Thermal conductivity and compressive strength anisotropy in vermiculite-ceramic composites with layered structure

Abstract

High strength vermiculite-ceramic composites with a layered structure were fabricated by adding cellulose fibers as a pore former and by simple uniaxial pressing and subsequent sintering. During uniaxial pressing, the cellulose fibers were aligned perpendicular to the pressing direction and formed an aligned pore structure during sintering. The thermal conductivity (0.81W/m·K) and compressive strength (39 MPa) of the composite fabricated from 35 mass% vermiculate, 30 mass% SiO2, 10 mass% Al 2O3 and 25 mass% cellulose fibers, measured perpendicular to the pressing direction, were higher than those (0.52W/m·K and 28 MPa) measured parallel to the pressing direction. The anisotropy in both thermal conductivity and compressive strength was attributed to the microstructural anisotropy. © 2011 The Ceramic Society of Japan.