Synthesis of Silicon Carbide Nanopowder Using Silica Fume

Abstract

Silica fume is a byproduct of producing silicon metal and ferrosilicon alloys, and contains 94–97 wt% SiO2. This study demonstrates, for the first time, that silica fume can be converted to nano‐SiC powder at 1500°C via carbothermic reduction with the aid of high‐energy ball milling of the silica fume plus graphite mixture at room temperature. The nano‐SiC synthesized has particle sizes as small as 30 nm. The effects of the carbothermic reduction temperature and the graphite concentration in the starting SiO2+C mixture on the conversion of SiO2 to SiC have been investigated. The reaction pathways of carbothermic reduction have been identified. A carbon elimination treatment using H2 to remove the free carbon in the nano‐SiC powder has also been proven effective and the extent of carbon elimination depends on the reaction temperature, reaction duration, and quantity of the free carbon present before the carbon elimination treatment.

Preparation of SiC nanowires-filled cellular SiCO ceramics from polymeric precursor

“…However, the irregularly shaped particles were not observed on the surface of the SiCO ceramic. It is a reasonable assumption that the particles can react with residual carbon or CO. Zhong et al reported different reaction pathways of carbothermic reduction from silica [35]. It is well accepted that SiC formation from carbothermic reduction occurs through the following overall reaction (1).…”

Synthesis and characterization of SiC and SiC/Si3N4 composite nano powders from waste material

“…Nano SiC have been studied intensively for high temperature structural applications, such as turbine and automobile engine components and heat exchangers, as well as energy applications [11,12]. Recently, using a process called as the integrated mechanical and thermal activation (IMTA) process, nano-SiC and SiC/Si 3 N 4 nanocomposite have been produced from silica fume at 1500 • C [13][14][15][16][17]. Since rice husk contains a higher silica content (15-20 wt.%), it should also be a promising material for producing nano SiC powder to reduce the cost of the starting raw materials, also while attaining the powder with nanostructures for advanced technology applications.…”

“…(i) cooking at lower temperature (400-800 • C) in a controlled manner to remove volatiles and (ii) reacting the cooked rice husk at high temperature (>1300 • C) to form SiC [1,[4][5]. The potential feature of rice husk is their high silica content (15)(16)(17)(18)(19)(20) wt.%) with small amount of alkalis and trace elements [6,7]. Heating the husks produces amorphous carbon as by-product of cellulose carbonization, while silica remains unchanged.…”

Tailoring the Relative Si3N4 and SiC Contents in Si3N4/SiC Nanopowders through Carbothermic Reduction and Nitridation of Silica Fume

“…Although most of the processes resulted in highly uniform and homogeneously distributed composites, most of them require expensive starting materials or high cost equipment. Recently, using a process called as the integrated mechanical and thermal activation (IMTA) process, nano‐SiC has been produced from silica fume by subjecting the mixture of silica fume + graphite to carbothermal reduction and nitridation at 1500°C . The current method of production of nanostructured Si 3 N 4 /SiC composite powders differs from conventional carbothermal reduction and nitridation, in that the starting raw materials, silica fume and graphite, are mechanically activated at room temperature before subjecting them to the high‐temperature synthesis reaction.…”

“…Recently, using a process called as the integrated mechanical and thermal activation (IMTA) process, nano-SiC has been produced from silica fume by subjecting the mixture of silica fume + graphite to carbothermal reduction and nitridation at 1500°C. 23 The current method of production of nanostructured Si 3 N 4 / SiC composite powders differs from conventional carbothermal reduction and nitridation, 24 in that the starting raw materials, silica fume and graphite, are mechanically activated at room temperature before subjecting them to the high-temperature synthesis reaction. Due to the mechanical activation at ambient temperature, the IMTA process substantially reduces the reaction time and temperature required for the reaction, in addition to utilizing low cost starting raw materials.…”