Synthesis and pyrolysis evolution of glucose-derived hydrothermal precursor for nanosized zirconium carbide

Nanosized zirconium carbide (ZrC) was synthesized successfully by a novel hydrothermal precursor conversion method using chelation of polydentate glucose as the carbon source. During the pyrolysis, the core-matrix structure of intimate nanosized ZrO2 and amorphous carbon mixture forms, resulting in short diffusion path and limit of grain growth. ZrC first appears at a much lower temperature of 1200 °C and completes conversion at 1400 °C in comparison with that of precursor without hydrothermal treatment. By raising the heating temperature to 1600 °C, oxygen content could be reduced (0.55 wt%) with a low residual carbon content (2.3 wt%), and the average size of the spherical crystallite increases from 100 nm to 200 nm. Based on above ZrC powders, the additive-free ceramic with 99.4% relative density by spark plasma sintering (SPS) at a low temperature of 1700 °C has been achieved.