Low-temperature Magnesiothermic Synthesis of Mesoporous Silicon Carbide from an MCM-48/Polyacrylamide Nanocomposite Precursor

Saeedifar, Zahra; Nourbakhsh, Amir Abbas; Kalbasi, Roozbeh Javad; Karamian, Ebrahim

doi:10.1016/j.jmst.2013.01.007

Cited by 23 publications

(10 citation statements)

References 26 publications

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“…Mesoporous silica and mesoporous SiC have similar Brunauer–Emmett–Teller data, as previously reported (total pore volume, average pore diameter, and BET surface area of 0.7 or 0.5 cm 3 /g, 2.2 or 5.81 nm, and 1200 or 331 m 2 /g, respectively) . High‐energy ball milling was carried out in a planetary ball mill at 600 rpm using a ball/powder mass ratio of 55:1 (total powder mass = 2–4 g).…”

Section: Methodssupporting

confidence: 55%

A New Route to High Yield Mesostructure Boron Carbide Powder from SiC/Si₃N₄ Whiskers

Saeedifar

2017

J Chinese Chemical Soc

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Boric acid/Mg (magnesiothermic or metal sintering aid)/C (activated carbon)/N 2 or Ar (atmosphere)/ additives (mesoporous SiO 2 or mesoporous SiC or SiC/Si 3 N 4 whiskers) systems were used in the onestep synthesis of mesostructured B 4 C (221.04 m 2 /g). In this study, a mixture of the active precursors was allowed to react via a self-sustaining reaction (high-energy ball milling process). Also, the properties of the samples prepared using powdered activated carbon (PAC) and SiC/Si 3 N 4 whiskers (concentration in the range 5-10 wt%) as sources of carbon were investigated. X-ray diffraction results proved the presence of crystalline boron carbide in the peak positions of B 4 C (B 12 C 3 ). The advantage of the present route for yielding mesostructured B 4 C powder seems to be limited by the growth of carbide crystals. This restriction is believed to be imposed by a lack of whisker additives around the pores where B 4 C crystals grow. The results also show that the best mesoporous additive for the synthesis of nanoscale boron carbide is mesoporous SiC. The effect of the concentration of CO (reduction of α-Fe 2 O 3 to Fe by CO) on the B 4 C synthesis suggests that, in addition to the concentration of CO, the pressure of the N 2 atmosphere is an important factor in the synthesis of mesostructured B 4 C.

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Section: Methodssupporting

confidence: 55%

A New Route to High Yield Mesostructure Boron Carbide Powder from SiC/Si₃N₄ Whiskers

Saeedifar

2017

J Chinese Chemical Soc

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“…Synthesis process of SiC was similar to other reported (20,21) with the new input of using silica synthesized via sol-gel as a silicon source.…”

Section: Synthesis Of Sio 2 /C and Sicmentioning

confidence: 61%

“…Most common processes to obtain SiC need high temperatures, around 1150-1500°C (10-17), using different techniques as "nanocasting" (10,11), sol-gel (12)(13), molten salts (14), carbothermic reduction (15)(16)(17) and low temperature processes as magnesiothermic reduction method (18)(19)(20)(21); these methods use different materials as silicon precursors: SiO 2 (9,10,16-18), TEOS (12,13); and carbon: polycarbosilane (10,11), phenolic resine (12,13) graphite (17), resorcinol-formaldehyde (18,19).…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Characterization of Silicon Carbide in the Application of High Temperature Solar Surface Receptors

et al. 2014

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The use of ceramic surfaces for thermal solar concentrators are not new, but the high costs of fabrication and limited thermal properties have banned the application of such at large scale. Silicon carbide (SiC) is well known due to its high thermo-mechanical properties and spectral absorbance. Because of its capacities to enhance the energy transfer and its resistance to high temperatures silicon carbide have been recognized in our group as a possible improvement to increase the efficiency of electric energy production. At nano-scale SiC shows high surface area and porosity that could be tuned, making it a state-of-the-art material to be used in the application of thermal solar receptors in "Central Tower" power plants. Although the advantages are favorable, the high temperature needs for its synthesis have been an issue for its spread. In the present work, we introduce a novel method to synthesize SiC powders at lower temperature (650°C) we present also its characterization for the potential application in the concentration of thermal solar energy at high temperatures.

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“…Silicon carbide (or silicon nitride) can be produced by several methods including the reaction of elemental Si and C (or N 2 ), carbothermic reduction of SiO 2 (or SiO 2 /N 2 ), and metallothermic reduction of SiO 2 /C . Saeedifar and Karamian prepared mesoporous silicon carbide by in situ polymerization of acrylamide monomers inside the pores of mesoporous MCM‐48 (magnesiothermic reduction) for the first time. Wang and Fischman grew SiC whiskers by the carbothermal reduction of Si 3 N 4 in Ar atmosphere (1700°C/2 h).…”

Section: Introductionmentioning

confidence: 99%

Fabrication of SiC and Si₃N₄Whiskers under Pressurized Ar and N₂Atmosphere through High-Energy Ball Milling

Saeedifar

Saeedifar²

2017

Journal of the Chinese Chemical Society

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SiO 2(activated or mesoporous silica) /Mg (magnesiothermic or metal sintering aid) /C (activated or polymeric carbon) / N 2(atmosphere) systems were used in the one-step synthesis of β-SiC and β-Si 3 N 4 whiskers. In this study, a mixture of the active precursors was allowed to react via a self-sustaining reaction (highenergy ball milling process). Scanning electron micrographs and X-ray diffraction (XRD) analysis showed that the rod-like SiC whiskers (~800 μm) were synthesized in situ by the direct carbothermal reduction of silicon nitride (or silicon) with activated carbon in N 2 (or Ar) atmosphere. The results show that β-Si 3 N 4 (without β-SiC) was fully formed after 5 h of milling with four different morphologies, namely whisker tip (droplet/no droplet) and nonuniform whiskers (short hexagonal/ rhombohedral/rod-like) with a length of 0.1-400 μm. By adding metal sintering aids, the liquid phase Mg-Si-O-N and the rate of carbothermal reduction increased (enhanced densification via particle rearrangement) and their hexagonal whiskers tended to assume a rod-like shape. The effect of the concentration of CO (reduction of α-Fe 2 O 3 to Fe by CO) on the whisker synthesis suggests that, in addition to the concentration of CO, the nature of the family of mesoporous silica/carbon template is an important factor in the synthesis of β-SiC and β-Si 3 N 4 whiskers. The possible chemical reactions were investigated by studying the unwanted phases (MgO

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Low-temperature Magnesiothermic Synthesis of Mesoporous Silicon Carbide from an MCM-48/Polyacrylamide Nanocomposite Precursor

Cited by 23 publications

References 26 publications

A New Route to High Yield Mesostructure Boron Carbide Powder from SiC/Si₃N₄ Whiskers

A New Route to High Yield Mesostructure Boron Carbide Powder from SiC/Si₃N₄ Whiskers

Synthesis and Characterization of Silicon Carbide in the Application of High Temperature Solar Surface Receptors

Fabrication of SiC and Si₃N₄Whiskers under Pressurized Ar and N₂Atmosphere through High-Energy Ball Milling

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Low-temperature Magnesiothermic Synthesis of Mesoporous Silicon Carbide from an MCM-48/Polyacrylamide Nanocomposite Precursor

Cited by 23 publications

References 26 publications

A New Route to High Yield Mesostructure Boron Carbide Powder from SiC/Si3N4 Whiskers

A New Route to High Yield Mesostructure Boron Carbide Powder from SiC/Si3N4 Whiskers

Synthesis and Characterization of Silicon Carbide in the Application of High Temperature Solar Surface Receptors

Fabrication of SiC and Si3N4Whiskers under Pressurized Ar and N2Atmosphere through High-Energy Ball Milling

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A New Route to High Yield Mesostructure Boron Carbide Powder from SiC/Si₃N₄ Whiskers

A New Route to High Yield Mesostructure Boron Carbide Powder from SiC/Si₃N₄ Whiskers

Fabrication of SiC and Si₃N₄Whiskers under Pressurized Ar and N₂Atmosphere through High-Energy Ball Milling