A study on the effects of silica particle size and milling time on synthesis of silicon carbide nanoparticles by carbothermic reduction

Silicon carbide nanoparticles were produced by a carbothermic reduction of nano and micro size silica with graphite at 1450 °C for 1 h. The SiC nanoparticles were characterized by XRD, SEM and TEM. The results showed that in the case of nano silica, milling up to 20 h could develop SiC particles of 5–25 nm with some residual SiO2 particles. By extending milling time to 40 h, more energy was provided and produced Fe contamination, which could act as catalyst and increased SiC yield as well as Fe2Si phase formation after heat treatment. Coarser particles of micro silica caused higher Fe erosion, more SiC formation with 20–70 nm size and presence of Fe2Si phase at shorter milling times after heat treatment. Leaching treatment could purify SiC nanoparticles. Increase of milling from 20 to 40 h changed the morphology from polygonal shape to spherical with some reduction in the particle size.

Graphical abstractSilicon carbide (SiC) nanoparticles were produced by a carbothermic reduction of nano and micro size silica (SiO2) with graphite at relatively low temperature of 1450 °C for 1 h. The particle size of silica and milling time were important parameters determining the rate of carbothermic reduction and size and morphology of SiC particles produced. The SiC nanoparticles were between 5 and 25 nm by using nano silica and were in the range of 20–70 nm by using micro silica.Figure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights► SiC nanoparticles were synthesized by silica with graphite at 1450 °C for 1 h. ► Fe contamination during milling act as catalyst and increased SiC yield. ► Leaching treatment led to leaving behind single phase SiC nanoparticles. ► Size of SiO2 and milling time affected on the size and morphology of SiC. ► SiC from micro silica and nano silica were 20–70 and 5–25 nm, respectively.