Development of Nanosteel Chrome Replacement HVOF Coatings on High Strength Steel Components

High Velocity Oxygen Fuel (HVOF) tungsten carbide, WC-Co, WC-Co-Cr coatings have been in development for two decades for chrome replacement in aerospace applications and implemented on many components. These coatings have been limited for High Strength Steel (HSS) Landing Gear component applications due to spallation where the substrates stress levels approach yield. Now that chrome plating OSHA Permissible Exposure Limits (PEL) have been significantly reduced, the parts subjected to high stress applications need a suitable chrome replacement option for which HVOF nanosteel coatings show promise. This requirement has been identified for HSS landing gear applications and will most likely follow in similar aircraft applications such as flap and slat tracks, actuators, propeller systems and other engine / aircraft support structure. This proposal will discuss the development and qualification requirements and related concerns to replace these chrome plating applications on highly stresses HSS components with HVOF nanosteel coatings that will meet the original design criteria.