Zhou Shiquan, Tong Rui, Li Hongtao, Tao Xiang, Chen Jian
College of Materials Science and Engineering, Nanjing Tech University, Nanjing 211816, China.
Materials (Basel). 2025 Jun 22;18(13):2949. doi: 10.3390/ma18132949.
In this work, micro-arc oxidation (MAO) under constant- and gradient-current modes was used to modify the surface of 6061 aluminum alloy. A black coating was created in situ on the alloy surface by controlling the spark discharge parameters during MAO. Using an electrochemical workstation (Metrohm Autolab, PGSTAT302 N, Herisau, Switzerland), energy-dispersive spectroscopy (EDS, JEOL, JSM-IT500A, Tokyo Metropolis, Japan), and scanning electron microscopy (SEM, JEOL, JSM-7900F, Tokyo Metropolis, Japan), the effects of the current output modes on the coating growth rate, energy consumption, colorimetric parameters (L*, a*, b*), microstructure, and corrosion resistance were methodically examined. The findings showed that the gradient-current mode (6 → 4 → 2 A/dm) greatly lowered the micropore size (from 3.89 μm to 1.52 μm) and improved the coating compactness (porosity dropped by 40%), and all coatings satisfied the necessary blackness criterion (L* < 30). Additionally, this mode achieved excellent corrosion resistance, as demonstrated by a one-order-of-magnitude reduction in the corrosion current density (2.55 × 10 A/cm vs. 2.34 × 10 A/cm), while minimizing the energy consumption (2.37 kW·h/m·μm vs. 3.45 kW·h/m·μm for constant current).
在本研究中，采用恒流模式和梯度电流模式下的微弧氧化（MAO）对6061铝合金表面进行改性。通过控制微弧氧化过程中的火花放电参数，在合金表面原位生成黑色涂层。利用电化学工作站（瑞士万通Autolab，PGSTAT302 N型，赫里绍）、能谱仪（日本电子，JSM-IT500A型，东京都）和扫描电子显微镜（日本电子，JSM-7900F型，东京都），系统研究了电流输出模式对涂层生长速率、能耗、比色参数（L*、a*、b*）、微观结构和耐蚀性的影响。结果表明，梯度电流模式（6→4→2 A/dm）大大降低了微孔尺寸（从3.89μm降至1.52μm），提高了涂层致密性（孔隙率下降40%），且所有涂层均满足所需的黑色标准（L*<30）。此外，该模式具有优异的耐蚀性，腐蚀电流密度降低了一个数量级（2.55×10 A/cm对2.34×10 A/cm），同时将能耗降至最低（恒流模式下为3.45 kW·h/m·μm，梯度电流模式下为2.37 kW·h/m·μm）。
