From design to characterization of zirconium nitride/silicon nitride nanocomposites

ZrN/Si3N4 nanocomposites have been prepared by chemically crosslinking two polysilazanes with a zirconium-based compound and subsequent heat-treatment at temperatures ranging from 1000 to 1600 degrees C. The polymer synthesis has been systematically investigated using FT-IR, solid-state NMR, and elemental analyses. Then, the pyrolysis under ammonia at 1000 degrees C trigering the thermo-chemical polymer-to-ceramic conversion was examined, leading to X-ray amorphous ceramics with yields governed by the chemistry of the neat polysilazane. Investigations of the structural evolution of the single-phase amorphous ceramic network above 1000 degrees C by X-ray diffraction and Raman spectroscopy pointed out that the ZrN phase already segregated at 1400 degrees C and formed highly crystalline ZrN/Si3N4 nanocomposites at 1600 degrees C. HRTEM investigations validated the unique nanostructural feature of the nanocomposites made of ZrN nanocrystals distributed in alpha- and beta-Si3N4 phases. Our preliminary investigations of the optical properties showed that these structural changes allowed tuning the optical properties of ZrN/Si3N4 nanocomposites.

Automated summary

ZrN/Si3N4 nanocomposites with unique nanostructure have been successfully prepared by chemically crosslinking two polysilazanes and subsequent heat treatment. The optical properties of these nanocomposites can be tuned by adjusting their structure.