涂漆铝合金铆接件在美济礁大气环境中初期失效行为

Degradation Behaviors of Coated Riveted Structure during the Early Stages of Exposing to Marine Atmospheric Environment at Mischief Reef

目的研究铆接结构件在南海热带岛礁海洋大气环境暴露初期的失效行为。方法通过对在热带岛礁大气环境中暴露初期的试样进行外观拍照、光泽度测试、色差测试、光学显微拍照、以及电化学阻抗测试(EIS),描述相关变化过程。结果试样暴露1 a后,失光率和色差分别达到67.0%和10.67,平面位置呈现出沟壑状形貌特征,连接缝隙底部和铆钉顶部存在明显的涂层缺陷。平面位置0.01 Hz处的阻抗模值由初始的2.81×10^10Ω降低为8.19×10^8Ω,而铆钉位置0.01 Hz处的阻抗模值由初始的1.09×10^9Ω降低为2.92×10^6Ω。结论试样在热带岛礁大气环境暴露初期的外观变化主要表现为失光和变色,平面位置、连接缝隙底部及铆钉顶部均存在一定程度的微观形貌变化。随暴露时间的增加,电化学阻抗呈下降趋势,且铆钉位置的下降幅度相对更大。

Objective To study on the degradation behaviors of coated riveted structure during the early stage of exposing to marine atmospheric environment at a tropical island.Methods Relevant changes were described by analyzing relevant data of macro photos,glossiness,chromatic aberration,optical micro images and EIS of specimens in the early stage of exposing to marine atmospheric environment at a tropical island.Results It was found that the glossiness loss rate and the chromatic aberration of the specimens exposed for 1 year were 67.0%and 10.67,respectively.Some ravines-and gullies-liked patterns can be seen at flat area,while defects can be found in the coatings at rivet and crevice.Additionally,the impedance magnitude of flat area at 0.01 Hz was changed from 2.81×10^10Ωto 8.19×10^8Ω.Meanwhile,that data at rivet was changed from 1.09×10^9Ωto 2.92×10^6Ω.Conclusion The appearance change of specimens exposed to marine atmospheric environment at a tropical island are mainly embodied on glossiness loss and color change.Certain morphology change can be found on the coatings at flat area,rivet and crevice.In addition,the impedance decreases with the increase of the exposure time.Nevertheless,it has a relatively larger decrease range at rivet compared to that at flat area.