Crystalline silicon oxycarbide: Is there a native oxide for silicon carbide?

2004 ◽  
Vol 84 (24) ◽  
pp. 4845-4847 ◽  
Author(s):  
Cesar R. S. da Silva ◽  
João F. Justo ◽  
Inés Pereyra
1991 ◽  
Vol 6 (12) ◽  
pp. 2723-2734 ◽  
Author(s):  
Gary M. Renlund ◽  
Svante Prochazka ◽  
Robert H. Doremus

Silicon oxycarbide glass is formed by the pyrolysis of silicone resins and contains only silicon, oxygen, and carbon. The glass remains amorphous in x-ray diffraction to 1400 °C and shows no features in transmission electron micrographs (TEM) after heating to this temperature. After heating at higher temperature (1500–1650 °C) silicon carbide lines develop in x-ray diffraction, and fine crystalline regions of silicon carbide and graphite are found in TEM and electron diffraction. XPS shows that silicon-oxygen bonds in the glass are similar to those in amorphous and crystalline silicates; some silicons are bonded to both oxygen and carbon. Carbon is bonded to either silicon or carbon; there are no carbon-oxygen bonds in the glass. Infrared spectra are consistent with these conclusions and show silicon-oxygen and silicon-carbon vibrations, but none from carbon-oxygen bonds. 29Si-NMR shows evidence for four different bonding groups around silicon. The silicon oxycarbide structure deduced from these results is a random network of silicon-oxygen tetrahedra, with some silicons bonded to one or two carbons substituted for oxygen; these carbons are in turn tetrahedrally bonded to other silicon atoms. There are very small regions of carbon-carbon bonds only, which are not bonded in the network. This “free” carbon colors the glass black. When the glass is heated above 1400 °C this network composite rearranges in tiny regions to graphite and silicon carbide crystals. The density, coefficient of thermal expansion, hardness, elastic modulus, index of refraction, and viscosity of the silicon oxycarbide glasses are all somewhat higher than these properties in vitreous silica, probably because the silicon-carbide bonds in the network of the oxycarbide lead to a tighter, more closely packed structure. The oxycarbide glass is highly stable to temperatures up to 1600 °C and higher, because oxygen and water diffuse slowly in it.


2006 ◽  
Vol 21 (10) ◽  
pp. 2550-2563 ◽  
Author(s):  
Maxime J-F. Guinel ◽  
M. Grant Norton

The oxidation of both single crystal and relatively pure polycrystalline silicon carbide, between 973 and 2053 K, resulted in the formation of cristobalite, quartz, or tridymite, which are the stable crystalline polymorphs of silica (SiO2) at ambient pressure. The oxide scales were found to be pure SiO2 with no contamination resulting from the oxidizing environment. The only variable affecting the occurrence of a specific polymorph was the oxidation temperature. Cristobalite was formed at temperatures ≥1673 K, tridymite between 1073 and 1573 K, and quartz formed at 973 K. The polymorphs were determined using electron diffraction in a transmission electron microscope. These results were further confirmed using infrared and Raman spectroscopies. Cristobalite was observed to grow in a spherulitic fashion from amorphous silica. This was not the case for tridymite and quartz, which appeared to grow as oriented crystalline films. The presence of a thin silicon oxycarbide interlayer was detected at the interface between the SiC substrate and the crystalline silica using x-ray photoelectron spectroscopy.


1994 ◽  
Vol 339 ◽  
Author(s):  
L. Rimai ◽  
R. Ager ◽  
W. H. Weber ◽  
J. Hangas ◽  
B. D. Poindexter

ABSTRACTSilicon carbide films are grown epitaxially on crystalline silicon substrates heated above 1000 °C, by laser ablation of pure carbon targets to thicknesses between 300 and 400 nm. These films grow on top of the silicon substrate from the carbon in the ablation plume and from the silicon of the substrate. By using a method of alternate ablation of a pure carbon and a pure silicon target, similar epitaxial films can be grown to thicknesses in excess of 1 μm with part of the silicon being supplied by the ablation plume of the silicon target.


2018 ◽  
Vol 912 ◽  
pp. 141-146 ◽  
Author(s):  
Glauson Aparecido Ferreira Machado ◽  
Rosa Maria Rocha ◽  
Ana Helena Almeida Bressiani

Alumina-mullite composites with low shrinkage can be made by reaction bond using mixtures of alumina, aluminum and silicon carbide. In this work, an alternative route is used to produce alumina composites with low shrinkage. Here alumina samples containing additions of 10 and 20 wt% of a preceramic polymer were warm-pressed and treated in the range of 900 -1500°C to produce alumina based composites. The obtained composites were analyzed by linear shrinkage and compared to pure alumina samples sintered at the same temperature range. It were also evaluated the density variation and crystalline phases formed during heat treatment of alumina composites. Results showed that alumina-silicon oxycarbide and alumina-mullite composites were obtained with lower shrinkage than pure alumina samples.


ACS Nano ◽  
2019 ◽  
Vol 13 (10) ◽  
pp. 11572-11581 ◽  
Author(s):  
Hoang-Phuong Phan ◽  
Yishan Zhong ◽  
Tuan-Khoa Nguyen ◽  
Yoonseok Park ◽  
Toan Dinh ◽  
...  

2015 ◽  
Vol 15 (2) ◽  
pp. 1660-1668 ◽  
Author(s):  
Huan Zhang ◽  
Weiqiang Ding ◽  
Daryush K. Aidun

2020 ◽  
Vol 101 ◽  
pp. 107625
Author(s):  
Debarati Mukherjee ◽  
Filipe Oliveira ◽  
Simone Camargo Trippe ◽  
Shlomo Rotter ◽  
Miguel Neto ◽  
...  

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