Enhancing the accuracy of vat photopolymerization 3D printed silica-based ceramic cores via nano-Si powder addition

Ceramic cores are critical components for the fabrication of single-crystal alloy blades in aero-engines. At present, the preparation of ceramic cores with complex structures via vat photopolymerization (VPP) 3D printing technology is a major research focus in the relevant field. However, during the VPP 3D printing of ceramics, ultraviolet light scatters easily under the influence of ceramic particles, making the overcuring of ceramic slurries inevitable, which increases the overcuring width of the system and significantly impairs the forming accuracy of ceramic cores. To solve the above problem, this study inhibits overcuring by adding pre-oxidized nano-silicon powder and systematically investigates the effect of pre-oxidized nano-silicon powder content on the forming accuracy and properties of silicon-based ceramic cores. The results show that when the addition amount of pre-oxidized nano-silicon powder is 5 wt.% and the slice thickness is 100 μm, the overcuring phenomenon of the prepared ceramic components is negligible. When the sintering temperature is 1200 °C, the ceramic core with 5 wt.% pre-oxidized nano-silicon powder exhibited excellent mechanical properties. Under this condition, the flexural strength of the ceramic core reached 13.4 MPa, with a shrinkage rate of 4.21%. This study provides an effective scheme for the additive manufacturing of high-precision ceramic cores.