Abstract

In this study, as-received diatomite from Turkish origin was used as a silica (SiO2) precursor in the synthesis of silicon carbide (SiC) powders. Carbon black, used as reducing agent, was mixed with grinded diotomite with constant C/SiO2 molar ratio of 4. Mixed powders were subjected to carbothermal-reduction reaction (CRR) process at temperatures of 1450, 1500 and 1550°C for 1 h. The CRR processes were conducted in atmosphere-controlled tube furnace under argon flow of 5 cm3/min. After CRR, resultant powder products have been characterized via XRD and SEM-EDX to determine the transformation and morphology. The results show that high purity β-SiC powders with equiaxed grains can be synthesised from diatomite at all these temperatures for 1 h. The best transformation of SiC was carried out at 1550°C for 1 h and its average grain size is less than 200 nm.

Key words: Carbothermal-reduction reaction (CRR), characterisation, clay mineral, diatomite, silicon carbide (SiC), synthesising method.