Development of a Novel Erosion Resistant Coating System for Use on Rotorcraft Blades

The costs associated with extended use of helicopters in erosive environments are well documented. Main and tail rotor blade erosion is among the leading drivers of a helicopter's cost per flight hour. Improved polyurethane coatings provide a means to reduce these costs but require frequent touch up to prevent more severe damage. Furthermore, these coatings offer little protection from damage resulting from debris raised in the sand cloud generated during takeoffs and landings. An erosion resistant approach, developed in collaboration with AATD, ARL, United Technologies Research Center (UTRC) and Sikorsky utilizes a two part metal/cermet coating system on the leading edge of the blades to provide unmatched protection from sand, rain, and debris erosion. Tungsten carbide cobalt (WC-Co) is applied on the leading edge nose of the blade for direct impingement protection. Niobium is applied aft of the nose for indirect impingement protection. This paper will present techniques utilized to manage the process to meet the requirements of a fully functional coating without thermal damage to an expensive composite component.