摘要
采用周浸加速腐蚀试验和饱和Ca(OH)_(2)溶液浸泡试验,结合光学显微镜(OM)、扫描电子显微镜(SEM)、能谱仪(EDS)、X射线衍射仪(XRD)、动电位极化、电化学阻抗谱、电容电位法和线性极化法等表征手段研究9CrMo耐蚀钢筋的显微组织和腐蚀行为,从钝化、破钝和腐蚀稳定扩展的全寿命周期角度展开研究,研究结果可为其应用于高湿热海洋环境及服役寿命预测提供参考。结果表明,9CrMo钢筋显微组织为铁素体和贝氏体。在钝化阶段,相比普通碳钢钢筋(HRB400),9CrMo钢筋的电荷转移电阻和钝化膜电阻均更大,其钝化膜为n型和p型半导体的复相(Fe氧化物和Cr氧化物),且钝化膜施主电荷密度是HRB400的1/2,表明9CrMo钢筋钝化膜阻碍电子传导能力更强。相比HRB400,在不同Cl-含量的模拟混凝土孔隙液中,9CrMo钢筋具有更低的腐蚀电流密度和维钝电流密度、更高的点蚀电位、电荷转移电阻和钝化膜电阻,表明其在较高Cl-含量还保持良好的钝化效果。在破钝阶段,9CrMo钢筋的破钝临界氯离子浓度是HRB400的10倍以上。在模拟腐蚀稳定扩展阶段,9CrMo钢筋的腐蚀速率呈先增大后减小的趋势,相比HRB400,腐蚀速率降低60%~84%;9CrMo钢筋主要以局部腐蚀为主,内锈层存在Cr的富集,锈层的α*/γ*((α-FeOOH+Fe_(3)O_(4)/γ-Fe_(2)O_(3))/(γ-FeOOH+β-FeOOH))质量比值随着腐蚀周期延长而增大,且9CrMo钢筋的α*/γ*值是HRB400的1.6倍,锈层保护能力更强。
Periodic immersion accelerated corrosion test and saturated Ca(OH)_(2)solution immersion test,combined with OM,SEM,EDS,XRD,potentiodynamic polarization,electrochemical impedance spectroscopy,capacitance potential method and linear polarization method,were used to study the microstructure and corrosion behavior of 9CrMo corrosion-resistant steel bars,and conduct research from the perspective of passivation,passivation and corrosion stability.It can provide reference for its application and service life prediction in high-humidity marine environment.The results show that the microstructure of 9CrMo steel bars is ferrite and bainite.In the passivation stage,the charge transfer resistance and the passivation film resistance of 9CrMo steel bar are larger than those of ordinary carbon steel bar(HRB400),the passivation film is a complex phase of n-type and p-type semiconductor(Fe oxide and Cr oxide),and the donor charge density of the passivation film is 1/2 that of HRB400,indicating that the passivation film of 9CrMo steel bar has a stronger ability to hinder electron conduction.Compared with HRB400,9CrMo steel bars have lower corrosion current density and passive current density,higher pitting potential,charge transfer resistance and passivation film resistance in simulated concrete pore solution with different Cl-concentrations,it shows that it still maintains a good passivation effect at higher Cl-concentrations.In the blunt stage,the chloride threshold value for passivation of 9CrMo steel bar is more than 10 times that of HRB400.Under the stage of simulated corrosion stable expansion,the corrosion rate of 9CrMo steel bars increases first and then decreases.Compared with HRB400,the corrosion rate decreased by 60%-84%;9CrMo steel bars were mainly localized corrosion,there is Cr enrichment in the inner rust layer,theα*/γ*((α-FeOOH+Fe_(3)O_(4)/γ-Fe_(2)O_(3))/(γ-FeOOH+β-FeOOH))mass ratio of the rust layer increases with the prolongation of the corrosion period,and theα*/γ*value of 9CrMo steel bar is 1.6 times that of HRB400,the rust layer is more protective.
作者
王进建
刘静
陈润农
曹燕光
张建
李昭东
WANG Jin-jian;LIU Jing;CHEN Run-nong;CAO Yan-guang;ZHANG Jian;LI Zhao-dong(The key Laboratory of Refractories and Metallurgy,Wuhan University of Science and Technology,Wuhan 430081,Hubei,China;Structural Steels Research Institute,Central Iron and Steel Research Institute Co.,Ltd.,Beijing 100081,China;Technology Center,Maanshan Iron and Steel Co.,Ltd.,Maanshan 243000,Anhui,China)
出处
《钢铁》
CAS
CSCD
北大核心
2023年第5期112-123,共12页
Iron and Steel
基金
国家重点研发计划资助项目(2021YFB3701702)。
