Development and Optimization of HVOF Applied Carbide Erosion Resistant Coatings for Large Compressor and Fan Airfoils in STOVL Aircrafts

Short Take-off and Vertical Landing (STOVL) aircrafts will operate in desert environments and suffer from impact and erosion caused by particles ingested into the engines and lift fans. The effects of such ingestion and damage to the engine compressor and fan can result in loss of aircraft system performance and safety of flight. Solid particle erosion resistant coatings are required for protecting aircrafts operating in such environments to improve the engine performance and safety-of-flight. Historically, the application of erosion-resistant coatings in the compressor section of helicopter engines has resulted in increased engine time-on-wing and engine performance retention. However, the same coating systems may not be applicable directly onto the large-sized airfoils in STOVL aircrafts. The authors proposed to apply HVOF carbide coatings for erosion resistance of the airfoils. The advantage of the HVOF technology is that it enables the application of various coatings on those large components with good erosion resistant properties. Unique powder morphology and optimal nano-structures of the proposed HVOF sprayed coatings were proven to provide superior erosion resistant properties. The optimal coatings were developed by design of experiments (DOE) statistical technique, and the resultant coatings were characterized for their erosion behavior, physical and mechanical properties in details.