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

While lithographic additive manufacturing (AM) of oxide ceramics is starting to become well established, the use of non-oxide ceramics for this particular printing approach is still less matured. One main reason for that is the higher light absorption that non-oxide ceramic powders often have due to their coloration.
This contribution focuses on the advances concerning AM of aluminum nitride, silicon nitride and silicon carbide-based ceramics. By using the so-called Lithography-based Ceramic Manufacturing (LCM) process it was possible to print and sinter silicon nitride components with the same thermal and mechanical properties as from parts made by conventional manufacturing (isostatic pressing). With relative density of 99.8 %, a hardness of 1500 and a biaxial bending strength of 760 MPa the tested composition is exactly at eye-level with its conventionally processed analogue (hardness of 1500 and biaxial bending strength of 770 MPa) or aluminum nitride components with a thermal conductivity of 175 W/m.K. These material properties in combination with the high precision of the LCM process allow the production of highly complex components that have not been feasible before and that are fully functional. Beside the printing process and the properties of the ceramic material, this presentation will also give an outlook on the status of lithographic printing of other non-oxides such as silicon carbide. For these silicon carbide-based ceramics, first components could be successfully manufactured using two different material routes: one involved the shaping of classic photocurable suspension and the subsequent infiltration with molten silicon giving Si-SiC, the other route was based on the concept of structuring preceramic polymers leading to SiOC. Using both routes it was possible to obtain precise and defect-free components, showing that lithographic AM can indeed be used for broad range of ceramic materials.