航空用铝合金表面化学镀镍磷层的制备及其耐蚀性

Preparation and Corrosion Resistance of Electroless Nickel-Phosphorus Coating on Surface of Aluminum Alloy for Aviation

为了保证航空铝合金在海洋环境中的安全服役,设计了一种低磷镍/中磷镍/高磷镍的组合梯度化学镀镍磷层.采用SEM和XRD表征镀层的微观形貌和相结构,并通过电化学方法评价了镀层的耐蚀性.结果表明:相比于2A11铝合金基体,化学镀镍磷层的自腐蚀电位更正,自腐蚀电流更低;组合梯度镀层试样在35℃,5%NaCl盐雾环境中腐蚀500 h后,表面未见明显腐蚀现象,能满足航空铝合金耐腐蚀性能的要求.

In order to ensure the safe service of aviation aluminum alloy in marine environment,a combined gradient electroless nickel-phosphorus coating of low phosphorus nickel/medium phosphorus nickel/high phosphorus nickel was designed.The micro morphology and phase structure of the coating were characterized by SEM and XRD,and the corrosion resistance of the coating was evaluated by electrochemical method.The results showed that the self-corrosion potential of electroless nickel-phosphorus coating was more positive and the self-corrosion current was lower than those of 2A11 aluminum alloy substrate.After combined gradient coating sample was corroded in 35℃,5%NaCl salt spray environment for 500 h,no obvious corrosion phenomenon was observed on the surface,which could meet the requirements of corrosion resistance of aviation aluminum alloy.