THE EFFECT OF PROCESSING PARAMETERS ON SOL GEL SYNTHESIS OF β-SiC NANO POWDER

Mono dispersed nano SiC particles with spherical morphology were synthesized in this project by hydrolysis and condensation mechanism during sol gel processing. pH, temperature and precursor’s ratio considered as the main parameters which could influence particles size. According to DLS test results, the smallest size of particles in the sol (<۵nm) was obtained at pH<۴. It can be observed from rheology test results optimum temperature for achieving nanometeric gel is about ۶۰ ˚C. The optimum pH values for sol stabilization was (۲-۵) determined by zeta potentiometery. Si ۲۹NMR analysis was used in order to get more details on final structure of gel powders resulted from initial sol. X-ray diffraction studies showed sythesized powder consists of β-SiC phase. Scanning electron microscopy indicated agglomerates size in β-SiC synthesis is less than ۱۰۰ nm. Finally, TEM studies revealed morphology of β-SiC particles treated in ۱۵۰۰˚C and after ۱hr aging is spherical with (۲۰-۳۰) nm size

Keywords:

carbides , nanostructures , sol-gel chemistry , nuclear magnetic resonance (NMR) , microstructure.