Study on Wettability and Corrosion Behavior of Al 2 O 3 Doped Polyurea Coatings
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ANOSCALE AND NANOSTRUCTURED MATERIALS AND COATINGS
Study on Wettability and Corrosion Behavior of Al2O3 Doped Polyurea Coatings Jiaao Yana, Zhiming Gaoa, *, Qingchao Tana, Xian Yanga, and Wenbin Hua, b aTianjin
Key Laboratory of Composite and Functional Materials, School of Materials Science and Engineering, Tianjin University, Tianjin, 300072 China b Key Laboratory of Advanced Ceramics and Machining Technology (Ministry of Education), Tianjin University, Tianjin, 300072 China *e-mail: [email protected] Received August 16, 2019; revised September 17, 2019; accepted September 24, 2019
Abstract—The Al2O3 powder was added as a filler to polyurea and the effect of doping amount on Shore hardness and wetting property were investigated. The electrochemical impedance spectroscopy (EIS) was used to investigate the corrosion resistance of coating/aluminum alloy system in 0.1 mol/L NaOH solution. The results showed that with the increase of the doping amount, the Shore hardness of the coating increased and the contact angle on the aluminum alloy matrix decreased. By analyzing the results of the characteristics of EIS and the fitting results, doped Al2O3 powder can improve the coating corrosion resistance, but it may affect the density of the coating and reduce the impedance modulus during the initial stage of immersion. The relationship between the doping amount of Al2O3 powder and the corrosion resistance in this test was 5 wt % > 10 wt % > 15 wt % > 0 wt %. In general, in the doping range of this test, since the powder was uniformly distributed in the polyurea coating, the cohesive force of the polyurea can be lowered to cause an increase in the wetting property. At the same time, excessive dopped Al2O3 powder may deteriorate the compactness of the polyurea and the binding property of the polyurea itself may decrease, resulting in deterioration of corrosion resistance. However, the proper doping of Al2O3 powder in polyurea improves its overall performance. Keywords: polyurea, contact angle, EIS, corrosion resistance DOI: 10.1134/S2070205120050275
1. INTRODUCTION Polyurea coating is a kind of new environmentally friendly coating and widely used in steel structure anticorrosion and concrete structure waterproofing because of its performance of fast curing, high density, good adhesion and anti-UV [1, 2]. Polyurea coating has shown tremendous technical and market advantages in terms of corrosion protection and environmental protection [3]. However, the surface of the polyurea coating exposed to the harsh environment is prone to aging discoloration and corrosion failure, which seriously affects the application of the polyurea coating [4, 5]. The multi-walled carbon nanotubes (MWNTs) is subjected to mixed acid oxidation treatment to obtain hydroxyl-modified MWNTS. The end aminopolyether solidified isocyanate prepolymer was synthesized by in-situ polymerization of a hydroxyl group and an isocyanate to obtain the MWNTS/polyurea composite material, the tensile strength and gel content can be significantly improved [6]. Adding
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