摘要
设计制备了新型高氮低镍奥氏体不锈钢(高氮钢)。采用阳极动电位极化法测量了此钢在不同浓度和不同pH值的NaCl溶液中的点蚀电位,获得了点蚀电位随溶液浓度及pH值变化的关系曲线,并与800H钢进行了对比。用扫描电镜(SEM)对样品表面进行了形貌观察对点腐蚀坑处进行了线扫描,分析了高氮钢耐点蚀的机理。研究表明在不同浓度和pH值的NaCl溶液中,高氮钢的点蚀电位达到1.2V(va SCE)以上,800H钢的点蚀电位在0.3 V(vs SCE)以下。扫描图显示腐蚀区域内高氮钢的点蚀坑稀少且面积较小,800H钢的点蚀坑密集且面积较大。线扫描表明氮在腐蚀坑内的含量略有下降;氮在钝化膜/金属界面富集,形成NH_4^+,并且抑制侵蚀性Cl^-的吸附是提高高氮钢耐蚀性的原因。
A new austenitic stainless steel with high nitrogen and low nickel was designed and prepared.Pitting potential of the as-prepared steel and 800 H steel in NaCl solution with different concentration and pH values were studied using anodic potentiodynamic polarization method.Curves of the pitting potential changing with solution concentration and pH values were obtained.Mechanism of pitting corrosion resistance of the high nitrogen steel compared with the 800 H steel was analyzed through the surface morphology observation and the line scan across the corrosion pit.The results show that the pitting potentials of high nitrogen steel and 800 H steel are about 1.2 V（vs SCE） and0.3 V（vs SCE）,respectively,under different concentration and pH values NaCl solution.Scanograms show that the high nitrogen steel has a little pitting pits and exhibits the smaller pit area,while the 800 H steel exhibits the dense pitting pits with larger area.The linear scan shows that the pit inner nitrogen decreases slight,nitrogen richens in interface between passive film and base metal then forms NH4＋,which inhibits the absorption of corrosive Cl-,that is the cause for enhancing the corrosion resistance of high nitrogen steel.
出处
《金属热处理》
CAS
CSCD
北大核心
2015年第12期11-16,共6页
Heat Treatment of Metals
基金
国家高技术研究发展计划(863计划)(2012AA03A501)
江苏省产学研联合创新资金--前瞻性联合研究项目(BY2012169)
关键词
高氮低镍奥氏体不锈钢
点腐蚀
腐蚀电位
线扫描
high nitrogen and low nickel austenitic stainless steel
pitting corrosion resistance
corrosion potential
line scan
