镁合金表面原位生长有机膦酸盐薄膜及耐蚀行为

摘要

利用超声辅助的浸渍涂布方法,在AZ91D镁合金表面原位生长了氨基二乙酸亚甲基膦酸镁铝薄膜,其中包含具有纳米尺度的变形六边形板状颗粒.塔菲尔极化曲线、电化学阻抗谱测量表明,修饰后的AZ91D镁合金的耐腐蚀行为依赖于浸渍所用的膦酸浓度、pH值、温度及时间等.在3.5％ NaCl溶液中,未修饰的AZ91D其腐蚀活化能是18.1 kJ·mol-1,而在1.5 mmol·L-1膦酸溶液中pH值分别是1.7、11.5时浸渍涂布有机膦酸盐薄膜后,AZ91D的腐蚀活化能分别是27.9、37.8 kJ·mol-1.%Through a sonication assisted dip-coating method,a nanoscale deformed hexagonal platelet magnesium aluminium iminodiacetato-methylphosphonate (IDMP) film is formed in situ on AZ91D magnesium alloy surface.The corrosion inhibiting behavior of the film,evaluated by the Tafel polarization and electrochemical impedance spectroscopy (EIS) measurements in 3.5％ NaCl solution,is dependent on the concentration of IDMP,solution pH value,dip-coating temperature and time.The activation energies of the corrosion reaction in 3.5％ NaCl solution for bare AZ91D and AZ91D dip-coated by 1.5 mmol·L-1 IDMP at pH value of 1.7 and 11.5 are 18.1 kJ.mol-1,27.9 kJ· mol-1,and 37.8 kJ· mol-1,respectively.