The Sr/F co-doped CaP(Sr/F-CaP)coatings were prepared by micro-arc oxidation(MAO)under different voltages to modify the microstructure and corrosion behavior of Mg-4Zn-1Mn alloy.The surface and interface characteristi...The Sr/F co-doped CaP(Sr/F-CaP)coatings were prepared by micro-arc oxidation(MAO)under different voltages to modify the microstructure and corrosion behavior of Mg-4Zn-1Mn alloy.The surface and interface characteristics investigated using scanning electron microscopy(SEM)and energy dispersive X-ray spectrometer(EDS)showed that the MAO coatings displayed uneven crater-like holes and tiny cracks under lower voltage,while they exhibited relatively homogeneous crater-like holes without cracks under higher voltage.The thickness of MAO coatings increased with increasing voltage.The corrosion behavior of Mg-4Zn-1Mn alloy was improved by the MAO coatings.The MAO coatings prepared under 450 V and 500 V voltages possessed the best corrosion resistance with regard to the electrochemical corrosion tests and immersion corrosion tests,respectively.The MAO coatings fabricated under 450-500 V could provide a better corrosion protection effect for the substrate.展开更多
利用扫描电镜(SEM)、X射线衍射(XRD)分析稀土元素La对Mg-Hg-Ga阳极材料显微组织的影响,并采用恒电流放电、动电位极化扫描、交流阻抗法、阳极效率测试和化学浸泡法研究La对Mg-Hg-Ga阳极材料腐蚀电化学性能的影响。结果表明:La的添加能使...利用扫描电镜(SEM)、X射线衍射(XRD)分析稀土元素La对Mg-Hg-Ga阳极材料显微组织的影响,并采用恒电流放电、动电位极化扫描、交流阻抗法、阳极效率测试和化学浸泡法研究La对Mg-Hg-Ga阳极材料腐蚀电化学性能的影响。结果表明:La的添加能使Mg-Hg-Ga合金晶粒细化,大量的Mg17La2和La Hg6相聚集在晶界处呈网状分布。随着La含量的升高,合金电化学活性下降,耐腐蚀性能先降低后增加,阳极效率先下降后升高,Mg-Hg-Ga-2%La合金的析氢速率为17.92 m L/(cm2·h),阳极效率为50.3%;而Mg-Hg-Ga-6%La合金的析氢速率仅为0.45 m L/(cm2·h),阳极效率为82.5%。这是因为随着La含量的升高,合金中新增的Mg17La2和La Hg6相为弱阴极性相,与α-Mg之间形成的腐蚀原电池驱动力较小,从而抑制镁基体的腐蚀。展开更多
文摘The Sr/F co-doped CaP(Sr/F-CaP)coatings were prepared by micro-arc oxidation(MAO)under different voltages to modify the microstructure and corrosion behavior of Mg-4Zn-1Mn alloy.The surface and interface characteristics investigated using scanning electron microscopy(SEM)and energy dispersive X-ray spectrometer(EDS)showed that the MAO coatings displayed uneven crater-like holes and tiny cracks under lower voltage,while they exhibited relatively homogeneous crater-like holes without cracks under higher voltage.The thickness of MAO coatings increased with increasing voltage.The corrosion behavior of Mg-4Zn-1Mn alloy was improved by the MAO coatings.The MAO coatings prepared under 450 V and 500 V voltages possessed the best corrosion resistance with regard to the electrochemical corrosion tests and immersion corrosion tests,respectively.The MAO coatings fabricated under 450-500 V could provide a better corrosion protection effect for the substrate.
基金Project(20110162120051)supported by Specialized Research Fund for the Doctor Program of Higher Education,ChinaProject(51101171)supported by the National Natural Science Foundation of China
文摘采用动电位极化和恒电流曲线测试合金元素Ga和In对Mg阳极材料电化学性能的影响。采用扫描电镜法分析Mg In Ga合金的显微组织和腐蚀表面,并用X射线衍射法检测Mg 0.8%In合金和Mg 0.8%Ga 0.3%In合金的腐蚀产物。结果表明:Mg xIn(x=0 0.8%)合金中没有第二相出现,Mg 0.8%In xGa(x=0 0.8%)合金中存在富含Ga和In元素的晶间化合物。合金元素In和0.05%0.5%Ga的添加提高了镁阳极的耐腐蚀性能,Ga元素的添加更促进了Mg In合金的电化学活性。Mg 0.8%In 0.8%Ga合金的平均电位最负,为1.682 V,此电位比AZ91D合金的1.406 V更负。Mg In Ga合金的腐蚀类型是全面腐蚀,其腐蚀产物是Mg(OH)2。
文摘利用扫描电镜(SEM)、X射线衍射(XRD)分析稀土元素La对Mg-Hg-Ga阳极材料显微组织的影响,并采用恒电流放电、动电位极化扫描、交流阻抗法、阳极效率测试和化学浸泡法研究La对Mg-Hg-Ga阳极材料腐蚀电化学性能的影响。结果表明:La的添加能使Mg-Hg-Ga合金晶粒细化,大量的Mg17La2和La Hg6相聚集在晶界处呈网状分布。随着La含量的升高,合金电化学活性下降,耐腐蚀性能先降低后增加,阳极效率先下降后升高,Mg-Hg-Ga-2%La合金的析氢速率为17.92 m L/(cm2·h),阳极效率为50.3%;而Mg-Hg-Ga-6%La合金的析氢速率仅为0.45 m L/(cm2·h),阳极效率为82.5%。这是因为随着La含量的升高,合金中新增的Mg17La2和La Hg6相为弱阴极性相,与α-Mg之间形成的腐蚀原电池驱动力较小,从而抑制镁基体的腐蚀。
基金supported by the National Natural Science Foundation of China(Nos.51571089, 51871093)the Natural Science Foundation of Hunan Province, China(No. 2019JJ40044)
