Structure and chemistry of silicon carbide whisker surfaces

1986 ◽  
Vol 44 ◽  
pp. 472-473 ◽  
Author(s):  
L. F. Allard ◽  
P. Pendleton ◽  
J. S. Brinen
Keyword(s):  
Silicon Carbide ◽  
High Resolution ◽  
Dispersed Phase ◽  
Analysis Techniques ◽  
Silicon Carbide Whisker ◽  
Silicon Carbide Whiskers ◽  
Surface Analysis Techniques ◽  
Surface Energetics ◽  
High Resolution Tem

Silicon carbide whiskers are of interest as dispersed phase strengthened in metals, ceramics, and polymer composites. Characterization of whisker structure, including surface morphology, crystallography and chemistry, is important so that whisker models can be devised on which calculations of surface energetics controlling wetting/bonding phenomena can be accurately based. In current work, the microstructures of several commercially-available SiC whisker types have been characterized by high resolution TEM and surface analysis techniques. Results of the characterization of one manufacturer's whiskers, Tateho Chemical Industries, are described in this paper.

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

scholarly journals Common Phase and Structure Misidentifications in High-Resolution TEM Characterization of Perovskite Materials

2020 ◽  
Vol 6 (1) ◽  
pp. 1
Author(s):  
Yu-Hao Deng
Keyword(s):  
High Resolution ◽  
Research Field ◽  
Structure Characterization ◽  
Phase Identification ◽  
Lead Iodide ◽  
Perovskite Materials ◽  
High Resolution Tem ◽  
Methylammonium Lead Iodide ◽  
Dose Imaging

High-resolution TEM (HRTEM) is a powerful tool for structure characterization. However, methylammonium lead iodide (MAPbI3) perovskite is highly sensitive to electron beams and easily decomposes into lead iodide (PbI2). Misidentifications, such as PbI2 being incorrectly labeled as perovskite, are widely present in HRTEM characterization and would negatively affect the development of perovskite research field. Here misidentifications in MAPbI3 perovskite are summarized, classified, and corrected based on low-dose imaging and electron diffraction (ED) simulations. Corresponding crystallographic parameters of intrinsic tetragonal MAPbI3 and the confusable hexagonal PbI2 are presented unambiguously. Finally, the method of proper phase identification and some strategies to control the radiation damage in HRTEM are provided. This warning paves the way to avoid future misinterpretations in HRTEM characterization of perovskite and other electron beam-sensitive materials.

Structural Characterization of Epitaxial GMR Magnetic Multilayers and Spin Valves Grown by Sputter Deposition

2000 ◽  
Vol 614 ◽  
Author(s):  
H. Geng ◽  
R. Loloee ◽  
J.W. Heckman ◽  
J. Bass ◽  
W.P. Pratt ◽  
...  
Keyword(s):  
High Resolution ◽  
Epitaxial Growth ◽  
Magnetic Multilayers ◽  
Sputter Deposition ◽  
Dc Magnetron Sputtering ◽  
Cu Films ◽  
Electron Backscatter ◽  
High Resolution Tem ◽  
Fcc Structure

ABSTRACTEpitaxial Cu/Py/FeMn and (Cu/Co)×20 GMR magnetic multilayers were grown on single crystal (011) Nb that was deposited on (1121) Al2O3 substrates by dc magnetron sputtering. Electron backscatter patterns (EBSPs) revealed that the Cu films display two twin variants, corresponding to two stacking sequences of {111} planes in fcc. The epitaxial orientation relationship between the bcc Nb and both fcc Cu variants was the Nishiyama-Wasserman (N-W) relationship. Conventional TEM observations revealed epitaxial growth for both the Cu/Py/FeMn and (Cu/Co)×20 multilayers. High-resolution TEM confirmed epitaxial growth of close packed (011) Nb on (1120) Al2O3 substrates with [111]Nb∥[0001]Al2O3. Numerous small twins were observed in the Cu near the Cu-Nb interface of the Cu/Py/FeMn multilayer. In the Cu/Co multilayer, the growth planes of the Cu and Co were found to be {100} instead of the expected close-packed {111} planes of the fcc structure.

Characterization of recent silicon carbide whiskers

1991 ◽  
Vol 26 (1) ◽  
pp. 103-111 ◽  
Author(s):  
K. R. Karasek ◽  
S. A. Bradley ◽  
J. T. Donner ◽  
H. C. Yeh ◽  
J. L. Schienle
Keyword(s):  
Silicon Carbide ◽  
Silicon Carbide Whiskers

High-resolution TEM characterization of MOVPE-grown (111)-BP layer on hexagonal 6H (0001)-SiC

2005 ◽  
Vol 244 (1-4) ◽  
pp. 285-288 ◽  
Author(s):  
T. Udagawa ◽  
M. Odawara ◽  
G. Shimaoka
Keyword(s):  
High Resolution ◽  
Tem Characterization ◽  
High Resolution Tem

Synthesis and characterization of nano-scale and submicro-scale silicon carbide whiskers on C/C composites

2017 ◽  
Vol 714 ◽  
pp. 270-277 ◽  
Author(s):  
Fang-xu Niu ◽  
Yan-xiang Wang ◽  
Lian-Ru Ma ◽  
Shan-long Fu ◽  
Imran Abbas ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Synthesis And Characterization ◽  
Nano Scale ◽  
Silicon Carbide Whiskers

scholarly journals Spectrometric and morphological characterization of condensed phase zirconium species produced during electrothermal heating on a graphite platform

2005 ◽  
Vol 20 (5) ◽  
pp. 385-394 ◽  
Author(s):  
M. A. Castro ◽  
A. J. Aller ◽  
A. McCabe ◽  
W. E. Smith ◽  
D. Littlejohn
Keyword(s):  
Surface Analysis ◽  
Condensed Phase ◽  
Morphological Characterization ◽  
Chemical Modifier ◽  
Mechanistic Studies ◽  
Analysis Techniques ◽  
Temperature Range ◽  
Surface Analysis Techniques

The characterization of condensed phase zirconium species on a graphite platform was accomplished over the temperature range 200–2500 °C using surface analysis techniques. This resulting information will be of relevance for mechanistic studies using zirconium as a chemical modifier.

Preparation and Characterization of La1Sr2Nb5O10−x Specimens

1990 ◽  
Vol 209 ◽  
Author(s):  
Donald H. Galvàn ◽  
M. Avalos-Borja ◽  
L. Cota-Araiza ◽  
J. Cruz-Reyes ◽  
E. A. Early
Keyword(s):  
High Temperature ◽  
High Resolution ◽  
X Rays ◽  
High Resolution Tem ◽  
Nominal Stoichiometry

ABSTRACTRecently Ogushi et al reported a La-Sr-Nb-O compound with a superconducting temperature of about 225 K. The possibility of having superconductors with such a high temperature is certainly technologically relevant. We prepared specimens with the same nominal stoichiometry and performed characterization by SEM, high resolution TEM, Scanning Auger and X-rays.

Sign in / Sign up

Export Citation Format

Share Document