Structural and Microstructural Evolution of Fused Filament Fabricated SiOC(N) via Polymer-Derived Ceramics Route

Cellular SiOC(N) ceramics were produced by impregnating a 3D-printed TPU lattice with polysilazane, followed by pyrolysis in an inert atmosphere. During pyrolysis, TPU decomposes while polysilazane converts to ceramic. The process was analyzed across the full temperature range via weight loss, shrinkage, density, porosity, specific surface area, FTIR and Vickers hardness. TPU decomposes between 380 and 550 °C with significant weight loss, while ceramization of polysilazane occurs between 550 and 800 °C, forming SiOC(N). Transient micro- and mesoporosity develops only at 600–700 °C. Skeletal density and hardness increase steadily up to 1200 °C.