| Abstract Scope |
Zirconium carbide has a wide range of substoichiometry facilitated by varying carbon vacancy concentration. Most experimental studies consider a disordered solid solution of carbon and vacancies, however theoretical studies predict the low temperature stability of several superstructural long-range ordered phases, which have been partially validated by careful experiment. The thermophysical properties of zirconium carbide are, therefore, affected not only by the number of carbon vacancies but also their arrangement, increasing its potential as a tuneable ceramic. We summarise experimental and theoretical studies exploring the long-range ordered zirconium carbides including its crystal structures, the mechanism for vacancy ordering, and the presently available information on the thermophysical properties. Explanations for the infrequent experimental observations of ordered zirconium carbides are also discussed considering fabrication temperatures, vacancy diffusion, and the effects of impurities, which may be helpful for future synthesis. Areas where more experimental and theoretical studies are needed are highlighted. |