The influence of the chemically bonded interface between fillers and binder on the failure behaviour of an epoxy coating under marine alternating hydrostatic pressure

Understanding the anticorrosive protective mechanisms of modified epoxy coatings with improved barrier, active and self-healing functionalities: EIS and spectroscopic techniques

“…Meanwhile, the Warburg impedance (Z W ) in the second circuit (Fig. 5b ) represents the diffusion of corrosive ions within the coating pores 49 , 50 . The electrical circuit in Fig.…”

“…It is well documented previously in the literature that the magnitude of impedance modulus at low frequency (|Z| 0.01 Hz) is an appropriate parameter for evaluating the overall corrosion protection performance in organic protective coatings 52 , 53 , while the charge transfer resistance ( R ct ) reflects the resistance to electron transfer reaction at the metal surface underneath the coating – which is inversely proportional to the undercoating corrosion rate 12 , 49 – 53 .…”

Electrochemical Evaluation Technologies of Organic Coatings

“…Murray [6] reported the typical epoxy coated sample potential-time data through 3000 h of exposure to the ASTM-D-1141 substitute ocean water test solution. Figure 3 shows the OCP curve of epoxy mica coating/steel system in 3.5 wt.% NaCl solution under alternating hydrostatic pressure (AHP) condition [10]. OCP of the coating as a whole has a negative relationship with immersion time.…”

“…Meng et al [10] investigated the failure behavior of epoxy mica (EM) coating under AHP environment by EIS, which could be a typical example of organic coating with inert pigment. Four distinct stages of the coating deterioration were determined according to the evolution of EIS plots and the fitting results of EEC models (Figure 5a-d).…”

Assessment of Self-Healing Epoxy-Based Coatings Containing Microcapsules Applied on Hot Dipped Galvanized Steel

“…EIS is used as a powerful tool to investigate the barrier properties of the coating systems developed in the current study and to assess the impact of the addition of a liquid rubber polymer either as a container surface modified or as an additive incorporated in free form in the epoxy matrix. As it has been well-documented previously in literature, the magnitude of impedance modulus at low frequency (|Z| 0.01 Hz) can be used to assess the overall anti-corrosive behavior of an organic coating system, while the charge transfer resistance (R ct ) indicates the resistance to a flow of charge, electronic or ionic, which is inversely proportional to the corrosion rate underneath the coating and its enhancement is associated with self-healing effects (Zhang et al, 2004;Zheludkevich, 2009;Borisova et al, 2013;Meng et al, 2015;Njoku et al, 2017;Ubaid et al, 2019). Figure 6 illustrates the Bode diagrams of (a) the impedance plot vs. frequency and (b) the phase angle diagram vs. the frequency resulting from the exposure of intact coatings to artificial sea water (ASTM D 1141-98) over a period of 223 days.…”