SiCw/SiCp reinforced 3D-SiC ceramics using direct ink writing of polycarbosilane-based solution: Microstructure, composition and mechanical properties

The addition of fillers in preceramic precursor plays an important role in maintaining the shape and diminishing defects in polymer-derived-ceramics. SiCw/SiCp reinforced 3D-SiC was prepared via direct ink writing of polycarbosilane-based slurries. Effects of SiCp content and the sintering temperature on the microstructure, pyrolysis process, composition and mechanical properties were studied. Complex structures of SiC ceramics with good retention were obtained using PCS/n-hexane/SiCw-SiCp solutions. Printed lines showed a feature of core-shell structure, owing to the decreased shear stress along the radial direction of the nozzle. Increased SiCp/PCS ratios greatly decreased the linear shrinkage and weight loss from 18.2% to 8.3% and 17.5% to 10.6%, respectively. Satisfactory tensile strength of 21.3 MPa was achieved for 3D-SiC lattices with a SiCp/PCS ratio of 0.7, owing to the low porosity and particle reinforcement. This study provides a way to prepare strengthened 3D ceramics using direct ink writing via the polymer precursor routes.