High-strength and low-silicon SiC ceramics prepared by extrusion molding 3D printing

Material extrusion is a promising additive manufacturing technique for fabricating high-performance SiC composites with complex structures. In this work, a novel strategy for fabricating SiC composites via material extrusion combined with solvent debinding and gaseous-liquid two step silicon infiltration was developed. The mixture used for material extrusion was composed of an organic binder, such as high-density polyethylene, ethylene vinyl acetate, paraffin wax and a C/SiC inorganic powder. The experimental results revealed that 89 wt% of the soluble components could be removed after debinding at 40 °C for 10 h in kerosene solvent, and the morphology was satisfactory after subsequent thermal debinding. After reactive sintering, the density of the SiC composite reached 3.12 ± 0.02 g/cm3, with a theoretical residual silicon content of 10.13 vol%. The flexural strength and elastic modulus reached the maximum values of 465 ± 35.35 MPa and 425 ± 11.78 GPa, respectively.