Corrosion Monitoring Of Sacrificial Anodes Based On Contour Plot Analysis Of Electro-Mechanical Impedance Spectra

In this paper, we utilize a graphical technique originally proposed for damage assessment in beams, to determine the extent of corrosion of sacrificial zinc anode discs instrumented with piezoelectric transducers using Electro-Mechanical Impedance (EMI) measurements. The underlying parameters determining extent of corrosion (thicknesses of the zinc and zinc oxide films) are extracted from measured resonance frequencies of radial and transverse vibration modes by finding roots of the characteristic equations of these modes graphically through contour plot. This technique shows excellent agreement with experimental results, requires no calibration and is computationally inexpensive unlike optimization techniques.