Low temperature consolidation for fine-grained zirconium carbide from nanoparticles with ZrH2 as sintering additive

Zirconium carbide (ZrC 0.84 O 0.13 ) nanopowders were consolidated using plasma activated sintering with 0–8   wt% ZrH 2 as the sintering additive to improve the sinterability. Compared with pure ZrC sintering, ZrH 2 additive led to the higher sintering kinetics and lower sintering temperature . This improvement was attributed to the increased carbon-vacancy concentration in the non-stoichiometric ZrC in the presence of ZrH 2 additive during the sintering process. Fully dense and fine-grained ZrC ceramics (1.3   ±   0.2   μm) were achieved at 1650   °C with 6   wt.% ZrH 2 . The final product exhibited the Vicker’s hardness of 21.2   ±   1.0   GPa and fracture toughness of 2.2   ±   0.3   MPa   m 1/2 .