CATHODIC DISBONDING OF INDUSTRIAL CHLORINATED RUBBER BASED PRIMER USED IN RUBBER/METAL COMPOSITES: AN ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY ANALYSIS
ABSTRACT Chemlok 205 primer is a common bonding agent used together with a top coat in rubber/metal bonded composites. Recent studies indicated that a stand alone Chemlok 205 primer failed when its metal substrate underwent corrosion. The failure was suspected to be caused by coating degradation, followed by cathodic disbonding, induced from the corrosion reaction. Therefore, in this work, the effect of cathodic polarization on the coating delamination was further investigated. The work intends to focus on understanding the adhesion failure processes involved. Thus, electrochemical impedance spectroscopy (EIS) was employed on a stand alone industrial coating Chemlok 205 primer on mild steel substrate subjected to cathodic polarization potential of 0.8 V versus Ag/AgCl reference electrode in 0.5 M NaCl. The coating barrier properties were interpreted through Nyquist and Bode plots of the EIS plots for a selected time interval. The data obtained were modeled against three distinguished electrical equivalen.