Abstract

Mackinawite was biologically synthetized by immersing carbon steel coupons in artificial seawater containing Sulphate-Reducing Bacteria (SRB) for 6 months. These coupons were removed from the culture medium solution and some were stored in air while others were placed in SRB-free culture medium solution. In operando Raman spectroscopy was used to analyse all these coupons immediately after extraction from the incubation medium and nanocrystalline, well-crystallized and partially oxidized mackinawite was detected. The evolution of these corrosion products was also monitored as a function of ageing time with this technique. Nanocrystalline and well-crystallised mackinawite transformed into partially oxidised mackinawite, greigite and sulphate green rust for an ageing time between 4 and 72 h. After 120 h, maghemite, magnetite, lepidocrocite, goethite appeared on the coupons placed in SRB-free culture medium solution as opposed to those stored in air atmosphere. Greigite and sulphate green rust were not observed for Raman measurements performed in air.

摘要

Mackinawite 通过将碳钢试样浸入含有硫酸盐还原细菌 (SRB) 的人造海水中 6 个月进行生物合成。这些试样从培养基溶液中取出，一些储存在空气中，而另一些则放置在不含 SRB 的培养基溶液中。在操作中，拉曼光谱用于在从培养介质中提取后立即分析所有这些试样，并检测到纳米晶、结晶良好和部分氧化的 mackinawite。这些腐蚀产物的演变也被监测为使用这种技术的老化时间的函数。 在 4 到 72小时的老化时间下，纳米晶和结晶良好的麦基纳石转变为部分氧化的麦基纳石、白灰石和硫酸盐绿锈。120后 h，磁赤铁矿、磁铁矿、纤铁矿、针铁矿出现在放置在无 SRB 培养基溶液中的试样上，而不是储存在空气中的试样上。对于在空气中进行的拉曼测量，没有观察到灰石和硫酸盐绿锈。