Stability of an Electrodeposited Nanocrystalline Ni-Based Alloy Coating in Oil and Gas Wells with the Coexistence of H₂S and CO₂.
Stability of an Electrodeposited Nanocrystalline Ni-Based Alloy Coating in Oil and Gas Wells with the Coexistence of H₂S and CO₂.
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DOI：
10.3390/ma10060632
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发表时间：
2017-06-09
期刊：
影响因子：
--
通讯作者：
Zhao W
中科院分区：
文献类型：
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作者：
Sui Y;Sun C;Sun J;Pu B;Ren W;Zhao W
通过电化学测量、失重法和表面表征，研究了电沉积纳米晶镍基合金涂层在H2S/CO2环境中的稳定性。结果表明：ni基合金镀层的阴极和阳极过程同时受到抑制，腐蚀电流密度显著降低；ni基合金涂层的腐蚀受H2S腐蚀控制，在试验温度下呈现出一般的腐蚀形态。腐蚀产物主要由Ni3S2、NiS或Ni3S4组成，在酸性溶液中具有良好的稳定性。随着温度的升高，腐蚀速率降低，而腐蚀垢的附着力增大。随着温度的升高，腐蚀产物的沉积形态和组成发生变化，腐蚀垢中的NiS含量增加，腐蚀垢的稳定性和粘接强度提高。镍基合金镀层的腐蚀尺度稳定致密，附着力强，失重率低，因此用失重法计算的腐蚀速率不能反映镀层的实际氧化速率。随着腐蚀时间的延长，镀层变薄，腐蚀垢变厚。腐蚀垢与涂层紧密结合，但不能完全阻止腐蚀反应物到达基体。
The stability of an electrodeposited nanocrystalline Ni-based alloy coating in a H2S/CO2 environment was investigated by electrochemical measurements, weight loss method, and surface characterization. The results showed that both the cathodic and anodic processes of the Ni-based alloy coating were simultaneously suppressed, displaying a dramatic decrease of the corrosion current density. The corrosion of the Ni-based alloy coating was controlled by H2S corrosion and showed general corrosion morphology under the test temperatures. The corrosion products, mainly consisting of Ni3S2, NiS, or Ni3S4, had excellent stability in acid solution. The corrosion rate decreased with the rise of temperature, while the adhesive force of the corrosion scale increased. With the rise of temperature, the deposited morphology and composition of corrosion products changed, the NiS content in the corrosion scale increased, and the stability and adhesive strength of the corrosion scale improved. The corrosion scale of the Ni-based alloy coating was stable, compact, had strong adhesion, and caused low weight loss, so the corrosion rates calculated by the weight loss method cannot reveal the actual oxidation rate of the coating. As the corrosion time was prolonged, the Ni-based coating was thinned while the corrosion scale thickened. The corrosion scale was closely combined with the coating, but cannot fully prevent the corrosive reactants from reaching the substrate.