Biomimetic synthesis of cellular SiC based ceramics from plant precursor

Abstract

A novel biomimetic approach in designing and fabricating engineering ceramic materials has gained much interest in recent times. Following this approach, synthesis has been made of dense Si-SiC duplex ceramic composites and highly porous SiC ceramics in the image of the morphological features inherent in the caudex stem of a local monocotyledonous plant. The process route involves making of a carbonaceous biopre-form and its subsequent reaction with an infiltrating silicon melt to yield the biomorphic Si-SiC ceramic composites with flexural strength and Young's modulus of 264 MPa and 247 Gpa, respectively and loss in weight of only ∼9% during oxidative heating up to 1200°C in flowing air. The Si-SiC composites were transformed into porous (49 vol.%) SiC ceramics with complete preservation of microcellular anatomy of the parent plant, by depleting residual silicon phase in channel pores through reaction with carbon. SiC based materials so derived can be used in structural applications and in designing high temperature filters and catalyst supports.