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

Abstract

* sı Supporting Information 5 ABSTRACT: The implementation of stereolithography (SLA) for 6 fabricating 3D-structured polymer-derived ceramics (PDCs) has 7 greatly improved the resolution, manufacturing potential, and 8 capability to produce complicated component geometries in 9 ceramic materials. However, different material systems impose 10 challenges to the traditional UV SLA photo-cross-linking process 11 due to a narrow window of material selection requirements�UV 12 transparency, UV degradation resistance, the ability to support the 13 photoinduced radical curing mechanism, and ambient shelf life 14 stability. Herein, a near-infrared (NIR) thermal SLA printing 15 technology is demonstrated on a composite thermally curable 16 acrylate-based highly loaded resin to overcome current issues with 17 UV light-driven SLA additive manufacturing of preceramic polymers (PCP). For this thermal SLA cross-linking method without UV 18 photopolymerization, a high-intensity NIR laser (λ = 808 nm) was used to generate localized thermal heating at the resin pool 19 interface, which led to rapid, targeted thermal free-radical polymerization and solidification of the SiC particle-laden acrylate-based 20 resin during laser scanning. Thermally cured printed parts were demonstrated using a gantry-based movement platform and a resin 21 pool in a top-down laser scanning configuration. After printing, the green bodies were debinded, followed by polymer infiltration and 22 pyrolysis (PIP) during postprocessing, which enhanced the mechanical strength of the pyrolyzed samples. This work demonstrated 23 the fabrication of a reinforced PDC composite material with crystalline silicon carbide (SiC) fillers and an amorphous matrix made 24 of silicon oxycarbide (SiOC) and silicon carbonitride (SiCN). The flexural strength of the NIR-printed samples reached 48 MPa 25 with a fracture toughness of 4 MPa·m 1/2. 26