Polymer-derived silicon nitride ceramics by digital light processing based additive manufacturing

In this work, silicon nitride ceramic components with simple cuboid and complex honeycomb and lattice structures from preceramic polymers were fabricated by using digital light processing (DLP) based additive manufacturing and pyrolysis. The photosensitive precursor for DLP based additive manufacturing was prepared by mixing high ceramic yield polysilazane with commercial acrylic resin and photoinitiator. The material formulation and the structure of the green body were characterized by using FTIR. Si₃N₄ ceramic cuboid, 2D-structured Si₃N₄ ceramic honeycomb, and 2D-structured Si₃N₄ ceramic lattice with high precision were fabricated. The DLP-prepared specimens were pyrolyzed at different temperatures, and the crystalline phases after pyrolysis were analyzed by using XRD. The optimal pyrolysis temperature was found to be 1400°C.microstructures were characterized by using SEM. The compressive behavior of the complex-shaped Si₃N₄ ceramic structures was measured and discussed in detail.