Influence of SiN fillers and pyrolysis profile on the microstructure of additively manufactured silicon carbonitride ceramics derived from polyvinylsilazane.

In this work, various methods were used to improve the printability of a photocurable polyvinylsilazane resin filled with silicon nitride particles for digital light processing. The developed resin was used as a preceramic polymer for polymer-to-ceramic conversion. The pyrolysis-induced structural changes of the additively manufactured objects were evaluated by comparing samples with different thicknesses, filler amounts and heating profiles. The printed green body retained its original geometry better and showed fewer cracks due to the addition of silicon nitride particles to the resin. Based on the thermally induced changes in a polyvinylsilazane resin system, a customized heating profile for the pyrolysis process was developed, which contributed to the reduction of pores and cracks while the average pyrolysis heating rate remained relatively high. This work provides insight into the pyrolysis of additively manufactured preceramic polymer green bodies and highlights various strategies for additive manufacturing of polymer-derived ceramics.