Deposition of TRISO Particles With Superhard SiC Coatings and the Characterization of Anisotropy by Raman Spectroscopy

Author(s):  
E. López-Honorato ◽  
P. J. Meadows ◽  
J. Tan ◽  
Y. Xiang ◽  
P. Xiao

In this work we have deposited silicon carbide (SiC) at 1300°C with the addition of small amounts of propylene. The use of propylene and high concentrations of methyltrichlorosilane (9 vol %) allowed the deposition of superhard SiC coatings (42 GPa). The superhard SiC could result from the presence of a SiC–C solid solution, undetectable by X-ray diffraction but visible by Raman spectroscopy. Another sample obtained by the use of 50 vol % Argon, also showed the formation of SiC with good properties. The use of a flat substrate together with the particles showed the importance of carrying out the analysis on actual particles rather than in flat substrates. We show that it is possible to characterize the anisotropy of pyrolytic carbon by Raman spectroscopy.

Author(s):  
Eddie Lo´pez-Honorato ◽  
Philippa J. Meadows ◽  
Jun Tan ◽  
Yang Xiang ◽  
Ping Xiao

In this work we have deposited SiC at 1300°C with the addition of small amounts of propylene. The use of propylene and high concentrations of methyltrichlorosilane (9 vol%) allowed the deposition of superhard SiC coatings (42 GPa). The superhard SiC could result from the presence of a SiC-C solid solution, undetectable by X-ray diffraction but visible by Raman spectroscopy. Another sample obtained by the use of 50 vol% Argon, also showed the formation of SiC with good properties. The use of a flat substrate together with the particles showed the importance of carrying out the analysis on actual particles rather than in flat substrates. We show that it is possible to characterize the anisotropy of PyC by Raman spectroscopy.


2009 ◽  
Vol 2009 ◽  
pp. 1-4 ◽  
Author(s):  
L. Bourja ◽  
B. Bakiz ◽  
A. Benlhachemi ◽  
M. Ezahri ◽  
J. C. Valmalette ◽  
...  

A series of ceramics samples belonging to theCeO2-Bi2O3phase system have been prepared via a coprecipitation route. The crystallized phases were obtained by heating the solid precursors at600∘Cfor 6 hours, then quenching the samples. X-ray diffraction analyses show that forx<0.20a solid solutionCe1−xBixO2−x/2with fluorine structure is formed. For x ranging between 0.25 and 0.7, a tetragonalβ′phase coexisting with the FCC solid solution is observed. For x ranging between 0.8 and 0.9, a new tetragonalβphase appears. Theβ′phase is postulated to be a superstructure of theβphase. Finally, close tox=1, the classical monoclinicα Bi2O3structure is observed. Raman spectroscopy confirms the existence of the phase changes as x varies between 0 and 1.


2020 ◽  
Vol 98 (5) ◽  
pp. 457-464
Author(s):  
Woo Sik Yoo ◽  
Kitaek Kang ◽  
Toshikazu Ishigaki ◽  
Jung Gon Kim ◽  
Noriyuki Hasuike ◽  
...  

1996 ◽  
Vol 10 (23) ◽  
pp. 1159-1159
Author(s):  
THOMAS PREETHI CICILY ◽  
K. MANOJ KUMAR ◽  
NAYAR V. UNNIKRISHANAN ◽  
V. VIDYALAL ◽  
C.P.G. VALLABHAN

1998 ◽  
Vol 269-272 ◽  
pp. 473-478 ◽  
Author(s):  
Francsco Cardellini ◽  
Vittoria Contini ◽  
Gregorio D'Agostino ◽  
Adriano Filipponi

1996 ◽  
Vol 11 (4) ◽  
pp. 268-275 ◽  
Author(s):  
Winnie Wong-Ng ◽  
F. Jiang ◽  
Bryan R. Jarabek ◽  
Gregory J. McCarthy

Powder X-ray diffraction was used to investigate the solid solution range of the Bi14SrxCa12−xO33 series in the Bi–Sr–Ca–O system. Solid solution forms over the range 1≤x≤7 in Bi14SrxCa12−xO33. Experimental X-ray reference patterns of selected members with x=1, 3, 5, and 7 have been prepared for the powder diffraction file (PDF). These phases are monoclinic, C2/m, with cell parameter a ranging from 21.473(4) to 21.868(4) Å, b from 4.3564(9) to 4.3898(9) Å, c from 12.753(2) to 12.962(2) Å, β from 102.91(2)° to 102.79(1)°, and V from 1162.9(3) to 1213.5(3) Å3, respectively. These parameters increase monotonically as Ca is continuously replaced by the larger Sr.


2013 ◽  
Vol 203-204 ◽  
pp. 193-197
Author(s):  
Piotr Sagan ◽  
Volodymyr Popovych ◽  
Mariusz Bester ◽  
Marian Kuzma

In this paper we have obtained CdCrTe thin layers by PLD method using the YAG:Nd3+ laser with pulse length 250μs. Synthesized CdCrTe solid solution with 50% at. of Cr has been taken as a target. The layers were deposited on KCl substrate. The target and films were analyzed using X-ray diffraction, TEM microscope and THEED electron diffraction. The morphology of the layers are homogenous. However, we have detected several crystallographic phases: cubic CdTe, hexagonal Cr and hexagonal Te. From the measurements of lattice constant of the layer, their composition was determined to be x=0,14


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