This paper reviews the advantages and disadvantages of various thermal barrier coatings (TBC) systems, with the aim of custom designing a TBC system to be both strain tolerant and have a low thermal conductivity.Methods of heat transfer within zirconia based ceramics are discussed, including the influence of coating microstructure and ceramic composition. It is shown the addition of dopant atoms (colouring) is effective in reducing 'phonon' transport while that layered microstructures are effective in reducing 'photon' transport.Advanced processing, using EB-PVD coating methods has allowed both coloured and layered ceramic coatings to be produced. Measured thermal conductivities of 1.0 W/mK have been achieved using these methods, much lower than current commercial EB-PVD coatings at 1.5-1.9 W/mK.
Surface engineering is now a key materials technology in the design of future advanced gas-turbine engines. This article focuses on coating systems for hot-gas-path components, which can vary from low-cost aluminide diffusion coatings to the more exotic, and therefore expensive, thermal-barrier coatings. Available coating systems and their relative benefits are reviewed in terms of performance against manufacturing complexity and cost. Future trends in the design of environmental- and thermal-protection coatings are discussed, including the addition of multiple reactive elements, modified aluminide coatings, diffusion-barrier concepts, the design of “smart” corrosion-resistant coatings, and the development of structurally modified, low-thermal-conductivity thermal-barrier coatings.
Overview Oxidation ResistanceThis article examines the historical development of high-temperature, oxidation-and corrosion-resistant coatings, demonstrating how diffusion surface treatments, modified diffusion coatings, the design of M-Cr-Al-X corrosion-resistant overlay coatings, and the application of thermal-barrier coatings can be used to reduce the scaling (oxidation) rate of coated components. Future trends in hightemperature coating design are also reviewed, including the custom design of corrosionresistant alloys, smart overlay coating concepts, diffusion barriers, and the use of layered thermal-barrier coating structures. INTRODUCTIONSurface engineering plays an important role in the operation of all hightemperature plants, whether for power generation, chemical processing, or component heat treatment. In its simplest form, the surface engineering of structural alloys results from the growth of a protective oxide, due to the selective oxidation of alloying additions within the alloy. The desire for higher operating temperature; improved performance; extended component lives; and cleaner, more fuel-efficient power plant/processes places severe demands on the structural materials used to construct such a high-temperature plant. As a result, many components operating at high temperature within such plants are coated or surface treated.The use of coatings, or surface treatments, permits the separation (or partial separation) of surface-and substrate-
An international working party was convened in Rome, Italy on 16-17 June, 2005, with the purpose of developing a consensus on the application of the circular stapling instrument to the treatment of certain rectal conditions, the so-called Stapled Transanal Rectal Resection (STARR). Since the procedure has been submitted to only limited objective analysis it was felt prudent to hold a meeting of interested individuals for the purpose of evaluating the current status and to make conclusions and recommendations concerning the applicability of this new approach.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.