Materials Aspects of Thermal Barrier Coatings
Thermal barrier coatings (TBCs) are being used for the past few decades for providing thermal insulation to metallic components of hot parts of gas turbine engines. The low thermal conductivity ceramic coatings contribute toward maintaining a large temper
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Ashutosh S. Gandhi
Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bond Coats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Thermal Barrier Coatings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Yttria-Stabilized Zirconia TBCs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Testing and Characterization of TBCs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Factors Affecting the Durability of YSZ Thermal Barrier Coatings . . . . . . . . . . . . . . . . . . . . . . New Materials for TBCs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Guidelines for Obtaining Low Thermal Conductivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Abstract
Thermal barrier coatings (TBCs) are being used for the past few decades for providing thermal insulation to metallic components of hot parts of gas turbine engines. The low thermal conductivity ceramic coatings contribute toward maintaining a large temperature difference between the hot gases in the gas turbine and the superalloy components. High engine efficiency as well as prolonged component lifetime can be achieved by integrating TBCs with gas turbine components at the design stage itself. While yttria-stabilized zirconia emerged as the work-horse TBC material, a few other advanced compositions are also being used by some of the engine manufacturers. Prominent among these are zirconiabased compositions with rare-earth oxide additions, either with tetragonal or pyrochlore structure. A lot of research activity has focused on durability issues relevant to the TBC technology, for enhancing reliability as well as performance. Phase transformations, oxidation-induced residual stress, changes in fracture A. S. Gandhi (*) Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai, India e-mail: [email protected] © Springer Nature Switzerland AG 2020 Y. R. Mahajan, R. Johnson (eds.), Handbook of Advanced Ceramics and Composites, https://doi.org/10.1007/978-3-030-16347-1_50
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toughness, and thermochemic
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