近海含SO_2环境中高压隔离开关铝合金部件的组织及腐蚀特征

Microstructure and Corrosion Characteristics of Aluminum Alloy High Voltage Isolation Switch Parts Applied in Offshore Environment with SO_2

运用光学显微镜(OM)、扫描电镜(SEM)、透射电镜(TEM)和X射线衍射仪(XRD)对近海含SO_2环境中使用过的高压隔离开关2A12-T4铝合金部件的组织以及腐蚀特征进行分析。结果表明:2A12-T4铝合金晶粒沿变形方向拉长,并形成了一定数量的亚晶;主要的第二相是T相,并有大量的位错缠绕在T相周围。2A12-T4铝合金主要的腐蚀产物是Al(OH)_3和Al2(SO_4)_3·14H_2O,腐蚀主要受到湿润条件下Cl-和SO_2两种腐蚀性介质的联合作用,而拉长变形的晶粒以及第二相粒子则加速了腐蚀。

The mierostructure and corrosion characteristics of 2Al2-T4 aluminum alloy high voltage isolation switch parts used in offshore environment with SO2 were investigated by optical microscopy （OM）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM） and X-ray diffraction （XRD）. The results show that the grains of 2A12-T4 aluminum alloy were elongated along the deformation direction, and a certain number of sub- crystals formed. The main second phase was T phase surrounded by a mass of dislocations. The main corrosion products of 2A12-T4 aluminum alloy were Al（OH）3 and Al2 （SO4）3 · 14H2O. The corrosive behavior was mainly controlled by CI- and SO2 in moist environment. Additionally, the deformed elongated grains and the second phase particles accelerated the corrosion.