Complex SiC-based structures with high specific strength fabricated by vat photopolymerization and one-step pyrolysis

Abstract Lightweight and strong silicon carbide (SiC) ceramics with complex lattice structures were fabricated by vat photopolymerization 3D printing technology followed by a one-step pyrolysis process. The UV-light penetration depth of the SiC ceramic slurries was increased more than three times based on the formation of SiC@SiO2 core@shell structured particles through pre-oxidation processing. To reduce the sintering temperature and shrinkage of SiC ceramics, 40 vol.% solid loading SiC@SiO2 ceramic slurries mixed with photocurable resins containing 0~70 wt.% of polysiloxane were prepared. SiC@SiO2/SiOC ceramic with less than 8% linear shrinkage rate was obtained after pyrolysis at 1000~1200℃. The pyrolyzed SiC@SiO2/SiOC lattice ceramics exhibited a specific strength of 4.6×104 N.m/kg with a cellular density of 0.87 g/cm3, surpassing various other lattice structures and porous ceramics with similar porosity. The complex structure forming ability, mechanical performance and its short developing cycle make this technology to be a promising method for structural integrated SiC ceramic manufacturing.