【摘要】 采用热浸镀的方法,通过改变Mg,RE的添加量来制备不同成分合金涂层。通过扫描电子显微镜(Scanning electron microscope,SEM)、盐雾实验、腐蚀失重测试来分别研究Mg,RE添加量对55%Al-Zn-1.6%Si-MgRE合金涂层耐蚀性的影响;并通过对最佳成分的合金涂层电化学测试和X射线衍射仪(X-ray diffraction,XRD)物相分析,与55%Al-Zn-1.6%Si进行对比,判断其腐蚀机理。实验结果表明:Mg能细化晶粒,强化晶界,1.5%Mg添加量耐蚀性最为优异;RE可以减小熔液表面张力,细化晶粒,提高耐蚀性,0.12%RE添加量较为合适;Mg和RE的加入使涂层中Al发生了择优取向,使涂层中的择优晶面的数量减少,涂层表面电位趋于均匀化,微电池腐蚀的驱动力变小,从而导致了涂层的腐蚀速度降低,在腐蚀溶液中耐蚀能力增强,55%Al-Zn-1.6%Si-1.5%Mg-0.12%RE合金涂层的自腐蚀电位为-0.983V,自腐蚀电流密度仅为16.91μA/cm2。更多还原

【Abstract】 55%Al-Zn-1.6%Si coating with different amounts of Mg and RE is prepared by the hot dip plating method.The morphology and corrosion resistance are charactered by scanning electron microscope(SEM),salt spray test and corrosion weightless test,respectively.The influence of the amount of Mg and RE in 55%Al-Zn-1.6%Si alloy coating on corrosion resistance is studied.The corrosion mechanisms are discussed based on the X-ray diffraction(XRD)results and the electrochemical tests of55%Al-Zn-1.6%Si-Mg-RE and 55%Al-Zn-1.6%Si coatings.The results show that Mg can refine the grains and strengthen the grain boundary,and the best addition amount of Mg is 1.5%.RE can reduce the liquid surface tension,refine the grains and improve the corrosion resistance,and the best addition amount of RE is 0.12%.The addition of Mg and RE causes Al preferred crystal to decrease,so that the surface potential of coating tends to be homogenization,and the corrosion speed of micro cell is reduced.The corrosion potential of 55%Al-Zn-1.6%Si-1.5%Mg-0.12%RE coating is-0.983 Vand the corrosion current density is 16.91μA/cm2.更多还原