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通过4 a的现场大气暴露实验,利用SEM/EDS,OM,XRD技术和电化学测试技术,研究了包/不包铝的2024铝合金在中国西部盐湖大气环境中的局部腐蚀行为.结果表明,包/不包铝的2024铝合金在盐湖大气环境中发生了严重的点蚀,暴露2 a后,包铝层已被腐蚀穿透;不包铝的2024铝合金最大点蚀深度已达约320μm个别位置发生穿孔.包/不包铝的2024铝合金的主要腐蚀产物都是层状双金属氢氧化物—[Mg_(1-x)Al_x(OH)_2]~(x+)(Cl~-,CO~(2-))_x·mH_2O.电化学测试分析结果表明,随Cl~-浓度的升高,2024铝合金的开路电位不断降低,耐蚀性变差.
The local corrosion behavior of 2024 aluminum alloy clad / unalloyed aluminum in the atmospheric environment of salt lake in western China was studied by 4-day atmospheric exposure experiments using SEM / EDS, OM, XRD and electrochemical techniques. The results show that, The severe pitting corrosion of the 2024 aluminum alloy with / without aluminum coating occurred in the atmospheric environment of the salt lake. After being exposed for 2 years, the aluminum coating has been eroded through. The maximum pitting depth of 2024 aluminum alloy without aluminum coating has reached about 320μm Perforation occurred in some locations. The major corrosion products of the 2024 aluminum alloy with / without aluminum were all layered double hydroxides - [Mg 1-x Al x (OH) 2] x (x) The results of electrochemical tests showed that the open circuit potential of 2024 aluminum alloy decreased continuously with the increase of Cl ~ - concentration, and the corrosion resistance deteriorated.