Effect of ionic resistance on cathodic delamination resistance of bituminous coatings

Two types of bituminous coating, bitumen and coal tar pitch, were investigated using electrochemical impedance spectroscopy (EIS) and cathodic delamination measurements. The softening point of both bituminous materials was 80oC. The Bituminous coatings applied on shot blasted steel with 100 µm thickness and then subjected to EIS and cathodic delamination tests in %3.5 NaCl w/w solution. The ionic resistance of coatings were extracted from bode and Nyquist diagrams by fitting of appropriate electrical model. The cation diffusion mechanism in cathodic delamination process examined for each of coatings. Results revealed effective role of ionic resistance on cation diffusion process and rate of delamination in cathodic delamination test.

کلیدواژه ها:

bituminous coatings ، EIS ، ionic resistance ، cathodic delamination