|关键词||铜 微生物腐蚀 硫酸盐还原菌 超疏水表面 Cuo|
（4）化学刻蚀得到微纳米表面结构之后，通过电沉积的方法在CuO的表面成功地制备了WO3薄膜。CuO-WO3复合超疏水薄膜展现出了超强的耐酸特性，在0.1 M H2SO4溶液中浸泡48 h以后，静态水接触角仍然可以达到160o。同时，平面放置的样品表面的盐粒会在自我潮解之后，互相融合且滚离表面，保持了表面的清洁和干燥，阻碍了液膜的形成和电化学反应的进行。对CuO-WO3超疏水表面的微生物附着进行了初步的探讨，发现其具有良好的抑制微生物附着的作用。
Copper, as important material in marine environment and other industrial environment, is facing severe microbiologically influenced corrosion (MIC) problem. So, it is significant to research the mechanism of copper MIC and its protection. Pure copper was used as research object in this paper. The mechanism of copper corrosion induced by sulfate reducing bacteria (SRB) was studied and super-hydrophobic films were fabricated on copper. The organic carbon source and headspace were controlled to research the characteristics of SRB corrosion. Compared to the mechanism of carbon steel corrosion induced by SRB, the different mechanism of SRB corrosion of copper was verified experimentally to be the type of metabolite-microbiologically influenced corrosion (M-MIC). This is entirely different from mechanism of carbon steel corrosion induced by SRB which is extracellular electron transfer-MIC (EET-MIC). This research enriched the understanding of mechanisms of MIC, provided theoretical basis for diagnosis, prevention and mitigation for MIC and verified the wide prospect on prevention of MIC by using a super-hydrophobic film on copper. The main research contents are following:
(1) The mechanism of copper corrosion induced by SRB with different carbon source levels was investigated. With the increase of carbon source in the culture medium, the extent of copper corrosion was more severely. With 100% carbon source in the culture medium, copper caused most severe corrosion. Furthermore, the mechanism of C1018 carbon steel corrosion induced by SRB with different carbon source level was researched for comparison. The characteristics of copper and C1018 carbon steel corrosion by SRB were compared to verify that the mechanism of copper corrosion belong to M-MIC while C1018 carbon steel corrosion belong to EET-MIC.
(2) The mechanism of copper corrosion induced by SRB in vials with different headspace volume was investigated. The headspace to culture medium liquid volume ratio affected both of SRB growth and the concentration of dissolved H2S. With an increase of headspace, the SRB grew better while the concentration of dissolved H2S was decreased. With a small headspace space, SRB did not grew well but it resulted in a high concentration of H2S in the culture medium which accelerated the copper corrosion. This further verified that the mechanism of copper corrosion by SRB belongs to M-MIC.
(3) Super-hydrophobic surfaces on copper was prepared and their barrier effect against corrosive media was researched. Using the chemical etching method, different micro-nanostructures were obtained by controlling the etching time. After that, the surface was immersed in a perfluorodecyltrichoxysilane (PFDS) solution for further treatment. Finally, the super-hydrophobic surfaces were obtained. The relationship between the morphology of micro-nano structure and hydrophobicity was discussed. When the etching time was controlled at 10 min, the surface presented a dense and sharp needle structure. Under this condition, the surface possessed perfect hydrophobicity with the highest static water contact angle. NaCl salt particles were deliquesced and rolled away from the surface before it deliquesced completely. The surface remained dry and clean. A liquid film could not form on the surface and then this prevented electrochemical corrosion.
(4) After obtaining the micro-nano structure with chemical etching, a WO3 film was deposited on the CuO surface through the electro-deposition method. The composite super-hydrophobic CuO-WO3 film presented very high corrosion resistance. After immersion in 0.1 M H2SO4 solution for 48 h, the static water contact angle reached 160o. Meanwhile, the salt particles deliquesced on a horizontal surface and merged with each other and then rolled away from the surface. The surface remained dry and clean. This prevented the formation of a liquid film on the surface and electrochemical corrosion. The attachment of microbes on super-hydrophobic CuO-WO3 surface was discussed preliminarily and found that the surface possessed good inhibition of attachment of microbes.
|窦雯雯. 纯铜的微生物腐蚀及其耐蚀超疏水表面的制备[D]. 中国科学院海洋研究所. 中国科学院大学,2018.|