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Title: Microstructural investigations of plasma-sprayed yttria partially stabilized zirconia TBC (in relation to thermomechanical resistance and high-temperature oxidation mechanisms)

Abstract

This study deals with microstructural investigations of plasma-sprayed yttria partially stabilized zirconia thermal barrier coatings, performed by classical and analytical transmission electron microscopy. The aim of the study was to determine eventual relationships between coating microstructure and toughness. The ceramic/metal interface, which plays an important role during TBC thermomechanical solicitation, has also been studied. In the 6--8 wt. percent Y[sub 2]O[sub 3] range, the metastable tetragonal t[prime] phase is observed, showing special faulted microstructural features, such as grain twinning and antiphase boundary planes. Moreover, after high-temperature annealing in air, a very fine and stable precipitation of the equilibrium cubic phase appears. It is believed that these microstructural elements could act as crack deviation sites and enhance the coatings' intrinsic toughness. Microstructural investigations of the alumina scales grown during high-temperature annealing reveal yttrium segregation at oxide grain boundaries as well as significant quantities of zirconium inside the alumina grains. The oxide growth seems to be dominated by a classical grain boundary oxygen diffusion mechanism. The presence of zirconium inside the alumina grains suggests that Al[sub 2]O[sub 3] also partially forms by chemical reduction of ZrO[sub 2] by Al.

Authors:
;  [1]
  1. O.N.E.R.A., Chatillon (France). Materials Science Dept.
Publication Date:
OSTI Identifier:
7237175
Resource Type:
Journal Article
Journal Name:
Journal of Engineering for Gas Turbines and Power; (United States)
Additional Journal Information:
Journal Volume: 116:1; Journal ID: ISSN 0742-4795
Country of Publication:
United States
Language:
English
Subject:
20 FOSSIL-FUELED POWER PLANTS; 36 MATERIALS SCIENCE; GAS TURBINES; HEAT RESISTANT MATERIALS; MICROSTRUCTURE; YTTRIUM OXIDES; ZIRCONIUM OXIDES; SPRAYED COATINGS; CHALCOGENIDES; COATINGS; EQUIPMENT; MACHINERY; MATERIALS; OXIDES; OXYGEN COMPOUNDS; TRANSITION ELEMENT COMPOUNDS; TURBINES; TURBOMACHINERY; YTTRIUM COMPOUNDS; ZIRCONIUM COMPOUNDS; 200104* - Fossil-Fueled Power Plants- Components; 360201 - Ceramics, Cermets, & Refractories- Preparation & Fabrication

Citation Formats

Alperine, S, and Lelait, L. Microstructural investigations of plasma-sprayed yttria partially stabilized zirconia TBC (in relation to thermomechanical resistance and high-temperature oxidation mechanisms). United States: N. p., 1994. Web. doi:10.1115/1.2906802.
Alperine, S, & Lelait, L. Microstructural investigations of plasma-sprayed yttria partially stabilized zirconia TBC (in relation to thermomechanical resistance and high-temperature oxidation mechanisms). United States. https://doi.org/10.1115/1.2906802
Alperine, S, and Lelait, L. 1994. "Microstructural investigations of plasma-sprayed yttria partially stabilized zirconia TBC (in relation to thermomechanical resistance and high-temperature oxidation mechanisms)". United States. https://doi.org/10.1115/1.2906802.
@article{osti_7237175,
title = {Microstructural investigations of plasma-sprayed yttria partially stabilized zirconia TBC (in relation to thermomechanical resistance and high-temperature oxidation mechanisms)},
author = {Alperine, S and Lelait, L},
abstractNote = {This study deals with microstructural investigations of plasma-sprayed yttria partially stabilized zirconia thermal barrier coatings, performed by classical and analytical transmission electron microscopy. The aim of the study was to determine eventual relationships between coating microstructure and toughness. The ceramic/metal interface, which plays an important role during TBC thermomechanical solicitation, has also been studied. In the 6--8 wt. percent Y[sub 2]O[sub 3] range, the metastable tetragonal t[prime] phase is observed, showing special faulted microstructural features, such as grain twinning and antiphase boundary planes. Moreover, after high-temperature annealing in air, a very fine and stable precipitation of the equilibrium cubic phase appears. It is believed that these microstructural elements could act as crack deviation sites and enhance the coatings' intrinsic toughness. Microstructural investigations of the alumina scales grown during high-temperature annealing reveal yttrium segregation at oxide grain boundaries as well as significant quantities of zirconium inside the alumina grains. The oxide growth seems to be dominated by a classical grain boundary oxygen diffusion mechanism. The presence of zirconium inside the alumina grains suggests that Al[sub 2]O[sub 3] also partially forms by chemical reduction of ZrO[sub 2] by Al.},
doi = {10.1115/1.2906802},
url = {https://www.osti.gov/biblio/7237175}, journal = {Journal of Engineering for Gas Turbines and Power; (United States)},
issn = {0742-4795},
number = ,
volume = 116:1,
place = {United States},
year = {Sat Jan 01 00:00:00 EST 1994},
month = {Sat Jan 01 00:00:00 EST 1994}
}