METHODS (1)
ELECTROCHEMICAL IMPEDANCE MEASUREMENTS
- instruments: EG&G Potenziostat/Galvanostat mod. 273A and Frequency Response Analyser FRA 1255.
- operating parameters: three-electrode cell. 3% NaCl aqueous solution, frequency range: 10mHz- 100kHz, ac amplitude: 20mV vs open circuit potential.
- data analysis: fitting with equivalent circuit:
Ru: resistance of the electrolyte
Rp: pore resistance of the coating
Z: general impedance, which models the corrosion reaction