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首页> 外文期刊>Anti-Corrosion Methods and Materials >Improvement of corrosion protection properties of calcareous deposits on carbon steel by pulse cathodic protection in artificial sea water
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Improvement of corrosion protection properties of calcareous deposits on carbon steel by pulse cathodic protection in artificial sea water

机译：人造海水中脉冲阴极保护改善碳钢上钙质沉积物的腐蚀防护性能

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Purpose - This study aims to evaluate the influence of pulsed cathodic protection on calcareous deposit formation on structures submerged in the synthetic sea water. Design/methodology/approach - Chronoamperometric and CHF methods have been used to evaluate the influence of pulsed cathodic protection on decreasing the required cathodic current for protection and also decreasing the surface coverage. The morphology of the formed deposits was evaluated using scanning electron microscopy. Chemical analyses of the formed deposits were performed using energy dispersive X-ray spectrometer and X-ray diffraction. Findings - It was observed that pulse frequency influenced both the structure and the composition of the deposits. The most compact aragonite layer was obtained at high frequencies and at a high off-time. It was clearly shown that by applying currents with less than 100 Hz frequency, the deposits formed on the sample involved CaCO{sub}3 (aragonite) and Mg(OH){sub}2 (brucite). However, the kinetics of deposits formed when applying pulse current have been improved, compared to deposits formed by conventional cathodic protection. The reason is that large electrode overpotential favors nucleation through a decrease in the energy of nucleus formation. On the other hand, by intensive decrease of surface potential, repulsion of aggressive anions such as (SO{sub}4){sup}(2-) and Cl{sup}- occurs. These anions inhibit the formation of aragonite deposits. Research limitations/implications - In order to have a better investigation of electrodeposition processes in the shorter time, the use of more advanced techniques and analysis methods such as XPS is recommended. Furthermore, EHD techniques could be used for measurements of thickness of the layers. Practical implications - The pulsed cathodic protection method is a relatively new method for the protection of buried and submerged structures. Recently, many researches have investigated that the influence of this technique on increasing the throwing power, decreasing interference effects on neighboring structures and increasing the uniformity of current distribution under cathodic protection. Originality/value - Very little attention has been paid in the past to the effect of pulsed CP on deposit formation. The present paper, therefore, contributes useful understanding of the mechanism and advantages of such deposits in improving the effectiveness and lowering the operational cost of cathodic protection in use on offshore structures.
机译：目的-这项研究旨在评估脉冲阴极保护对合成海水淹没结构中钙质沉积物形成的影响。设计/方法/方法-计时电流法和CHF方法已用于评估脉冲阴极保护对降低保护所需阴极电流并减小表面覆盖率的影响。使用扫描电子显微镜评估形成的沉积物的形态。使用能量色散X射线光谱仪和X射线衍射对形成的沉积物进行化学分析。发现-观察到脉冲频率会影响沉积物的结构和组成。在高频率和高关闭时间下获得最致密的文石层。清楚地表明，通过施加频率低于100 Hz的电流，样品上形成的沉积物包括CaCO {sub} 3（文石）和Mg（OH）{sub} 2（青石）。但是，与通过常规阴极保护形成的沉积物相比，施加脉冲电流时形成的沉积物的动力学得到了改善。原因是大的电极超电势通过减少核形成能而有利于成核。另一方面，通过表面电位的强烈降低，发生侵蚀性阴离子如（SO {sub} 4）{sup}（2-）和Cl {sup}-的排斥。这些阴离子抑制文石沉积物的形成。研究的局限性/意义-为了在较短的时间内更好地研究电沉积过程，建议使用更先进的技术和分析方法，例如XPS。此外，EHD技术可以用于测量层的厚度。实际意义-脉冲阴极保护方法是一种相对较新的保护埋入式和淹没式结构的方法。近来，许多研究已经研究了该技术对增加阴极保护下的投掷功率，减小对相邻结构的干扰影响以及增加电流分布的均匀性的影响。创意/价值-过去很少关注脉冲CP对沉积物形成的影响。因此，本论文对此类沉积物的机理和优点做出了有益的理解，有助于提高海上构筑物中使用阴极保护的有效性并降低其运营成本。

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