Growth of SiC whiskers in the system SiO2-C-H2nucleated by iron

Bootsma, G.A.; Knippenberg, W.F.; Verspui, Göran

doi:10.1016/0022-0248(71)90100-x

Cited by 107 publications

(48 citation statements)

References 10 publications

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“…This may indicate another different formation route. It is well known that SiC whiskers or nanowires are produced according to the vapour-liquidsolid (VLS) mechanism in the presence of metal catalysts, and the driving force for SiC growth by the VLS mechanism is the carbon activity gradient between the VL and LS interfaces [26][27][28]. Reasonably, we suggest that the beaded SiC nanochains are produced via the VLS mechanism.…”

Section: (C)) Electron Energy Loss Spectrum (Eels) Analysis Demonstrmentioning

confidence: 98%

Beaded silicon carbide nanochains via carbothermal reduction of carbonaceous silica xerogel

Hao¹,

Wagner²,

Su³

et al. 2006

Nanotechnology

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Novel silicon carbide nanostructures, beaded nanochains, are prepared from the carbothermal reduction of a carbonaceous silica xerogel with cetyltrimethylammonium bromide and lanthanum nitrate as additives. The nanochains consist of a stem with a diameter of about 50 nm and uniform beads with diameters of 100-200 nm. It is demonstrated that the tensile strength of an epoxy composite filled with the SiC nanochains improves significantly due to the unusual morphology of the nanochains.

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Section: (C)) Electron Energy Loss Spectrum (Eels) Analysis Demonstrmentioning

confidence: 98%

Beaded silicon carbide nanochains via carbothermal reduction of carbonaceous silica xerogel

Hao¹,

Wagner²,

Su³

et al. 2006

Nanotechnology

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“…Several methods and various starting raw materials have been used to grow SiC whiskers. In papers [6,[11][12][13][14], SiC whiskers were formed by the vapour-liquid-solid (VLS) process with transition metals (especially Fe, Co and Ni) as catalysts. This method involves vapour transport of the precursors to a liquid catalyst located at the tip of the whiskers, incorporation of the constituents into the liquid and precipitation of the solid crystal at the liquid-solid interface.…”

Section: Introductionmentioning

confidence: 99%

“…SiC whiskers are nearly single crystals and expected to have very high tensile strengths [6,7], which makes them excellent candidates for reinforcement and toughening of ceramic and glass matrix composites [8][9][10]. Several methods and various starting raw materials have been used to grow SiC whiskers.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of SiC whiskers by VLS and VS process

Zhang

Tronstad

et al. 2016

Ceramics International

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This study investigates the mechanisms of SiC whisker formation in the carbothermal reduction of quartz to SiC in different gas atmospheres. Reduction of quartz by graphite was studied in Ar, H2, and CH4-H2-Ar gas mixture in a laboratory fixed bed reactor. The reduction products were characterised by XRD, SEM and TEM. Whiskers were not formed in the carbothermal reduction of quartz in argon. Two types of SiC whiskers were observed in the carbothermal reduction of quartz in H2 and CH4-H2-Ar gas mixture. In the process of reduction at 1400-1600 °C in H2 and at 1200-1600 °C in CH4-H2-Ar gas mixture, whiskers with hexagonal shape with diameter 100-800 nm and length up to tens of microns were formed by the VLS mechanism under catalytic effect of iron. The whiskers with the characteristics of cylindrical shape and high aspect ratio were synthesized in CH4-H2-Ar gas mixture at 1400-1600 °C by VS mechanism. Disciplines Engineering | Science and Technology Studies AbstractThis study investigates the mechanisms of SiC whisker formation in the carbothermal reduction of quartz to SiC in different gas atmospheres. Reduction of quartz by graphite was studied in Ar, H 2 , and CH 4 -H 2 -Ar gas mixture in a laboratory fixed bed reactor. The reduction products were characterised by XRD, SEM and TEM. Whiskers were not formed in the carbothermal reduction of quartz in argon. Two types of SiC whiskers were observed in the carbothermal reduction of quartz in H 2 and CH 4 -H 2 -Ar gas mixture. In the process of reduction at 1400-1600 o C in H 2 and at 1200-1600 °C in CH 4 -H 2 -Ar gas mixture, whiskers with hexagonal shape with diameter 100-800 nm and length up to tens of microns were formed by the VLS mechanism under catalytic effect of iron. The whiskers with the characteristics of cylindrical shape and high aspect ratio were synthesized in CH 4 -H 2 -Ar gas

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“…These whiskers were thick and straight, grown on the iron-rich globule, suggesting that they were formed through Reaction [17] by a vapor-liquid-solid (VLS) mechanism. [24,[28][29][30] The iron was originated from impurities in quartz and contamination of a pellet in the process of pressing with stainless steel die. [24] The rest SiC was in the form of irregular particles and flakes, similar to the structure in Figure 11(b).…”

Section: þ; ½14mentioning

confidence: 99%

Carbothermal Reduction of Quartz in Methane–Hydrogen–Argon Gas Mixture

Zhang

Tang

et al. 2015

Metall Mater Trans B

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Synthesis of silicon carbide (SiC) by carbothermal reduction of quartz in a CH4-H2-Ar gas mixture was investigated in a laboratory fixed-bed reactor in the temperature range of 1573 K to 1823 K (1300 °C to 1550°C). The reduction process was monitored by an infrared gas analyser, and the reduction products were characterized by LECO, XRD, and SEM. A mixture of quartz-graphite powders with C/SiO2 molar ratio of 2 was pressed into pellets and used for reduction experiments. The reduction was completed within 2 hours under the conditions of temperature at or above 1773 K (1500 °C), methane content of 0.5 to 2 vol pct, and hydrogen content ≥70 vol pct. Methane partially substituted carbon as a reductant in the SiC synthesis and enhanced the reduction kinetics significantly. An increase in the methane content above 2 vol pct caused excessive carbon deposition which had a detrimental effect on the reaction rate. Hydrogen content in the gas mixture above 70 vol pct effectively suppressed the cracking of methane. Carbothermal Reduction of Quartz in MethaneHydrogen-Argon Gas Mixture XIANG LI, GUANGQING ZHANG, KAI TANG, OLEG OSTROVSKI, and RAGNAR TRONSTAD Synthesis of silicon carbide (SiC) by carbothermal reduction of quartz in a CH 4 -H 2 -Ar gas mixture was investigated in a laboratory fixed-bed reactor in the temperature range of 1573 K to 1823 K (1300°C to 1550°C). The reduction process was monitored by an infrared gas analyser, and the reduction products were characterized by LECO, XRD, and SEM. A mixture of quartz-graphite powders with C/SiO 2 molar ratio of 2 was pressed into pellets and used for reduction experiments. The reduction was completed within 2 hours under the conditions of temperature at or above 1773 K (1500°C), methane content of 0.5 to 2 vol pct, and hydrogen content ‡70 vol pct. Methane partially substituted carbon as a reductant in the SiC synthesis and enhanced the reduction kinetics significantly. An increase in the methane content above 2 vol pct caused excessive carbon deposition which had a detrimental effect on the reaction rate. Hydrogen content in the gas mixture above 70 vol pct effectively suppressed the cracking of methane.

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Growth of SiC whiskers in the system SiO2-C-H2nucleated by iron

Cited by 107 publications

References 10 publications

Beaded silicon carbide nanochains via carbothermal reduction of carbonaceous silica xerogel

Beaded silicon carbide nanochains via carbothermal reduction of carbonaceous silica xerogel

Synthesis of SiC whiskers by VLS and VS process

Carbothermal Reduction of Quartz in Methane–Hydrogen–Argon Gas Mixture

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