|
|||||
|
|
High-growth rate YSZ thermal barrier coatings deposited by MOCVD demonstrate high thermal cycling lifetime |
|
| Authors: | V.G. Varanasi T.M. BesmannE.A. Payzant B.A. PintJ.L. Lothian T.J. Anderson |
| Affiliation: | a Division of Biomaterials and Bioengineering, University of California, San Francisco, CA 94143-0758, United States b Materials and Science Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, United States c Department of Chemical Engineering, University of Florida, Gainesville, FL 32611-0005, United States |
| Abstract: | Yttria-stabilized zirconia (YSZ) thermal barrier coatings (TBC) were prepared by metalorganic chemical vapor deposition (MOCVD) using Y(OButn)3, Zr(OButn)4 precursors and O2 carrier gas. A thermodynamic analysis guided experiments by optimizing elemental molar (n) stoichiometric ratios for the (Zr-Y-O-C-H system). This analysis showed single-phase YSZ was favored at 950 °C, 1 kPa, nO/(nY + nZr) > 30, nY/(nY + nZr) = 0.06-0.10 (fixed nC, nH). Experimental YSZ growth had multiple phases (fcc, monoclinic), had a relatively high growth rate (43 μm/h, 1005 °C), had an Arrhenius dependence (845-950 °C, Ea = 53.8 ± 7.9 kJ/mol), had columnar grains (SEM analysis), and had a coating through-thickness nY/(nY + nZr) = 0.04 (EPMA analysis). Doubling the inlet yttrium precursor mole fraction resulted in fcc YSZ growth with a coating through-thickness nY/(nY + nZr) = 0.07. Hot-insertion thermal cycling of YSZ coatings on FeCrAlY bond coats showed >1000 h lifetime, matching current standards for EB-PVD YSZ coatings. |
| Keywords: | Yttria-stabilized zirconia Metalorganic chemical vapor deposition Thermal barrier coating Butoxide precursor Aerosol-assisted liquid delivery |
| 本文献已被 ScienceDirect 等数据库收录！ | |