Based on the first principles density functional theory,the equilibrium geometric structure and surface electronic properties of Cl and H2O co-adsorption on the Fe(100) surface are investigated.The results indicate that the optimal adsorption site for Cl and H2O co-adsorption on the Fe(100) surface is the location of Cl at the bridge site and H2O at the top site.Compared with the Fe(100)/H2O adsorption system,remarkable changes in geometric structure and electronic properties occur,owing to the presence of Cl in the Fe(100)/(H2O+Cl) adsorption system.The analysis of equilibrium geometric structure and surface electronic properties shows that the presence of Cl in the Fe(100)/(H2O+Cl) adsorption system unstablizes the Fe surface,making it easy to lose electrons.
To clarify the water erosion mechanism of the mild carbon steels, the water erosion experiments were performed by using deionized water as steam source. The results showed that under the damage threshold velocity of liquid impact, the material surface would not be destroyed. However, when the micro-particles were added into the steam, the pits appeared on the surface soon. By comparison, it is found that the pits are quite different from those induced by micro-particles impact without steam, but similar to those induced by cavitation erosion. The results indicated that the water erosion mechanism was similar to that of cavitation erosion under the damage threshold velocity. The micro-particles carry the micro-bubbles to approach the surface of the material, and the micro-bubbles collapse and generate micro-jet to impinge vertically on the surface, which lead to the produce of pits.
XU WanLi QIN Li WANG JiaDao CHEN HaoSheng CHEN DaRong
