镁锂合金腐蚀行为及干法镀膜防护工艺研究  

Corrosion Behavior and Dry Coating Protection of Magnesium Lithium Alloy

作　　者：姚彦[1,2] 丁雪峰[2] 杨丽景[2] 鞠鹏飞 何燕霖[1] 宋振纶[2] 

机构地区：[1]上海大学材料科学与工程学院,上海200072 [2]中国科学院海洋新材料与应用技术重点实验室、浙江省海洋材料与防护技术重点实验室,中国科学院宁波材料技术与工程研究所,宁波315201 [3]上海航天设备制造总厂,上海200245

出　　处：《表面技术》2016年第12期56-61,共6页Surface Technology

基　　金：浙江省公益项目(2015C31031)~~

摘　　要：目的利用PVD磁控溅射技术,在样品上沉积纯铝膜,以提高镁锂合金的耐腐蚀性能。方法采用动态极化曲线、交流阻抗方法研究镁锂合金在去离子水和3.5%Na Cl溶液两种介质中的电化学行为,并利用感应耦合等离子体发射光谱仪技术和荧光金相显微镜,分别测定合金的成分,分析微观组织结构。采用扫描电子显微镜和EDS能谱仪分析镁锂合金纯铝膜的组织形貌与结构成分。此外,采用电化学技术测试纯铝膜的保护行为。结果在3.5%Na Cl溶液中,镁锂合金的腐蚀电流密度比去离子水介质中的高约两个数量级,且腐蚀电位较负;交流阻抗结果显示,比去离子水中的阻抗模值低一个数量级,说明镁锂合金抗Cl?侵蚀的能力较差。通过磁控溅射技术,获得了厚度为4μm致密的纯铝膜。镀铝后,镁锂合金的腐蚀电流密度降低了约一个数量级,腐蚀电位正移,耐蚀性提高。结论致密的纯铝膜在3.5%Na Cl溶液介质中容易发生钝化,阻碍Cl?的扩散,进而提高了镁锂合金耐Cl?侵蚀性。The work aims to improve corrosion resistance of Mg-Li alloy by depositing pure Al film on a sample by means of PVD magnetron sputtering technology. The electrochemical behavior of Mg-Li alloy in deionized water and 3.5% Na Cl solution was studied by virtue of dynamic polarization curve and AC impedance spectrum. The alloy composition was determined and microstructure was analyzed by virtue of inductively coupled plasma emission spectrometer（inductively coupled plas-ma-AES） and fluorescence metallographic microscope. The morphology and compositionof pure Al film on Mg-Li alloy were analyzed by scanning electron microscope（SEM） and energy disperse spectroscopy. The electrochemical behavior of the sample with pure Al film was also tested on electrochemical workstation. For uncoated Mg-Li alloy, the corrosion current density was two orders of magnitude higher than that in deionized water when tested in 3.5% Na Cl solution, the corrosion potential was more negative. According to alternating-current impedance results, the impedance modulus value obtained in 3.5% Na Cl solution was about one order of magnitude lower than that in deionized water. Compared with uncoated alloy, resistance of Mg-Li alloy to Cl？ corrosion was weaker. A 4 μm dense pure Al film was obtained by virtue of magnetron sputtering technology. After being aluminized, corrosion current density of the Mg-Li alloy reduced by nearly one order of magnitude, the corrosion potential moved positively and corrosion resistance increased. Dense pure Al film is susceptible to passivation in 3.5% Na Cl solution, hindering the diffusion of Cl？ and further improving the erosion resistance of Mg-Li alloy to Cl？.

关 键 词：镁锂合金 腐蚀行为 PVD 纯铝膜 组织形貌 

分 类 号：TG174[金属学及工艺—金属表面处理]