Application of Electrochemical Frequency Modulation (EFM) to Monitor Localized Corrosion and Efficiency of Green Inhibitors (Toepassing van de elektrochemische frequentie modulatie (EFM) techniek voor het monitoren van lokale corrosie en de efficientie van milieuvriendelijke ("groen") inhibitoren)
Application of Electrochemical Frequency Modulation (EFM) to Monitor Localized Corrosion and Efficiency of Green Inhibitors
Rauf, Abdul; S0015953
Amongst existing electrochemical measuring techniques for uniform corrosion, (e.g. LPR, EIS, etc), EFM (Electrochemical Frequency Modulation) has emerged as a promising technique with enormous untapped potential. Besides its use for determining the corrosion rate without a prior knowledge of the so-called Tafel constants, EFM offers the measurement of the corrosion rate, Tafel parameters and causality factors (CFs) in a single set of data. The experimental base for detecting localized corrosion (LC) through EFM was devised through investigating three types of LC (Pitting, Crevice, and Stress Corrosion Cracking - SCC) followed by comparative analysis between EFM and EN, and the use of EFM for the screening of corrosion inhibitors. The three types of LC were investigated through measuring the various behaviors in the so-called "causality factors", which are calculated from the ratio of the current components in the AC-response. CFs, resulting from an EFM test and in the ideal case having values of 2 and 3 respectively, are normally used for quality and data validation purposes. While investigating pitting corrosion, they showed different behavior leading to the CPT (critical pitting temperature) detection.The results showed that in most cases the CFs do change when the system goes from uniform corrosion to crevice corrosion.