Microstructures and Properties of Nickel-Aluminum-Bronze Coating by Laser Wire Additive Manufacturing

This study investigates the microstructure, mechanical properties, and corrosion resistance of nickel-aluminum bronze (NAB) coatings fabricated on Q235 steel using laser fused wire additive manufacturing (LFWAM). The coatings were characterized using X-ray diffraction (XRD), electron backscatter diffraction (EBSD), and electrochemical analysis. The main phases identified in the NAB coating are α-phase Cu, κⅠ-phase AlFe₃, and κⅡ-phase AlNi. The microstructure is fine, dense, and uniform, with an average microhardness of 259 HV0.2. The average coefficient of friction and wear rate are 0.317 and 1.694 × 10-6g/(N·m), respectively. Corrosion tests show a corrosion potential of -0.21 V and a corrosion current density of 6.201 × 10-7A/cm². The solid solution of Al and Ni in the coating enhances strength through solid solution strengthening. Grain refinement from Al and the formation of a dense oxide layer, along with the presence of the Ni-rich κⅡ-phase, significantly improve the coating’s strength, wear resistance, and corrosion resistance, contributing to its excellent overall performance.

本研究针对Q235钢表面采用激光熔丝增材制造（laser fused wire additive manufacturing, LFWAM）制备的镍铝青铜（nickel-aluminum bronze, NAB）涂层的微观组织、力学性能与耐腐蚀性能展开探究。采用X射线衍射（X-ray diffraction, XRD）、电子背散射衍射（electron backscatter diffraction, EBSD）以及电化学分析对该涂层进行表征。经鉴定，该镍铝青铜涂层中的主要物相为α相铜、κⅠ相AlFe₃以及κⅡ相AlNi。其微观组织细密致密、均匀一致，平均显微硬度为259 HV0.2。平均摩擦系数与磨损率分别为0.317与1.694 × 10⁻⁶ g/(N·m)。腐蚀测试结果显示，该涂层的腐蚀电位为-0.21 V，腐蚀电流密度为6.201 × 10⁻⁷ A/cm²。涂层内铝与镍的固溶体通过固溶强化作用提升了涂层强度。铝元素带来的晶粒细化效应、致密氧化层的形成，以及富镍κⅡ相的存在，共同显著改善了涂层的强度、耐磨性与耐腐蚀性能，助力其具备优异的综合服役性能。