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采用失重法、Tafel极化曲线、电化学阻抗谱和扫描电镜(SEM)等,研究了NaF对AZ91D镁合金在1g/L NaCl溶液中的缓蚀作用。结果表明,腐蚀介质中加入NaF,在AZ91D镁合金表面形成MgF2保护膜,阻止了腐蚀性Cl-在试样/介质界面的吸附,从而较好地抑制镁合金的腐蚀。随NaF的质量浓度增加缓蚀率增大,以点蚀为主的腐蚀坑减少,变浅,腐蚀电位正移,阻抗谱、容抗弧增大。其缓蚀作用属于阳极抑制型缓蚀作用。在NaF作用下168h的缓蚀效率均大于50%,最高达到85%。
The corrosion inhibition of AZ91D magnesium alloy in 1g / L NaCl solution was studied by weight loss method, Tafel polarization curve, electrochemical impedance spectroscopy and scanning electron microscopy (SEM). The results show that NaF is added into the corrosive medium to form MgF2 protective film on the surface of AZ91D magnesium alloy, which prevents the adsorption of corrosive Cl- on the sample / medium interface and thus inhibits the corrosion of magnesium alloy. With the increase of mass concentration of NaF, the corrosion inhibition rate increases. The corrosion pits mainly dominated by pitting decrease and become shallow, and the corrosion potential shifts forward. The impedance spectrum and the capacitive reactance arc increase. Its corrosion inhibition is anodic inhibition of corrosion inhibition. Under the action of NaF, the corrosion inhibition efficiency of 168 h is more than 50%, up to 85%.