Synthesis and Characterization of Oxide Superlattice Coatings

During this reporting period, we have made progress in the deposition and characterization of novel nanometer-layered yttriazirconia coatings. Fully oxidized Y2O3ZrO2 superlattices of bilayer thicknesses A ranging from 2 nm to 100 nm have been deposited at high rates of approximately equal 3.4 micronshour, or 70 of the pure metal rates. The superlattices were structurally characterized using X-ray diffraction XRD and transmission electron microscopy TEM. The ZrO2 layer exhibited its high temperature greater than or equal 2400 deg C cubic-fluorite structure at small layer thickness less than or equal 7 nm, epitaxially stabilized by the cubic Y2O3. The mechanical properties of the superlattices were measured using a nanoindenter and the thermal conductivity measurements by the 3omega method. The optical properties of oxides of Al, Y, Zr, and Y2O3ZrO2 superlattices was investigated using spectroscopic ellipsometry. In addition, the thermal stability of the superlattices was investigated.