Microstructure and Densification of Sintered (B+C)-Doped β-Silicon Carbide

1993 ◽  
Vol 327 ◽  
Author(s):  
Wolfgang Braue ◽  
Hans-J. Kleebe ◽  
Carsten Wehling
Keyword(s):  
Silicon Carbide ◽  
Phase Transformation ◽  
Surface Layer ◽  
Preliminary Data ◽  
Combined Approach ◽  
Early Stages ◽  
Α Phase ◽  
Powder Particles

AbstractThe role of boron and carbon during densification of sintered β-SiC was investigated through the combined approach of in-situ dilatometry and CTEM/AEM inspection of TEM-foils referring to well-defined densification events. Preliminary data obtained indicate that in the early stages of densification, boron is not enriched in the continuous carbon-rich surface layer covering the β-SiC powder particles nor does it segregate to internal interfaces in high quantities. Small boron quantities are dissolved in the SiC grains- Simultaneously with the β- to α- phase transformation, decomposition of foam-like B4C aggregates releases small B4C particles, which are bound intragranularly to α-SiC.

In-situ generation of graphene network in silicon carbide fibers: Role of iodine and carbon monoxide

Carbon ◽  
2020 ◽  
Vol 158 ◽  
pp. 110-120
Author(s):  
Junsung Hong ◽  
Youngjin Ko ◽  
Kwang-Yeon Cho ◽  
Dong-Geun Shin ◽  
Prabhakar Singh ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Silicon Carbide ◽  
Silicon Carbide Fibers ◽  
In Situ Generation

Processing of silicon carbide ceramics using chemically modified polycarbosilanes

1999 ◽  
Vol 14 (1) ◽  
pp. 189-195 ◽  
Author(s):  
Sachiko Okuzaki ◽  
Yuji Iwamoto ◽  
Shinji Kondoh ◽  
Koichi Kikuta ◽  
Shin-ichi Hirano
Keyword(s):  
Silicon Carbide ◽  
Phase Transformation ◽  
Nucleation Site ◽  
Metal Alkoxide ◽  
Transformation Behavior ◽  
Ceramic Yield ◽  
Chemically Modified ◽  
Α Phase ◽  
Carbide Ceramics ◽  
Silicon Carbide Ceramics

Chemically modified polycarbosilane (PC) which contains Si–Al–C–O component, PCOAl, was synthesized using PC and aluminum triisopropoxide. Ceramic yield was greatly improved through the modification of PC with a metal alkoxide. The phase transformation behavior and microstructure development of silicon carbide (SiC) were studied on β–SiC powders coated with chemically modified PC. The β-α phase transformation of SiC was enhanced by the coating of chemically modified PC on β–SiC powder. A unique microstructure with submicron-sized plate-like grains was developed, since the fine a phase produced at low temperature served as a nucleation site for the β-α phase transformation of SiC.

Role of Ions in Bias Enhanced Nucleation of Diamond

1995 ◽  
Vol 388 ◽  
Author(s):  
J.M. Lannon ◽  
J.S. Gold ◽  
Cd. Stinespring
Keyword(s):  
Thin Films ◽  
Silicon Carbide ◽  
Surface Composition ◽  
Hydrogen Ions ◽  
Ion Energy ◽  
Transfer Processes ◽  
Ion Interactions ◽  
Ion Energies

AbstractIon-surface interactions are thought to play a role in bias enhanced nucleation of diamond. To explore this hypothesis and understand the mechanisms, surface studies of hydrogen and hydrocarbon ion interactions with silicon and silicon carbide have been performed. the experiments were carried out at room temperature and used in-situ auger analyses to monitor the surface composition of thin films produced or modified by the ions. Ion energies ranged from 10 to 2000 eV. Hydrogen ions were found to modify silicon carbide thin films by removing silicon and converting the resulting carbon-rich layers to a mixture of sp2- and sp3-C. the interaction of hydrocarbon ions with silicon was shown to produce a thin film containing SiC-, sp2-, and sp3-C species. IN general, the relative amount of each species formed was dependent upon ion energy, fluence, and mass. the results of these studies, interpreted in terms of chemical and energy transfer processes, provide key insights into the mechanisms of bias enhanced nucleation.

In Situ Studies of Variant Selection During the α-β-α Phase Transformation in Zr-2.5Nb

2011 ◽  
Vol 8 (1) ◽  
pp. 103066 ◽  
Author(s):  
P. Mosbrucker ◽  
M. R. Daymond ◽  
R. A. Holt ◽  
P. Barberis ◽  
S. W. Dean
Keyword(s):  
Phase Transformation ◽  
Variant Selection ◽  
In Situ Studies ◽  
Α Phase

In-situ observation of deformation induced α″ phase transformation in a β-titanium alloy

2016 ◽  
Vol 182 ◽  
pp. 281-284 ◽  
Author(s):  
Tingting Yao ◽  
Kui Du ◽  
Yulin Hao ◽  
Shujun Li ◽  
Rui Yang ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Phase Transformation ◽  
In Situ Observation ◽  
Α Phase

In Situ Observation on the Influence of ß Grain Growth on Texture Evolution during Phase Transformation in Ti-6A-4V

2011 ◽  
Vol 702-703 ◽  
pp. 854-857
Author(s):  
Gideon C. Obasi ◽  
R.J. Moat ◽  
D. G. Leo Prakash ◽  
W. Kockelmann ◽  
Joao Quinta da Fonseca ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Neutron Diffraction ◽  
Grain Boundary ◽  
Grain Growth ◽  
Texture Evolution ◽  
Α Phase ◽  
Texture Modification ◽  
The Common ◽  
Grain Boundary Pinning

In the present study, in situ phase transformation experiments have been carried out using neutron diffraction to monitor the texture evolution during the α→ß→α phase transformation in Ti-6Al-4V with and without 0.4% yttrium additions. The aim of adding yttrium was to control ß grain growth above the transus ß by grain boundary pinning. In the present case, strengthening of the ß texture, occurring during ß grain coarsening resulted in strengthening of particular ß texture components, which increases the likelihood of α texture modification by selective growth of α variants on the common (110) ß grain boundaries into unoccupied large β grains.

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