Preparation and heat-insulating properties of Al2O3–ZrO2(Y2O3) hollow fibers derived from cogon using an orthogonal experimental design

Abstract

Bionic design is efficient to develop high-performance lightweight refractories with sophisticated structures such as hollow ceramic fibers. Here, we report a four-stage procedure for the preparation of Al₂O₃–ZrO₂(Y₂O₃) hollow fibers using the template of cogon—a natural grass. Subsequently, to optimize the thermal performance of the fibers, four sets of preparation parameters, namely, x(Al₂O₃), solute mass ratio of the mixture, dry temperature, and sintering temperature were investigated. Through an orthogonal design, the optimal condition of each parameter was obtained as follows: x(Al₂O₃) was 0.70, solute mass ratio of the mixture was 15 wt%, dry temperature was 80 °C, and sintering temperature was 1100 °C. Overall, Al₂O₃–ZrO₂(Y₂O₃) hollow fibers show relatively low thermal conductivity (0.1038 W m⁻¹ K⁻¹ at 1000 °C), high porosity (95.0%), and low density (0.05–0.10 g cm⁻³). The multiphase compositions and morphology of Al₂O₃–ZrO₂(Y₂O₃) hollow fibers, which may contribute to their thermal properties, were also discussed.