3D SiC containing uniformly dispersed, aligned SiC whiskers: Printability, microstructure and mechanical properties

Abstract

3D SiC-based lattices with aligned SiC whiskers were prepared via direct ink writing of SiCw/polycarbosilane (PCS)-based suspensions. Suspensions with different solid loading were prepared and used to investigate the morphology and printability of 3D SiCw/SiC lattices. Filaments with the morphologies of accumulation, coiling, meandering and straight were achieved with different printing height and speed. Higher printing height favored the formation of coiled filaments with longer periodic structure and increased amplitude. 3D lattices with straight filaments and good retention of shape were achieved only when applying a suitable printing parameters for SiCw/PCS-based suspensions with a solid loading of 62.3 vol%. The resulted 3D lattices with the porosity around 62% showed impressive bending and compression strength of 33.2 ± 5.2 MPa and 30.6 ± 4.3 MPa, respectively. The satisfactory properties of 3D SiCw/SiC lattices were contributed by the pullout of the aligned SiC whiskers. Furthermore, this 3D technique via the Polymer-derived Ceramics (PDCs) route allows the fabrication of large sized samples, which opens new opportunities for the fabrication of 3D structures with unique mechanical and functional properties in practical dimensions.