Thermal Conductivity Prediction of Ceramic Materials at High Temperature

Many applications such as effective thermal barrier coatings require ceramic materials to have low thermal conductivities at high temperature. In these crystals, phonons are the main heat carriers and thermal conductivity is largely determined by phonon-phonon interactions. We predict this key property of ceramic materials using first-principles calculations, where we consider recent theoretical advances: four-phonon scattering and phonon renormalization. We find these two effects to be significant at high temperatures, a condition where ceramics are expected to work. Our predictions agree well with available experimental data and our own measurements, and can guide thermal barrier coating design for high temperature applications.