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

本研究对细菌进行金属加工的可能性进行了研究。关注被称为氧化亚铁硫杆菌(TFO)的铁氧化细菌，对钢铁微加工进行了考察。首先，使用了从矿山废液中收集的各种TFO。接下来，使用基因分析后的纯细菌。据了解，铁素体是优先处理的，主要是铁素体-珠光体钢在PH2的硫酸介质(9K型)中浸泡TFO的组织。珠光体I S由细小的铁素体和渗碳体组成的片层结构。渗碳体主要残留在未加工的地方。也就是说，由骨单位结构组成的微固体结构中的渗碳体能够形成。对过共晶钢进行浸渍试验，进一步观察渗碳体的残留情况。结果，生菌的处理速度是无菌情况下的8倍以上，而且在活菌情况下也明显地保留了渗碳体。TFO是通过利用2值的铁离子氧化3值时产生的能量而变得活跃的。非菌场上几乎不存在3值的铁离子，但表现出较强的氧化性。在TFO作用下，铁素体容易被3值的铁离子加工，渗碳体由于是铁和碳的化合物，很难加工。探讨了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.