【摘要】 为了提高镁合金基体与化学镀镍层间的耐电偶腐蚀性能,采用两步电沉积方法,在AM60镁合金上沉积金属锌镀层作为镁合金基体与化学镀镍层之间的过渡层。SEM观察显示,从硫酸锌为主盐的镀锌液中沉积的初始锌层较为粗糙,从碱性镀锌液中沉积的锌镀层覆盖在初始沉积层上,形成均匀致密的电镀锌层。电位-时间曲线结果表明,锌镀层的自腐蚀电位接近-1.3V(SCE),较镁合金基体电位有所提高。锌中间层的存在有利于降低化学镀镍层与镁合金基体间的电偶腐蚀。更多还原

【Abstract】 Electroless Ni coating was deposited on AM60 magnesium alloy via a two-step route so as to improve the resistance to galvanic corrosion.Thus Zn coating was electrodeposited on the Mg alloy substrate in the first step,then electroless Ni coating was prepared in the second step using the electrodeposited Zn coating as the transition coating.The morphologies and microstructures of the coatings were analyzed by means of scanning electron microscopy,while their corrosion resistance was evaluated by plotting the potential-time curves.It was found that the Zn coating electrodeposited from the bath containing zinc sulfate as the main salt was rough,while the one electrodeposited from alkaline Zn-plating bath was uniform and compact.The electrodeposited Zn coating had a corrosion potential of about-1.3 V(vs SCE),which was a little larger than that of the Mg alloy substrate.Moreover,the electrodeposited Zn coating as the intermediate layer was beneficial to retarding the galvanic corrosion between the electroless Ni coating and Mg alloy substrate.更多还原