Effect of Applied Strain on Protective Properties of Aviation Organic Coatings
LUO Chen1, CAI Jian-ping1, CHEN Ya-zheng2, LIU Ming1, ZHAO Liang-liang1, SUN Zhi-hua1, TANG Zhi-hui1, LU Feng1
1. Metal Corrosion and Protection Laboratory, Beijing Institute of Aeronautical Materials, Beijing 100095, China;
2. Structure Department, Shenyang Aircraft Design & Research Institute, Shenyang 110035, China
Abstract：A method of pre-strain application on strip coating specimens was introduced. The strain of organic coating was quantitatively measured by microscopy observation of original mark on the coating. Outdoor exposure of the strip organic coating specimens with various strain was carried out, which realized the combination of natural environmental effect and mechanical effect. Therefore, the protective properties of organic coating in real service state can be more precisely evaluated. The result shows that the electrochemical impedance of zinc yellow acrylic polyurethane coating without pre-strain is gradually reduced from 1.8×109Ω to 4.7×105Ω in 36 months of outdoor exposure in Wanning. Electrochemical impedance modulus of coating specimens with either compressive pre-strain or tensile pre-strain decreases after outdoor exposure. However, coating specimens with tensile pre-strain exhibit more significant decrease than those with compressive pre-strain in electrochemical impedance, indicating the tensile pre-strain has a great effect on protective properties of organic coatings.
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