Effect of thermosetting resin coating modification on the properties of Si₃N₄ ceramics prepared by vat photopolymerization

Vat photopolymerization (VPP) technology allows for the direct formation of complex structural Si₃N₄ components, without the constraints of moulds, which is an emerging process for the preparation of Si₃N₄ ceramics. However, the low curing depth makes it difficult to prepare Si₃N₄ ceramics by VPP. To address this issue, the study proposes coating Si₃N₄ particles with thermosetting resin. The UV absorption of the modified composite powder were reduced. The thermosetting resin could be removed during the debinding process without introducing impurities, which has minimal impact on the properties of the Si₃N₄ parts. The study investigated the impact of E51 coating modification on the phopopolymerization of Si₃N₄ slurries, and the mechanical properties after sintering. Moreover, the peak flexural strength and density of Si₃N₄ prepared from modified Si₃N₄ using VPP technology combined with air pressure liquid-phase sintering process were 382.67 MPa and 2.95 ± 0.02 g/cm³, respectively, at 2 wt% of E51 coating.