The corrosion evolution processes of steel reinforced concrete under simulated tidal and immersion zones of marine environment were investigated by using electrochemical measurements and corrosion morphology observati...The corrosion evolution processes of steel reinforced concrete under simulated tidal and immersion zones of marine environment were investigated by using electrochemical measurements and corrosion morphology observations. The results indicate that the corrosion of rebar in concrete under both environments experiences the deterioration from passivation to pitting corrosion and then to general corrosion. Specially, the pitting plays the major role only in the early stage of corrosion, and the general corrosion replaces the dominate role of pitting during the long-term corrosion. In addition, both the pitting depth on local surface and the rust thickness on the overall surface of rebar in the tidal condition are larger than those in immersion condition, which is attributed to the faster corrosion rate in tidal zone caused by the concentrated chloride ions and sufficient oxygen supply.展开更多
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 adde...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 Ce_(2)O_(2) S inclusions precipitated on the surface of CeAlO_(3) 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 Ce_(2)O_(2) 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.展开更多
基金financially supported by the National Natural Science Foundation of China (Nos. 51501201, 51501204 and 51671200)the National Key Research and Development Program of China (No. 2017YFB0702302)
文摘The corrosion evolution processes of steel reinforced concrete under simulated tidal and immersion zones of marine environment were investigated by using electrochemical measurements and corrosion morphology observations. The results indicate that the corrosion of rebar in concrete under both environments experiences the deterioration from passivation to pitting corrosion and then to general corrosion. Specially, the pitting plays the major role only in the early stage of corrosion, and the general corrosion replaces the dominate role of pitting during the long-term corrosion. In addition, both the pitting depth on local surface and the rust thickness on the overall surface of rebar in the tidal condition are larger than those in immersion condition, which is attributed to the faster corrosion rate in tidal zone caused by the concentrated chloride ions and sufficient oxygen supply.
基金Project supported by the National Natural Science Foundation of China(U1860205,51541409)Innovation Team Cultivation Funding Project of Wuhan University of Science and Technology(2018TDX08)。
文摘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 Ce_(2)O_(2) S inclusions precipitated on the surface of CeAlO_(3) 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 Ce_(2)O_(2) 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.
