Low-cost electrochemical impedance spectroscopy system for corrosion monitoring of metallic antiquities and works of art

Electrochemical impedance spectroscopy (EIS) is recognised to be a powerful and non-invasive technique to test the integrity of protective coatings on memorials, but commercial EIS systems are rather costly though versatile devices. This paper describes a low cost and portable EIS system that is based on a compact DSP board. Such an EIS system employs a front end, which is based on a transimdedance amplifiers, and embeds the potentiostatic functions so that the EIS system can be used without requiring an external potentiostat. The software that runs on the DSP is designed to analyse the electrochemical impedance only in a reduced frequency range in order to produce a simple "corrosion alert" result. The device is equipped with a digital interface and can be connected to a portable personal computer to carry out a complete frequency analysis and perform a more complex data processing.