毕业论文 海水中假单胞菌对45钢腐蚀行为的电化学研究.doc
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毕业论文 海水中假单胞菌对45钢腐蚀行为的电化学研究,摘要海洋环境中碳钢的腐蚀是一个涉及物理、化学、生物等多方面因素的电化学过程，而海洋环境中的微生物更是加速碳钢腐蚀的一个重要因素，给碳钢在海洋工程上的使用带来了很大的安全隐患和经济损失。随着人们对海洋的广泛开发和利用，海洋环境中的海底输送管线、海上采油平台、海底采矿设备等金属材料构建物的 mic 引起了人们广泛的关注。目...
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摘要
海洋环境中碳钢的腐蚀是一个涉及物理、化学、生物等多方面因素的电化学过程，而海洋环境中的微生物更是加速碳钢腐蚀的一个重要因素，给碳钢在海洋工程上的使用带来了很大的安全隐患和经济损失。随着人们对海洋的广泛开发和利用，海洋环境中的海底输送管线、海上采油平台、海底采矿设备等金属材料构建物的 MIC 引起了人们广泛的关注。目前在这一领域已有较多的研究，主要集中于微生物腐蚀机理方面，特别在铁细菌、硫酸盐还原菌、脱硫肠状菌属以及排硫杆菌等微生物腐蚀方面的研究已取得了可喜的成果。然而，对于假单胞菌对碳钢的腐蚀行为的研究却较少。
本文是采用微生物学法在海水中分离、提纯出假单胞菌，测定假单胞菌的生长曲线，确定假单胞菌的生长周期。然后，在实验室中模拟假单胞菌在海水中的生活环境，以45钢为研究对象，运用电化学测量技术，如：开路电位的测量、动电位循环扫描极化曲线和交流阻抗谱测试等方法，对海水体系中假单胞菌对45钢的腐蚀过程进行跟踪研究，从而获得碳钢在海水中的腐蚀电位、阻抗随时间的变化趋势以及阳极和阴极极化特征，揭示假单胞菌对45钢在海水中腐蚀的电化学行为影响。
用最大可能菌数法（MPN）测定了海水中假单胞菌的数量，绘制生长曲线，得到了海水中假单胞菌的生长规律（分为四个生长周期：迟缓期、对数生长期、稳定生长期、衰亡期）。用自腐蚀电位、极化曲线和电化学阻抗谱的电化学特征有效的评测了45钢在假单胞菌-海水体系作用下的电化学腐蚀行为。生长曲线表明，海水中假单胞菌的生长期分为迟缓期、对数生长期、稳定生长期、衰亡期四个周期，在海水条件下假单胞菌可以在相对长的时间内稳定生长。自腐蚀电位表明，完整生物膜的形成不会改变电极阴极的极化类型和控制步骤，假单胞菌的新陈代谢作用决定了45钢电极的性质和腐蚀速度。电化学阻抗谱表明，腐蚀产物层和双电层的双层作用而导致的阴极反应的电荷和物质在两相界面的传输速率的变化是控制45钢海水腐蚀的主要因素。
关键字：微生物腐蚀；假单胞菌；45钢；电化学
Abstract
In the marine environment , corrosion of carbon steel is the electrochemical process, influenced by physical, chemical, biological and other factors. Microbiology is a more important factor of accelerated corrosion of carbon steel, and has been given a lot of security risks and economic losses for use of carbon steel in marine engineering. With a widly development and utilization of marine resources, the microbiologically influenced corrosion (MIC) has been given much attention in marine environment concerned of all kinds of structure constructions, such as undersea pipelines, offshore oil platforms, seabed mining equipment, etc. Presently, most researches focus on the corrosion mechanism of microbiology in this area and especially the researches of the iron bacteria, sulfate-reducing bacteria, desulfotomaculum bacteria and sulfur bacteria have made encouraging results. However, the corrosion behavior of carbon steel by pseudomonas is few.
In this paper，the growth curve of pseudomonas was measured in order to know the growth cycle. Pseudomonas isolated and purified from carbon steel corrosion products by biology techniques. Then, the living environment of pseudomonas is simulated in the laboratory. The process of the corrosion of 45 steel was tracked in seawater with pseudomonas by electrochemical measurement techniques, which contain open circuit potential measurement, potentiodynamic cyclic polarization curve and AC impedance. Those can be obtained the corrosion potential, Rp trends curve with time and characteristics of the anode and cathode polarization from those. Some conclusions of the formation rule on corrosion of 45 steel can be achieved in seawater with pseudomonas.
The number of pseudomonas in different time was measured by method of most probable number (MPN) methed in seawater experiment.Growth curve of pseudomonas was described in order to investigate the vegetal rule of seawater (four periods:logy periods,logarithmic periods,steady growth periods,contabescence periods). The variety of the corrosion behavior of the 45 steel are investigated by the open circuit potential, polarization curves and electrochemical impedance spectroscopy in seawater with pseudomonas. Growth curves shows that the growth phase of pseudomonas divide into logy periods, logarithmic periods, steady growth periods, contabescence periods and can be a relatively long period of time in the steady growth periods in seawater and pseudomonas. The open circuit potential shows that full biofilm formation does not change the cathode electrode polarization type and control steps and the metabolism of pseudomonas determines the electrode nature and electrode corrosion rate of the corrosion of 45 steel. Electrochemical impedance spectroscopy shows that the transmission rate of charge and material of cathode reaction in the two-phase change interface is the main factors of the corrosion of the steel by product layer and double layer.
Keywords: MIC;Pseudomonas,;electrochemistry
目录
摘要∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙&#..
海洋环境中碳钢的腐蚀是一个涉及物理、化学、生物等多方面因素的电化学过程，而海洋环境中的微生物更是加速碳钢腐蚀的一个重要因素，给碳钢在海洋工程上的使用带来了很大的安全隐患和经济损失。随着人们对海洋的广泛开发和利用，海洋环境中的海底输送管线、海上采油平台、海底采矿设备等金属材料构建物的 MIC 引起了人们广泛的关注。目前在这一领域已有较多的研究，主要集中于微生物腐蚀机理方面，特别在铁细菌、硫酸盐还原菌、脱硫肠状菌属以及排硫杆菌等微生物腐蚀方面的研究已取得了可喜的成果。然而，对于假单胞菌对碳钢的腐蚀行为的研究却较少。
本文是采用微生物学法在海水中分离、提纯出假单胞菌，测定假单胞菌的生长曲线，确定假单胞菌的生长周期。然后，在实验室中模拟假单胞菌在海水中的生活环境，以45钢为研究对象，运用电化学测量技术，如：开路电位的测量、动电位循环扫描极化曲线和交流阻抗谱测试等方法，对海水体系中假单胞菌对45钢的腐蚀过程进行跟踪研究，从而获得碳钢在海水中的腐蚀电位、阻抗随时间的变化趋势以及阳极和阴极极化特征，揭示假单胞菌对45钢在海水中腐蚀的电化学行为影响。
用最大可能菌数法（MPN）测定了海水中假单胞菌的数量，绘制生长曲线，得到了海水中假单胞菌的生长规律（分为四个生长周期：迟缓期、对数生长期、稳定生长期、衰亡期）。用自腐蚀电位、极化曲线和电化学阻抗谱的电化学特征有效的评测了45钢在假单胞菌-海水体系作用下的电化学腐蚀行为。生长曲线表明，海水中假单胞菌的生长期分为迟缓期、对数生长期、稳定生长期、衰亡期四个周期，在海水条件下假单胞菌可以在相对长的时间内稳定生长。自腐蚀电位表明，完整生物膜的形成不会改变电极阴极的极化类型和控制步骤，假单胞菌的新陈代谢作用决定了45钢电极的性质和腐蚀速度。电化学阻抗谱表明，腐蚀产物层和双电层的双层作用而导致的阴极反应的电荷和物质在两相界面的传输速率的变化是控制45钢海水腐蚀的主要因素。
关键字：微生物腐蚀；假单胞菌；45钢；电化学
Abstract
In the marine environment , corrosion of carbon steel is the electrochemical process, influenced by physical, chemical, biological and other factors. Microbiology is a more important factor of accelerated corrosion of carbon steel, and has been given a lot of security risks and economic losses for use of carbon steel in marine engineering. With a widly development and utilization of marine resources, the microbiologically influenced corrosion (MIC) has been given much attention in marine environment concerned of all kinds of structure constructions, such as undersea pipelines, offshore oil platforms, seabed mining equipment, etc. Presently, most researches focus on the corrosion mechanism of microbiology in this area and especially the researches of the iron bacteria, sulfate-reducing bacteria, desulfotomaculum bacteria and sulfur bacteria have made encouraging results. However, the corrosion behavior of carbon steel by pseudomonas is few.
In this paper，the growth curve of pseudomonas was measured in order to know the growth cycle. Pseudomonas isolated and purified from carbon steel corrosion products by biology techniques. Then, the living environment of pseudomonas is simulated in the laboratory. The process of the corrosion of 45 steel was tracked in seawater with pseudomonas by electrochemical measurement techniques, which contain open circuit potential measurement, potentiodynamic cyclic polarization curve and AC impedance. Those can be obtained the corrosion potential, Rp trends curve with time and characteristics of the anode and cathode polarization from those. Some conclusions of the formation rule on corrosion of 45 steel can be achieved in seawater with pseudomonas.
The number of pseudomonas in different time was measured by method of most probable number (MPN) methed in seawater experiment.Growth curve of pseudomonas was described in order to investigate the vegetal rule of seawater (four periods:logy periods,logarithmic periods,steady growth periods,contabescence periods). The variety of the corrosion behavior of the 45 steel are investigated by the open circuit potential, polarization curves and electrochemical impedance spectroscopy in seawater with pseudomonas. Growth curves shows that the growth phase of pseudomonas divide into logy periods, logarithmic periods, steady growth periods, contabescence periods and can be a relatively long period of time in the steady growth periods in seawater and pseudomonas. The open circuit potential shows that full biofilm formation does not change the cathode electrode polarization type and control steps and the metabolism of pseudomonas determines the electrode nature and electrode corrosion rate of the corrosion of 45 steel. Electrochemical impedance spectroscopy shows that the transmission rate of charge and material of cathode reaction in the two-phase change interface is the main factors of the corrosion of the steel by product layer and double layer.
Keywords: MIC;Pseudomonas,;electrochemistry
目录
摘要∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙∙&#..
