Biomorphic SiC: porous SiC and ultrafine SiC powder formation through biomimicking route

Natural wood is a ready-to-use template for making porous silicon carbide (SiC) body. Biomorphic beta-SiC was synthesised from wood of a mango (Mangifera Indica) tree. Carbon template was made by carbonising this wood at 1000 degrees C in argon gas atmosphere. Thus formed template was repeatedly infiltrated with a mixture of tetraethyl-orthosilicate (TEOS) (in alcohol) and oxalic acid solution (aqueous). Heat treatment at 1600 degrees C for 1 h in vacuum converted the infiltrated template to beta-SiC with a complex hierarchical cellular structure- a mimic of the plant structure. To produce phase pure SiC, unreacted carbon (C) and silica (SiO2) (if any) were removed by burning in air followed by treating with hydrofluoric acid. Mono dispersed SiC powder having particle size of similar to 225 nm has been obtained by crushing, grinding and milling of thus formed biomorphic SiC body. A grinding limit is reported for the first time in SiC system.