0

Full Content is available to subscribers

Subscribe/Learn More  >

Role of Platinum in Thermal Barrier Coatings Used in Gas Turbine Blade Applications

[+] Author Affiliations
H. M. Tawancy, Luai M. Al-Hadhrami

King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia

Paper No. GT2009-59153, pp. 765-776; 12 pages
doi:10.1115/GT2009-59153
From:
  • ASME Turbo Expo 2009: Power for Land, Sea, and Air
  • Volume 4: Cycle Innovations; Industrial and Cogeneration; Manufacturing Materials and Metallurgy; Marine
  • Orlando, Florida, USA, June 8–12, 2009
  • Conference Sponsors: International Gas Turbine Institute
  • ISBN: 978-0-7918-4885-2 | eISBN: 978-0-7918-3849-5
  • Copyright © 2009 by ASME

abstract

Current technology of thermal barrier coating systems used in gas turbine blade applications relies upon the use of a metallic bond coat, which has a two-fold function: i) it develops a thin layer of aluminum oxide enhancing the adhesion of the ceramic top coat, and ii) it provides an additional resistance to oxidation. It was the objective of this study to develop an understanding of the role of platinum in bond coats of the diffusion-type deposited on a nickel-base superalloy. Two Pt-containing bond coats were included in the study: i) a platinum-aluminide and ii) a bond coat formed by interdiffusion between an electroplated layer of platinum and the superalloy substrate. In both cases, the top ceramic coat was yttria-stabilized zirconia. For reference purposes, a simple aluminide bond coat free of Pt was also included in the study. Thermal exposure tests at 1150 °C with a 24-hour cycling period to room temperature were used to compare the coating performance. Microstructural features were characterized by various electron-optical techniques. Experimental results indicated that Pt acts as a “cleanser” of the oxide-bond coat interface by decelerating the kinetics of interdiffusion between the bond coat and superalloy substrate. This was found to promote selective oxidation of Al resulting in a purer Al2 O3 scale of a slower growth rate increasing its effectiveness as “glue” holding the ceramic top coat to the underlying metallic substrate. However, the exact effect of Pt was found to be a function of the state of its presence within the outermost coating layer. Of the two bond coats studied, a surface layer of Pt-rich gamma prime phase (L12 superlattice) was found to provide longer coating life in comparison with a mixture of PtAl2 and beta phase. This could be related to the effectiveness of gamma prime phase as a sink for titanium minimizing its detrimental effect on the adherence of aluminum oxide.

Copyright © 2009 by ASME

Figures

Tables

Interactive Graphics

Video

Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature

Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal

NOTE:
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In