Abstract: Corrosion law and mechanism of 20# low-carbon steel in near-neutral in soil were studied by experiments of buried specimens in laboratory. In three kinds of soils, the corrosion features and products were analyzed by EDS and XRD, and the relation of corrosion rates, open-circuit potential and polarization curve with times were tested. The results indicate that corrosion rates changed incessantly along. On the condition of the same times, specimens and different soil samples, the corrosive degree of 1# and 2# specimens are serious, but 3# specimen is serious lightly. The corrosion products are main non-crystalloid, Fe（OH）3 and Fe2O3.The change rules of different times and soils are different, and are accordant with that of corrosion rates. The corrosion mechanism is discussed in near-neutral soils lastly.

Key words: Buried pipeline , Near-neutral soil , Corrosion mechanism

摘要： 通过实验室内埋片试验研究了20 #钢在南京沿江近中性土壤中的腐蚀规律和机理。在3 种不同土壤
中埋片, 对腐蚀后的试样腐蚀形貌和产物进行EDS 和XRD 分析, 并测定了试样的腐蚀速率、自腐蚀电位以及极化曲
线随时间的变化关系。试验结果表明, 随着时间的延长, 腐蚀速率是不断变化的;3 种不同土壤中的钢试样经过相同
的腐蚀时间后, 1 #和2 #腐蚀最为严重, 3#腐蚀程度稍轻;经过2 个月腐蚀后, 能谱和射线分析其腐蚀产物主要是非
晶质、Fe(OH)3 和Fe2O3 ;不同时间和土壤的电位变化规律是不同的, 与腐蚀速率变化规律是一致的。并探讨了近
中性土壤腐蚀机理。

关键词: 埋地管道 , 近中性土壤 , 腐蚀机理