Manufacturing of porous oxide ceramics by replication of plant morphologies

Biomorphic oxide ceramics of alumina, mullite and zirconia with a directed pore morphology on the micrometer level were manufactured from bioorganic plant structures by sol-gel processing as well as sol-assisted nano-powder infiltrations. The inherent open porous morphology of natural grown rattan palms was used for vacuum-infiltration with aluminum isopropoxide (Al(OC3H7)(3)), zirconium oxichloride (ZrOCl2. 8H(2)O) and SiO2 nano powder. Hydrolysis of the sols by adding HNO3 and pyrolysis in inert atmosphere at 800 degreesC resulted in the formation of biocarbon/ceramic replica of the original wood morphology. The specimens were sintered in air at temperatures up to 1600 degreesC to yield porous oxide ceramics with an unidirected pore structure similar to the original plant material. Repeated infiltration, hydrolysis and annealing steps were applied to increase the density of the ceramic materials.