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目的评价服役于高原大气环境中的直升机蒙皮典型结构及其防护体系的防护性能。方法通过模拟高原大气环境加速试验方法再现直升机蒙皮典型结构防护体系实际服役过程中出现的损伤,利用扫描电镜对表面微观形貌进行观察,采用电化学阻抗谱测试研究有机涂层阻抗的变化。结果在实验室加速试验中,蒙皮试验件螺钉周边先出现局部腐蚀,之后腐蚀产物又逐渐减少,而铆钉周边经过多个周期后腐蚀产物都没有显著增多。螺钉中间区域有机涂层电化学阻抗模值直至第8个周期后与原始情况相比才大幅度下降,而铆钉中间区域有机涂层电化学阻抗模值在试验中多次明显下降。结论铆钉周边的有机涂层经过多个周期加速试验仍具有阻挡腐蚀性介质的作用。与螺钉结构的情况相比,铆钉中间区域有机涂层防护性能退化显著。
Objective To evaluate the typical structure of helicopter skin serving in the plateau atmosphere and its protective performance. Methods By simulating the accelerating test of atmospheric environment at high altitude, the damage occurred during the actual service of helicopter skin protection system was simulated. The surface microscopic morphology was observed by SEM, and the change of impedance of organic coating was studied by electrochemical impedance spectroscopy. Results In the laboratory accelerated test, partial corrosion was observed in the periphery of the screw on the skin test piece, and then the corrosion products decreased gradually. However, the corrosion products did not increase significantly after several cycles in the periphery of the rivet. The mechanical impedance of the organic coating in the middle of the screw did not decrease significantly until the 8th cycle compared with the original condition, while the electrochemical impedance of the organic coating in the middle of the rivet decreased significantly several times during the experiment. Conclusion The organic coatings around the rivets still have the effect of blocking corrosive media after several cycles of accelerated testing. In contrast to the case of the screw structure, the protective properties of the organic coating in the middle of the rivet degenerated significantly.