目的 制备具有不同电位差的多层阳极Ni-P/Ni-Zn-P复合镀层。方法 采用化学镀的方法，在Q235钢基体表面制备内层为低磷Ni-P合金、中层为高磷Ni-P合金、外层为Ni-Zn-P合金镀层的三层复合镀层。通过金相显微镜、扫描电子显微镜(SEM)、X射线能谱仪(EDS)、X射线衍射仪(XRD)、电化学工作站等仪器对复合镀层表面形貌、成分结构及腐蚀电位进行分析。结果 相较于低磷Ni-P镀层和高磷Ni-P镀层，Ni-P/Ni-Zn-P三层复合镀层的晶胞大小均匀一致且胞与胞之间致密平滑。内层低磷Ni-P镀层断面厚度约为14.5 μm，镍的质量分数约为96.5%，磷的质量分数为3.5%;中层高磷Ni-P镀层断面厚度约为17.6 μm，镍的质量分数约为90.2%，磷的质量分数约为9.8%;Ni-P/Ni-Zn-P三层复合镀层断面总厚度约为40 μm，镍的质量分数约为80.7%，锌和磷的质量分数分别为7.6%和11.7%。在Tafel极化曲线中，Ni-P/Ni-Zn-P三层复合镀层的腐蚀电流密度最小，为3.815×10^–6 A/cm²，具有更好的耐蚀性。在模拟海水环境(5%NaCl溶液)中腐蚀220 h后，内层、中层组织腐蚀成片，出现孔洞且有点蚀，而Ni-P/Ni-Zn-P三层复合镀层几乎没有腐蚀，只有部分区域出现点蚀，组织较为完整，说明三层镀层较单层、双层镀层具有更好的耐腐蚀性。结论 制备具有电位差的多层阳极Ni-P/Ni-Zn-P复合镀层具有更好的性能，且相较于内层单层、中层双层Ni-P合金镀层，其腐蚀速率也明显降低，耐腐蚀性能更好。

Multi layer anode Ni-P/Ni-Zn-P composite coatings with different potential difference were prepared. A three-layer composite coating was prepared on the surface of Q235 low-carbon steel substrate by electroless plating, the inner layer was low-phosphorus Ni-P alloy, the middle layer was high-phosphorus Ni-P alloy, and the outer layer was Ni-Zn-P alloy coating. The surface morphology, composition structure and corrosion potential of the composite coating were analyzed by metallographic microscope, scanning electron microscope (SEM), energy dispersive X-ray spectrometer (EDS), X-ray diffraction (XRD) and electrochemical workstation. Compared with the the low-phosphorus Ni-P coating and the high-phosphorus Ni-P coating, the three-layer Ni-P/Ni-Zn-P composite coating has uniform cell size, and the cells are dense and smooth. The thickness of the inner layer of low phosphorus Ni-P coating is about 14.5 μm, the mass fraction of nickel is about 96.5%, and the mass fraction of phosphorus is 3.5%. The section thickness of the middle layer high phosphorus Ni-P coating is about 17.6 μm, the mass fraction of nickel is about 90.2%, and the mass fraction of phosphorus is about 9.8%. The total section thickness of Ni-P/Ni-Zn-P composite coating is about 40 μm, the mass fraction of nickel is about 80.7%, the mass fraction of zinc and phosphorus are 7.6% and 11.7%, respectively. In Tafel polarization curve, the corrosion current density of Ni-P/Ni-Zn-P composite coating is the smallest, which is 3.815×10–6 A/cm2 and has better corrosion resistance. After 220 h corrosion in simulated seawater 5%NaCl solution, the inner layer and middle layer were corroded into pieces, with holes and pitting corrosion. However, the Ni-P/Ni-Zn-P three-layer composite coating almost had no corrosion, only some of them had pitting corrosion, which indicated that the three-layer coating had better corrosion resistance than single-layer and double-layer coating. The preparation of multi-layer anode Ni-P/Ni-Zn-P composite coating with different potential difference has better performance and the corrosion rate is significantly reduced compared with the inner single layer and the middle double layer Ni-P alloy coating, and the corrosion resistance is better.