Manufacture of Biomorphic SiC Components with Homogeneous Properties from Sawdust by Reactive Infiltration with Liquid Silicon

摘要

Biomorphic SiC components with homogeneous properties were manufactured from sawdust using a novel method to produce preforms, without addition of any extra binder, but with enough mechanical strength to be carbonized up to 1400℃ without deformation. Reactive infiltration of carbon preforms of an adequate open porosity with liquid silicon has been successfully used to prepare biomorphic components. Moreover, the modification of bioSiC properties induced by the structural rearrangement of carbon preforms when they are further heat treated at 2500℃ was additionally studied. BioSiC components showed a maximum in bending strength when the material is processed from carbon preforms exhibiting around 40% of open porosity, which seems to be the optimum value for carbon preforms treated at 1400° and 2500℃. However, the heat treatment of the carbon preforms at 2500℃ produced bioSiC components with a finer and more homogeneous microstructure than those obtained from carbon preforms treated at 1400℃, improving their bending strength up to 22%.