For release: July 6, 2005

Contacts: 
Brian Gleeson, Ames Laboratory (515) 294-4446
Daniel Sordelet, Ames Laboratory (515) 294-4713
Saren Johnston, Ames Laboratory (515) 294-3474
Mike Krapfl, ISU News Service (515) 294-4917

AMES LABORATORY SCIENTISTS WIN R&D 100 AWARD FOR
A DISCOVERY THAT IMPROVES JET ENGINES

AMES, Iowa – Two researchers at the U.S. Department of Energy’s Ames Laboratory and Iowa State University have won a prestigious R&D 100 Award for a coating that may allow gas turbine engines in jet aircraft and other power-generating technologies to better withstand severe, high-temperature environments.

The thermal barrier coating, developed by Brian Gleeson and Dan Sordelet, significantly improves reliability and durability of turbine blades, thus enabling higher operating efficiencies and extending engine life. According to Tim Studt, the editor in chief of R&D magazine, the coating was among the top 100 products of technological significance that were marketed or licensed during the previous calendar year. The R&D 100 Awards, now in their 43rd year, have been called the “Oscars of applied science” by the Chicago Tribune.

This is the 15th R&D 100 Award won by Ames Laboratory and the 27th overall for Iowa State University researchers. The award is the first for both Gleeson, the director of the materials and engineering physics program at Ames Laboratory and a professor of materials science and engineering at ISU, and Sordelet, who is a senior scientist at the Ames Laboratory and an adjunct assistant professor of materials science and engineering at ISU.

“This is quite an honor to be selected for such a prestigious award,” Gleeson said. “I also think winning the award is a credit to ISU and the Ames Lab and the excellent support that they provide. This is really a fantastic place to do research.”

Gleeson and Sordelet have conducted the research for Iowa State with support from Ames Laboratory for about four years. Their work has been supported by more than $1 million from the Office of Naval Research, the Wright-Patterson Air Force Base and the Rolls-Royce jet engine manufacturing company, which is also helping test the coatings.

“This award demonstrates that DOE scientists and researchers are hard at work developing the technologies of the future,” said Secretary of Energy Samuel W. Bodman. “In the past, breakthroughs like this have played an important role in both our economic and national security.”

“It would be difficult to overestimate the importance of these novel coatings,” said Ames Lab Director Tom Barton, “in enhancing the capabilities of the next generation of jet engines in commerical and military aviation.”

Commercial thermal barrier coatings consist of three layers. The first layer is typically an aluminum-rich bond coat that is based on the compound nickel-aluminum, or NiAl. The bond coat is applied directly to the turbine blade. The second layer is a thin, thermally grown oxide, or TGO, which forms as the aluminum in the bond coat oxidizes. The third layer, a thin (around half a millimeter) ceramic top coat, has a low thermal conductivity and, therefore, acts as a barrier against heat damage.

“By applying a thermal barrier coating to a turbine blade, it is possible to increase the combustion temperature of the engine, which leads to significantly improved efficiency in gas turbines,” said Sordelet. He added that the ability of the bond coat to oxidize and form a continuous, slow-growing and adherent TGO layer is critical to creating a resilient and reliable thermal barrier coating.

Quite unexpectedly, the two researchers found that the addition of platinum significantly improved the oxidation resistance of nickel-rich bulk alloys having the same type of structure as the turbine alloy and that the platinum changed the diffusion behavior of aluminum in their nickel-rich compositions.

“Instead of aluminum going from the bond coat down into the substrate, it was moving up from the substrate into the bond coat,” Gleeson explained. “This phenomenon is referred to as ‘uphill diffusion,’ and it’s a consequence of the strong chemical interaction between aluminum and platinum. With our new bond coating compositions, the substrate can act as a large reservoir for aluminum and hence maintain the protective growth of the oxide layer.”

This year’s R&D 100 Awards will be featured in the September issue of R&D 100 magazine. The winners will be recognized at a Chicago banquet in October.

Ames Laboratory is operated for the Department of Energy by Iowa State University. The Lab conducts research into various areas of national concern, including energy resources, high-speed computer design, environmental cleanup and restoration, and the synthesis and study of new materials.

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