Executive Summary 3 Thermal barrier coating (TBC) ceramic topcoats made from Y 2 O 3-stabilized ZrO 2 (YSZ) have been used successfully in gas-turbine engine applications for more than 30 years. YSZ derives its favorable performance from a combination of properties that include low thermal conductivity, high thermal expansion coefficient, and phase stability to relatively high temperatures. Wit...

The thermal barrier coating (TBC) of jet engine turbines permits operation at what otherwise would be prohibitively high temperatures. Ideally, a jet engine should operate at very high temperatures to maximize fuel efficiency and power. Combustion gases are often held at temperatures above 1370° C, while engine metal superalloys have melting points that range between 1230° and 1315° C. As a res...

Thermal barrier coating (TBC) systems are coating systems containing a metallic bond coat and a ceramic top coat. TBCs are used in gas turbines for thermal insulation and oxidation resistance. Life prediction of TBCs is important as high-temperature exposure degrades the coatings through mechanisms such as thermal fatigue and the formation and growth of thermally grown oxides (TGOs). This thesi...

Micromechanical models are developed to explore the effect of embedded metal layers upon thermal cycling delamination failure of thermal barrier coatings (TBCs) driven by thickening of a thermally grown oxide (TGO). The effects of reductions in the steady-state (i.e. maximum) energy release rate (ERR) controlling debonding from large interface flaws and decreases in the thickening kinetics of T...

Thermal barrier coating are perceived as an enabling technology to increase the performance of, improve efficiency within, and lower the emissions from, modern gas turbines. To fully utilise this capability one has to be able to accurately predict the life of these coatings under conditions relevant to gas turbine service. This paper addresses the failure of TBC systems as a result of erosion a...

Multilayer thermal barrier coatings (TBCs) deposited on superalloy turbine blades provide protection from combustion temperatures in excess of 1500 1C. One of the dominant failure modes comprises cracking from undulation growth, or rumpling, of the highly compressed oxide layer that grows between the ceramic top coat and the intermetallic bond coat. In this paper, a mechanistic model providing ...

Progress in gas-turbine engine (GTE) manufacturing is continuously linked with a rise of operating temperature and stresses of engine gas path elements, especially the turbine parts. More advanced cooling systems, structural materials and thermal barrier coatings (TBC) and other coatings provide the required life and strength reliability of these components. While engines are in use, the necess...

We have theoretically investigated the effect of a coating made of the elastically dissimilar material on the acoustic phonon properties of semiconductor nanowires. It is shown that the acoustic impedance mismatch at the interface between the nanowire and the barrier coating affects dramatically the phonon spectra and group velocities in the nanowires. Coatings made of materials with a small so...