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

Mono dispersed nano sic particles with spherical morphology were synthesized in this project by hydrolysisand condensation mechanism during sol gel processing. ph, temperature and precursor’s ratio considered as the mainparameters which could influence particles size. according to dls test results, the smallest size of particles in the sol( < 5nm) was obtained at ph < 4. it can be observed from rheology test results optimum temperature for achievingnanometeric gel is about 60 ?c. the optimum ph values for sol stabilization was (2-5) determined by zetapotentiometery. si29 nmr analysis was used in order to get more details on final structure of gel powders resulted frominitial sol. x-ray diffraction studies showed sythesized powder consists of b-sic phase. scanning electron microscopyindicated agglomerates size in b-sic synthesis is less than 100 nm. finally, tem studies revealed morphology of b-sic particles treated in 1500?c and after 1hr aging is spherical with (20-30) nm size.