摘要
目的为掌握航空用CFRP在老化过程中的电化学特性,准确获得CFRP/金属偶对中金属的当量折算系数,方法以海洋环境为背景,以飞机常用的CF8611/AC531复合材料和7B04铝合金为研究对象,开展了CFRP的加速老化试验及其在不同电解液中的极化试验,并使用光学显微镜、SEM、FTIR等设备,观测其在老化过程中的性能变化。同时,在充分考虑电偶效应腐蚀加速作用的前提下,改进当量折算系数计算方法,基于电偶腐蚀模型获得CFRP/7B04偶对的电偶电流,并计算了相应的折算系数。结果随着老化的进行,该型CFRP表面环氧树脂逐渐分解,使得碳纤维裸露,阴极性质得到增强。在含Cu^(2+)的电解液中极化时,碳纤维裸露区域会形成Cu单质聚集,老化420h后,裸露面积占比维持在0.9左右,不再增长,即阴极性质达到相对稳定状态,据此获得了CFRP的自腐蚀电流密度与碳纤维裸露面积的关系曲线,并划分了表面活性阴极区和惰性阴极区,明确了其老化机制和阴极反应机制。得到了CFRP/7B04偶对的相关腐蚀参数和改进后的当量折算系数。结论该型复合材料的阴极性质良好,活性阴极区是其阴极性质的重要来源,在使用时应避免与金属直接接触。在设计结构件的加速腐蚀环境谱时,务必考虑电偶效应,以提高环境谱的精度和适用性。
In order to master the electrochemical characteristics of aviation CFRP in the aging process,and accurately obtain the equivalent conversion coefficient of the metal in CFRP/metal coupling,CF8611/AC531 composite and 7B04 aluminum alloy commonly used in aircraft were studied under the background of marine environment.The accelerated aging test and polarization test of the CFRP in different electrolytes were carried out,and optical microscope,SEM and FTIR were used at the same time to observe the change of its performance during aging time.Under the premise of fully considering the galvanic effect corrosion acceleration,the equivalent conversion coefficient calculation method was improved,and the galvanic current of CFRP/7B04 couple was obtained based on the galvanic corrosion model,and the corresponding conversion coefficient was calculated.The results show that with the aging process,the epoxy resin on the surface of CFRP decomposes gradually,which makes the carbon fiber exposed and the cathode property is enhanced.When the CFRP is polarized in the electrolyte containing Cu^(2+),the bare area of carbon fiber will form the aggregation of Cu.The ratio of the bare area remains about 0.9 after 420 h,which means that the cathode property reaches a relatively stable state.The relationship between the self-corrosion current density and the exposed area of carbon fiber is obtained,and the aging mechanism and cathodic reaction mechanism are defined by dividing the surface-active cathode area and the inert cathode region.The corrosion parameters of CFRP/7B04 couple and the improved equivalent conversion coefficient are obtained.The cathode property of this type of composite is very well,and the active cathode area is the important source of its cathode property,so direct contact with metal should be avoided.The influence of galvanic effect must be considered in the design of accelerated corrosion environmental spectrum of structural parts in laboratory,so as to improve the accuracy and applicability of environmental spectr
作者
王安东
魏梓林
胡建军
张勇
卞贵学
陈跃良
WANG An-dong;WEI Zi-lin;HU Jian-jun;ZHANG Yong;BIAN Gui-xue;CHEN Yue-liang(Qingdao Campus of Naval Aviation University,Qingdao 266041,China;Chinese People's Liberation Army 92543 Beijing,Changzhi 046011,China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2021年第7期318-327,336,共11页
Surface Technology
基金
山东省高等学校“青创科技计划”资助项目(2020KJA014)。
关键词
复合材料
老化
电化学
铝合金
电偶腐蚀
当量折算系数
composite
aging
electrochemistry
aluminum alloy
galvanic corrosion
equivalent conversion coefficient
