A3钢在人造污染介质中的大气腐蚀行为

采用于湿交替复合循环模拟大气腐蚀过程，研究了Ａ３钢在含ＮａＣｌ、Ｎａ２ＳＯ４、ＮａＮＯ３、ＮａＣｌ＋Ｎａ２ＳＯ４和Ｎａ２ＳＯ４＋ＮａＮＯ３介质中的腐蚀行为．通过电化学测量，评价了Ａ３钢及其在加速腐蚀过程中形成的锈层的电化学行为和锈层的保护性，并利用ＸＲＤ分析了腐蚀产物的组成．试验结果表明，ＳＯ４２－腐蚀性最强，Ｃｌ－次之，ＮＯ３－最弱，且有一定的钝化作用；Ａ３钢在混合介质中的腐蚀行为不同于在单一介质中的腐蚀行为，每种介质在腐蚀的不同阶段分别起主要作用．

BEHAVIOUR OF ATMOSPHERIC CORROSION OF CARBON STEEL IN ARTIFICIALLY POLLUTED MEDIA

In this srudy, the accelerated weathering test consisting of cyclic immersion-wet-dry steps was applied to simulate the process of atmospheric corrosion. The solutions of NaCl, Na2SO4, NaNO3, NaCl Na2SO4 and NaNO3 Na2SO4 were selected as immersion media. The corrosion behaviour of mild steel in these artificially polluted environments was examined. The relative corrosiveness of the pollutants was ranked in the order: SO42- >Cl- >NO3- with the NO3 acting as a passivating agent. The corrosion performance of the steel in mixed media was different from that in single medium. Every component played its own role in different period of corrosion process. Protective character and composition of rust layer on mild steel after the accelerated test were evaluated and analysed by electrochemical measurements and XRD.The corrosion mechanism involved is briefly discussed.