New Method Using Bilinear Transformation for Parameter Identification of Anticorrosion Coatings

− The paper presents a new method of anticorrosion coatings diagnostics using bilinear transformation. It is possible to identify the parameters of the equivalent circuit of the coating on the basis of object impedance measurement at a few, optimally selected measurement frequencies. The rules of optimal frequency selection are given. The number of frequencies is equal to the number of the equivalent circuit components. The developed identification algorithm enables continuous monitoring of the coating performance. The main advantage of the method is a few (more than 10) times shorter identification process compared to traditional identification technique based on impedance spectroscopy followed by impedance spectrum fitting using computer programs (e.g. LEVM or EQUIVCRT), which are utilising complex non-linear least squares (CNLS) method.