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Islam, M. S.*; Otani, Kyohei; Sakairi, Masatoshi*
no journal, ,
In the previous study, it was founded that Zn
significantly inhibited the corrosion of mild steel in Cl
aqueous solution at room temperature. It is still not fully elucidated the corrosion inhibition ability of Zn concentration on the steel in Cl aqueous solutions. In the present study, the effects of Zn concentration on the corrosion inhibition of mild steel were investigated by immersion tests. From the immersion tests, it was found that mass change of specimen closely related to the Zn concentration in the solutions. SEM images showed that the numbers of pits are decreasing with increasing the Zn concentration. XPS and AES results showed that Zn existed as hydroxides by forming a layer with the surface film and the coverage of the layer is increased with increase in Zn concentration.
Igarashi, Takahiro; Komatsu, Atsushi; Yamaguchi, Masatake; Ebihara, Kenichi; Ueno, Fumiyoshi
no journal, ,
Hydrogen embrittlement has become important because of demand for higher strength steel. To clarify the mechanism, it is one of the important issues to evaluate hydrogen distribution in steel. Recently, metal surface potential mapping has used to evaluate hydrogen distribution in metal using surface potential lowering by hydrogen adsorption on metal surface. However, the mechanism of that behavior has been unclear. To elucidate the surface potential lowering mechanism of iron by hydrogen atom, work function and electric dipole moment analysis by density functional theory (DFT) calculation method were carried out. In the study, Fe(100) clean surface and oxygen adsorbed surface were prepared. Hydrogen atoms were adsorbed on surface or penetrated into interior of iron slab in the model. There was a negative correlation between work function and electric dipole. In addition, the surface potential decreased due to hydrogen adsorption on oxygen adsorption surface. It is suggested that electronic state around surface was changed by hydrogen atom adsorption and then surface potential was lowered by the electric dipoles on the surface generated.