Dual Component Polymeric Epoxy-Polyaminoamide Based Zinc Phosphate Anticorrosive Formulation for 15CDV6 Steel

Abstract

The present research is focused on a formulation with two active components as an anticorrosive polymer coating for 15CDV6 steel. The dual component formulation (epoxy-zinc phosphate (ZP) coating) consists of a polymeric epoxy resin Bisphenol A diglycidyl ether (DGEBA) cured with a polyaminoamide as a first component and zinc phosphate (Zn 3 (PO 4 ) 2 (H 2 O) 4 ) (ZP) added in 5% by weight as a second component. The anticorrosive performance of the epoxy-ZP coating was evaluated against the standard coating, which consists of only one component, the cured polymeric epoxy resin. The two polymer coatings were evaluated by electrochemical impedance spectroscopy (EIS). The surface morphology was of the two polymer coatings were characterized by scanning electron microscopy (SEM). The coated samples of 15CDV6 steel were tested in a harsh environment of corrosive electrolytes (3 wt % NaCl solution). Under these conditions, a very high impedance value was obtained for 15CDV6 steel coated with the epoxy-ZP coating. Even after exposure for a long period of time (5856 h), the performance was still acceptable, indicating that the epoxy-ZP coating is an excellent barrier. The standard epoxy coating provided an adequate corrosion protection performance for a short period of time, then the performance started to decline. The results were confirmed by surface characterization, a cross-sectional image obtained by optical microscopy for an epoxy-ZP coating applied on 15CDV6 steel exposed for 5856 h to a salt spray test showed that the coating is homogeneous and adheres well to the surface of the steel. So, the coating with a dual component could have great potential in marine applications as anticorrosive for steel.Coatings 2019, 9, 463 2 of 11 coating, the cross-linking density in the coating, and the functional group present on the coating surface which affects the strength of adhesion to the metal surface. Among organic coatings, water-based epoxy coatings are the most attractive due to their unique mechanical properties, superior adhesion to substrate, good thermal stability, excellent corrosion resistance and chemical resistance. In addition, they can be available at a low cost [10,11] and are nontoxic. These attractive properties could be attributed to high the cross-linking density and to the functional groups such as amines and hydroxyl present in the polymer coating [12]. However, long term exposure to corrosive materials, cause partial diffusion of corrosive species into the polymer coating from scratches or inherent pores. Eventually the diffusing materials will reach the metal-coating interface. This causes the initiation of corrosion reactions and slow pealing of the coatings [13][14][15].Using inorganic pigments such as zinc chromate as a corrosion inhibitor has become popular in recent years [16]. They tend to improve the adhesion and anticorrosion performance of organic coatings. A couple of published studies showed that some of the inorganic pigments dissolve in water. The dissolved part tends to undergo oxidatio...

Ultrasonic Sensors-Assisted Corrosion Studies on Surface Coated AlSi9Cu3 Alloy Die Castings

“…The acrylic paint ED coatings exhibited higher resistance in AC and lowered resistance in DC; on the other hand, other coatings exhibited lower resistance in AC and higher resistance in DC. In future work, advanced digital-driven transformation technologies (Industry X.0), including artificial intelligence approaches, shall be deployed for overcoming the challenges faced due to corrosion and related issues [25][26][27][28][29][30][31][32][33][34][35][36], thereby improving the quality of the coating longevity. The salt spray test results confirm that 3-coat polyester with epoxy primer coated sample exhibits an oxide film on the surface that temporarily resist the local corrosion attack.…”

Development and Characterization of PA 450 and PA 3282 Epoxy Coatings as Anti-Corrosion Materials for Offshore Applications

“…These are widely used in many industrial applications, especially petrochemical, aeronautic, and automotive [ 13 , 14 , 15 ]. Epoxy resins are chosen because of their mechanical strength, excellent adhesion, corrosion and chemical resistance, and thermal stability [ 16 ]. These properties could be attributed to the higher cross-linked density of epoxy due to the presence of amines (NH 2 ) and hydroxyl groups in the polymer coating system [ 17 ].…”

Highly durable macromolecular epoxy resin as anticorrosive coating material for carbon steel in 3% NaCl: Computational supported experimental studies

“…The attractive properties could be attributed to the high cross linking density and functional groups such as the amines and hydroxyls present in the epoxy coating. However, long‐term exposure to corrosive materials causes partial diffusion of corrosive species into the epoxy coating, inherent scratches, or pores …”

“…However, long-term exposure to corrosive materials causes partial diffusion of corrosive species into the epoxy coating, inherent scratches, or pores. [16,17] Present study composed of two parts, first part is focused toward the synthesis and applying of DGEDDS-MDA coating on the carbon steel as well as monitoring the anticorrosive performance in 3% NaCl by the PDP and EIS. The anticorrosive performance was also demonstrated using SEM technique.…”