Micro Machining by an Element Selective Corrosion Action of Thiobacillus Genus Bacterium

本研究探讨了利用细菌进行金属加工的可能性。以铁氧化细菌TFO为研究对象，探讨了铁和钢的微细加工。首先，使用从矿井废液中收集的各种TFO。接下来，使用基因分析的纯细菌。在PH 2的硫酸培养基（9 K型）中，TFO浸钢优先处理铁素体，主要是铁素体-珠光体钢的组织。珠光体是由细小的铁素体和铁素体组成的层状组织。大部分未加工的残留物。换句话说，能够形成由骨单位结构组成的微固体结构。对过共晶钢进行了浸渍试验，进一步检验了过共晶钢中的铁素体残留情况。结果，生菌的处理速度变为无菌情况的8倍以上，并且可以理解，在活菌的情况下也明显地残留有细菌。TFO通过利用2值的铁离子在3值中氧化时发生的能量而变得活跃。在无菌条件下，3价铁离子几乎不存在，但表现出较强的氧化性。铁氧体易被3价铁离子与TFO反应，而碳酸镁由于是铁与碳的化合物，不易被反应。考察了TFO金属结构选择性微细加工的可能性。

The possibility of metal processing by a bacterium was studied in this research. Paying attention to iron oxidation bacteria called Thiobacillus-ferrooxidans (TFO) it examined about micro processing of iron and steel. At the first, TFO of the various kinds that it gathered from a mine waste fluid were used. Next, the pure bacteria that were analyzed on gene were used. It understood that ferrite is processed preferentially mainly a microstructure of ferrite-pearlite steel dipping in TFO with the sulfuric acid culture medium (9K type) of PH2. Pearlite i s composed of a laminar structure of fine ferrite and cementite. The cementite mainly remains without being processed. In other words, micro solids structure that is composed of bone unit structure of cementite able to be formed. Hyper-eutectic steel was done the dipping test to inspect the remaining of cementite furthermore. As a result, processing speed of raw bacteria becomes over 8 times of unbacteria case and understood that also cementite remained obviously in the case of live bacteria. TFO is getting active by utilizing energy that occurs when iron ions of 2 values oxidized in 3 values. An iron ion of 3 values hardly exists on unbacteria field, although strong oxidation nature is shown. A ferrite was easily processed by iron ions of 3 values with TFO, cementite was difficult to process because it was compound between iron and carbon. The possibility of metal structural selective micro machining of TFO was inspected.