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The effects of multiwalled carbon nanotubes (MWCNTs) on the adhesion strength and corrosion resistance of the acrylic nanocomposite coatings were evaluated on Q235 substrates via pull-off tests and electrochemistry measurements (EIS, LEIS). Addition of MWCNTs to the acrylic resulted in an up to ∼50% increase in the adhesion strength. After 36 h of immersion in 3.5 wt% NaCl, the coating resistance of the native acrylic coating was 235.8 Ω cm 2 , whereas those of the nanocomposite coatings containing 0.5 and 1 wt% MWCNTs were 1.36 × 10 5 and 9.27 × 10 7 Ω cm 2 , respectively. LEIS analysis indicated that the addition of MWCNTs increased the adhesion strength and retarded the delamination. The results demonstrated the positive effects of the incorporation of MWCNTs on the anticorrosive ability of the coatings. [ABSTRACT FROM AUTHOR]

• The EIS technique combined with LEIS technique was used to study the failure process of waterborne acrylic coating. • The effects of defect size, chloride ion concentration and resin type on failure process of waterborne acrylic coating were investigated. • The key factor in the failure process of the waterborne coating were studied by compared two types of waterborne acrylic coating during immersion. Cathodic delamination—weakening or loss of adhesion between the coating and the metal—is one of the major failure processes of organic coatings. Generally, it is almost inevitable to introduce defects to the coating during processing and operation. In this work, the delamination process of coatings around defects and the corrosion in defective coated metals was elucidated using immersion and electrochemical impedance tests. Two types of coatings (styrene-acrylic coating and terpolymer coating) were compared. The effects of defect size, chloride ion concentration and resin type on cathodic delamination were investigated. A small defect may affect the metal corrosion. Increasing the chloride ion concentration can promote the corrosion of metal but may not accelerate the delamination of the coating. The resin type is the key factor in the failure process of the coating. [ABSTRACT FROM AUTHOR]