Fabrication of SiC by Carbothermal-Reduction Reactions of Sepiolite

2007 ◽  
Vol 555 ◽  
pp. 261-265 ◽  
Author(s):  
A. Devečerski ◽  
A. Radosavljević-Mihajlović ◽  
A. Egelja ◽  
M. Pošarac ◽  
B. Matović
Keyword(s):  
Silicon Carbide ◽  
Carbothermal Reduction ◽  
Phase Evolution ◽  
Reducing Agent ◽  
Phase Content ◽  
Reduction Reactions ◽  
Effective Source

The objective of this manuscript was to investigate the synthesis of SiC by carbothermal– reduction reactions of sepiolite. Sepiolite of Serbian origin and carbon (from various precursors) as a reducing agent were used. The green bodies with various C/SiO2 ratios were carbonized at 1073 K and heattreated at 1673 K in a controlled Ar flow atmosphere. Phase evolution and phase content were followed as a function of C/SiO2 ratio and carbon origin. The starting materials and products were characterized by means of XRD and SEM. The results show that sepiolite can be very effective source for obtaining silicon carbide powders.

scholarly journals Synthesis of Silicon Carbide Powders from Methyl-Modified Silica Aerogels

2020 ◽  
Vol 10 (18) ◽  
pp. 6161
Author(s):  
Kyoung-Jin Lee ◽  
Yanggu Kang ◽  
Young Hun Kim ◽  
Se Won Baek ◽  
Haejin Hwang
Keyword(s):  
Silicon Carbide ◽  
High Purity ◽  
Silica Aerogel ◽  
Carbothermal Reduction ◽  
Single Phase ◽  
Phase Evolution ◽  
Silica Aerogels ◽  
Methyl Groups ◽  
Modified Silica ◽  
Lower Temperature

β-silicon carbide (SiC) powders were synthesized by the carbothermal reduction of methyl-modified silica aerogel/carbon mixtures. The correlations between the phase evolution and morphologies of the SiC powders and the C/SiO2 ratio were investigated. At a C/SiO2 ratio of 3, β-SiC formed at 1425 °C and single-phase SiC powders were obtained at 1525 °C. The methyl groups (-CH3) on the silica aerogel surfaces played important roles in the formation of SiC during the carbothermal reduction. SiC could be synthesized from the silica aerogel/carbon mixtures under lower temperature and C/SiO2 ratios than those needed for quartz or hydrophilic silica. The morphology of the SiC powder depended on the C/SiO2 ratio. A low C/SiO2 ratio resulted in β-SiC powder with spherical morphology, while agglomerates consisting of fine SiC particles were obtained at the C/SiO2 ratio of 3. High-purity SiC powder (99.95%) could be obtained with C/SiO2 = 0.5 and 3 at 1525 °C for 5 h.

scholarly journals Carbonitriding reactions of diatomaceous earth: phase evolution and reaction mechanisms

2006 ◽  
Vol 71 (6) ◽  
pp. 677-683 ◽  
Author(s):  
Branko Matovic ◽  
Aleksandra Saponjic ◽  
Snezana Boskovic
Keyword(s):  
Reaction Mechanisms ◽  
Carbothermal Reduction ◽  
Diatomaceous Earth ◽  
Phase Evolution ◽  
Raw Material ◽  
Low Temperature Synthesis ◽  
Temperature Synthesis ◽  
X Ray ◽  
Oxide Powders ◽  
Effective Source

The possibility of using diatomaceous earth as Si precursor for low temperature synthesis of non-oxide powders by carbothermal reduction-nitridation was studied. It was found that carbonitriding reactions produce phases of the Si-Al-O-N system. Already at 1300 ?C, nanosized non-oxide powders were obtained. The comparatively low reaction temperatures is attributred to the nano-porous nature of the raw material. The evolution of crystalline phases proceeded via many intermediate stages. The powders were characterized by X-ray and SEM investigations. The results showed that diatomaceous earth can be a very effective source for obtaining non-oxide powders.

scholarly journals Fabrication of ZrC/SiC, ZrO2/SiC and ZrO2 powders by carbothermal reduction of ZrSiO4

2011 ◽  
Vol 5 (2) ◽  
pp. 103-112 ◽  
Author(s):  
Ljiljana Kljajevic ◽  
Branko Matovic ◽  
Snezana Nenadovic ◽  
Zvezdana Bascarevic ◽  
Nikola Cveticanin ◽  
...  
Keyword(s):  
Carbothermal Reduction ◽  
Phase Evolution ◽  
Ex Situ ◽  
Phase Content ◽  
X Ray Diffraction ◽  
Natural Mineral ◽  
X Ray ◽  
Eds Analysis ◽  
Zircon Powder ◽  
Controlled Flow

The zirconia/silicon carbide (ZrO2 /SiC) and ZrO2 powders are prepared by carbothermal reduction of natural mineral zircon (ZrSiO4). The zircon powder was mixed with activated carbon as a reducing agent and heattreated in a controlled flow atmosphere of Ar. Phase evolution and phase content were followed as a function of temperature (1573-1973 K) and C/ZrSiO4 ratio (C/ZrSiO4 = 1, 4, 5 and 7), by means of ex-situ X-ray diffraction and SEM/EDS analysis. By varying the temperature and C/ZrSiO4 ratio, different powder compositions were obtained (m-ZrO2; m-ZrO2/c-ZrO2; c-ZrO2; c-ZrO2/SiC). .

Fabrication of Silicon Carbide from Rice Husk by Carbothermal-Reduction and In Situ Reaction Bonding Technique

2014 ◽  
Vol 608 ◽  
pp. 235-240 ◽  
Author(s):  
Chalermkwan Makornpan ◽  
Charusporn Mongkolkachit ◽  
Suda Wanakitti ◽  
Thanakorn Wasanapiarnpong
Keyword(s):  
Silicon Carbide ◽  
Rice Husk ◽  
Carbothermal Reduction ◽  
Nitrogen Atmosphere ◽  
Silicon Oxynitride ◽  
Reaction Bonding ◽  
Silicon Carbide Particle ◽  
Silicon Carbide Whisker ◽  
Sic Ceramics

Silicon carbide (SiC) ceramics were prepared by carbothermal reduction together with in-situ reaction bonding. Raw rice husk was carbonized in an incineration furnace. The carbonized rice husk was ground and was then treated with hydrochloric acid by varying concentrations. The sample powders were mixed with silicon metal powder and pyrolyzed at various temperatures in either argon or nitrogen atmosphere. Silicon carbide phase was found in all pyrolyzed samples. Cristobalite was found in argon atmosphere pyrolyzed samples while silicon oxynitride was found in the samples pyrolyzed in nitrogen atmosphere at lower than 1500 °C. Silicon carbide whisker is the main phase on the surface of pyrolyzed sample. Increasing pyrolysis temperatures decreased the amount and size of silicon carbide whisker but increased the silicon carbide particle. Porosity and weight loss of samples after pyrolysis were increased with increasing temperatures due to the reaction in the system.

Biomorphic SiC Prepared from Carbonized Millet by Sol-Gel and Carbothermal Reduction Processing

2010 ◽  
Vol 152-153 ◽  
pp. 1683-1686
Author(s):  
Qing Wang ◽  
Ya Hui Zhang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Silicon Carbide ◽  
Phase Composition ◽  
Carbothermal Reduction ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Carbon Template ◽  
Scanning Electron

Biomorphic silicon carbide (bioSiC) was prepared by high temperature pyrolysis and sol-gel and carbothermal reduction processing at 1600 oC. The morphology and microstructure of carbon-silica composites and purified bioSiC samples were characterized by scanning electron microscopy. The phase composition of the resulting sample was analyzed by X-ray diffraction. The results suggest that the bioSiC mainly consists of cubic ß-SiC, and principally replicates the shape and microstructure of the carbon template.

Synthesis of Biomorphic Silicon Carbide from Wood

2008 ◽  
Vol 1094 ◽  
Author(s):  
Kwok Cheung Li ◽  
Dickon H. L. Ng
Keyword(s):  
Silicon Carbide ◽  
Carbothermal Reduction ◽  
Wood Sample ◽  
Sol Gel ◽  
Reduction Process ◽  
Delonix Regia ◽  
Specific Strength ◽  
Sic Ceramics ◽  
Gel Technique

AbstractWe have successfully produced biomorphic SiC ceramics from silica-infiltrated wood samples of balsa (Ochroma pyramidale) and flame tree (Delonix regia). This conversion of wood sample to a structure of SiC was performed by a sol-gel technique and a carbothermal reduction process. The biomorphic products were confirmed containing β-SiC and their structures were replica of the original structures of the raw wood samples. The biomorphic products from the denser flame tree (C-SiC) had higher specific strength than that from the biomorphic product from balsa (SiC).

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