Solution Mechanisms for Dopant Oxides in Yttria

Solution mechanisms in Y 2 O 3 have been studied by using atomistic simulation. Various defect reactions for the solution of A 2+ , M 3+ , and B 4+ ions, assuming either single isolated impurities or defect clusters, have been considered. Generally, the radius of the dopant cation is an important factor in determining the solution site and cluster geometry, and it can be critical in deciding the solution mechanism. Mechanisms that are associated with codoping A 2+ and B 4+ ions also have been considered. Surprisingly, this action does not always result in a reduction in the solution enthalpy.