低碳贝氏体钢在薄液膜下的初期腐蚀.pdf

第 31 卷 第 2 期 北 京 科 技 大 学 学 报 Vol . 31 No. 2 2009 年 2 月 Journal of University of Science and Technology Beij ing Feb. 2009 低碳贝氏体钢在薄液膜下的初期腐蚀 王树涛 　高克玮 　杨善武 　贺信莱 北京科技大学材料科学与工程学院 , 北京 100083 摘 　要 　用质量分数 35 %的NaCl 溶液作为腐蚀液 ,滴于低碳铁素体钢 、09Cu PCrNi 钢和低碳贝氏体钢的表面并形成薄液 膜 ,用金相显微镜观测薄液膜下三种钢的初期腐蚀. 低碳铁素体钢和 09Cu PCrNi 钢均出现了明显的晶界择优腐蚀 ,而低碳贝 氏体钢没有出现明显的晶界择优腐蚀. 钢基体的电化学阻抗谱和极化曲线测量结果显示低碳贝氏体钢具有最高极化电阻和 最小腐蚀电流 ,表明细晶组织的低碳贝氏体钢的初期腐蚀速率低于其他两种钢. 关键词 　低碳贝氏体钢 ; 薄液膜 ; 初期腐蚀 ; 择优腐蚀 ; 腐蚀速率 分类号 　T G 172 3 Initial corrosion of lowcarbon bainitic steel under thin l iquid f il m WA N G S hutao , GA O Kew ei , YA N G S hanw u , H E X inlai School of Materials Science and Engineering , Univer sit y of Science and Technology Beijing , Beijing 100083 , China ABSTRACT 　35 % NaCl (mass fraction) aqueous solution as corrosion medium was dropp ed onto t he surfaces of lowcarbon ferritic steel , 09Cu PCrNi steel and lowcarbon bainitic steel to form t hin liquid films. Initial corrosion of t he steels was observed by metallo grap hic microscop e . Selected attack along grain boundaries occurred in bot h lowcarbon ferritic steel and 09Cu PCrNi steel , while t his did not occur in lowcarbon bainitic steel . The electrochemical imp edance sp ectrum and polarization curve of t he steel matrixes indicate t hat lowcarbon bainitic steel exhibit s t he highest polarization resistance and t he lowest corrosion current , so t he initial corrosion rate of fine crystalline lowcarbon bainitic steel was lower t han t hat of t he ot her two steels. KEY WORDS 　lowcarbon bainitic steel ; t hin liquid film ; initial corrosion ; preferential corrosion ; corrosion rate 　　大气腐蚀是包括化学和 电化学反应的复杂过 400 M Pa 以下 ,若要提高其强度 ,则需提高珠光体的 程 ,湿度 、温度和污染物等都直接影响金属的大气腐 含量 ,这对低温韧性极为不利. 细化钢的显微组织 蚀过程 ,