航空有机涂层在户内加速试验与户外暴露中的损伤等效关系

Equivalent Degradation of Aviation Organic Coating During Indoor Accelerated Testing and Outdoor Exposure

开展航空有机涂层在户内加速试验与户外暴露过程中的损伤等效关系研究,为飞机蒙皮的寿命预测提供基础数据。进行涂层的长期户外暴露和户内加速试验,同时跟踪观察涂层表面形貌变化,利用电化学阻抗谱(EIS)定量分析涂层损伤,进而研究涂层在户内加速试验和5年热带海洋大气环境中的损伤行为。研究发现,有机涂层试样在经历7个户内加速试验周期和5年户外暴露后,试样中心区域仍然十分完整,但是电化学阻抗模值显著下降;有机涂层户外暴露与户内加速试验的相关系数为ρ=0.77,经过6个户内加速试验周期的有机涂层试样的损伤与在海南万宁3年户外暴露的损伤等效;经过3年户外暴露或者5个户内加速试验周期后,有机涂层试样的特定频率电化学阻抗模值Zf=0.1开始与合金基体的Zf=0.1在一个数量级上,由TB06-9锌黄丙烯酸聚氨酯底漆和TS96-71氟聚氨酯无光磁漆组成的有机涂层开始失效。

The relationship between indoor accelerated testing and outdoor exposure in terms of equivalent degradation in aviation organic coating is studied in order to provide fundamental data for the life prediction of aircraft skin. Long-term outdoor exposure and indoor accelerated testing of the coating are carried out, with surface morphology periodically examined. Electrochemical impedance spectroscopy （EIS） is used to quantitatively analyze the damage of organic coating. Thus, the degradation behavior of the coating in indoor accelerated testing and tropical marine atmosphere for 5 years is investigated. tt is found that the central area of organic coating specimen is intact after 7 cycles of indoor accelerated testing and 5 years outdoor exposure, but exhibits significant decrease in electrochemical impedance modulus. The organic coating＇s correlation coefficient （p） between outdoor exposure and indoor accelerated testing is 0.77. The degradation of organic coating after 6 cycles of indoor accelerated testing is equivalent to that after 3 years outdoor exposure in Wanning, Hainan. 3 years outdoor exposure or 5 cycles of indoor accelerated testing led to the fact that the special frequence electrochemical impedance modulus ｜ Z ｜ f=0.1 of organic coating specimen is in the same order with ｜ Z ｜ f=0.1 of alloy substrate. Since then, the organic coating which is comprised of zinc yellow acrylic polypropylene and fluorinated polyurethane fails to protect the alloy any more.