摘要
采用原位分析法及化学浸泡法并结合扫描电镜和能谱仪分析,对316L不锈钢中三种典型铬硅锰氧化物夹杂诱发不锈钢点蚀行为进行分析,并探究其腐蚀机理。结果表明,在质量分数为6%的FeCl 3溶液浸泡腐蚀下,316L不锈钢中三种典型铬硅锰氧化物夹杂耐蚀性从大到小的顺序依次为:单一贫铬相(w(Cr)<15%)铬硅锰氧化物夹杂>单一富铬相(w(Cr)>15%)铬硅锰氧化物夹杂>MnS与铬硅锰氧化物复合相夹杂;单一相夹杂诱发的点蚀是以小孔腐蚀的形式始发于夹杂物内部,其部位靠近夹杂与基体界面处;而对于MnS与铬硅锰氧化物复合相夹杂诱发的点蚀,首先是夹杂外层包裹的硫化物在较短时间内发生溶解,使得夹杂与基体交界处产生微缝隙,进而导致不锈钢点蚀的产生;铬硅锰氧化物夹杂中铬含量过高(w(Cr)>15%)或过低(w(Cr)<6%),均会降低不锈钢的抗腐蚀性能。
With the application of in-situ analysis method and chemical immersion method,by using scanning electron microscopy and energy dispersive spectroscopy,the pitting corrosion behavior of the 316L stainless steel induced by three typical oxide inclusions was analyzed and the corrosion mechanism was studied.The results show that by the immersion corrosion of FeCl 3 solution at 6%,the corrosion resistance of three typical(Cr,Si,Mn)-oxide inclusions in 316L stainless steel from large to small is:single-phase inclusion of Cr-depleted(w(Cr)<15%)>single-phase inclusion of Cr-rich(w(Cr)>15%)>composite-phase inclusions of MnS and(Cr,Si,Mn)-oxide.The pitting corrosion induced by single-phase inclusion originates in the form of small-hole corrosion from the inside of the inclusions,and its location is near the interface between the inclusions and the substrate.For the pitting corrosion induced by composite-phase inclusions of MnS and(Cr,Si,Mn)-oxide,the sulfide of the outer layer cover dissolves within a short period of time firstly,resulting in micro gaps at the interface between the inclusions and the substrate and leading to pitting corrosion.If the chromium content in(Cr,Si,Mn)-oxide inclusions is too high(w(Cr)>15%)or too low(w(Cr)<6%),the corrosion resistance of 316L stainless steel will be reduced.
作者
闵梁
马国军
张翔
李志
刘孟珂
宋明明
Min Liang;Ma Guojun;Zhang Xiang;Li Zhi;Liu Mengke;Song Mingming(Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education,Wuhan University of Science and Technology,Wuhan 430081,China)
出处
《武汉科技大学学报》
CAS
北大核心
2020年第4期255-261,共7页
Journal of Wuhan University of Science and Technology
基金
国家自然科学基金资助项目(50804037)
湖北省自然科学基金资助项目(2018CFB30).
关键词
氧化物夹杂
316L不锈钢
点蚀诱发
点蚀行为
铬含量
腐蚀机理
oxide inclusion
316L stainless steel
pitting initiation
pitting behavior
chromium content
corrosion mechanism
