Synthesis and Characterization of A Metastable (SiC)aN4 Phase

1994 ◽  
Vol 354 ◽  
Author(s):  
C. Uslu ◽  
B. Park ◽  
D. B. Poker

AbstractA metastable C-Si-N compound has been synthesized by high dose N+ implantation into polycrystalline /8-SiC (cubic phase). The thin films formed upon 100 keV implantations were characterized with respect to various ion doses and target temperatures. X-ray diffraction with a position-sensitive detector and cross-sectional transmission electron microscopy revealed that the as-implanted surfaces contained ∼0.15 jttm thick continuously-buried amorphous layers. Rutherford backscattering spectroscopy showed that the peak concentration of nitrogen saturated up to approximately 54 at. % with increasing doses, suggesting a new phase formation.

1993 ◽  
Vol 316 ◽  
Author(s):  
C. Uslu ◽  
D. H. Lee ◽  
Y. Berta ◽  
B. Park ◽  
N. N. Thadhani ◽  
...  

ABSTRACTWe have investigated the synthesis of carbon-silicon-nitride compounds by ion implantation. In these experiments, 100 keV nitrogen ions were implanted into polycrystalline β-SiC (cubic phase) at various substrate temperatures and ion doses. These thin films were characterized in detail by x-ray diffraction with a position-sensitive detector, transmission electron microscopy with chemical analysis, and Rutherford backscattering spectroscopy. The as-implanted samples show a buried amorphous layer at a depth of 170 nm. The peak concentration of nitrogen saturates at approximately 45 at. % with doses above ~9.0×1017 N/cm2 at 860°C. These results suggest formation of a new phase by nitrogen implantation into β-SiC.


1995 ◽  
Vol 10 (10) ◽  
pp. 2401-2403 ◽  
Author(s):  
Q.X. Jia ◽  
S.G. Song ◽  
S.R. Foltyn ◽  
X.D. Wu

Highly conductive metal-oxide RuO2 thin films have been successfully grown on yttria-stabilized zirconia (YSZ) substrates by pulsed laser deposition. Epitaxial growth of RuO2 thin films on YSZ and the atomically sharp interface between the RuO2 and the YSZ substrate are clearly evident from cross-sectional transmission electron microscopy. A diagonal-type epitaxy of RuO2 on YSZ is confirmed from x-ray diffraction measurements. The crystalline RuO2 thin films, deposited at temperatures in the range of 500 °C to 700 °C, have a room-temperature resistivity of 35 ± 2 μω-cm, and the residual resistance ratio (R300 k/R4.2 k) is around 5 for the crystalline RuO2 thin films.


1991 ◽  
Vol 220 ◽  
Author(s):  
P. M. Adams ◽  
R. C. Bowman ◽  
V. Arbet-Engols ◽  
K. L. Wang ◽  
C. C. Ahn

ABSTRACTP-I-N diodes whose intrinsic region consists of strained layer superlattices (SLS), separated by 40 nm Si spacers, have been grown by MBE on Si substrates with <100>, <110>, and <111> orientations. These structures have been characterized by x-ray diffraction (XRD) and cross-sectional transmission electron microscopy (XTEM). The dual periodicities in these structures produced unique XRD effects and the quality was highly dependent on substrate orientation. The <100> sample was in general free of defects, whereas the <110> and <111> specimens contained significant numbers of twins and dislocations.


2013 ◽  
Vol 785-786 ◽  
pp. 444-448 ◽  
Author(s):  
Yang Liu ◽  
Jun Su

A novel MgO-filled rectangular carbon nanocapsules was fabricated by pyrolyzing acetonitrile with the assistance of MgO and a small quantity of Fe3+. The nanocapsules were analyzed by powder X-ray diffraction, transmission electron microscopy, and energy dispersive X-ray spectroscopy. The lengths of the rectangular nanocapsules sides range from 40 nm to 60 nm and the core part of the rectangular carbon nanocapsules consists of cubic phase MgO. A small quantity of Fe catalysts plays an important role in the growth of rectangular carbon nanocapsules.


2013 ◽  
Vol 678 ◽  
pp. 46-49 ◽  
Author(s):  
Ponnaian Peula Kumari ◽  
Rachel Oommen ◽  
Chinna Kannaiyan Senthil Kumaran ◽  
Mariyappan Thambidurai ◽  
Natarajan Muthukumarasamy ◽  
...  

Fe and Fe2 O3 nanoparticle have been synthesized by chemical precipitation method. The x-ray diffraction studies indicate the formation of Fe and Fe2 O3 nanoparticles with cubic phase and no secondary phase was observed. Surface morphology of Fe and Fe2 O3 has been studied using scanning electron microscopy (SEM). Transmission electron microscopy (TEM) images reveal that Fe and Fe2 O3 nanoparticle have size ranging from 25-41 nm.


Author(s):  
R. E. Herfert

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.


2020 ◽  
Vol 86 (6) ◽  
pp. 29-35
Author(s):  
V. P. Sirotinkin ◽  
O. V. Baranov ◽  
A. Yu. Fedotov ◽  
S. M. Barinov

The results of studying the phase composition of advanced calcium phosphates Ca10(PO4)6(OH)2, β-Ca3(PO4)2, α-Ca3(PO4)2, CaHPO4 · 2H2O, Ca8(HPO4)2(PO4)4 · 5H2O using an x-ray diffractometer with a curved position-sensitive detector are presented. Optimal experimental conditions (angular positions of the x-ray tube and detector, size of the slits, exposure time) were determined with allowance for possible formation of the impurity phases during synthesis. The construction features of diffractometers with a position-sensitive detector affecting the profile characteristics of x-ray diffraction peaks are considered. The composition for calibration of the diffractometer (a mixture of sodium acetate and yttrium oxide) was determined. Theoretical x-ray diffraction patterns for corresponding calcium phosphates are constructed on the basis of the literature data. These x-ray diffraction patterns were used to determine the phase composition of the advanced calcium phosphates. The features of advanced calcium phosphates, which should be taken into account during the phase analysis, are indicated. The powder of high-temperature form of tricalcium phosphate strongly adsorbs water from the environment. A strong texture is observed on the x-ray diffraction spectra of dicalcium phosphate dihydrate. A rather specific x-ray diffraction pattern of octacalcium phosphate pentahydrate revealed the only one strong peak at small angles. In all cases, significant deviations are observed for the recorded angular positions and relative intensity of the diffraction peaks. The results of the study of experimentally obtained mixtures of calcium phosphate are presented. It is shown that the graphic comparison of experimental x-ray diffraction spectra and pre-recorded spectra of the reference calcium phosphates and possible impurity phases is the most effective method. In this case, there is no need for calibration. When using this method, the total time for analysis of one sample is no more than 10 min.


1995 ◽  
Vol 418 ◽  
Author(s):  
J. Forbes ◽  
J. Davis ◽  
C. Wong

AbstractThe detonation of explosives typically creates 100's of kbar pressures and 1000's K temperatures. These pressures and temperatures last for only a fraction of a microsecond as the products expand. Nucleation and growth of crystalline materials can occur under these conditions. Recovery of these materials is difficult but can occur in some circumstances. This paper describes the detonation synthesis facility, recovery of nano-size diamond, and plans to synthesize other nano-size materials by modifying the chemical composition of explosive compounds. The characterization of nano-size diamonds by transmission electron microscopy and electron diffraction, X-ray diffraction and Raman spectroscopy will also be reported.


2012 ◽  
Vol 600 ◽  
pp. 174-177 ◽  
Author(s):  
Jian Fei Xia ◽  
Zong Hua Wang ◽  
Yan Zhi Xia ◽  
Fei Fei Zhang ◽  
Fu Qiang Zhu ◽  
...  

Zirconia-graphene composite (ZrO2-G) has been successfully synthesized via decomposition of ZrOCl2•6H2O in a water-isopropanol system with dispersed graphene oxide (GO) utilizing Na2S as a precursor could enable the occurrence of the deposition of Zr4+ and the deoxygenation of GO at the same time. Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) techniques were used to characterize the samples. It was found that graphene were fully coated with ZrO2, and the ZrO2 existing in tetragonal phase, which resulted in the formation of two-dimensional composite.


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