Point Defect Effects on Hot Corrosion of Zirconia-Based Coatings.

摘要

Thermal barrier coatings are vulnerable to certain types of hot corrosion: sulfidation and vanadic attack. Stabilized zirconia, an often used thermal barrier coating, is degraded by dissolution of the stabilizing component (e.g. yttrium oxides). To obtain the dissolution of the stabilizing components, mass transport in the coating must occur. The presence of point defects in a crystalline solid greatly affect the transport properties in that solid. The nature and concentration of these defects can be altered which, in turn, can impart large changes in the transport properties of a material (eg. ionic conductivity and diffusion). In this study, we are determining the defect structure of yttria and ceria-stabilized zirconium oxides. Using electrical conductivity measurements, the activation energies of yttria-stabilized zirconia have been examined as a function of grain size and composition.