NaF对AZ91D合金在NaCl介质中的缓蚀作用

Corrosion Inhibition of AZ91D Alloy in NaCl with Sodium Fluoride

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 AZ91 Dmagnesium alloy in 1g/L NaCl solution with sodium fluoride was detected by weightless,Tafel polarization curves,electrochemical impedance spectroscopy（E IS）and scanning electron microscopy（SEM）.With adding sodium fluoride into salt solution,protective coating MgF2 is formed on AZ91 Dsurface,which prevents Cl-adsorption on the interface between the sample and corrosive medium,therefore inhibiting the corrosion.With the concentration of sodium fluoride from 1g/L to 3g/L,the inhibition efficiency is increased,and the depth and quantity of pits become shallow and less with the corrosion potential moving positively and the capacitive loop of electrochemical impedance spectroscopy increases.Sodium fluoride is the corrosion inhibition of anode inhibited type.The inhibition efficiency is more than 50%and the highest value reaches 85%in 1g/L NaCl with NaF for 168 h.