Pitting corrosion behavior of cerium treated HSLA steel induced by sulfide inclusions in 3.5 wt% NaCl solution
来源期刊：JOURNAL OF RARE EARTHS2021年第3期
论文作者：Wan Zheng Xueqiang Yan Shan Xiong Guowei Wang Guangqiang Li
摘 要：Pitting corrosion behavior of Ce treated HSLA steels induced by sulfide inclusions in 3.5 wt% NaCl solution was investigated with potentiodynamic polarization and immersion corrosion test.The results show that Ce added steels exhibit better pitting corrosion resistance with lower corrosion current density and bigger pitting potential compared with steel without Ce,which is mainly attributed to optimized characteristics of spherical Ce-oxysulfide inclusions with less number density,smaller average size and lower pitting corrosion susceptibility.The spherical Ce2O2 S inclusions precipitated on the surface of CeAlO3 inclusions in the Ce added steels induce pits with bigger opening mouth and shallow depth,reducing their tendency of extension to go deeper due to occlusion corrosion battery in the pitting holes.Furthermore,corrosion inhibitor Ce（OH）3 generated by Ce2O2 S hydration can weaken electrochemical corrosion of the matrix micro-region around the pits.To avoid harmful bigger inclusions,Ce content in steels should be regulated within reasonable range,0.015 wt% Ce in present steels effectively modified inclusions to acquire the best pitting corrosion resistance of the steels.
Wan Zheng1,2,3，Xueqiang Yan1,2，Shan Xiong1,2，Guowei Wang1,2，Guangqiang Li1,2,3
1. State Key Laboratory of Refractories and Metallurgy,Wuhan University of Science and Technology2. Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education,Wuhan University of Science and Technology3. Hubei Provincial Key Laboratory for New Processes of Ironmaking and Steelmaking,Wuhan University of Science and Technology
摘 要：Pitting corrosion behavior of Ce treated HSLA steels induced by sulfide inclusions in 3.5 wt% NaCl solution was investigated with potentiodynamic polarization and immersion corrosion test.The results show that Ce added steels exhibit better pitting corrosion resistance with lower corrosion current density and bigger pitting potential compared with steel without Ce,which is mainly attributed to optimized characteristics of spherical Ce-oxysulfide inclusions with less number density,smaller average size and lower pitting corrosion susceptibility.The spherical Ce2O2 S inclusions precipitated on the surface of CeAlO3 inclusions in the Ce added steels induce pits with bigger opening mouth and shallow depth,reducing their tendency of extension to go deeper due to occlusion corrosion battery in the pitting holes.Furthermore,corrosion inhibitor Ce（OH）3 generated by Ce2O2 S hydration can weaken electrochemical corrosion of the matrix micro-region around the pits.To avoid harmful bigger inclusions,Ce content in steels should be regulated within reasonable range,0.015 wt% Ce in present steels effectively modified inclusions to acquire the best pitting corrosion resistance of the steels.
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