Development of Corrosion Sensor Technology for Rotorcraft

Corrosion of rotorcraft transmission gear boxes is dependent on the atmospheric exposure cycles experienced during flight and storage of the rotorcrafts. The development of location specific corrosion sensors and atmospheric corrosion sensors for commercial and military rotorcraft is part of an Aviation Applied Technology Directorate Operation Support and Sustainment Technology (OSST) program aimed, in part, at developing and implementing corrosion evaluation sensor technology for an onboard rotorcraft transmission gearbox corrosion diagnostic and prognostic health monitoring system. Typical gearbox components consist of dissimilar metals made of magnesium, aluminum, and/or steel alloys. Even though the mating surfaces are sealed to prevent galvanic corrosion, aging, and/or mechanical damage of the protective coatings during assembly or flight promote the creation of crevices susceptible to corrosion. This work tested the application feasibility for various environment and material loss sensor technologies intended to be implemented as corrosion monitoring devices onboard rotorcraft gearboxes for the detection and monitoring of corrosive environments and material loss in realtime. The work presented in this paper includes the testing of three environment sensors: wetness interdigitated sensors, corrosivity interdigitated sensors, and miniaturized multi-electrode array sensors (mMAS) as well as the testing of a material loss sensor: magnetostrictive sensor.