Thermal conductivities of MgO–Al2O3 hollow fibers formed by biomimetic synthesis

Abstract

abstract MgO–Al2O3 hollow fibers were effectively prepared by bionics using cogon as a low-cost natural template. Through orthogonal experimental design, the preparation parameters were optimized as follows: Al2O3: MgO ratio of 0.60, mass ratio of 25% solute in the mixture, drying temperature of 80 °C, and sintering temperature of 1100 °C. Overall, with inner pore sizes ranging from 5 μm to 10 μm, the MgO–Al2O3 hollow fibers are a novel low-cost lightweight refractory material. Their stack density is approximately 0.120 g cm−3 and thermal conductivity is 0.2050 W m−1 K−1 at 1273 K. In addition, the porosity and average pore area of the hollow fibers are 80.9% and 0.96 m2 g−1, respectively. Here, the effects of pore size, average pore area, and phase composition on the thermal conductivity of the MgO–Al2O3 hollow fibers are discussed synthetically.