Mechanical properties and microstructure of Si/SiC materials derived from native wood

Mechanical properties and microstructure of Si/SiC ceramics derived from native wood were investigated. Three types of native natural wood (pine, birch, bamboo) and a man-made wood (MDF: medium density fiberboard) were pyrolyzed at 900°C in an inert atmosphere to prepare charcoal. The silicon melt was infiltrated into the porous charcoal while the sample was heated to 1600°C under vacuum. XRD analysis indicated that the final product prepared by this technique was a multi-phase dense solid, composed of β-SiC and free silicon. The material derived from birch showed the highest strength of 300 MPa and toughness of 4.0 MPa·√m, which increased with SiC content. These Si/SiC materials have a cell-pipe structure similar to the original natural wood. The material derived from MDF gave lower strength and toughness than that from natural wood with cell-pipe structure.