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从锈层中分离出黄色细菌,经分子生物学技术鉴定为海藻希瓦氏(Shewanella algae,SA)菌.采用分光光度法研究了其生长曲线的变化,发现该细菌的生长分为3个阶段:指数生长阶段、稳定阶段和衰亡阶段.采用电化学交流阻抗技术、扫描电镜和荧光显微技术等方法研究了SA菌对Zn-A1-Cd牺牲阳极材料腐蚀行为的影响.结果表明,含SA菌培养基的试样的开路电位要高于无菌培养基中试样的电位,电荷传递电阻R_(ct)值大于无菌培养基的R_(ct)值,说明该SA菌能够抑制试样的腐蚀.分析原因是细菌在试样表面形成生物膜,隔离了腐蚀介质与试样的接触,同时,细菌的生长消耗了氧气,抑制了腐蚀的发生;试样在含SA体系中,5 d时,其表面覆盖比较致密的生物膜;而在不含细菌的体系中,试样表面有明显的腐蚀坑;试样在含SA体系中7 d时,生成比较完整的生物膜,随着体系中营养物质及氧气的减少,SA菌逐渐减少,11 d后试样表面附着的SA菌所剩不多.
Yellow bacteria were isolated from the rust layer and identified as Shewanella algae (SA) by molecular biology techniques.The growth curve of the bacteria was studied by spectrophotometry and the growth of the bacteria was divided into three stages : Exponential growth phase, steady phase and decay phase.The effects of SA bacteria on the corrosion behavior of Zn-Al-Cd sacrificial anode materials were studied by means of electrochemical impedance spectroscopy, scanning electron microscopy and fluorescence microscopy.The results showed that SA- The open circuit potential of the sample in the bacterial culture medium was higher than that in the sterile medium, and the value of the charge transfer resistance R ct was larger than the value of R ct in the sterile medium, indicating that the SA bacteria could inhibit the sample The reason for the analysis is that the bacteria form a biofilm on the surface of the sample, isolating the contact between the corrosive medium and the sample, and at the same time, the growth of the bacteria consumes oxygen and inhibits the occurrence of corrosion. , The surface covered with a relatively dense biofilm; while in bacteria-free system, obvious corrosion pits were found on the surface of the sample; when the sample contained SA system for 7 d, a relatively complete biofilm was formed, and as the system In nutrients and oxygen reduction, SA bacteria Gradually reducing, 11 d attached to the surface of the sample after the few remaining bacteria SA.