Bond Coating Helps Turbines Resist Heat

Aero-News has learned Rolls-Royce Corp. recently acquired exclusive rights to use a coating invented by Iowa State University researchers, that helps turbines stand up to the heat in jet engines.

The unique bond coating will be applied to engine turbine blades made of nickel-based superalloys. Those superalloys are designed for strength but need help withstanding metal temperatures approaching 2,100 degrees Fahrenheit inside the hot section of a jet engine, said Brian Gleeson, Iowa State's Alan and Julie Renken Professor in Materials Science and Engineering and a co-inventor of the coating.

The bond coating improves the durability and reliability of a ceramic thermal barrier that's applied over the bond coat, said Daniel Sordelet, a senior scientist and group leader for the US Department of Energy's Ames Laboratory on the Iowa State campus and a co-inventor of the technology. 

"This coating composition is very good in terms of performance," Gleeson said. "It offers significant advantages over existing coating technologies."

"This new coating offers excellent oxidation resistance," added Dr. William J. Brindley, the chief technologist for Rolls-Royce Corp. "It's a new concept in coatings and a real step forward in understanding how and why coatings work. The technology also represents a remarkably quick transition from fundamental science to practical application."

Gleeson said the coating is based on a composition comprising platinum, nickel, aluminum and hafnium. It was invented by Gleeson, Sordelet and Wen Wang, a former Iowa State postdoctoral student. Gleeson, Sordelet, Brindley and Bingtao Li, a former Iowa State doctoral student and postdoctoral researcher, also developed a cost-effective method for applying the coating to engine parts.

Nita Lovejoy, the associate director of the Iowa State University Research Foundation, Inc., said Rolls-Royce will have an exclusive license to commercialize the inventions. She said patents are pending for the inventions and the term of the license agreement is for the life of any patents. She also said the license has the potential to be an important source of revenue for the research foundation.

Inventions developed at Iowa State are protected by the research foundation with patents and are transferred for commercial use under licenses. Any licensing revenues after expenses and administrative fees are split among the inventor, the inventor's college within the university and the research foundation. The research foundation supports itself and the Office of Intellectual Property and Technology Transfer with its share of the revenues and provides grants to support Iowa State research programs.

Sordelet said the coating compositions grew out of basic research that began about seven years ago and was supported by the Office of Naval Research. He said a key advantage to this technology is that it is mechanically compatible with the superalloys it covers and protects. It reacts to the heat and stress of an engine about the same way the superalloy does. And that gives the coating composition -- and therefore the engine parts -- better performance and a longer life.

The Iowa State researchers continue to work on the coating composition project. Sordelet said they're hoping to develop a better and cheaper way to produce the coating. They're also looking for new coating compositions and new ways to deposit them on materials.

"We say that we put science to practice," Gleeson said, referring to the "Science with Practice" motto on the university seal. "And this is an excellent example of that."

The coating won a prestigious R&D 100 Award in 2005. The annual awards have been called the "Oscars of applied science" by the Chicago Tribune, according to Iowa State.

FMI: www.iastate.edu, www.rollsroyce.com