海洋环境下机载电连接器腐蚀分析与失效机理

为分析海洋环境对机载航空电连接器的腐蚀情况的影响,将电连接器进行自然暴晒试验和实验室多应力加速试验,采用扫描电子显微镜(SEM)、X射线能谱仪(EDS)和光学显微镜等表征手段对试验件腐蚀程度、腐蚀区的微量元素定性定量分析。结果显示,电连接器的中间轴身和头部高应力接触区易发生腐蚀。电连接器主要的腐蚀方式有电应力腐蚀和电化学腐蚀。高温、高盐、高湿和高辐射的海洋环境加速了电连接器被腐蚀的过程。被腐蚀的电连接器局部镀层破损甚至脱落,基底材料暴露在外且被腐蚀和破坏,并形成大量的金属盐腐蚀产物,导致失效概率增加。出现失效的主要原因是电连接器的接触电阻增加、绝缘性能降低、电偶腐蚀、应力松弛和蠕变。

Corrosion Analysis and Failure Mechanism of Airborne Electrical Connectors in Marine Environment

In order to analyze the effect of marine environment on the corrosion of the airborne electrical connector, the con.nectors are subjected to natural exposure tests and laboratory multi-stress acceleration tests, and characterization meanssuch as scanning electron microscopy (SEM), energy dispersive spectrum(EDS) and optical microscopy are used to analyzethe corrosion degree of test parts and trace elements in the corrosion area qualitatively and quantitatively. The results showthat the middle shaft body and the high stress contact area of the head of the electrical connector are prone to corrosion. Themain corrosion modes of electrical connectors mainly fail by stress corrosion and electrochemical corrosion. High tempera.ture, high salt, high humidity and high radiation of the marine environment accelerate the corrosion process. The local coat.ing of the corroded circular connector presented breakage or even peeling, the substrate material is exposed, corroded anddestroyed, and a large amount of metal salt corrosion products are formed on the substrate, which increases the probability offailure of the electrical connector. The main causes of failure are increased contact resistance, reduced insulation, galvaniccorrosion, stress relaxation and creep of the connector.