Evolution of the Corrosion Product Film and Its Effect on the Erosion–Corrosion Behavior of Two Commercial 90Cu–10Ni Tubes in Seawater

作     者：Okpo O. Ekerenam Ai-Li Ma Yu-Gui Zheng Si-Yu He Peter C. Okafor 

作者机构：CAS Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal Research Chinese Academyof Sciences Shenyang 110016 China University of Chinese Academy of Sciences (UCAS)Beijing 100049 China Department of Pure and Applied Chemistry University of Calabar PMB 1115 Calabar CRS Nigeria 

出 版 物：《Acta Metallurgica Sinica(English Letters)》 (金属学报（英文版）)

年 卷 期：2018年第31卷第11期

页      面：1148-1170页

核心收录：

学科分类：080503[工学-材料加工工程] 0817[工学-化学工程与技术] 0806[工学-冶金工程] 08[工学] 0807[工学-动力工程及工程热物理] 0805[工学-材料科学与工程（可授工学、理学学位）] 0802[工学-机械工程] 0703[理学-化学] 0811[工学-控制科学与工程] 

基　　金：supported by the National Natural Science Foundation of China(Grant No.51601200) the National Environmental Corrosion Platform(No.2005DKA10400) 

主　　题：Copper-nickel alloy Seawater immersion Erosion-corrosion Corrosion product film Flow velocity 

摘      要：The composition and structural evolution of the corrosion product film of two commercial 90Cu-10Ni tubes, namely TubeA and Tube B, after being immersed in natural seawater for 1, 3, and 6 months were characterized by scanning electronmicroscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy, and its effecton the erosion--corrosion behavior of the tubes was determined through a rotating cylinder electrode system using variouselectrochemical techniques. For the freshly polished samples used as contrast samples, the flow velocity mainly enhancedthe cathodic reaction at low flow velocities while both the anodic and the cathodic reactions were remarkably accelerated athigher flow velocities. The corrosion product films formed on the two commercial 90Cu-10Ni tubes after being immersedin seawater for up to 6 months are of a complex three-layer or multilayer structure. The structural evolution of the films isout of sync for the two tubes. A continuous residual substrate layer depleted of Ni was observed in the inner layer of thefilms on Tube B after 30, 90, and 180 days＇ immersion, while it was observed in the film on Tube A only after 180 days＇immersion. The nature of the inner layer plays a crucial role in the erosion-corrosion resistance of the 90Cu-10Ni tubes athigher flow velocity. The film with a compact and continuous inner layer of Cu20 doped with Ni2＋ and Ni3＋ which bondsfirmly with the substrate could survive and even get repaired with the increased flow velocity. The film on Tube Bpossessing a hollow and discontinuous inner layer composed of the residual substrate was degraded rapidly with increasingrotation speed in spite of its quite good resistance at the stagnant or lower speed conditions.