The Corrosion Protection Behaviour of Zinc Rich Epoxy Paint in 3% NaCl Solution

Abstract

Electrochemical impedance spectroscopy (EIS) in the l00 kHz-10 mHz frequency range was employed as the main electrochemical technique to study the corrosion protection behaviour of zinc rich epoxy paint in 3% NaCl solution. The EIS results obtained at the open-circuit corrosion potential have been interpreted using a model involving the impedance of particle to particle contact to account for the increasing resistance between zinc particles with immersion period, in addition to the impedance due to the zinc surface oxide layer and the electrical resistivity of the binder. Galvanic current and dc potential measurements allowed us to conclude that the cathodic protection effect of the paint takes some time to be achieved. The loss of cathodic protection is due to a double effect: the decrease of the Zn/Fe area ratio due to Zn corrosion and the loss of electric contact between Zn to Zn particles. Even when the cathodic protection effect by Zn dust become weak, the substrate steel is still protected against corrosion due to the barrier nature of the ZRP film reinforced by Zn

A Review of Modern Assessment Methods for Metal and Metal-Oxide Based Primers for Substrate Corrosion Protection

“…The most basic means of directly measuring the magnitude of achieved galvanic protection is via the OCP 2 (Pereira et al, 1990;Feliu et al, 1993aFeliu et al, , 2001Danford et al, 1995;Hammouda et al, 2011;Santucci et al, 2017b;McMahon et al, 2019a). Feliu et al have demonstrated, through intermittent OCP measurement, that ZnRPs can maintain galvanic protection on steels for 10 FIGURE 12 | (A) Optical images of a bare Mg/AA2024-T4 microelectrode array used to diagnostically assess the throwing power of Mg over a representative bare AA2024-T4 scratch in an RH controlled cabinet (Feliu et al, 1993b).…”

“…Thus, Zn-rich primers have become especially useful for steel protection. Zn-based primers (ZnRPs) function mainly through galvanic interactions with the substrate to provide sacrificial protection, and with time of exposure the buildup of corrosion products has been demonstrated to offer secondary impedance barrier protection and/or chemical protection as well (Feliu et al, 1993a(Feliu et al, ,b, 2001Bierwagen et al, 2007;Hammouda et al, 2011;Krieg et al, 2012;Cubides and Castaneda, 2016;McMahon et al, 2019a). Magnesiumbased MRPs (MgRPs) have been demonstrated to continue providing substrate protection on aluminum after 4 years' atmospheric exposure even after all sacrificial metallic pigment has been converted to MgO through a combined galvanic and chemical inhibition mechanism (Santucci et al, 2017a,b).…”

Eco‐friendly, acrylic resin‐modified potassium silicate as water‐based vehicle for anticorrosive zinc‐rich primers

“…The used metallic substrate was SAE 1010 steel with dimensions of 15 3 7 3 0.2 cm 3 . Before applying the coating, the metal surface was sandblasted according to SA 2-1/2 (SIS Standard 05 59 00/1967).…”

“…[1][2][3][4][5][6][7] The waterborne inorganic zincrich coatings have been used because their environment friendliness and no volatile organic compound contents. These coatings initially have a porous nature, so electrolyte permeates through the coating and reaches to the steel/coating interface.…”

Investigation of corrosion protection afforded by inorganic anticorrosive coatings comprising micaceous iron oxide and zinc dust

“…1,3,[16][17][18][19][20][21] The impedance spectra of series 2 specimens showed this increase, but all of the specimens of series 1 showed an inverse trend. In the case of series 1 specimens, corrosion products that had filled the pores during the salt spray became unstable in the immersion condition of electrochemical tests and underwent some changes (e.g.…”