In-situ process for the monitoring of localized pitting corrosion

A method and apparatus are provided for monitoring localized pitting corrosion in metal pipes or storage vessels. Electrochemical probes are used for sensing electrochemical noise voltage values and electrochemical noise current values. The root-mean-square electrochemical noise current and voltage values are calculated and stored for the sensed electrochemical noise voltage values and the electrochemical noise current values. The stored electrochemical noise current and voltage values are processed by transforming the stored electrochemical noise current and voltage values into power spectral density data utilizing a fast Fourier transform. A slope of the power spectral density data relative to frequency is calculated. The electrochemical probes include a pair of working electrodes formed of the same material of the monitored metal pipes or storage vessels and a reference electrode formed of a corrosion resistant material. A linear slope of a low-frequency portion of the power spectral density data is calculated by using a least-square method.