(1. 有研科技集团有限公司 国家有色金属及电子材料分析测试中心，北京 100088；
2. 国标（北京）检验认证有限公司，北京 100088；
3. 北京有色金属研究总院，北京 100088；
4. 中国船舶重工集团有限公司第七二五研究所，青岛 266237)
摘 要: 铜镍合金管材腐蚀失效分析多集中于表面电化学腐蚀行为及钝化膜结构与耐腐蚀性能的关系。然而，铜镍合金管材表面微观组织结构对其耐腐蚀性能的影响尚未澄清。本文采用扫描电镜背散射电子衍射(SEM-EBSD)和原子力显微镜(AFM)对铜镍合金管材表面晶粒取向和腐蚀形貌演化进行了定位跟踪观察，以揭示不同取向晶粒的腐蚀行为和腐蚀形貌演化规律。结果表明：随着铜镍合金管材表面晶粒取向与〈111〉方向之间夹角的减小，晶粒表面腐蚀深度增加，腐蚀形貌由扇贝状转变为阶梯状或四面体凸起状。这与晶粒表面能直接相关，符合台阶生长模型(TLK)。
关键字: 铜镍合金；定位跟踪表征；晶粒取向；腐蚀形貌
（1. National Analysis and Testing Center for Nonferrous Metals and Electronic Materials, GRINM Group Co., Ltd., Beijing 100088, China;
2. Guobiao (Beijing) Testing & Certification Co., Ltd., Beijing 100088, China;
3. General Research Institute for Nonferrous Metals, Beijing 100088, China;
4. Luoyang Ship Material Research Institute, Qingdao 266237, China）
Abstract:The corrosion failure analysis of copper-nickel alloy pipes was mostly focused on the surface electrochemical corrosion behavior and the correlation between the structure of the passive film and the corrosion resistance. However, the effect of the surface microstructure of the copper-nickel alloy pipe on the corrosion resistance has not been clarified by now. In this paper, both the scanning electron microscopy with back scattered electron diffraction (SEM-EBSD) and atomic force microscopy (AFM) were utilized to characterize the orientation and corrosion morphology of the grains of the copper-nickel alloy pipe by indentation-tracking, so as to reveal the corrosion behavior and corrosion morphology evolution of the differently oriented grains. The results show that the corrosion depth of the grains increases and the corrosion morphology changes from scallop-like to step-like or tetrahedral convex shape as the angle between the grain orientation and the 〈111〉 direction decreases. It is directly related to the surface energy of the grains, which is in line with the terrace ledge kink (TLK) model.
Key words: copper-nickel alloy; indentation-tracking; grain orientation; corrosion morphology
