Processing of vermiculite-silica composites with prefer-oriented rod-like pores

Abstract

Vermiculite-silica composites with a layered structure were fabricated by adding cellulose fibers as a pore former and by a simple uniaxial pressing and subsequent sintering process. Three different combinations of additives were used and their effects on the compressive strength and thermal conductivity of the composites were investigated. Both compressive strengths (42-128 MPa) and thermal conductivities (0.75-1.48 W/m· K) in the direction perpendicular to the pressing direction (T) were higher than those (19-81 MPa and 0.32-1.04 W/m·K) in the direction parallel to the pressing direction (S) in all samples. The anisotropy in both properties was attributed to the microstructural anisotropy, which was caused by the layered structure developed in the composites.