航天器用镁合金高耐蚀化学镀镍层制备工艺研究

针对镁合金材料耐蚀性差，同时结合航天器电子结构产品对高导电的技术要求，采用碱性镀镍和酸性镀镍相结合的工艺方法，在AZ40M镁合金表面制备具有高耐蚀特性的Ni-P合金镀层。分别采用扫描电镜（Scanning electronic microscope，SEM）、能量色散谱（Energy dispersive spectroscopy，EDS）、X-射线衍射（X-ray diffraction，XRD）对镀层的微观形貌及相组成进行表征分析；采用动电位极化曲线及中性盐雾实验对镀层防腐蚀性能进行评价。实验结果表明：采用该工艺制备的Ni-P合金镀层为明显的非晶态结构，含磷量约为8%，属中磷镀层；当酸性镀镍时间达到60 min以上时，镀层自腐蚀电位在-0.55 V以上，中性盐雾实验48 h表面腐蚀，说明该镀层致密性好，具有优异的耐蚀性能，保证航天器镁合金电子结构产品在地面贮存、实验及空间应用的可靠性。

High-Corrosion Resistance Electroless Ni-P Coating on Spacecraft Magnesium Alloys

The process method of alkaline and acidic nickel plating combination is studied on AZ40M magnesium alloy. The high-corrosion resistance Ni-P coating is prepared to meet the corrosion and conductive technology requirements of spacecraft magnesium alloy electronic structure products. The properties of the Ni-P plating are studied by scanning electronic microscope(SEM) and its energy dispersive spectroscopy(EDS), X-ray diffraction (XRD), electrochemical polarization curves and neutral salt spray experiment. The result shows that the plating is amorphous structure and the phosphorus content is about 8%. The self-corrosion potential of magnesium alloys reached -0.55 V above and the corrosion current density declined obviously, and it is not eroded by neutral salt spray experiment for 48 h, when the electroless nickel time is more than 60 min, which indicates that the plating is dense and has excellent corrosion resistance to ensure the reliability of spacecraft electronic structure products on the ground storage, experiment and space application.