| Abstract Scope |
Ultra-High Temperature Ceramics (UHTCs) are promising materials for use in extreme temperature and radiation environments owing to their high melting points and excellent thermo-mechanical properties. However, poor thermal shock resistance and evaporative mass-loss in these materials severely limit their long-term service. To address this shortcoming, we are studying the synthesis and high-temperature oxidation behavior of nanoporous UHTCs infiltrated with a protective secondary phase. These materials are fabricated by first exposing nanoporous refractory metals to a reactive-gas environments, and then imbibing with a viscous phase that solidifies inside the pores. The performance of these materials is governed by the length scale of the characteristic feature (the ligament diameter) – with smaller ligaments leading to superior performance – which can degrade via coarsening during service. In this talk we will discuss the synthesis of these materials, their overall performance at elevated temperatures, and governing kinetic equations describing their stability and decomposition. We will also provide an outlook on our processing method towards compositionally complex UHTC formulations. |