Gas turbine engines operate under punishing conditions, with temperatures regularly exceeding 800°C, or 1,470°F. These conditions can accelerate wear, increase friction, and shorten component life. Researchers at Concordia University have developed a ceramic coating designed to address these problems while repairing cracks caused by repeated heating and cooling, tells Tech Xplore.
The research was led by Andre Mayer, a postdoctoral researcher in Concordia University’s Department of Chemical and Materials Engineering. Working at the university’s Thermal Spray and Surface Engineering Research Center, Mayer investigated the role of oxides that form naturally on engine components. Although oxidation is often associated with material degradation, certain oxides can form protective layers that prevent metal surfaces from sticking together at high temperatures.
The researchers sought to reproduce this beneficial behavior in a controlled coating. They developed a ceramic layer made from cobalt and chromium oxides that mimics naturally occurring glaze layers. These glaze layers normally develop only under specific operating conditions and on certain engine components. Applying similar chemistry directly to a component could provide protection even where natural glaze layers would not normally form. The coating is approximately as thick as a human hair.
Tests under simulated engine conditions showed improvements in wear and friction. More significantly, the coating demonstrated self-healing behavior. Extreme heat caused metal expansion and produced cracks in the coating. As the material cooled, however, researchers observed that the cracks repaired themselves and disappeared, preserving the coating’s integrity.
The technology could help extend gas turbine engine life while reducing maintenance requirements. Its composition may also address rising costs and supply concerns associated with commonly used engine materials. The patent-pending technology was developed with aerospace applications in mind, but researchers believe the same principle could protect components in other engineering systems exposed to extreme operating environments.
