HETEROEPITAXY OF CUBIC ZIRCONIA ON BASAL AND PRISMATIC PLANES OF SAPPHIRE

The epitaxial growth of yttria stabilized cubic zirconia produced via the solution precursor route deposited onto the basal and prismatic planes of sapphire was characterized. The evolution of the polycrystalline thin film was described with reference to two concurrent physical processes: abnormal grain growth due to the growth of grains with preferred orientations and a morphological instability which resulted in an uncovering of the substrate. X-ray diffraction, electron backscattering patterns (EBSP), and transmission electron microscopy (TEM) (plan- and cross-sectional view) were used to determine the epitaxial relation (normal and in-plane). The observed epitaxial orientations for the two substrate planes are listed in Table 1. A computer search was used to determine the planar, near coincident site lattices (NCSL) for the observed normal epitaxial relations (c-plane: [001]ZrO2 parallel-to [0001]Al2O3; a-plane: [001l]ZrO2 parallel-to [1210BAR]Al2O3). The determined NCSL's did include all the observed epitaxial relations, but also included others not observed within the same range of misfit and coincident site density.