Biotemplating of highly porous oxide ceramics

Autor(en): Cao, Jing Göttingen, 28. Juli 2005 Seiten: 150 Auflage: 1 Sprache: ISBN-10: 3865375324 ISBN-13: 9783865375322 Zugeordnete Fachbereiche: Ingenieurwissenschaften Kategorie: Dissertation Bezugsmöglichkeiten Print Version 23,00 € 21,85 € In den Warenkorb eBook (20850.0 kB) 23,00 € In den Warenkorb

Kurzbeschreibung

Novel oxide ceramic structures were designed by biotemplating the structures of native as well as preprocessed lignocellulosics precursor. In this investigation, naturally grown plants, e.g. pine wood and rattan, and preprocessed lignocellulose fiber products, e.g. cellulose fiber felts and corrugated cardboards were used as biological templates and vacuum infiltrated with different low viscous sols, such as TiO2-, Al2O3- and ZrO2-sols, which were prepared by the hydrolysis and condensation of Ti[OCH(CH3)2]4, Al[OCH(CH3)2]3 and Zr[O(CH2)2CH3]4, respectively. Pyrolysis at 800 °C in N2-atmosphere and subsequent annealing in air resulted in the formation of porous biomorphic rutile TiO2, -Al2O3 and cubic ZrO2 (stabilized by 8 mol% Y2O3), maintaining the microstructural features of the original biological templates. The morphology of the porous ceramics and the oxide phase formation during processing were monitored by SEM/EDX, DTA/TG and XRD measurements. Density, specific surface area, porosity and pore size distribution were compared with those of the biological templates. Compression strength and permeability of the final products were determined with respect of orientation, fractional density and strut microstructure. Biostructure derived oxide ceramics of low density but high thermal stability and corrosion resistance, could be of particular interest for applications as heat insulation structures, filters and catalyst carriers in high temperature processes as well as for medical implant structures.

Keywords: Biotemplating, cellular structure, pine, rattan, cellulose fiber felts, cardboards, TiO2, Al2O3, ZrO2