铝酸钠溶液中S2-浓度对20Cr钢腐蚀行为的影响  

Effect of S2- Concentration on Corrosion Behavior of 20Cr Steel in Sodium Aluminate Solution

作　　者：周鑫强 陈朝轶[1,2] 付慧 陈侣[1,2] 杨彬 龙玉斌 ZHOU Xin-qiang;CHEN Chao-yi;FU Hui;CHEN Lyu;YANG Bin;LONG Yu-bin(School of Materials and Metallurgy,Guizhou University,Guiyang 550025,China;Key Laboratory of Metallurgical Engineering and Process Energy Conservation of Guizhou Province,Guiyang 550025,China)

机构地区：[1]贵州大学材料与冶金学院,贵阳550025 [2]贵州省冶金工程与过程节能重点实验室,贵阳550025

出　　处：《表面技术》2019年第12期264-270,共7页Surface Technology

基　　金：国家自然科学基金(51574095,517741022,51664005);贵州省教育厅项目(黔教合KY(2015)334);黔科合平台人才([2017]5626、[2017]5788);贵大SRT字(2017)012~~

摘　　要：目的研究20Cr钢在铝酸钠溶液中不同S2?浓度下的腐蚀行为及产物形成过程,探索腐蚀机理。方法20Cr钢在不同S^2-浓度的溶液中进行高温浸泡腐蚀实验与电化学测试,结合扫描电子显微镜(SEM)、X射线能谱仪(EDS)、X射线衍射仪(XRD)等分析技术,观察腐蚀产物的微观形貌、元素含量与组成。运用失重法、极化曲线和交流阻抗图分析样品的腐蚀速率。结果S^2-质量浓度从0g/L增加到5g/L时,腐蚀速率由3.43 g/(m^2·d)上升到25.20 g/(m^2·d),腐蚀产物逐渐增多,S^2-质量浓度在6 g/L时,腐蚀速率下降到21.30 g/(m^2·d)。EDS结果表明,随S^2-浓度的增加,腐蚀产物中铬元素含量增加,铁元素总体含量降低,氧、铝元素含量呈现先增长后降低趋势。XRD结果显示,加入S^2-与未加S^2-相比,腐蚀产物物相组成由Fe3O4和FeOOH变为Fe3O4、Fe Cr2O4和FeS。电化学测试得到S^2-质量浓度从0 g/L到5 g/L时,腐蚀电流密度由22.87μA/cm^2上升到586.02μA/cm^2,S^2-质量浓度在6 g/L时,电流密度下降到183.06μA/cm^2。结论S2?质量浓度在0~5 g/L范围时,20Cr钢的腐蚀速率逐渐增加,腐蚀产物中形成FeS,S^2-的加入能够促进腐蚀反应,破坏未加入硫元素时形成的较致密腐蚀物;当S^2-质量浓度超过5 g/L后,形成致密的FeCr2O4尖晶石氧化物,粘附在试样表面,对腐蚀起到抑制作用。The work aims to explore the corrosion mechanism and corrosion process of 20Cr steel in different sodium aluminate solutions with different S^2- concentrations.20Cr steel was subjected to high temperature immersion corrosion test and electrochemical test in different S^2- concentration solutions.Combined with scanning electron microscope(SEM),X-ray energy disperse spectroscopy(EDS),X-ray diffraction(XRD)and other analytical techniques,the microstructure,element content and composition of corrosion products were observed.The corrosion rate of the sample was analyzed by weight loss method,polarization curve and AC impedance map.With the concentration of S^2- from 0 g/L to 5 g/L,the corrosion rate increased from 3.43 g/(m^2·d)to 25.20 g/(m^2·d),and the corrosion product increased gradually.The corrosion rate decreased to 21.30 g/(m^2·d)when the concentration of S^2- was 6 g/L.The results of EDS showed that with the increase of S^2- concentration,the content of chromium in corrosion products increased,the total content of iron decreased,and the content of oxygen and aluminum increased first and then decreased.XRD results showed that the phase composition of the corrosion product changed from Fe3O4 and FeOOH to Fe3O4,FeCr2O4 and FeS after S^2- was added.Electrochemical tests showed that when the S^2- concentration ranged from 0 g/L to 5 g/L,the corrosion current density increased from 22.87μA/cm^2 to 586.02μA/cm^2,and when the S^2- concentration was 6 g/L,the current density decreased to 183.06μA/cm^2.When the concentration of S^2- is in the range of 0~5 g/L,the corrosion rate of 20 Cr steel increases gradually,and FeS is formed in the corrosion product.The addition of S^2- can promote the corrosion reaction and destroy the dense corrosive formed when no sulfur element is added.After the S^2- concentration exceeds 5 g/L,a dense FeCr2O4 spinel oxide is formed,which adheres to the surface of the sample and inhibits corrosion.

关 键 词：20CR钢 S^2-浓度 铝酸钠溶液 高温浸泡腐蚀 电化学 

分 类 号：TG172[金属学及工艺—金属表面处理]