纳米结构304不锈钢在硫酸溶液中的腐蚀行为

Corrosion Behavior of Nanostructured 304 Stainless Steel in H_2SO_4

采用高频表面机械研磨方法在304不锈钢中制备出纳米晶和纳米孪晶结构。采用腐蚀失重试验和极化曲线测试等方法测试两种纳米结构304不锈钢在室温及80℃条件下5%硫酸溶液中的耐腐蚀性能,并利用透射电镜和扫描电镜分析其腐蚀性能和微观结构的关系。失重试验结果表明在80℃条件下5%硫酸溶液中,纳米孪晶比纳米晶结构的304不锈钢耐腐蚀性能好,以均匀腐蚀为主,点蚀为辅;而纳米晶则发生严重的点蚀。电化学测试结果表明:在室温条件下,纳米孪晶结构304不锈钢呈现高的自腐蚀电位和宽的钝化区间,但在80℃条件下,纳米晶和纳米孪晶结构304不锈钢的耐腐蚀性比粗晶不锈钢差。

Nanocrystallized and nanotwinned microstructures were prepared in 304 stainless steels（SS）by surface mechanical attrition treatment（SMAT）with a high impacting frequency.The corrosion properties of the two nanostructured 304 SS were measured by weight loss and potentiodynamic polarization tests in 5%H2SO4solution at room temperature（RT）and 80℃,respectively.The relationship of microstructure and corrosion properties was investigated by transmission electron microscopy and scan electron microscopy.Weight loss tests show that the nanotwinned 304 SS exhibits lower corrosion rate than the nanocrystallized sample,which is characterized by uniform corrosion with a few pitting points in 5% H2SO4 at 80℃.However,pitting corrosion was observed on the surface of nanocrystallized 304 SS.Potentiodynamic polarization tests indicate that the nanotwinned 304 SS presents a lower self-corrosion potential and a wider passive potential region at RT.Nevertheless,both the nanocrystallinized and nanotwinned 304 SS show a worse corrosion resistance at 80℃ compared with as-received 304 SS.