EFFECTS OF SEVERAL IONS ON ION-SELECTIVITY OF IRON SULFIDE FILM
几种离子对硫化亚铁膜离子选择性的影响

The ion selectivity of iron sulfide and effects of several anions and cations and imidazoline inhibitor have been investigated by measuring film potentials.The results show that iron sulfide film formed on steel surface is one kind of bipolarized film consisting of an inner cation-selective layer and an outer anion-selective layer,which accelerates anodic dissolution and leads to serious corrosion.The ion-selectivities of the precipitate membrane are altered from bipolar to anion-selective with adsorption of Ca~(2+),Mg~(2+) and Ba~(2+) ions,or to cation-selective with adsorption of MoO~(2-)_4,PO~(3-)_4 and imidazoline compound.The cation- selective film has some protective effect on metal.The corrosion behavior of A3 steel with iron sulfide product has been studied in different solutions by means of potential scanning,little effect of Ca~(2+) on polarization curves is observed,Na_2MoO_4 and imidazoline compound show inhibition on the anodic and cathodic process,which decrease the corrosion rate.