分析不同环境下N80钢和20#钢的腐蚀行为 材料学硕士论文精心编辑6篇第五篇：分析不同环境下N80钢和20#钢的腐蚀行为 摘要 随着能源需求的不断增大，环境复杂的高含CO2、CO2/H2S油气不断被开采，实际工况环境下糟糕的腐蚀破坏现象威胁着人员生命和设备平安因此对油气田中各腐蚀过程进展理解与研究具有着重要的意义 本文选用目前油田现场使用较为广泛的N80油管用钢和20#集输管线用钢作为实验研究材料，采用延长油田某采油厂XX区块产出液为腐蚀介质，利用SEM、XRD技术对腐蚀产物膜的外表构造和成分进展了分析，并运用电化学方法研究了覆盖有腐蚀产物膜碳钢的电化学特性，探究了N80钢和20#钢在通入CO2和CO2/H2S气体产出液中，随着腐蚀时间的变化，两种钢材的腐蚀速率、腐蚀产物膜成分、腐蚀产物膜微观形貌以及电化学特征的变化，提醒了不同环境下N80钢和20#钢的腐蚀行为 CO2对N80钢和20#钢的腐蚀为全面腐蚀，随着腐蚀时间延长膜层内出现FeCO3和Fe,它们可以保护基体并降低其腐蚀速率；含CO2环境下，初始阶段会形成保护性FeCO3膜，腐蚀产物不断在N80钢和20#钢外表堆积，最终外侧膜层由于受到较严重的腐蚀，呈现海绵状形态；含CO2情况下，Nyquist图谱特征为单一容抗弧，随着腐蚀时间增大，自腐蚀电位逐渐降低，腐蚀电流升高，当电流密度较高时，低频区出现Warburg阻抗特征；N80钢和20#钢腐蚀产物膜的M-S曲线斜率都有由N型转化为具有P型半导体特性的产物膜，产物膜具有N-P双极性特征。
CO2/H2S环境下N80钢和20#钢基体的腐蚀具有两种方式：其一、在腐蚀产物膜脱落的部位与裸露的基体直接接触发生点蚀；其二、Fe2+会穿过腐蚀产物膜，到达基体外表并发生反响，致使基体外表形成片层状脱落，且含H2S环境中的部分腐蚀需要一个较长的孕育期含H2S环境下，初始在N80钢和20#钢外表形成的膜颗粒均匀覆盖，但由于附着性较差，部分膜层会脱落，经过一段孕育期，在膜层脱落或者出现裂缝的部位重新生成新的腐蚀产物膜；在CO2/H2S共存环境下，腐蚀产物膜颗粒主要是Fe3O4和Fe,在初始阶段以较大的颗粒状态覆盖于基体外表，随着腐蚀时间的延长，腐蚀膜层颗粒细化，颗粒间距变小，颗粒之间逐渐形成胶状粘合，腐蚀产物膜致密性进步随着腐蚀时间的增大自腐蚀电位逐渐降低，溶液电阻Rs降低，并且各时间下的反响过程均有Warburg阻抗的出现当金属基体外表的腐蚀产物膜不断堆积后，阴极反响受扩散过程的影响不大；说明在此过程中腐蚀产物膜的堆积不会影响到试样阴极的腐蚀过程及机理在这种情况下，腐蚀产物膜层便可以表达出其对基体的保护作用说明膜层的空隙度较小、致密，离子不易通过腐蚀产物与基体发生反响两种碳钢在外表形成的腐蚀产物膜具有N-P型半导体特征，随着腐蚀时间的增加，外表形成腐蚀产物膜的受主密度和施主密度相对增大，这说明随着腐蚀时间增加产物膜的阻抗腐蚀性能有所降低。
关键词：腐蚀产物膜；腐蚀机理；电化学特性 Abstract As the demand for energy continues to increase, the highly plex CO2 and CO2/H2S oil and gas are continuously being mined. The poor corrosion damage in actual working conditions threatens the lives of people and equipment. Therefore, it is of great significance to understand and study the various corrosion processes in oil and gas fields. In this paper, N80 and 20#steel, which are widely used at the construction site, are selected as experimental research materials. The produced liquid of XX block of a certain oil production plant in Yanchang Oilfield is used as the corrosion medium, and the surface structure and position of the corrosion scale are treated by SEM and XRD techniques. The electrochemical characteristics of carbon steel coated with corrosion scale were studied by electrochemical method. The N80 and 20#steel were introduced into CO2 and CO2/H2S gas. Corrosion behavior of N80 and 20#steel in different environments was revealed by the change of corrosion time, the corrosion rate of the two steel materials, the corrosion scale position, the corrosion scale morphology and the electrochemical characteristics. The corrosion of N80 and 20#steel by CO2 is prehensive corrosion. With the corrosion time prolonging the appearance of FeCO3 and Fe in the scale layer, they can protect the matrix and reduce its corrosion rate. Under the condition of CO2, the protective FeCO3scale will be formed in the initial stage. Corrosion scale are continuously deposited on the surface of N80 and 20#steel, and the outer layer is sprinkled due to severe corrosion. In the case of CO2, the Nyquist spectrum is characterized by a single capacitive reactance arc. As the corrosion time increases, the self-corrosion potential gradually decreases and the corrosion current increases. When the current density is high, the Warburg impedance characteristic appears in the low frequency region; The slope of the MS curve of corrosion scale on N80 and 20#steel is converted from N-type to a scale having P-type semiconductor characteristics, and the scale has NP bipolar characteristics. Corrosion of N80 and 20#steel matrix in CO2/H2S environment has two ways: one is pitting corrosion directly in contact with the exposed substrate at the site where the corrosion scale falls off; the Fe2+ passes through the corrosion scale, reaching the surface of the substrate and reacting, causing the surface of the substrate to form a lamellar shedding, and the local corrosion in the H2S-containing environment requires a longer incubation period. In the H2S-containing environment, the scale particles formed on the surface of N80 and 20#steel are uniformly covered. However, due to poor adhesion, some of the scale will fall off. After a period of incubation, the scale will be re-formed at the site where the scale is peeled off or cracked. A new corrosion scale; in the CO2/H2S existing environment, the corrosion scale particles are mainly Fe3O4 and Fe, covering the surface of the substrate with a large particle state at the initial stage, and the corrosion scale layer is fine with the prolongation of the corrosion time. The particle spacing bees smaller, and the gel-like adhesion gradually forms between the particles, and the density of the corrosion scale is improved. As the corrosion time increases, the corrosion potential decreases gradually, the solution resistance Rsdecreases, and the Warburg impedance appears in the reaction process at each time. When the corrosion scale on the surface of the metal substrate is continuously accumulated, the cathode reaction is not affected by the diffusion process; it indicates th。