3.5%NaCl薄液膜下碳钢的腐蚀行为研究

Corrosion Behaviors of Carbon Steel Under 3.5% NaCl Thin Liquid Film

为了进一步研究碳钢的海洋大气腐蚀机理,为减缓碳钢在海水环境薄液膜下的腐蚀提供理论与实验依据,采用自制的薄液膜腐蚀实验装置,利用交流阻抗法和极化曲线法讨论了碳钢材料在不同厚度3.5%Na Cl薄液膜下腐蚀行为。结果表明,碳钢在薄液膜下的腐蚀比在全浸状态下的腐蚀更为严重;薄液膜腐蚀过程主要由浓度极化和活化极化两部分共同控制。在较薄液膜下,金属腐蚀速度主要由浓度极化控制;膜层较厚时,腐蚀速度主要由活化极化反应控制。溶液电阻随着膜厚的增大先迅速降低然后呈缓慢降低趋势,最终趋于稳定。

In order to further study the sea atmospheric corrosion mechanism of carbon steel,and to provide theoretical and experimental basis for the reduction of carbon steel corrosion under seawater environment thin liquid film,the home-made experimental device of thin liquid film is used,and the corrosion behaviors of carbon steel under 3. 5% Na Cl thin film with different thickness are discussed by using AC impedance and polarization curve technique. The results show that the corrosion of carbon steel under the thin liquid film is more severe than that in full immersion condition; the corrosion process under thin liquid film is mainly controlled by both the concentration polarization and activation polarization. When the liquid film thickness is thinner,the corrosion speed of carbon steel is controlled mainly by the concentration polarization; with the increase of the thickness of liquid film,corrosion speed turns to be controlled mainly by the activation polarization reaction. The resistance of the solution reduces quickly with the increase of the thickness of liquid film,and then the trend becomes slow and stable finally.