Layer-by-layer flash pyrolysis of polysilazane based polymers into a green UHTCMC and ablation resistance of the final dense composites

The oxidation and ablation resistance are key properties of the Ultra-High Temperature Ceramics (UHTC) which are usually used as thermal protection system materials, and bulk materials for heating elements. In order to improve the oxidation and ablation resistanceof Ultra-High Temperature Ceramic Matrix Composites (UHTCMCs) based on ZrB2 matrix and 0/90 carbon fibers, we have infiltrated the green samples with a preceramic polymer. The aim is to deposit layer-by-layer preceramic polymer films around the carbon fibers having a thickness of few hundred nm in order to pyrolyse the thin polymeric films in few seconds - by means the so-called flash pyrolysis - and obtain a crack-free SiNC coating. The resulting UHTCMCs were characterized by XRD, SEM, and RAMAN spectroscopy to highlight the conversion of polymer into ceramic phase and to characterize the microstructure of the composites. Finally, the ablation resistance has been investigated and here presented.