Q235焊缝表面镍基合金熔覆层在NaCl溶液中的腐蚀行为

目的 采用激光、等离子熔覆技术在低碳钢焊缝表面制备镍基耐腐蚀涂层，提高钢管焊缝表面的耐蚀性能。方法 通过浸泡腐蚀、动电位极化法、交流阻抗法，研究不同试样在质量分数为3.5%的NaCl溶液中的腐蚀行为。利用OM、SEM、EDS和XPS分析腐蚀试样表面、截面的微观组织和腐蚀产物成分。结果 采用激光、等离子熔覆技术均可制得成形良好、表面光滑、无宏观裂纹的涂层，且表现出良好的抗点蚀能力；等离子熔覆层晶粒相较于激光熔覆层晶粒更均匀、细小，析出的碳化物(Cr₂₃C₆、Cr₇C₃)、硼化物(CrB)等硬质点提高了涂层的硬度，对于抗蚀性有着积极的作用。试样的耐蚀性排序为等离子熔覆层>激光熔覆层>基体。浸泡失重腐蚀实验表明，基体、激光熔覆层、等离子熔覆层的腐蚀速率分别为0.182 9、0.125 6、0.102 7 g/(m²·h)。从极化曲线看出，激光熔覆层(-0.503 4 V)、等离子熔覆层(-0.546 6 V)的自腐蚀电位相较于基体(-0.858 4 V)发生了正移。基体、...

Corrosion Behavior of Nickel-based Alloy Cladding Layer on Q235 Weld in NaCl Solution

The work aims to prepare Ni60 nickel based corrosion resistant coatings on the weld surface of Q235 low carbon steel by laser cladding technology and plasma cladding technology. Corrosion resistance of the sample in 3.5% NaCl solution was tested by weight-loss corrosion and electrochemical corrosion tests. The microstructure morphology, chemical composition, coating phase and electronic structure of corrosion product film on the surface of the corrosion sample were tested by OM, SEM, EDS, XRD and XPS, so as to reveal the corrosion resistance mechanism of Ni60 corrosion-resistant coating.