MANUFACTURING OF CERAMIC MATRIX COMPOSITES BY DIRECT INK WRITING OF PRE-CERAMIC POLYMERS

In the work reported in this thesis it was possible to test different technologies, derived form the Direct Ink Writing for the production of CMCs from Pre-Ceramic Polymer-based slurries. The work initially focused on the production of SiCN-based CMCs by either solid, partially cured silazane and liquid. The first material showed issues of repeatability due to incomplete dissolution in the solvent; the second one, on the other hand, had strong issues of aging, making it difficult to use. The work shifted to the production of SiOC-based CMCs. In particular, it was possible to shape the silicone-based slurries by Direct Ink Writing, Embedded-Direct Ink Writing, and Dynamic Molding. A new hardware was successfully developed to introduce continuous fibers in the Direct Ink Writing process. The system created was used to print filaments reinforced with continuous fibers and, although the development is still in the initial stages, the shaping of complex geometries was also tested, analysing the issues that may occur during fabrication.