Alpha-Si3N4 Precipitation in C/C-SiC Composites from inherent Fiber Impurity Sources

Carbon Fibers ◽

Vapor Phase ◽

Reaction Front ◽

Reactive Nitrogen ◽

Transmission Electron ◽

Silicon Vapor ◽

Sic Composites

ABSTRACTThe formation of crystalline α-Si3N4 filaments grown inside the pore channels of HT-carbon fibers from a 2D C/C-SiC composite is investigated by transmission electron microscopy. Precipitation of α-Si3N4 is promoted by a low carbonization heat treatment of the C/C material prior to liquid silicon infiltration and results from the interaction of a highly reactive nitrogen-rich vapor phase released from the fiber and silicon vapor diffusing ahead of the SiC reaction front into the porous microtexture of the fiber.

Metalorganic vapor phase epitaxy growth, transmission electron microscopy, and magneto-optical spectroscopy of individual InAsxP1−x/Ga0.5In0.5P quantum dots

Physical Review Materials ◽

10.1103/physrevmaterials.1.034605 ◽

2017 ◽

Vol 1 (3) ◽

Cited By ~ 1

Author(s):

O. Del Pozo-Zamudio ◽

J. Puebla ◽

A. Krysa ◽

R. Toro ◽

A. M. Sanchez ◽

...

Keyword(s):

Electron Microscopy ◽

Quantum Dots ◽

Optical Spectroscopy ◽

Vapor Phase ◽

Metalorganic Vapor Phase Epitaxy ◽

Vapor Phase Epitaxy ◽

Microstructural Studies of High Coercivity Nd15Fe77B8 Sintered Magnets

MRS Proceedings ◽

10.1557/proc-96-193 ◽

1987 ◽

Vol 96 ◽

Cited By ~ 3

Author(s):

M. H. Ghandehari ◽

J. Fidler

Keyword(s):

Electron Microscopy ◽

Heat Treatment ◽

Grain Boundary ◽

Electron Microprobe ◽

Boundary Phase ◽

High Coercivity ◽

Transmission Electron ◽

Microstructural Studies ◽

Domain Reversal

ABSTRACTMicrostructures of Nd15−xDyxFe77B8 prepared by alloying with Dy, and by using Dy2O3 as a sinl'ken adidive, have been determined using electron microprobe and transmission electron microscopy. The results have shown a higher Dy concentration near the grain boundaries of the 2–14–1 phase for magnets doped with Dy2O 3, as compared to the Dy-alloyed magnets. A two-step post sintering heat treatment was also studied for the two systems. The resultant concentration gradient of Dy in the 2–14–1 phase of the oxide-doped magnets is explained by the reaction of Dy2O3 with the Nd-rich grain boundary phase and its slow diffusion into thg 4–14–1 phase. Increased Dy concentration near the grain boundary is more effective in improving the coercivity, as domain reversal nucleation originates at or near this region.

The effect of grain size on microstructure and stress relaxation in polycrystalline Y1Ba2Cu3O7−δ

Journal of Materials Research ◽

10.1557/jmr.1989.0248 ◽

1989 ◽

Vol 4 (2) ◽

pp. 248-256 ◽

Cited By ~ 96

Author(s):

T. M. Shaw ◽

S. L. Shinde ◽

D. Dimos ◽

R. F. Cook ◽

P. R. Duncombe ◽

...

Keyword(s):

Electron Microscopy ◽

Heat Treatment ◽

Grain Size ◽

Stress Relaxation ◽

Optical Microscopy ◽

Slow Cooling ◽

Hierarchical Arrangement ◽

Transmission Electron ◽

Processing Variables

We have used transmission electron microscopy and optical microscopy to examine the effect that grain size and heat treatment have on twinning and microcracking in polycrystalline Y1Ba2Cu3O7−δ. It is shown that isothermal oxygenation heat treatments produce twin structures consisting of parallel twins, with a characteristic spacing that increases with increasing grain size. Slow cooling through the temperature range where the orthorhombic-to-tetragonal transformation induces twinning, however, produces a structure consisting of a hierarchical arrangement of intersecting twins, the scale of which appears to be independent of grain size. It is also shown that the microcracking induced by anisotropic changes in grain dimensions on cooling or during oxygenation can be suppressed if the grain size of the material is kept below about 1 μm. The results are examined in the light of current models for transformation twinning and microcracking and the models used to access the effect other processing variables such as oxygen content, doping or heat treatment may have on the microstructure of Y1Ba2Cu3O7−δ.

Dynamic Compaction of Al Alloys

MRS Proceedings ◽

10.1557/proc-28-163 ◽

1983 ◽

Vol 28 ◽

Cited By ~ 1

Author(s):

J.W. Sears ◽

B.C. Muddle ◽

H.L. Fraser

Keyword(s):

Electron Microscopy ◽

Heat Treatment ◽

Al Alloys ◽

Dynamic Compaction ◽

Al Alloy ◽

Analytical Transmission Electron Microscopy ◽

Projectile Velocity ◽

ABSTRACTPowders of Al alloy 7091 have been consolidated by means of dynamic compaction. The dependence of density and hardness on projectile velocity has been determined. The resulting as-compacted material has been characterized using analytical transmission electron microscopy and evidence of interparticle melting observed. The microstructural responseof the compacted material to heat treatment at 523 and 723°K has been investigated.

Novel Methods for Preparation and Surface Treatment of Nano-CaCO3

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.750-752.336 ◽

2013 ◽

Vol 750-752 ◽

pp. 336-339

Author(s):

Fa Chao Wu ◽

Teng Fei Shen

Keyword(s):

Electron Microscopy ◽

Heat Treatment ◽

Scanning Electron Microscopy ◽

Particle Size ◽

Fourier Transform ◽

Room Temperature ◽

Transmission Electron ◽

Reduce Energy Consumption ◽

Scanning Electron

In this work, CaCO3 nanoparticles have been synthesized via heat-treatment of a new precursor. Effect of calcinations temperature on particle size has been investigated. The products were characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). nanoCaCO3 was modified using chloroform as solvent and fatty acid as modifier atroom temperature. The advantage of this modification is that it can be proceed at room temperature and it can reduce energy consumption.

Transmission electron microscopy study of an AlN nucleation layer for the growth of GaN on a 7-degree off-oriented (001) Si substrate by metalorganic vapor phase epitaxy

Journal of Crystal Growth ◽

10.1016/j.jcrysgro.2003.08.074 ◽

2004 ◽

Vol 260 (3-4) ◽

pp. 360-365 ◽

Cited By ~ 3

Author(s):

Shigeyasu Tanaka ◽

Yoshio Honda ◽

Norifumi Kameshiro ◽

Ryuta Iwasaki ◽

Nobuhiko Sawaki ◽

...

Keyword(s):

Electron Microscopy ◽

Vapor Phase ◽

Microscopy Study ◽

Metalorganic Vapor Phase Epitaxy ◽

Electron Microscopy Study ◽

Si Substrate ◽

Transmission Electron Microscopy Study ◽

Nucleation Layer ◽

Oxygen Precipitation Effects in Degenerately – Doped Silicon

MRS Proceedings ◽

10.1557/proc-14-181 ◽

1982 ◽

Vol 14 ◽

Cited By ~ 2

Author(s):

G. A. Rozgonyi ◽

R. J. Jaccodine ◽

C. W. Pearce

Keyword(s):

Electron Microscopy ◽

Heat Treatment ◽

Low Temperature ◽

Temperature Step ◽

Supersaturation Ratio ◽

Oxygen Precipitation ◽

Transmission Electron ◽

Doped Silicon ◽

High Supersaturation

ABSTRACTIn this paper we report preliminary observations of oxygen precipitation in degenerately-doped silicon using etching, optical microscopy and transmission electron microscopy. It was found that n+ material was resistant to precipitation, but p+ material precipitated readily. A multistep heat treatment starting with a low temperature step to achieve a high supersaturation ratio was sucessfully used to induce precipitation in n+ material.

A Study of Fibre/Matrix Interfaces in TiAl/Sic Composites

MRS Proceedings ◽

10.1557/proc-364-1035 ◽

1994 ◽

Vol 364 ◽

Cited By ~ 2

Author(s):

S. Djanarthany ◽

C. Servant ◽

C. Colin

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Hot Pressing ◽

Matrix Interface ◽

Arc Spray ◽

Transmission Electron ◽

Sic Composites ◽

Fibre Matrix ◽

Scanning Electron

AbstractA continuous fibre reinforced SiC/TiAl composite has been prepared by arc spray and hot pressing. The as-fabricated fibre/matrix interface of monotapes and composites have been examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The arc-spray conditions result in a decohesion at the fibre/matrix interface.

Cross-Sectional TEM Study Of Phase Separation In Reaction Of Ni-Ta Films With GaAs

MRS Proceedings ◽

10.1557/proc-54-355 ◽

1985 ◽

Vol 54 ◽

Author(s):

A. Lahav ◽

M. Eizenberg ◽

Y. Komem

Keyword(s):

Electron Microscopy ◽

Heat Treatment ◽

Phase Separation ◽

Gaas Substrate ◽

Auger Spectroscopy ◽

X Ray Diffraction ◽

Cross Sectional ◽

X Ray ◽

ABSTRACTThe reaction between Ni60Ta40 amorphous alloy and (001) GaAs was studied by cross-sectional transmission electron microscopy, Auger spectroscopy, and x-ray diffraction. At 400°C formation of Ni GaAs at the interface with GaAs was observed. After heat treatment at 600°C in vacuum a layered structure of TaAs/NiGa/GaAs has been formed. The NiGa layer has epitaxial relations to the GaAs substrate. The vertical phase separation can be explained by opposite diffusion directions of nickel and arsenic atoms.