Investigation of Fine Biomachining of Metals by Using Microbially Influenced Corrosion

为了将微生物影响的腐蚀(通常为MIC)用于金属的精细生物加工，研究了pH对一种铁氧化细菌的氧化亚铁硫杆菌的培养以及在9K介质中对低碳钢和铜的生物加工质量损失以及细菌培养液的影响。此外，通过在9K介质和细菌培养液中的电化学测量和表面膜的观察，研究了Metak的生物机械加工机理。2.0版本。2.5和3.0。但在除1.5以外的其他pH值下，它们在3-4天内达到最大值。低碳钢和铜在细菌培养液中的生物去除质量损失在pH为1.5时最大，在pH为2.5时最小，在pH为3.0时又增加。细菌培养产生的Fe_2(SO_4)_3加速了铁和铜的生物降解，使铁和铜的质量损失成为氧…更多的退光剂。在9K介质和细菌培养液中，铁和铜的生物机械加工质量损失分别约为30 mm/年和6 mm/年。在9K介质和细菌培养液中，碳钢的表面比铜的表面粗糙。在细菌培养液中进行生物磨削后，碳钢表面粗糙度约为30μm。另一方面，铜的粗糙度约为3μm，软钢和铜都受到了普遍的侵蚀。但在9K介质和细菌培养液中，通过低倍放大可以观察到低碳钢表面的局部点蚀。在所有溶液中，铜普遍受到攻击。铜的生物加工表面与低碳钢的不同之处在于其结构非常细微，在细菌培养液中，低碳钢的阴极极化曲线在-750~-900 mV zsSCE范围内发生了较大的去极化。Fe^&lt；3+&gt；+e→Fe^&lt；2+&gt；还原反应引起的退极化加速了金属的溶解。在9K介质中，FeSO4膜能阻止低碳钢和铜的溶解，而在细菌培养的溶液中，由于细菌的作用，FeSO4膜不能形成FeSO4膜，而Fe3+和Fe3+的氧化作用加速了FeSO4膜的溶解

In order to use microbially influenced corrosion (usually MIC) for the fine biomachining of metals, influence of pH on both culture of Thiobacillus Ferrooxidans of a kind iron oxidizing bacteria and biomachining mass loss of mild steel and copper in 9K medium and the and the bacteria-cultured solution has been investigated. Furthermore, the biomachining mechanism of metaks has been investigated both by electrochemical measurements in 9K medium and the bacteria-cultured solution and observations of the surface fils.The cells of bac-teria increased with culture time in 9k medium of pH 1.5. 2.0. 2.5 and 3.0. though they became maximum on 3 to 4 days at other pH except 1.5. The biomachining mass loss of mild steel and copper in the bacteria-cultured solution became larger at pH 1.5 than other pH and then after it became the least at pH 2.5, it increased again at pH 3.0. Fe_2 (SO_4)_3 whi-ch was produced through culture of bacteria accelerated biomachining mass loss of iron andcopper as oxi … More dizing agent. Biomachining mass loss of iron and copper were respectively about 30 mm/y and 6 mm/y of dissolution in 9K medium and the bacteria-cultured solution.The surface of mild steel was rougher than copper's in 9K medium and the bacteria-cultured solution. The surface roughness of mild steel was about 30 μm after biomachining in bacteria-cultured solution. On the other hand, the copper's roughness was about 3 μm. Both mild steel and copper were generally attacked. But localized pitting attacks were observed on the surface microstructures of mild steel through low magnification in 9K medium and the bacteria-cultured solution. In all solution, copper was generally attacked. The biomachined surface of copper differed from that of mild steel in the point of the very fine structures.Cathodic polarization curves of mild steel depolarized greatly in the region of -750 to -900 mV zs SCE in the bacteria-cultured solution. This depolarization caused by the reduction reaction of Fe^<3+> + e → Fe^<2+> accelerated the dissolution of metals. In 9K medium, the dissolution of mild steel and copper was prevented by FeSO_4 film, however, in the bacteria-cultured solution FeSO_4 film was not formed owing to the action of bacteria and the dissolution was accelerated by oxidizing effect of Fe^<3+> Less