Phase Stability and Thermal Transport in Yttria-Stabilized Zirconia: A Challenge for First-Principles Theory

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The development of innovative substances that bear the optimal combination of properties for a certain application plays a key role in scientific and technological advancement. Unfortunately, the search for novel materials is a tedious and costly task, in which progress can typically be achieved only by expensive prototyping and extended test series. Naturally, the development of computational methods to aid and guide such research in a rapid and cost-efficient way is desirable. Over the last decades, tremendous progress has been achieved in this field: Most notably, the development of ab initio approaches allowed the efficient and reliable computation of electronic and atomistic properties from first principles alone. Still, the first-principles assessment of macroscopic thermodynamic properties on the basis of such ab initio calculations is a conceptually and computationally formidable task that is still the topic of intensive scientific research. In this regard a series of approaches has recently been proposed in proof-of-concept studies. These innovative ab initio techniques shall be used in this project to asses the thermodynamic equilibrium (high phase stability) and non-equilibrium (low thermal conductivity) properties of yttria-stabilized zirconia. Due to these properties this material is used as a thermal barrier coating in aircraft and gas turbines. Such coatings protect the underlying alloys from the extreme temperatures generated during combustions and hence allow to increase the overall operational temperature and hereby lead to a higher fuel efficiency. In this research we want to unveil the atomistic mechanisms that determine the thermodynamic properties of yttria-stabilized zirconia. Such knowledge then allows us to specifically manipulate the phase stability and the thermal conductivity of this material and thus paves the way for the development of new and improved thermal barrier coatings.