Electrochemical characterisation of nickel-based alloys in sulphate solutions at 320 °C
Electrochemical characterisation of nickel-based alloys in sulphate solutions at 320 °C
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DOI：
10.1016/j.jnucmat.2004.04.327
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发表时间：
2004-08-15
影响因子：
3.1
通讯作者：
Dalard, F
中科院分区：
文献类型：
--
作者：
Le Canut, JM;Maximovitch, S;Dalard, F
压水堆（PWR）蒸汽发生器镍合金管对应力腐蚀开裂（SCC）非常敏感，利用电化学方法预测SCC的可能性是核工业的一个重要课题。研究了几种镍基合金在320 ℃、中性或弱碱性硫酸盐溶液中的电化学性能，通过线性伏安法和电化学阻抗谱（EIS）测量了腐蚀电位、极化曲线和极化电阻（R-p）。由于氧化铬的存在，钝化层在中性条件下更加稳定，并且合金600 TT和690显示出最好的钝化性。R-p测量证实合金600 TT和690具有最低的腐蚀速率。在碱性pH下，钝化电流高于在中性pH下获得的电流，并且合金表现出接近的行为。硫酸盐还原成硫化物似乎是可能的。计算结果与文献中热力学和表面分析数据一致。的电化学稳定性似乎没有直接关系到SCC的敏感性，因为它与SCC在硫酸盐介质中的pH依赖性成反比。(C)2004 Elsevier B. V.保留所有权利。
Nickel alloy steam generator tubes of pressurized water reactors (PWR) are sensitive to stress corrosion cracking (SCC) and the possibility of predicting SCC from electrochemical measurements is of considerable interest for nuclear industry. The electrochemical properties of several nickel-based alloys were studied at 320 degreesC in sulphate solutions at neutral or slightly alkaline pH from corrosion potential measurements, polarisation curves and polarisation resistance (R-p) measurements by linear voltammetry and electrochemical impedance spectroscopy (EIS). The passive layers were much more stable in neutral conditions, due to the presence of chromium oxide, and alloys 600TT and 690 showed the best passivity. R-p measurements confirmed that alloys 600TT and 690 have the lowest corrosion rates. At alkaline pH, the passivation currents were higher than those obtained at neutral pH, and the alloys showed a close behaviour. Reduction of sulphates to sulphides seemed to be possible. Results are in agreement with thermodynamic and surface analysis data of literature. The electrochemical stability did not appear to be directly related to SCC susceptibility since it varied inversely with the pH dependance of SCC in sulphate medium. (C) 2004 Elsevier B.V. All rights reserved.