Synthesis of Oxide Ecoceramics

Abstract

Main topics of this presentation will be synthesis of oxide ecoceramic materials by transforming of I bioorganic wood structure into an inorganic ceramic I material with tailored chemical, physical and mechanical properties. This biomimetic approach offers a new class of ceramics denoted as ecoceramics. Wood exhibits a hierarchical architecture with a cellular microstructure of high porosity due to specific function of living cells, such as transportation, storage and mechanical strengthening cells. These cells form pore channels system with a preferential orientation in axial direction. However, this feature offers the possibility to use liquid infiltration techniques to transform the hierarchical cellular structure of wood into inorganic materials while preserving the original cellular structure. Both highly anisotropic cellular structure and carbonous composition can be used as hierarchical template for the synthesis of novel oxide ceramics with micro, meso and macropores. Presentation will be focused on obtaining porous ceramics with high thermal resistance, high chemical stability, high electrical and ionic conductivities, as well as high mechanical strength. Different types of oxide and non-oxide composites with unusual properties will be discussed. In this work two different ceramic materials are obtained by applying biomimetic approach. Particularly, porous CeO2 and SiO(2) ceramics were prepared by wet impregnation from appropriate salt solution into biological template derived from linden wood (tilia amurensis). Repeated pressure impregnation and subsequent annealing in air atmosphere at 800 degrees C resulted in burn out of the template and consolidation of the oxide layers. The products exhibit structures corresponding to negative replication of biological templates. X-ray diffraction (XRD), scanning election microscopy (SEMI, Raman spectroscopy, BET measurements were employed to characterize the phases and structure of biomorphic ceramics. It was found that the bioorganic structure is converted into oxide ceramics preserving the microstructural features of the biological perform.