Properties and Characterization of SiC Woodceramics Fabricated from Boxwood

Abstract: SiC woodceramics is a new type of ceramic material with broad application prospects in recent years. Using green and renewable wood as the original material, the ceramics fabricated by the reaction sintering process has excellent high-temperature mechanical properties. In order to explore the factors that affect the properties of biomass ceramic materials, boxwood was pyrolyzed under the protection of nitrogen at 800 ℃ to form a biomass carbon template, and then SiC woodceramics were fabricated by liquid silicon infiltration at 1 650 ℃ and 1 900 ℃. In order to determine the prepared materials and their properties, the phase composition and microstructure were studied with X-ray diffraction (XRD) and scanning electron microscopy (SEM), the porosity and density were measured by Archimedes drainage method, the bending strength of ceramics was measured by three-point bending method, and the microhardness was determined by Vickers hardness tester. The results show that SiC woodceramics with uniform microstructure are fabricated by liquid silicon infiltration at 1 650 ℃. The mechanical properties and density (2.27 g/cm³) of ceramics fabricated by liquid silicon infiltration at 1 650 ℃ are better than those fabricated at 1 900 ℃, and the bending strength is 192.45 MPa. The free Si increases the density of SiC woodceramics as well as enhances the bending strength and microhardness.

Key words: SiC woodceramics, boxwood, liquid silicon infiltration, free Si, microstructure, mechanical property