ZM5镁合金化学镀Ni-P合金镀层的电化学腐蚀行为  

Electrochemical Corrosion Behavior of Electroless Ni-P Alloy Coating on ZM5 Magnesium Alloy

作　　者：安吉祥 吴向清[1] 谢发勤[1] 马冰[1] AN Jixiang;WUXiangqing;XIE Faqin;MA Bing(School of Aeronautics,Northwestern Polytechnical University,Xi'an710000,China)

机构地区：[1]西北工业大学航空学院,陕西西安710000

出　　处：《电镀与环保》2020年第4期34-39,共6页Electroplating & Pollution Control

摘　　要：在ZM5镁合金表面制备了化学镀Ni-P合金镀层,并对其微观形貌、成分、相结构及电化学腐蚀行为进行了分析。结果表明:化学镀Ni-P合金镀层的厚度约为25μm,表面均匀、平整,内部致密无缺陷,与基体结合紧密,其结构为非晶态。与ZM5镁合金基体相比,化学镀Ni-P合金镀层的自腐蚀电位正移了1.171 V,自腐蚀电流密度减小了近3个数量级,表现出良好的耐蚀性。化学镀Ni-P合金镀层在阴极极化电位和自腐蚀电位下的阻抗谱均由两个容抗弧半圆组成,表现为均匀腐蚀。而阳极电位下化学镀Ni-P合金镀层的阻抗谱由容抗弧和Warburg阻抗组成,表现为局部腐蚀。化学镀Ni-P合金镀层在自腐蚀电位和阴极极化电位下工作能显著提高耐蚀性,并且在自腐蚀电位下的耐蚀性更好。而化学镀Ni-P合金镀层在阳极极化电位下的耐蚀性较差,不利于镀镍镁合金的长期使用。Electroless Ni-P alloy coating was prepared on the surface of ZM5 magnesium alloy,and the micromorphology,composition,phase structure and electrochemical corrosion behavior of of electroless Ni-P alloy coating were analyzed.The results showed that the thickness of electroless Ni-P alloy coating was about 25 μm and the surface was even and flat,the interior was dense and defect-free,and it was tightly bonded to the substrate.The electroless Ni-P alloy coating was amorphous structure.Compared with the substrate of ZM5 magnesium alloy,the self-corrosion potential of electroless Ni-P alloy coating moved forward by 1.171 V,and the selfcorrosion current density decreased by nearly 3 orders of magnitude,showing good corrosion resistance.The electrochemical impedance spectra of electroless Ni-P alloy coating was composed of two capacitive reactance arc semicircles under cathode polarization potential and self-corrosion potential,showing uniform corrosion.At the anode potential,the impedance spectrum of electroless Ni-P alloy coating was composed of capacitive arc resistance and Warburg impedance,showing local corrosion.Electroless Ni-P alloy coating can significantly improve the corrosion resistance under the self-corrosion potential and cathodic polarization potential,and the corrosion resistance under the self-corrosion potential was better.The corrosion resistance under the anodic polarization potential was poor,it was not conducive to the long-term use of nickel-plated magnesium alloy.

关 键 词：ZM5镁合金 化学镀Ni-P合金镀层 腐蚀 极化曲线 电化学阻抗 

分 类 号：TQ153[化学工程—电化学工业]