铝合金在模拟SO2污染大气环境中的腐蚀行为

Corrosion Behaviors of Aluminum Alloys in Simulated SO_2 Pollute Atmosphere

采用扫描电镜(SEM/EDX)、增重法、傅立叶变换红外光谱(FTIR)和X射线衍射研究铝合金1060、铝合金2A12和7A04分别在表面沉积与未沉积70μg/cm2氯化钠条件下在含50×10-6SO2(50ppm)污染大气环境中的腐蚀行为和规律,并测试三种材料力学性能的变化。研究结果表明,随试验时间的延长,铝合金表面腐蚀产物不断增多,腐蚀增重符合指数衰减规律Δm/A=B+Dexp(-t/k),抗拉强度和延伸率呈下降趋势;表面腐蚀产物形貌呈团状或圆团状,并不断向外扩展延伸,呈现不均匀的凹凸形貌;铝合金在50ppm SO2污染大气环境中腐蚀产物少,腐蚀增重较少,表面腐蚀产物主要为氧化铝和硫酸铝;而表面沉积70μg/cm2NaC l的铝合金在模拟50ppm SO2污染大气环境中腐蚀产物明显增多,腐蚀增重大,力学性能下降幅度大,二氧化硫和氯化钠的协同作用明显促进铝合金的腐蚀,腐蚀产物主要为氧化铝、铝的硫酸盐和铝的氯化物。

The corrosion behaviors of aluminum alloys 1060, 2A12 and 7A04 in two different experimental conditions were investigated by scanning electron microscope （SEM） , energy dispersive X-ray detection （EDX） , Fourier transform infrared（FTIR） , X-ray diffraction （XRD） and mass gain method in simulated 50ppm SO2 pollute atmosphere. The mechanical capability of experimental materials under different corrosion time was tested. The results show that the corrosion product increases with testing hours prolonging, mass gain of corrosion product adding and according with exponential attenuation rule as Δm/A = B ＋ Dexp（ - t/k） , strength and elongation percentage declining. Surface observation showed that corrosion product was agglomerate and accidented, extending forth. The corrosion product of aluminum alloys in simulated 50ppm SO2 atmosphere was little and composed of alumina and aluminum sulfate. But the corrosion product of aluminum alloys on the surface of 70μg · cm^-2 sodium chloride was more in simulated 50ppm SO2 atmosphere, mass gain of corrosion product adding more, strength and elongation percentage declining more greatly, corrosion product made up of alumina, aluminum sulfate hydrate and aluminum chloride.