Binder jetting printed in situ mullite strengthened alumina ceramics with excellent mechanical and thermal properties through multi-phase infiltration

Binder jetting (BJ) additive manufacturing faces significant challenges in fabricating high performance alumina ceramics. In this study, a multi-phase infiltration method was successfully employed to prepare high-performance mullite strengthened alumina ceramics via the BJ process. The effects of printing, sintering, and infiltration processes on the microstructure and performance of the alumina-based ceramics were systematically investigated. The results indicate that the density and strength of the green body increased with increasing binder saturation and decreased with thicker powder layers. Upon sintering, the maximum bending strength of the alumina ceramics reached approximately 2.2 MPa, which increased with the sintering temperature. After further multi-phase infiltration, the maximum bending strength of the alumina-based ceramic composites reached 97.3 MPa, a 44-fold increase compared to before infiltration. Additionally, triple-periodic minimal surface structures from high-performance alumina-based ceramic composites were successfully fabricated. The compression behaviour and thermal properties of these TPMS structures were investigated for potential insulation applications.