High pressure investigations on ZrO2 doped with Cr, Fe and Nb

Article abstract of DOI:10.1016/0025-5408(91)90004-6

High-pressure X-ray investigations using a diamond anvil cell at ambient and higher temperatures show that the borderline between the fields of existence of different polymorphs of ZrO₂ in the p-T-diagram is heavily affected by doping zirconia with Cr, Fe or Nb. Furthermore, the transformation kinetics are enhanced by the dopant ions acting as additional nucleation sites for the transition from one polymorph to the other. The observed effects are explained on thermodynamic grounds by different entropy contents of the doped oxides and pure ZrO₂ in the low- and high-pressure modifications.