The effect of TaN and SiC addition on microstructural and mechanical characteristics of ZrB۲-based ceramics

Spark plasma sintering at ۲۰۰۰ °C yields dense ZrB۲-TaN ceramics, with porosity decreasing from ۴.۷% to ۱.۹% upon SiC incorporation. The SiC phase promotes densification by driving the removal of surface oxides, including the reduction of SiO۲ into graphite and volatile species. Structural and microstructural examinations reveal the in-situ formation of hBN at the ZrB۲/TaN interfaces, highlighting active interfacial reactions during consolidation. FESEM and EDS analyses reveal reduced porosity, pronounced interfacial diffusion, and localized in situ hBN formation within the ternary ceramic composite. Mechanical characterization shows that SiC contributes the highest hardness (۲۹ ± ۳ GPa), while the ZrB۲/TaN interface exhibits superior elastic modulus (۴۷۳ ± ۲۶ GPa) and stiffness (۰.۷۶ ± ۰.۱۳ mN/nm). These results demonstrate that tailored phase interactions and oxide-reduction pathways play a decisive role in optimizing the microstructure and performance of ultrahigh-temperature ceramic composites.

کلیدواژه ها:

ZrB۲ ، microstructural ، nanoindentation ، spark plasma sintering