Q235B在青岛海洋飞溅区的初期腐蚀行为

Corrosion Behavior of Q235B Steel at Early Stage Exposed in Marine Splash Zone in Qingdao

通过在青岛海洋飞溅区的暴露试验、腐蚀速率计算与点蚀深度测试、宏观与微观形貌观察、锈层成分分析等方法,研究了Q235B碳钢的初期(0~60 d)腐蚀行为。结果表明:随着暴露时间的延长,Q235B碳钢的平均点蚀深度和最大点蚀深度均呈增加的趋势,腐蚀速率呈现先上升后下降的趋势;在60 d时,在浪溅冲击、高频干湿交替和盐浓缩等多重作用下,Q235B碳钢表面出现多个小的孔隙和局部凸起鼓包的现象,腐蚀产物间有明显裂隙;腐蚀产物以铁的氧化物为主,随着暴露时间的延长,Fe含量下降和氧含量增加,氯离子的增加对局部腐蚀起到促进作用;在60 d时,Q235B碳钢表面的腐蚀产物主要物相为γ-FeOOH、β-FeOOH和Fe_(3)O_(4)等活性物质。

Corrosion behavior of Q235B carbon steel in early stage(0-60 d)was studied by exposure test in Qingdao marine splash zone,corrosion rate calculation,pitting depth test,macroscopic and microscopic morphology observation,rust layer composition analysis and other methods.The results show that with the increase of exposure time,the average pitting depth and maximum pitting depth of Q235B carbon steel increased,and the corrosion rate increased first and then decreased.At 60 d,under the multiple effects of splash impact,high-frequency dry-wet alternation and salt concentration,multiple small pores and local bulges appeared on the surface of Q235B carbon steel,and there were obvious cracks between the corrosion products.The corrosion products were mainly iron oxides.With the extension of exposure time,the content of Fe decreased and the content of oxygen increased.The increase of chloride ions promoted local corrosion.At 60 d,the main phases of corrosion products on the surface of Q235B carbon steel were active substances such asγ-FeOOH,β-FeOOH and Fe_(3)O_(4).