Preparation Of Silicon Carbide Woodceramics From Poplar Fiber

In recent years the material of Silicon carbide (SiC) woodceramics is a hot spot and important system of the research of the new type of ceramic. Silicon carbide (SiC) woodceramics is a new type of ceramic with some biological structures and special characteristics. High performance bulletproof woodceramics can be prepared by low cost and regeneration wood materials by reaction sintering, which can propel the area of bulletproof forward.In the previous studies, block of the wood, bamboo, MDF, wood powder and resin-based wood powder composite were used to prepare Silicon carbide (SiC) woodceramics, however, the woodceramics prepared from those materials have some defects. And in this study silicon carbide (SiC) woodceramics was fabricated by self-bonding hot-pressing, pyrolysis, and liquid silicon infiltration sequentially with poplar fiber as starting material directly. Poplar fiber molded block with homogeneous vertical density (VDP) profile and high hardness was prepared with optimized hot-pressing process. Carbon templates were fabricated by carbonization with slow temperature increasing program. Pore size distribution of the carbon templates was measured by scanning electron microscopy, transmission electron microscopy, mercury porosimetry and nitrogen adsorption and the carbon templates were also infiltrated with liquid silicon to evaluate their suitability to the liquid silicon infiltration process. Density, phase identification and microstructure of the silicon carbide woodceramics from poplar fiber were characterized with Archimedes' principle, X-ray diffraction (XRD) and scanning electron microscopy (SEM). And the mechanical properties (hardness, flexural strength and elastic modulus) of the silicon carbide woodceramics from poplar fiber were also investigated.The results indicated that there are negligible influences to the VDP on the fiber molded block by the different density designed and clear influences on the fiber molded block by preheat or not, the different hot-press temperature and different moisture content of the fiber. The optimized hot-pressing process is:preheated, low moisture content poplar fiber on the conditions of slow press-fitting process (0.1mm/s) and hot-press temperature (145℃). Carbon templates with complete pore structure can be prepared by slow temperature increasing program.The silicon carbide woodceramic from poplar fiber has characteristics of high density, even microstructure and high mechanical properties (Hardness:22.5 GPa, flexural strength:437 MPa).