Synthesis of zirconium oxycarbide (ZrCxOy) powders: Influence of stoichiometry on densification kinetics during spark plasma sintering and on mechanical properties

Different stoichiometries of zirconium oxycarbide (ZrCxOy) powders were synthesised by carboreduction to approach the role of the chemical composition on the densification behaviour during spark plasma sintering and on the mechanical properties. Chemical analyses were performed using complementary methods to determine the actual stoichiometry and homogeneity of powders. Evolution of relative density during SPS treatment and microstructure observations by SEM showed that oxygen and vacancy contents would enhance the densification kinetics by promoting the lattice diffusion of limiting species. A study of mechanical properties of SPS sintered specimens has highlighted their significant dependence on the oxycarbide stoichiometry, especially at high temperature.