碳钢在我国四种土壤中腐蚀机理的研究

Corrosion mechanism of carbon steel in four types of soil

利用Q2 35钢在我国四种典型土壤 (即大庆中心站苏打盐土、大港中心站滨海盐渍土、新疆中心站沙漠戈壁土、华南站酸性土 )中进行室内模拟加速腐蚀试验和电化学实验 ,并对腐蚀试验后的腐蚀产物进行了微观分析和微生物分析 .研究结果表明 ,碳钢在上述四种土壤中的腐蚀过程为 :阳极过程为铁的溶解 ,非晶态羟基氧化铁的生成 ,经老化最终成为褐铁矿 ;阴极过程为氧去极化为主的扩散控制过程 .华南土 pH值较低 ,同时伴随着氢去极化腐蚀的阴极过程 .大港土中检测出少量的FeS ,这是由于SRB参与氢去极化过程的结果 .腐蚀过程受阴极极化控制 。

The simulating accelerated corrosion indoors and electrochemistrical test were carried out by using type Q235 steel in four kinds of soil such as Daqing soda solonchak soil, Dagan costal solonchak soil, Xinjiang Gobi soil, Huanan acid soil. The corrosion product formed on Q235 steel in the soil was studied by means of microcosmic analysis and microbe analysis. The corrosion mechanism of carbon steel in the soil was researched by using metallic corrosion principle and electrochemistry theory. The result of the corrosion process of carbon steel showed as follows: the anodic process was ferric dissolution; the electrolyte could be changed to amorphous ferric oxyhydroxide; the amorphous was transformed into limonite via aging. The cathodic procession was predominantly diffusionally controlled by oxygen reduction. The cathodic process simultaneously existed hydrogen reduction in Huanan soil with a lower pH. The corrosion process was controlled by cathodic reduction, and diffusion control extent increased with soil temperature and water content.