碳钢在海水淡化一级反渗透产水中的腐蚀行为

Corrosion Behavior of Carbon Steel in Reverse Osmosis Permeate of Seawater

对碳钢在海水淡化一级反渗透产水中生成的锈层进行SEM、IR和XRD分析,并结合电化学测量,研究其腐蚀行为。结果表明,碳钢在一级反渗透产水中腐蚀过程受氧扩散控制,腐蚀产物包括γ-FeOOH、Fe_3O_4以及少量的α-FeOOH。锈层具有双层结构,外锈层很薄,主要成分为γ-FeOOH;内层占整个锈层比重很大,主要成分为Fe_3O_4。一级反渗透产水的弱酸性促使腐蚀产物γ-FeOOH迅速转化为Fe_3O_4,致使Fe_3O_4在金属表面大量堆积。由于Fe_3O_4层的导电性及不连续性,锈层不能阻碍阴极过程的进行,导致碳钢的腐蚀速度一直维持在高位。

The corrosion behavior of carbon steel in Reverse Osmosis（RO） permeate of seawater was studied by carrying out electrochemical measurements and analyzing corrosion products using SEM, IR and XRD. The results show that the corrosion process of carbon steel is controlled by the diffusion process of oxygen, and corrosion products contain r-FeOOH, Fe3O4 and a little a-FeOOH. The rust layer has double-layer structure, the outer including r-FeOOH is thin and the inner contains Fe3O4 which is the main proportion of rust layer. Due to the weak acidity of RO permeate, FeaO4 generates quickly and accumulates on metal surface. Because of the electrical conductivity and fractured surface of Fe304 layer, corrosion product layer canlt inhibit corrosion process through hindering the diffusion process of oxygen, and thus the corrosion rate of carbon steel is always high.