镁合金激光重熔后微弧氧化膜的微观组织和耐蚀性能

为了改善WE43镁合金的耐蚀性能,采用激光重熔(LSM)和微弧氧化(MAO)复合工艺对其表面进行了改性。通过扫描电子显微镜(SEM)、能谱仪(EDS)、X射线衍射仪(XRD)研究了WE43镁合金及其激光重熔层、微弧氧化膜层和激光重熔-微弧氧化膜层的微观组织、表面形貌和物相;通过GAMARY-Reference 600电化学工作站研究了其腐蚀行为,重点研究了镁合金激光重熔后微弧氧化膜层的微观组织、成分和耐蚀性能。结果表明:激光重熔使WE43镁合金晶粒细化、网状的β-Mg41Nd5相均匀分布和表面稀土元素Y及Nd增加,有效地改善了其耐蚀性能;微弧氧化膜和激光重熔后的微弧氧化膜层都可以显著提高WE43镁合金的耐蚀性能,但后者优于前者。

Microstructure and Corrosion Behavior of Micro-Arc Oxidation Composite Coating on Treated Magnesium Alloy by Laser Surface Melting

In order to improve the corrosion resistance of WE43 magnesium alloy,laser surface melting(LSM) and micro-arc oxidation (MAO) composite techniques were employed to modify the surface of alloy.Scanning electron microscope (SEM),energy dispersive spectrometer (EDS) and X-ray diffractometer (XRD) were utilized to study the microstructure,surface morphology and phase compositions of WE43 Mg alloy substrate,LSM coating and MAO-LSM coating.In addition,the electrochemical workstation was used to analyze the corrosion behavior.Microstructure,composition and corrosion resistance of LSM-MAO coating were studied.Results showed that LSM treatment could cause grain refinement of WE43 Mg alloy,uniform distribution of β-Mg41Nd5 phase and increase of Y and Nd on the surface,which could efficiently improve the corrosion resistance.In general,both MAO coating and LSM-MAO coating could significantly improve the corrosion resistance of WE43 Mg alloy,and the latter coating exhibited better corrosion resistance than the former coating.