CF8611/AC531复合材料性能及与7B04铝合金电偶腐蚀的电化学研究

借助电化学工作站、扫描电镜和能谱仪等设备,测量了CF8611/AC531复合材料的正面(FS)试件和侧面(SS)试件及7B04-T74铝合金在3.5%(质量分数,下同)NaCl或3.5%NaCl+12.5%Cu_2SO_4电解液中的极化曲线及电偶腐蚀参量,并观测了微观形貌;基于电化学理论、稳态腐蚀场和参数化扫描,建立了复合材料磨损状态下二者的电偶腐蚀动态模型。结果表明:该型复合材料性能稳定,但原始表面存在碳纤维裸露缺陷,缺陷位置常在碳纤维束重叠区,密度均值4.3个/mm^2,面积均值0.0184mm^2/个;阴极反应速率与缺陷面积密切相关,据此划分了活性阴极区和惰性阴极区;电偶腐蚀中,铝合金的主要腐蚀形式为点蚀,未见复合材料失效;电偶腐蚀有限元模型有效、可用,总电偶电流I_g与缺陷面积S正线性相关;当S_FS∶S_SS约为5.53∶1时,二者对7B04-T74铝合金的电偶效应相同。

Electrochemical study on performance of CF8611/ AC531 composite and galvanic corrosion coupled with 7B04 aluminum alloy

By means of the electrochemical workstation,scanning electron microscope,energy spectrometer and so on,the polarization curves and galvanic corrosion parameters of the front surface (FS) specimen and side surface (SS) specimen of CF8611/AC531 composite and the 7B04-T74 aluminum alloy in the electrolyte of 3.5%(mass fraction,the same below) NaCl or 3.5%NaCl+12.5% Cu2SO4 were measured,meanwhile the microstructure were observed.Based on the electrochemistry theory,steady corrosion field and parametric scanning technology,a dynamic model for galvanic corrosion under the wear status of composite was established.The results show that the performance of this composite is stable,but there are some carbon fibre exposed defects on the original surface.The defects are often located at the overlap area of carbon fibre bundles.There are 4.3 defects per square millimetre and the average area of each defect is 0.0184mm^2;the cathodic reaction rate is closely related to the area of the defects and consequently its surface is divided into the active and the inert cathode region;in the galvanic corrosion the main corrosion form of the aluminum alloy is pitting and no failure is found in the composite.The galvanic corrosion model established here is valid and available.There is a positive linear correlation between the total galvanic current Ig and the defect area S;the galvanic effect of FS and SS on the aluminum alloy is the same when SFS:SSS is about 5.53:1.