EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Aluminum nitride is a highly suitable material for thermal management applications due to its excellent thermal conductivity in combination with promising mechanical properties. However, owing to its tendency towards hydrolytic decomposition and the effect of oxygen impurities on its performance, the selection of shaping and processing methods typically employed is limited, resulting in rather simple geometries of parts typically available.
As complex shapes are desired for many currently envisioned application scenarios, the aim of this work is to present an approach towards developing an AlN materials system applicable for Lithography-based Ceramic Manufacturing (LCM), a state-of-the-art additive manufacturing technique.

In a first step, a starting powder system facilitating the generation of dense AlN ceramics by conventional cold-isostatic pressing and sintering with suitable thermal and mechanical properties is developed. A systematic investigation of the effects of a variety of compositional characteristics and sintering parameters combined with in-depth characterization of structural, thermal, and mechanical properties is conducted to obtain benchmark characteristics, to be compared with LCM-based materials later on.
Subsequently, these findings are transferred towards developing starting materials suitable for shaping by LCM, identifying a variety of necessary modifications, in particular during heat treatment steps.
Our results show that by carefully selecting the starting mixture, by tightly controlling debinding and sintering parameters, and by applying suitable post-processing treatments, complex-shaped parts with mechanical and thermal properties comparable to conventionally produced materials can indeed by obtained by LCM. These key findings demonstrate the suitability of these materials for highly demanding thermal management application scenarios.