Erosion Resistant Titanium Nitride Coating for Turbine Compressor Applications

While operating in dusty environments, the blades and vanes in turbine compressors are prone to degradation by solid particle erosion which causes surface roughening as well as loss of airfoil contour and changes in airfoil geometry. This results in decreased compressor performance, higher specific fuel consumption, and significantly increased operational costs. Erosion damage is more prominent in flight engines that cannot be protected by inlet filters.This paper describes the development and application of a thin ceramic titanium nitride coating to improve the erosion resistance of compressor airfoils. The coatings were produced by a Reactive Ion Coating (RIC) process and optimized to produce a very adherent erosion resistant coating structure.The coating process was successfully scaled up and applied to a complete Allison T56 compressor for engine test. The control laboratory tests showed that the thin coating had no significant influence on either the resonance frequency or the fatigue resistance of the blades and the instrumented engine tests confirmed that the performance was typical of overhauled engines. Therefore, titanium nitride coatings are suitable for service and can be retrofitted on existing engines to improve the life of the compressors.Copyright © 1992 by ASME