of alkynes. Here we show the influence of different dispersion times before microwave-induced decomposition of the precursors on the phase purity, as well as the influence of the time of microwave-induced decomposition on the crystallinity of the NiGa nanoparticles. Microwave-induced co-decomposition of all-hydrocarbon precursors [Ni(COD)2] (COD = 1,5-cyclooctadiene) and GaCp* (Cp* = pentamethylcyclopentadienyl) in the ionic liquid [BMIm][NTf2] selectively yields small intermetallic Ni/Ga nanocrystals of 5 ± 1 nm as derived from transmission electron microscopy (TEM) and high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and supported by energy-dispersive X-ray spectrometry (EDX), selected-area energy diffraction (SAED) and X-ray photoelectron spectroscopy (XPS). NiGa@[BMIm][NTf2] catalyze the semihydrogenation of 4-octyne to 4-octene with 100% selectivity towards (E)-4-octene over five runs, but with poor conversion values. IL-free, precipitated NiGa nanoparticles achieve conversion values of over 90% and selectivity of 100% towards alkene over three runs.

Transmission electron microscopy of SI-AL-O-N alloys

1978 ◽  
Vol 36 (1) ◽  
pp. 302-303 ◽  
Author(s):  
M. Kirn ◽  
M. Rühle ◽  
H. Schmid ◽  
L.J. Gauckler
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Imaging Technique ◽  
Construction Materials ◽  
Physical And Mechanical Properties ◽  
Operating Voltage ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

It is expected that Si-Al-O-N alloys are important high temperature construction materials. The phase diagrams for Si-Al-O-N alloys were studied systematically mainly by X-ray diffraction work (for a summary see). Different stable phases were found. For the understanding of the physical and mechanical properties it is of great interest to know for the different stable phases the microstructure and the morphology, which can be obtained by TEM observations. Results of some TEM studies are reported here utilizing not only the conventional TEM but also the lattice fringe imaging technique.Specimens of the different phases were produced as described in They were prepared for TEM observations. For high resolution work a Siemens ELMISKOP 102 (operating voltage 125 kV) was used fitted with a double tilting stage (± 45°), for conventional TEM studies the specimens were examined in an AEI EM7 high voltage EM operated at 1 MeV.

scholarly journals Changes In Properties and Microstructure of High-Chromium 9-12%Cr Steels Due to Long-Term Exposure at Elevated Temperature

2016 ◽  
Vol 61 (2) ◽  
pp. 957-964 ◽  
Author(s):  
A. Zieliński ◽  
J. Dobrzański ◽  
H. Purzyńska ◽  
G. Golański
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Phase Composition ◽  
High Chromium ◽  
X Ray ◽  
Supercritical Steam Parameters ◽  
Transmission Electron ◽  
Steam Parameters

AbstractThis paper presents the characteristics of the performance of P91 (X10CrMoVNb9-1), P92 (X10CrWMoVNb9-2) and VM12 (X12CrCoWVNb12-2-2) steels used for condition assessment of the pressure components of boilers with supercritical steam parameters. Studies on the mechanical properties, microstructure tests using scanning and transmission electron microscopy, and X-ray analysis of the phase composition of precipitates were performed for selected steels in the as-received condition and after long-term annealing. These steel characteristics are used for the evaluation of the microstructural changes and mechanical properties of the material of components after long-term service. The result of this study is the database of material characteristics representing the mechanical properties related to the microstructure analysis and it can be used for diagnosis of the components of pressure parts of power boilers.

scholarly journals Detection of isolated protein-bound metal ions by single-particle cryo-STEM

2017 ◽  
Vol 114 (42) ◽  
pp. 11139-11144 ◽  
Author(s):  
Nadav Elad ◽  
Giuliano Bellapadrona ◽  
Lothar Houben ◽  
Irit Sagi ◽  
Michael Elbaum
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Metal Ions ◽  
Single Particle ◽  
Dark Field ◽  
X Ray ◽  
X Ray Crystallography ◽  
Metal Atoms ◽  
Transmission Electron ◽  
Structural Methods

Metal ions play essential roles in many aspects of biological chemistry. Detecting their presence and location in proteins and cells is important for understanding biological function. Conventional structural methods such as X-ray crystallography and cryo-transmission electron microscopy can identify metal atoms on protein only if the protein structure is solved to atomic resolution. We demonstrate here the detection of isolated atoms of Zn and Fe on ferritin, using cryogenic annular dark-field scanning transmission electron microscopy (cryo-STEM) coupled with single-particle 3D reconstructions. Zn atoms are found in a pattern that matches precisely their location at the ferroxidase sites determined earlier by X-ray crystallography. By contrast, the Fe distribution is smeared along an arc corresponding to the proposed path from the ferroxidase sites to the mineral nucleation sites along the twofold axes. In this case the single-particle reconstruction is interpreted as a probability distribution function based on the average of individual locations. These results establish conditions for detection of isolated metal atoms in the broader context of electron cryo-microscopy and tomography.

scholarly journals (Al,Mg)3La: a new phase in the Mg–Al–La system

2018 ◽  
Vol 74 (4) ◽  
pp. 370-375 ◽  
Author(s):  
Charlotte Wong ◽  
Mark J. Styles ◽  
Suming Zhu ◽  
Dong Qiu ◽  
Stuart D. McDonald ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Powder Diffraction ◽  
Dark Field ◽  
Transmission Electron Microscopy Analysis ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Annular Dark Field ◽  
Electron Microscopy Analysis

During an investigation of the Mg-rich end of the Mg–Al–La system, a new ternary phase with the composition of (Al,Mg)3La was identified. The crystal structure of this phase was determined by conventional X-ray powder diffraction and transmission electron microscopy analysis and refined using high-resolution X-ray powder diffraction. The (Al,Mg)3La phase is found to have an orthorhombic structure with a space group of C2221 and lattice parameters of a = 4.3365 (1) Å, b = 18.8674 (4) Å and c = 4.4242 (1) Å, which is distinctly different from the binary Al3La phase (P63/mmc). The resolved structure of the (Al,Mg)3La phase is further verified by high-angle annular dark-field scanning transmission electron microscopy.

Effect of using polyimide capillaries during thermal experiments on the particle size distribution of supported Pt nanoparticles

2015 ◽  
Vol 48 (5) ◽  
pp. 1599-1603 ◽  
Author(s):  
Liliana Gámez-Mendoza ◽  
Oscar Resto ◽  
María Martínez-Iñesta
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Transmission Electron Microscopy ◽  
Low Cost ◽  
Pt Nanoparticles ◽  
Dark Field ◽  
High Angle ◽  
X Ray ◽  
Transmission Electron ◽  
Annular Dark Field

Kapton HN-type polyimide capillaries are commonly used as sample holders for transmission X-ray experiments at temperatures below 673 K because of their thermal stability, high X-ray transmittance and low cost. Using high-angle annular dark field scanning high-resolution transmission electron microscopy and thermogravimetric analysis, this work shows that using polyimide capillaries leads to the overgrowth of supported Pt nanoparticles during reduction at temperatures below the glass transition temperature (Tg= 658 K) owing to an outgassing of water from the polyimide. Quartz capillaries were also studied and this overgrowth was not observed.

Microstructure, Chemistry and Mechanical Properties of the Ni/AgBiCuSn/Ni Interconnections

2012 ◽  
Vol 186 ◽  
pp. 239-242
Author(s):  
Anna Sypień ◽  
Lidia Lityńska-Dobrzyńska ◽  
Anna Wierzbicka-Miernik ◽  
Pawel Zieba
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Shear Test ◽  
Intermetallic Phases ◽  
X Ray ◽  
Ni Substrate ◽  
Loading Direction ◽  
Transmission Electron ◽  
Tem Transmission Electron Microscopy

The paper presents results of electron microscopy studies on the microstructure, chemical composition and mechanical properties of the Ni/AgBiCuSn/Ni interconnections obtained due to the conventional soldering. The scanning (SEM) and (TEM) transmission electron microscopy combined with an energy dispersive X-ray spectroscopy allowed to reveal the presence of two intermetallic phases (Ag3Sn and Cu6Sn5) in the whole interconnection area for all the applied solders and soldering times. In the vicinity of Ni substrate both phases were modified with Ni (2-4.5 %at.). Some of Ag3Sn precipitates took the elongated shape and they were located across whole interconnection width. The SEM examination after shear test showed that the joints ruptured in a ductile manner, as manifested by the dimples present on the fracture surfaces. The dimples prove also that the plastic deformation occurred along the loading direction.

Structural and Chemical Characterization of Yb2O3-ZrO2 System by HAADF-STEM and HRTEM

2009 ◽  
Vol 15 (1) ◽  
pp. 46-53 ◽  
Author(s):  
C. Angeles-Chavez ◽  
P. Salas ◽  
L.A. Díaz-Torres ◽  
E. de la Rosa ◽  
R. Esparza ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Crystalline Structure ◽  
Sol Gel ◽  
Tetragonal Zirconia ◽  
Chemical Characterization ◽  
Dark Field ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission

AbstractZrO2:Yb3+ nanocrystalline phosphors with high concentrations of ytterbium ions were prepared using the sol-gel method. X-ray diffraction, high-angle annular-dark-field scanning transmission electron microscopy (HAADF-STEM), energy dispersive X-ray spectroscopy, and high-resolution transmission electron microscopy (HRTEM) were used to characterize the nanocrystalline phosphors annealed at 1000°C. Unit-cell distortion and changes in the crystalline structure of the monoclinic zirconia to tetragonal zirconia, and subsequently cubic zirconia, were observed with increased Yb concentration. Yb ions were randomly distributed into the lattice of the crystalline structure. No segregation of Yb2O3 phase was observed. The substitution of Zr atoms by Yb atoms on different crystalline phases was confirmed by the experimental results and theoretical simulations of HRTEM and HAADF-STEM.

Helium Implantation Damage in SiC

2005 ◽  
Vol 108-109 ◽  
pp. 709-712
Author(s):  
Stephanie Leclerc ◽  
Marie France Beaufort ◽  
Valerie Audurier ◽  
Alain Déclemy ◽  
Jean François Barbot
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Helium Ions ◽  
X Ray ◽  
Implantation Damage ◽  
Transmission Electron ◽  
Helium Implantation

Single crystals SiC were implanted with 50 keV helium ions at room temperature and fluences in the range 1x1016 -1x1017 cm-2. The helium implantation induced swelling was studied through the measurement of the step height. The damage was studied by using X-ray diffraction measurements and the transmission electron microscopy observations. Degradation of mechanical properties is found after helium implantation.

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