Additive manufacturing of aluminum nitride ceramics with high thermal conductivity via digital light processing

Aluminum nitride (AlN) powder systems for additive manufacturing (AM) via digital light processing (DLP) were successfully developed, shaped by a DLP-based manufacturing technique, and sintered at 1700 °C. Properties of the AM parts were compared to reference samples consolidated via cold-isostatic pressing. AlN powders from two different manufacturers were used in the powder mixtures, underlining the flexibility of the process. Thorough process control was crucial for obtaining materials with a high degree of densification, exhibiting microstructural, thermal, and mechanical properties comparable to conventionally processed reference materials. Thermal conductivity of AM samples exceeded 160 W m−1 K−1, while flexural strength of AM samples varied between 320 and 498 MPa, depending on the orientation of specimens with respect to the building direction. The feasibility of this approach to generate complex-shaped parts was successfully shown by fabrication of crack-free demonstrator parts, highlighting prospective novel use cases in advanced heat management applications.