scholarly journals Microstructure investigations of Pt-modified γ′-Ni3Al + γ-Ni coatings on Ni-based superalloys

2010 ◽  
Vol 25 (6) ◽  
pp. 1191-1195 ◽  
Author(s):  
Guanghui Cao ◽  
Taoping Ou ◽  
Hua Jiang ◽  
Alan M. Russell
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Single Crystal ◽  
Energy Dispersive ◽  
Single Crystal Superalloy ◽  
Refractory Element ◽  
Cross Sectional ◽  
X Ray ◽  
Topologically Close Packed ◽  
Transmission Electron

The microstructure of Pt-modified γ′-Ni3Al + γ-Ni coating on CMSX-4 single-crystal superalloy has been investigated by transmission electron microscopy (TEM). Cross-sectional TEM analyses showed the presence of precipitates in the coating. This precipitate was identified as the hexagonal topologically close-packed (TCP) μ phase with lattice parameters a = 0.473 nm and c = 2.565 nm. The energy-dispersive x-ray (EDX) spectrum of the μ phase suggested a refractory element rich compound comprising the elements Re, W, and Co. Twin domains parallel to (001) were found in the μ phase. The mechanisms of the μ phase and twinning formation were discussed.

Design of 2D-nanocrystals in water: preparation, structure and functionalization

2018 ◽  
Vol 90 (5) ◽  
pp. 833-844
Author(s):  
Leonid Aslanov ◽  
Valery Zakharov ◽  
Ksenia Paseshnichenko ◽  
Aleksandr Yatsenko ◽  
Andrey Orekhov ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Chemical Composition ◽  
High Resolution ◽  
Electron Diffraction ◽  
Single Crystal ◽  
Room Temperature ◽  
Energy Dispersive ◽  
X Ray ◽  
Transmission Electron

AbstractA new method for synthesis of 2D nanocrystals in water was proposed. The use of perfluorothiophenolate ions as surfactant allowed us to produce 2D single-crystal nanosheets of CaS at pH=9 and flat nanocrystals of PbS at pH=9 at room temperature. Mesocrystalline nanobelts of CdS and mesocrystals of PbS were obtained at pH=3–5 and pH=10–12, respectively. Morphology, structure and chemical composition of nanoparticles were characterized by high-resolution transmission electron microscopy, electron diffraction and energy dispersive X-ray spectroscopy. A mechanism of nanoparticles formation was discussed.

Pulmonary silicosis in 2 rock hyraxes, and literature review

2021 ◽  
pp. 104063872110575
Author(s):  
Bianca R. Pfisterer ◽  
Anthony L. Ashley ◽  
Robert L. Donnell ◽  
John R. Dunlap ◽  
Kim M. Newkirk
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Medical Center ◽  
Fibrous Tissue ◽  
Crystalline Silica ◽  
Energy Dispersive ◽  
Intact Male ◽  
Crystal Deposition ◽  
X Ray ◽  
Transmission Electron

Two rock hyraxes ( Procavia capensis), from the Chattanooga Zoo, were submitted separately for autopsy at the University of Tennessee Veterinary Medical Center. The first was a 4-y-old intact female that died without premonitory signs and the second was a 10-y-old intact male that was euthanized because of severe renal disease. Microscopically, the lungs of both hyraxes had multifocal-to-coalescing, <1-mm diameter aggregates of epithelioid macrophages separated by streams of fibrous tissue. Macrophages contained intracytoplasmic, clear, acicular, birefringent crystals. Transmission electron microscopy and energy-dispersive x-ray spectroscopy findings on the lung samples were consistent with silica crystal deposition. The hyraxes had been housed together on commercially sourced play sand composed of 99–99.5% quartz, a crystalline silica polymorph. The microscopic findings, transmission electron microscopy, and energy-dispersive x-ray spectroscopy of the intrahistiocytic crystals, in addition to the history of exposure to crystalline silica, were consistent with pulmonary silicosis. Pulmonary silicosis has not been reported previously in rock hyraxes, to our knowledge.

Structural and analytical studies of the silicified macrohairs from the lemma of the grass Phalaris canariensis L

1984 ◽  
Vol 222 (1229) ◽  
pp. 427-438 ◽  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Silica Particles ◽  
Time Dependent ◽  
Energy Dispersive ◽  
X Ray ◽  
Analytical Studies ◽  
Transmission Electron ◽  
Cellular Control ◽  
Phalaris Canariensis

Silicified macrohairs from mature and immature lemmas of the grass Phalaris canariensis L. have been studied by scanning (s.e.m.) and transmission electron microscopy (t.e.m.) and energy dispersive X-ray analysis (e.d.X.a.) at various times after emergence of the inflorescence. Within the macrohairs a variety of morphologies of silica particles was observed. E.d.X.a. revealed the time-dependent concentrations in the macrohairs of the elements K, Cl, P, and S, in addition to Si. Much lower levels of these elements were found in highly silicified mature macrohairs than in the immature macrohairs. It is proposed that the hairs are silicified under strict cellular control.

Direct Deposition Reactions Between Nickel and Silicon Substrates

1993 ◽  
Vol 311 ◽  
Author(s):  
Lin Zhang ◽  
Douglas G. Ivey
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Silicon Substrates ◽  
Silicide Formation ◽  
Cross Sectional ◽  
Deposition Rates ◽  
Plan View ◽  
X Ray ◽  
Si Substrates ◽  
Transmission Electron

ABSTRACTSilicide formation through deposition of Ni onto hot Si substrates has been investigated. Ni was deposited onto <100> oriented Si wafers, which were heated up to 300°C, by e-beam evaporation under a vacuum of <2x10-6 Torr. The deposition rates were varied from 0.1 nm/s to 6 nm/s. The samples were then examined by both cross sectional and plan view transmission electron microscopy (TEM), energy dispersive x-ray spectroscopy and electron diffraction. The experimental results are discussed in terms of a new kinetic model.

Determination of Dislocation Densities in Hexagonal Close-Packed Metals using X-Ray Diffraction and Transmission Electron Microscopy

1991 ◽  
Vol 35 (A) ◽  
pp. 593-599 ◽  
Author(s):  
M. Griffiths ◽  
J.E. Winegar ◽  
J.F. Mecke ◽  
R.A. Holt
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Single Crystal ◽  
Plastic Anisotropy ◽  
Zirconium Alloys ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hexagonal Close Packed ◽  
Transmission Electron ◽  
Dislocation Densities

AbstractX-ray diffraction (XRD) line-broadening analysis has been used to determine dislocation densities in zirconium alloys with hexagonal closepacked (hep) crystal structures and a complex distribution of dislocations reflecting the plastic, anisotropy of the material. The validity of the technique has been assessed by comparison with direct measurements of dislocation densities in deformed polycrystalline and neutron-irradiated single crystal material using transmission electron microscopy (TEM). The results show that-there is good agreement between the XRD and TEM for measurements on the deformed material whereas there is a large discrepancy for measurements on the irradiated single crystal; the XRD measurements significantly underestimating the TEM observations.

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