Multi-material hybrid additive manufacturing of polymer-derived SiC ceramic composites

Multi-materialization, multi-structuring and multi-functionalization of high-performance ceramics present an increasingly wide range and demand in the fields of special industries, biomedicine, microelectronics, aerospace. Most of the existing multi-material additive manufacturing technologies for ceramics use single-process methods, which have large limitations in the material constituent system, interface modulation, structure creation and anti-fouling measures. This paper presents a multi-material hybrid additive forming technique for polymerderived ceramics (PDC) to fabricate multi-material SiC ceramic components with surface free of deformation, damage and cracks. High-viscosity polycarbosilane (PCS) pastes with different solid contents and low-viscosity alumina (Al2O3)/PCS/silicon carbide whisker (SiCw) composite slurries were prepared for the stereolithographic light curing (SLA) and material extrusion (ME) compound processes, respectively. The curing behaviors of the different used materials were analyzed and an accurate prediction model of the curing characteristics was established. After the ceramization process, single-material pure SiC ceramics and multi-material SiC ceramics flexural test specimens were successfully obtained, and the latter showed more excellent flexural properties than the former. In addition, a variety of multi-material models were designed to focus on the bonding quality and microscopic morphology of the interfaces in the horizontal and vertical directions under the compound process. The generation mechanism of "staggered layer" at the multi-material interface and the principle of pyrolytic micro-deformation of multi-material components were revealed. The results show that the technique can produce multi-material polymer-derived ceramic components with high precision, excellent interfacial integration and less defects. The high compatibility of the self-developed novel multi-material ceramic hybrid additive manufacturing system and software also demonstrates the great potential of printing multi-material functional polymer-derived ceramics with complex structures.