MICROSTRUCTURES AND PHYSICAL PROPERTIES OF BIOMORPHIC SISIC CERAMICS MANUFACTURED VIA LSI-TECHNIQUE

Abstract

Biomorphic SiSiC ceramic composites were produced by liquid silicon infiltration (LSI) process. These materials are based on activated coal (ACBC) and wood fibers (MDF). Microstructural characteristics in green-, carbon- and SiSiC-body modification were investigated by analyzing curved structures (type charcoal) and planar structures (type MDF). Therefore polished and unpolished specimens have been examined with scanning electron microscopy (SEM), microfocus X-ray computed tomography (CT) and respective evaluation software. Focused on the objective of near net shape reproducibility for the ceramic composites, different shrinkage and silicon uptake behavior were identified. Furthermore, significant capillarities, densities and porosities could be determined and valued regarding the objective and highest possible SiC content. The appearing different SiSiC microstructures influence the physical properties of SiSiC ceramics such as flexural strength, Young’s modulus and hardness, which were detected with standardized testing methods.