A limited-scan backscatter technique for detection of hidden corrosion

A photon backscatter technique to detect corrosion hidden beneath an obstructing surface layer was investigated. The technique is sensitive to both composition and density changes resulting from corrosion in metals; further, the sensitivity of some system variables to corrosion-like conditions affords opportunity for design optimization and corrosion characterization. The primary application of the technology is in non-destructive evaluation of critical structures, such as aircraft, for detecting hidden and inaccessible corrosion.