稀土对CSP工艺下SPCC钢耐海洋大气腐蚀性能的影响

Effect of rare elements on marine corrosion behavior of SPCC in CSP

利用周期浸泡加速腐蚀实验的方法模拟钢铁材料在海洋大气环境中的腐蚀行为,研究了CSP工艺下稀土和非稀土SPCC钢在NaCl溶液中的腐蚀行为。采用SEM、XRD和极化曲线测量技术分别研究了SPCC钢的断面腐蚀形貌、腐蚀产物组成和电流密度。结果表明:SPCC稀土钢的锈层更致密、更薄,在锈层中,具有保护作用的α-FeOOH更多,活性的γ-FeOOH和β-FeOOH含量相对较少。随着稀土的添加,SPCC钢的电流密度降低,这使得钢基体表面的电化学反应减缓,腐蚀倾向降低。α-FeOOH的增多,能够阻碍腐蚀性氯离子向钢基体的运动,从而稀土能提高SPCC钢的耐蚀性。

The experiment of cyclic wet-dry immersion was used to simulate the corrosion behavior of SPCC steel in marine atmospheric environment, and the corrosion processes of SPCC steels with and without rare earth （RE） in NaC1 solution were investigated. The morphology, composition of corrosion products and electric current density of SPCC steel were investigated by SEM, XRD and measurement of polarization curve. The results show that rust layer of SPCC steel with RE is more compact and thiner than that of the steel without RE. The content of a-FeOOH favourable for anti-corrosion is higher and the contents of actived a-FeOOH and 15-FeOOH are less in the rust layer of the SPCC steel with RE. It also shows that current densities of SPCC steel is lower and the corrosive tendency decreases with the addition of RE. The increase of a-FeOOH could impede the transportation of corrosive ions such as C1- to the steel substrate and consequently the addition of RE can improve the corrosion resistance of the steel.