Fake diamonds help jet engines take the heat

Ceramic coating designed to resist molten glass (which is in a thin layer on top). The field of view is about half a millimeter. Click here for more information.

COLUMBUS, Ohio -- Ohio State University engineers are developing a technology to coat jet engine turbine blades with zirconium dioxide -- commonly called zirconia, the stuff of synthetic diamonds -- to combat high-temperature corrosion.

The zirconia chemically converts sand and other corrosive particles that build up on the blade into a new, protective outer coating. In effect, the surface of the engine blade constantly renews itself.

Ultimately, the technology could enable manufacturers to use new kinds of heat-resistant materials in engine blades, so that engines will be able to run hotter and more efficiently.

Nitin Padture, professor of materials science and engineering at Ohio State, said that he had military aircraft in mind when he began the project. He was then a professor at the University of Connecticut.

“In the desert, sand is sucked into the engines during takeoffs and landings, and then you have dust storms,” he said. “But even commercial aircraft and power turbines encounter small bits of sand or other particles, and those particles damage turbine blades.”

Jet engines operate at thousands of degrees Fahrenheit, and blades in the most advanced engines are coated with a thin layer of temperature-resistant, thermally-insulating ceramic to protect the metal blades. The coating -- referred to as a thermal-barrier coating -- is designed like an accordion to expand and contract with the metal.

The problem: When sand hits the hot engine blade it melts -- and becomes glass.

“Molten glass is one of the nastiest substances around. It will dissolve anything,” Padture said.