化学镀镍磷合金在浓NaOH溶液中的电化学腐蚀行为

Electrochemical Corrosion Behaviour of Electroless NickelPhosphorus Alloys in 35%NaOH Solution

采用动电位极化法、电化学交流阻抗技术、原子力显微镜（ＡＦＭ）等对镍磷合金镀层在质量分数为３５％的ＮａＯＨ溶液中的腐蚀行为进行了研究．结果表明，高磷镀层的阳极极化行为与低磷镀层相似，但高磷镀层的腐蚀电流密度明显低于低磷镀层．低磷镀层具有岛状结构的微观形貌，表面粗糙，其颗粒大小在０１～０５μｍ之间，颗粒之间的缝隙深度约１０～２０ｎｍ，在碱性介质中腐蚀严重，而高磷镀层的颗粒较小，颗粒之间的缝隙深度约２～５ｎｍ，镀层具有更平整光滑的表面，在碱性介质中只有轻微的腐蚀．

The corrosion behavior of electroless NiP deposits on the carbon steel in deaerated 35%NaOH solution have been studied by potentiodynamic polarization method, electrochemical impedance spectroscopy(EIS) technique and atomic force microscopy(AFM). The results showed that the anodic polarization behavior of the NiP deposit with high P content were very similar to that of low P deposit, but the corrosion current densities of the high P deposit were much lower than that of the low P deposit. The low phosphorus deposit exhibited a roundedmound structure surrounded by fairly deep crevices and the size of the nodules varied from 0105 m, the depth of the crevices was about 1020 nm. The high phosphorus deposit exhibited a more uniform and smoother surface structure, the size of the nodules was smaller and the depth of the crevices was approximately 25 nm.