Control of Porosity and Permeability of Wood by Fungi Action for Biotemplating of SiC

Abstract

Biotemplating is a process for the manufacturing of materials from natural resources. In this work, staining fungi were applied to control the porosity and permeability of wood templates for the production of biomorphic SiC ceramics. The action of fungi species Trichoderma sp. and Cytospora eucalypticola in Pinus elliottii var. elliottii wood was evaluated. The wood templates were inoculated with fungi, and the bioactivity was accompanied for 28 days. Air permeability and porosity of the samples were evaluated as a function of time. For ceramic conversion, the templates were then pyrolyzed at 900°C for 1 h in flowing N₂ atmosphere, followed by repeated infiltration of TEOS (tetraethyl-orthosilicate) into the pre-formed carbon. The impregnated

carbon templates were heat-treated at 1600°C for 3 h in Ar to promote carbothermal reaction of SiO₂ into biomorphic SiC.

Keywords:

• Biomorphic SiC
• fungus degradation
• softwood
• fungi
• biotemplating

Acknowledgments

The authors gratefully thank the Brazilian Council for Scientific and Technological Development (CNPq) for the financial support. EMBRAPA is also acknowledged for supplying fungi and wood samples.