Elaboration of complex aluminum nitride parts by binder jetting: Optimization of printing parameters and powder characteristics

Aluminum nitride (AlN) is a promising material for heat sinks and power electronics substrates due to its high thermal conductivity, electrical insulation, high mechanical strength, and low thermal expansion. At present, there is a significant demand for the development of ceramics with complex geometries that can achieve previously unmatched properties, and additive manufacturing (AM) techniques are well-suited to meet these challenges. In this study, we chose the binder jetting (BJ) technology and investigated the influence of printing parameters and powder characteristics on AlN part quality and densification. Different strategies were used to enhance densification: employing multimodal powders and adding Yttrium oxide (Y2O3) to improve the shrinkage, and optimizing the printing parameters. Multimodal powder was prepared using two AlN powders (D50 ~14.7 μm and 2.2 μm) at varying fine powder ratios. After sintering at 1900°C, monoclinic yttrium aluminum monoclinic and perovskite yttrium aluminum perovskite phases formed alongside AlN and Y2O3. The highest achieved densification, 64.2%, set a new record for BJ-printed AlN. This study demonstrates the feasibility of BJ for AlN ceramics and underscores the crucial role of powder selection and AM process parameters optimization.