A Sensor System Designed for Electrochemical Impedance Spectroscope-based Coating Performance Evaluation

Abstract

One of the traditional methods for coating performance evaluation is using Electrochemical Impedance Spectroscopy (EIS). The theory of using EIS to evaluate coating performance is to measure the coating impedance in a frequency range of 0.01 Hz to 100 KHz. Based on the observation of a number of the EIS data, the coating impedance variation trend in low frequency range has a corresponding impedance variation trend in high frequency range. Based on this idea, this work introduces an EIS-based sensor system designed for coating performance evaluation. The sensor system consists of one base station and one sensor node. Wireless communication is realized between the sensor node and the base station. The sensor node is smaller than a business card in size. Evaluation time is less than 10 seconds in the operation frequency range between 20 90 kHz. Three coated panels were used for testing. Testing results are presented for both the EIS instrument and the sensor system. Good correlations indicate that this new technique is valid for EIS based coating performance evaluation in high frequency range. The sensor system is powered by batteries. The power consumption is •120 m W which is lower than the commercial ElS instrument The sensor system is portable and easy to use in real time for fieId coating performance evaluation.