Microstructural and nanoindentation study of TaN incorporated ZrB and ZrB-SiC ceramics.

This study assessed the sinterability and microstructure of ZrB-SiC-TaN and ZrB-TaN ceramics. Spark plasma sintering at 2000 °C and 30 MPa for 5 min produced both ceramics. The relative density of ZrB ceramic containing TaN was 95.3%; the addition of SiC increased this value to 98.1%. SiC's contribution to the elimination of ZrB surface oxides was the primary factor in the advancement of densification. The in situ formation of hexagonal boron nitride at the interface of TaN and ZrB was confirmed by high-resolution transmission electron microscopy, field emission-electron probe microanalyzer, X-ray diffractometry, and field emission scanning electron microscopy. Moreover, the in situ graphite might be produced as a byproduct of the SiC-SiO process, hence boosting the reduction of oxide compounds in the ternary system. The SiC compound had the highest hardness (29 ± 3 GPa), while the ZrB/TaN interface exhibited the greatest values of elastic modulus (473 ± 26 GPa) and stiffness (0.76 ± 0.13 mN/nm).