Polarimetric mmW/THz Imaging Reflectometer for Non-destructive Inspection of Corrosion and Adhesion Defects Under Thick Polymer Coatings on Submersed Ship Hulls

Early detection of the corrosion and corrosion-induced defects under protective coatings and treatments is critical to improve the operational safety US Navy’s fielded assets and minimize mission downtime. The corrosive nature of the maritime environment is especially detrimental on many strategic assets and US Navy’s Global Fleet needs perpetual maintenance. Assessment of degradation and defects through visually-opaque paints and thick polymer coatings involve destructive removal of large sections of such coatings. Evidently, this process is labor-intensive and costly, resulting in very long maintenance and down-time while generating hazardous waste. An effective, low-cost, portable non-destructive inspection (NDI) method to detect and classify detrimental defects, delamination, de-bonding, corrosion, water/dust intrusion, as well as surface metal loss is badly needed to minimize maintenance/down-time of Navy’s assets, as well as to reduce the labor costs and environmental impact. To address this urgent necessity and unique challenges for effective NDI of defects, delamination, and various types of corrosion under thick coatings of submerged surfaces of ships, we propose to develop a novel, submersible sensor pod that houses a millimeter-wave polarimetric imaging reflectometer based on commercially-available radar chips. We will demonstrate the performance of the proposed polarimetric sensor and develop an autonomous/remotely-operated NDI system for detecting and classifying corrosion, defects, delamination, de-bonding, liquid agent intrusion, as well as surface metal loss under very thick polymer coatings utilized on the main hulls of Navy assets.