Non-reactively sputtered ultra-high temperature Hf-C and Ta-C coatings

Ab initio calculations predict an easy formation of vacancies on the C-sublattice, especially in the Ta-C system, and a temperature driven stabilization of defected structures at high temperatures, with fewer vacancies on the C sublattice for Hf-C than for Ta-C. The predicted phase stability is proven up to 2400 °C for both systems by annealing experiments in vacuum.