Fluorescence
spectroscopy is a common technique used to monitor
early metallic corrosion. The fluorescence response characteristics
of rhodamine-ethylenediamine toward Cu
2+
have been studied
using fluorescence and infrared spectroscopy. Fluorescence microscopy
and electrochemical impedance spectroscopy were used to study the
monitoring effect of rhodamine-ethylenediamine on the corrosion of
copper relics protected by an epoxy coating. The results showed a
strong fluorescent response and selectivity toward Cu
2+
that existed using rhodamine-ethylenediamine. Early metallic corrosion
of copper relics can be effectively monitored upon adding 0.8 wt %
rhodamine-ethylenediamine to an epoxy coating. When the soaking time
was increased, the fluorescence intensity of the fluorescent area
on the coating became stronger. In addition, the area of the luminous
coating reached ∼0.06 mm
2
and the area of corrosion
under the protective coating was ∼0.008 mm
2
, which
was about 1/10 of the fluorescence area observed on the coating.