Nanowire‐decorated SiC foam from tissue paper and silicon powder by filter‐pressing

Abstract

A facile and scalable method for the preparation of low‐density SiC foam from tissue paper and silicon powder is reported. The co‐dispersion of pulp‐containing tissue paper micro‐ribbons and silicon powder is coagulated by adjusting the pH to 3.5. The silicon particles adhere to the tissue paper micro‐ribbons during the coagulation. The coagulated co‐dispersion on filter‐pressing consolidates the silicon particle‐decorated tissue paper micro‐ribbons and orients them perpendicular to the filter‐pressing direction. The filter‐pressed body on drying followed by heat treatment at 1600°C in inert atmosphere produces SiC foam. The tissue paper micro‐ribbons retain their morphology during carbonization as well as high‐temperature reaction with the silicon. The enormous growth of carbon‐rich SiC nanowires is observed on the SiC micro‐ribbons. The random orientation of SiC micro‐ribbons in the X‐Y plane with the hairy nanowires on the surface and their stacking in the Z‐direction produces a porosity of ~94 vol.% with pore sizes in the range of 0.08 to 20 µm. The SiC foam shows a compressive strength and Young's modulus of 0.22 and 5.5 MPa, respectively. The thermal conductivity decreases from 0.11 to 0.07 W m−1 K−1 when temperature increases from 25°C to 350°C.

In situ growth of SiC wires on CVI densification of SiC foam

“…17 Wilson et al reported the formation of nanowire-decorated SiC foam from tissue paper and silicon powder by filter-processing technique. 18 Lee et al reported the carbothermal reduction process using a mixture of SiO 2 , carbon black, and phenolic resin to produce a porous SiC filter with SiC nanowires in the honeycomb structure. 19 Li et al reported SiC nanowire aerogel by polymer pyrolysis chemical vapor deposition (CVD) process in the pores of carbon foam.…”

“…Wilson et al. reported the formation of nanowire‐decorated SiC foam from tissue paper and silicon powder by filter‐processing technique 18 . Lee et al.…”