1050A铝合金在山东不同典型环境中的大气腐蚀行为特征研究

Corrosion Behaviour and Characteristics of 1050A Al-alloyExposed in Typical Atmospheres of Shandong Province

在山东青岛、东营、威海、潍坊等典型大气环境中对1050A铝合金进行了为期42个月的自然暴晒试验。暴晒一定周期试样取回,利用宏观形貌、微观形貌、腐蚀速率、腐蚀产物分析和电化学分析等手段研究了其在山东典型大气环境中的腐蚀行为特征。结果表明:1050A铝合金具有较好的耐大气腐蚀性能,在山东青岛、东营、威海和潍坊不同典型大气环境中暴晒42个月后,腐蚀产物主要以Al的氧化物和氢氧化物为主;相对来说腐蚀速率东营>威海>青岛>潍坊,其腐蚀速率随暴晒时间延长而降低,这可能有腐蚀产物膜有关。通过激光共聚焦微观形貌分析可见,腐蚀以局部腐蚀为主,暴晒42个月以后,点蚀坑主要分布在10μm以下。电化学阻抗结果表明在暴晒初期试样正反面腐蚀程度存在一定的差异,随着暴晒时间延长差异减弱。

A natural exposure test of 1050A Al-alloy was conducted in the typical atmospheric environments in the regions Qingdao,Dongying,Weihai and Weifang of Shandong Province for a period of 42 months.Afterwards,the corrosion behavior of the alloy was studied by means of macroscopic-and microscopic-morphology observation,corrosion rate measurement,corrosion product analysis and electrochemical test.The results show that 1050A Al-alloy has good atmospheric corrosion resistance,and the corrosion rate decreases with the increasing exposure time.Corrosion products are mainly Al-oxide and-hydroxide.The corrosion rate of 1050A Al-alloy tested at four different test sites may be ranked as following descending order:Dongying>Weihai>Qingdao>Weifang.The corrosion rate decreases with the extension of exposure time,which may be related to the presence of corrosion product scale.The laser confocal microscopic morphology analysis reveals that the corrosion is mainly pitting corrosion.The size of Pits was mainly below 10μm after 42 months of exposure.The EIS result indicates that there exists a discernible discrepancy in the corrosion extent between the upward-and downward-sides of the test coupons at the initial exposure stage,which then gradually diminishes as the exposure time prolongs.