Infrared Differential Reflectometer for Rapid Inspection of Aircraft Subsurface Corrosion

Subsurface corrosion has been implicated in a number of incidents in which aircraft have demonstrated a loss of structural integrity leading to emergency procedures and in one case, the loss of human life. Although several techniques are available to evaluate subsurface corrosion, no method has shown the ability to scan rapidly a wide area of the aircraft to alert maintenance personnel to the need for intensive inspection procedures. To meet this need, this proposal suggests the development of an infrared differential spectral reflectometer for detection of corrosion products beneath coated aircraft surfaces. The proposal is innovative in combining differential reflectance spectroscopy for in situ electrochemical evaluation of materials with infrared image detection to provide a noncontact, electrochemical, nondestructive evaluation method for aircraft inspection. The Phase I Technical Objectives include the development of an accelerated corrosion facility, acquisition of families of test data, application of signal processing procedures, and optimization of the Phase I instrument for development in Phase II of the program.