Terahertz reflective imaging of damage mechanisms in the coating on metal substrate

Terahertz reflective imaging is applied to characterize the damage mechanisms in the coating on metal substrate after aging. THz frequency-wavelet deconvolution is designed to resolve the overlapping echoes due to the optically thin coating. With the decovolved THz data, different types of damages including corrosion, blisters and delamination are characterized quantitatively in three dimensions.