Coating degradation monitoring

Impedance is a complex quantity that represents the ratio of voltage to current, indicating the ease or difficulty of current flow in an alternating current (AC)circuit (i.e., resistance). By using measuring equipment, a small AC voltage is applied to the object under test, and the resulting response current is detected. The value obtained by dividing the voltage by the current (impedance) serves as an indicator of the degradation level of the tested object. In other words, a lower measured impedance indicates a higher degree of coating deterioration, implying a more significant loss of protective function of the paint film