铝酸钠溶液中S^(2-)对低合金钢腐蚀行为的影响

Effect of S^(2-) on corrosion behavior of low alloy steel in sodium aluminate solution

采用钢弹群釜溶出装置进行高温腐蚀实验,结合SEM和XRD等分析技术,研究S2-对低合金钢在高温铝酸钠溶液中腐蚀行为的影响。采用极化曲线法分析S2-加速低合金钢腐蚀的原因。结果表明:在高温条件下,随着S2-和碱浓度的升高,低合金钢具有很高的腐蚀速率,而随着氧化铝浓度的升高,腐蚀速率减小。表面腐蚀产物主要成分为Fe3O4,其结构疏松,在搅拌条件下易于从表面脱落。低温极化研究表明,S2-加速腐蚀原因是在金属表面形成结构不稳定的铁硫化物,当该硫化物被氧化成具有较稳定结构的氧化物时,铁的腐蚀得到抑制。

The effect of S2- on the corrosion behaviors of low alloy steel in high temperature sodium aluminate was investigated by high temperature corrosion test conducted in steel bombs and analysis technologies of SEM and XRD. Polarization curve method was used to examine the origins of the corrosion acceleration. The results indicate that low alloy steel exhibits high corrosion rate as the concentrations of sulfide and hydroxide increase at high temperature,but the corrosion rate of low allay steel decreases with an increase in the concentration of alumina. The corrosion product mainly consists of Fe3O4,with a porous structure,which tends to fall off the surface easily when the solution is stirred. Polarization studies at lower temperature show that,accelerated corrosion is attributed to the formation of unstable iron sulfide with unprotected structure on the surface of metal,and when the sulfide is oxidized to oxide with stable structure,the corrosion of iron is inhibited.