Light-weight cellular ceramics from biologically-derived preforms

Advanced high-temperature, cellular materials can be prepared by using biologically-derived preforms as structural templates for ceramic composites. Two different processing routes will be presented in the paper. First, cellular ceramics with anisotropic pore structures at the micrometer level were processed by infiltrating liquid metal (silicon) into carbonized wood structures and subsequent reaction into SiC and SiSiC-ceramics at temperatures of 1600 °C. Secondly, low viscosity preceramic polymer/filler (silicon and aluminum) suspensions were infiltrated into 3-dimensional preprocessed paper structures having microstructures of various porosity and subsequently converted into high-temperature stable ceramic composites using a filler controlled reaction pyrolysis at 1450 °C. The resulting lightweight, cellular ceramic composites display low density, while having high specific strength and excellent high temperature stability.