Thermal Stereolithography of SiC-Loaded Acrylate Resins with Polymer-Derived Ceramic Infiltration

The implementation of stereolithography (SLA) for fabricating 3D-structured polymer-derived ceramics (PDCs) has greatly improved the resolution, manufacturing potential, and widespread capability to produce complicated component geometries in ceramic materials. However, different material systems impose challenges to the traditional UV SLA photo-cross-linking process due to a narrow window of material selection requirements-UV transparency, UV degradation resistance, the ability to support the photoinduced radical curing mechanism, and ambient shelf life stability. Herein, a near-infrared (NIR) thermal SLA printing technology is demonstrated on a composite thermally curable acrylate-based highly loaded resin to overcome current issues with UV light-driven SLA additive manufacturing of preceramic polymers (PCP). For this thermal SLA cross-linking method, a high-intensity NIR laser (λ = 808 nm) was used to generate localized thermal heating at the resin pool interface, which led to rapid, targeted thermal free-radical polymerization and solidification of the SiC particle-laden acrylate-based resin during laser scanning. Thermally cured printed parts were demonstrated using a gantry-based movement platform and a resin pool in a top-down laser scanning configuration. After printing, the green bodies were debinded, followed by polymer infiltration and pyrolysis (PIP) during postprocessing, which enhanced the mechanical strength of the pyrolyzed samples. This work demonstrated the fabrication of a reinforced PDC composite material with crystalline silicon carbide (SiC) fillers and an amorphous matrix made of silicon oxycarbide (SiOC) and silicon carbonitride (SiCN). The flexural strength of the NIR-printed samples reached 48 MPa with a fracture toughness of 4 MPa·m^1/2.