Highly-porous hierarchical SiC structures obtained by filament printing and partial sintering

Abstract

Three-dimensional (3D) porous silicon carbide (SiC) structures with total porosity in the range of 64–85% are achieved from nanosized SiC powders by filament printing and partial sintering in a spark plasma sintering (SPS) furnace. The effects of the SPS temperature (1500 and 1700 °C) and the addition of oxide sintering aids (7 wt. % Y2O3+Al2O3) on the porosity of the scaffolds are quantitatively compared. More specifically, hierarchical porosity consisting of meso-pores (< 50 nm) in the struts and open macro-pores (in the range of 500–700 μm) defined by the patterned structure is verified for the 1500 °C SPS treatment. The strength of the structures as a function of the density as well as their cooling profiles, once subjected to rapid heating under a direct flame, are analyzed. By following this easy route, an adaptable family of robust light 3D SiC structures with hierarchical porosity is accomplished.