Advanced materials inspired in the nature: cellular structures, fibers and composites

Abstract

Biomodeling is a recently developed technology to manufacture ceramics out of natural structures. After processing, the resulting material exhibits a cellular structure similar to the original. Biomorphic fibers of SiC were produced from bamboo, by means of the carbon-thermic reduction of silic naturally present. Pieces of bamboo when submitted to pyrolysis at 1,500 Celsius degrees (ºC) in argon atmosphere promote the reaction between silica and carbon. It generates biomorphical alumina by the vacuum infi ltration of aluminium steam in pyrolyzed pre-formed of rattan, pine tree, sisal agave and subsequent oxidation. During vacuum infi ltration at 1,600 ºC, bicarbonate andaluminium steam reacted forming Al4C3 totally converted in Al2O3. The biomorphic alumina obtained kept the morphologic characteristics of the original plants on the micrometric level. The microstructural and morphologic characterizations of the biomorphical ceramics were performed by electronic microscopy sweeping, x-ray diffractometry and helium pycnometry.