903钢在NaCl溶液和薄液膜中的腐蚀规律

Corrosion Behavior of 903 Steel in Solution of NaCl and Thin Film Electrolyte

金属在海洋中的腐蚀受Cl-浓度和溶液中溶解氧含量的影响,以往的研究多为低Cl-浓度下的腐蚀,对于高Cl-浓度及与溶解氧含量相关的研究较少。为此,采用动电位扫描和电化学阻抗谱(EIS)方法,研究了船用903钢在不同NaCl浓度溶液及薄液膜中的腐蚀规律,探讨了Cl-浓度变化过程中溶解氧含量对903钢腐蚀的影响。结果表明:903钢在NaCl溶液及薄液膜中的腐蚀规律是不同的,初期随Cl-浓度的升高,溶液中的腐蚀速率先升高后降低,而在薄液膜中腐蚀速率一直升高;相同Cl-浓度下,薄液膜中的溶解氧含量高于溶液中的溶解氧含量,其腐蚀速率比溶液中的高。腐蚀规律不同的主要原因是溶解氧含量不同。

The corrosion behavior of 903 steel in solution of NaCl containing various Cl-concentrations and thin film electrolyte was evaluated by means of potentiodynamic polarization scanning and electro-chemical impedance spectroscopy. The effect of dissolved oxygen content at varied Cl-concentrations on corrosion of the 903 steelwas investigated. Results show that the 903 steel has different corrosion behaviors in solution of NaCl and thin film electrolyte. Namely, at the early stage of test, the corrosion rate of the steel in solution of NaCl increased to a maximum and then decreased along with increasing content of NaCl, but the corrosion rate in thin film electrolyte increased monotonically with increasing con-tent of NaCl. Besides, under the same concentration of Cl-, the dissolved oxygen content in the thin film electrolyte was higher than that in the solution of NaCl, and the steel had a higher cor-rosion rate in the former than in the latter. This was mainly attrib-uted to the different contents of dissolved oxygen in the two cases.