Surface dependent segregation of Y2O3 in t-ZrO2

Atomistic simulation techniques have been used to predict the preferential segregation of Y³⁺ ions to the (100), (101) and (110) surfaces of tetragonal zirconia (t-ZrO₂). It is found that segregation energetics vary greatly between surfaces. In particular, dopant ions segregate to the top of the (101) surface. Conversely, although they also segregate towards the (100) and (110) surfaces, Y³⁺ becomes trapped just beneath these surfaces. For all of these surfaces, segregation effects are negligible below 12Å. The surface orientation dependence will result in significant variations in the concentration of yttrium at different surfaces. As a consequence, properties that are a function of defect concentration and distribution will be surface dependent. Predictive understanding of such segregation effects will provide the possibility of better engineered devices for a variety of thermal and electrochemical applications.