Title

Sintering, Phase Stability, and Thermal Conductivity of Plasma Sprayed Gd₂O₃-stabilized ZrO₂

Alternative Title

Sintering, phase stability, and thermal conductivity of plasma sprayed Gd2O3-stabilized ZrO2

Abstract

Thermal barrier coatings (TBCs) made of Y2O3-stabilized ZrO2 are used extensively to protect and insulate the metallic structure of advanced gas turbine engines. For applications that require prolonged exposure to temperatures above 1000-1200 DGC, structural changes produced by sintering and phase transformation limit the durability of the coatings. The objective of the present study was to investigate the use of Gd2O3 as an alternative stabilizer for ZrO2-based TBC materials. The influence of Gd2O3 concentration (4-20 mole percent) on the sintering and phase stability of plasma-sprayed ZrO2 powders was investigated and the data were compared with those for Y2O3-stabilized ZrO2. At an equivalent concentration (4 mole percent), Gd2O3stabilized ZrO2 sintered more slowly but had a lower resistance to destabilization of the metastable tetragonal (t') phase, when compared to Y2O3-stabilized ZrO2. The thermal conductivity of G42O3-stabilized ZrO2 was lower than that for Y2O3-stabilized ZrO2. Mechanisms for the effect of Gd2O3 on the behavior of ZrO2 are discussed.

Department(s)

Materials Science and Engineering

Keywords and Phrases

Ceramic Coatings; Gas Turbine Engines; Heat Transfer; Phase Stability; Phase Transformations; Protective Coatings; Sintering (Powder Metallurgy); Thermal Barrier Coatings; Thermal Conductivity; Zirconium Dioxide

Document Type

Article - Conference proceedings

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2005 American Ceramic Society, All rights reserved.

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