7B04铝合金在NaCl沉积与SO_2环境下的大气腐蚀行为

采用增重法、扫描电镜(SEM)、能谱分析(EDS)和X射线衍射仪(XRD)研究NaCl沉积对7B04铝合金大气腐蚀行为的影响,并对SO_2和NaCl协同作用进行了探讨。结果表明,25℃、95%RH条件下,7B04铝合金表面沉积NaCl在含有与未含有SO_2的环境中的腐蚀增重随时间变化均呈递增趋势并符合指数衰减规律,后期腐蚀减缓;NaCl和SO_2共存时,NaCl沉积在腐蚀初期作用比较明显,但随着腐蚀时间的延长,Cl-作用不断减弱,SO_2的作用则变强;NaCl和SO_2同时存在时,引起的腐蚀大于二者单独存在时引起的腐蚀之和,即NaCl与SO_2共存对7B04铝合金的大气腐蚀具有一定协同效应。

Atmospheric Corrosion Behavior of 7B04 Aluminum Alloy in the presence of NaCl and SO2

The effect of NaCl and SO2 on the atmospheric corrosion of 7B04 Aluminum Alloy is investigated by scanning electron microscope (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD) and weight gain method. The results show that the corrosion rate increased with exposure time and slowed down in the later period, weight gain of corrosion products are according with exponential attenuation rule as △m/A = B + Dexp( -t/k). NaCl accelerates the initial corrosion of 7B04, but the effect of Cl- is weakened while that of SO2 is enhanced with exposure time. The combined effect of NaCl and SO2 on the atmospheric corrosion is greater than that caused by each single component.