Permanence of Zirconia Stability, A Function of Purity

The stability permanence of calcia-stabilized zirconia was studied during the course of repeated heat treatments. Zirconias with various degrees of purity and initial stability were tested. X-ray diffraction and thermal expansion measurements were used to determine stability changes. Standard purity samples were partially destabilized by cyclic heating through the temperature of monoclinic-tetragonal phase change (between 954°C and 1260° C), while very high purity samples withstood this and even more severe heat tests.