Cl<sup>-</sup>对X80管线钢在NaHCO<sub>3</sub>溶液中腐蚀性能的影响

Cl^-对X80管线钢在NaHCO₃溶液中腐蚀性能的影响

摘要: 采用动电位极化方法研究了在0.5mol·L^-1 NaHCO₃溶液中Cl^-对X80管线钢腐蚀行为的影响,并通过电容测量方法对其腐蚀机理进行了探讨.实验结果表明:Cl^-使X80管线钢在0.5mol·L^-1 NaHCO₃溶液中发生了点腐蚀,且随着溶液中Cl^-含量增加,腐蚀坑的数量增多,腐蚀坑的直径增大,降低了X80管线钢的耐腐蚀性能.Mott-Schottky分析表明:随着溶液中Cl^-含量增加,X80管线钢钝化膜内的施主密度随之增大,增加了X80管线钢钝化膜局部破裂和腐蚀萌生的潜在位置,从而使其耐腐蚀性下降.

Abstract: The influence of chloride ions (Cl^-) on the corrosion resistance of X80 pipeline steel in 0.5 mol·L^-1 NaHCO₃ solution was discussed by potentiodynamic polarization technique, and the corrosion mechanism was investigated by capacitance The results show that Cl^- enhances the occurrence of pitting corrosion of X80 pipeline steel in 0.8mol·L^-1 NaHCO₃, and the density and size of corrosion pits increase with increasing Cl^- concentration. Mott-Schottky results indicated that the value of donor density of the passive film increases with increasing Cl^- concentration, which enhances the potential sites of film local breakdown and corrosion initiation. It is concluded that the addition of Cl^- decreases the corrosion resistance of X80 pipeline steel in 0.5 mol·L^-1 NaHCO₃ solution.