Evaluation of Corrosion Behavior of AISI ۴۳۰ Ferritic Steel Coated With Aluminum, Titanium and Aluminum - Titanium by Pack Cementation Method in NaCl ۳.۵%

In this research, the electrochemical behavior of AISI ۴۳۰ ferritic stainless steel at presence of Al, Ti and simultaneous co-deposition of Al-Ti diffusional coatings were studied in the simulated marine environment (NaCl ۳.۵%). To determine the microstructure and phases of the coatings, scanning electron microscopy (SEM) and X-ray diffraction (XRD) was used. To evaluate the corrosion resistance of coatings, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods were used. Electrochemical polarization results showed that co-deposition of Al-Ti coating has better corrosion resistance (۴.۵۵×۱۰-۴ μA.cm-۲) in comparison to Al (۳.۲۱×۱۰-۲ μA.cm-۲) and Ti (۳.۶×۱۰-۲ μA.cm-۲) coatings. Also the results of electrochemical impedance showed that co-deposition of Al and Ti have higher charge transfer resistance of electric double-layer in comparison with Al and Ti coatings.

Keywords:

Corrosion , Al , Ti , Polarization , Electrochemical impedance , خوردگی , آلومینیوم , تیتانیوم , پلاریزاسیون , امپدانس الکتروشیمیایی