Original scientific paper
https://doi.org/10.5599/jese.2012.0025
A comparison of pitting susceptibility of Q235 and HRB335 carbon steels used for reinforced concrete
Guoliang Zhan
; New Century Concrete of Guangdong Foundation Co., Ltd, Guangzhou 510660, China
Jiancheng Luo
; School of Chemistry and Environment, South China Normal University, Guangzhou 510006, China
Shaofei Zhao
; School of Chemistry and Environment, South China Normal University, Guangzhou 510006, China
Weishan Li
; School of Chemistry and Environment, South China Normal University, Guangzhou 510006, China
Abstract
The phase structure and the pitting susceptibility of two carbon steels, Q235 and HRB335, used for reinforced concrete, are investigated by phase observation, polarization curve measure-ments, electrochemical impedance spectroscopy, and Mott-Schottky analysis. It is found that Q235 is ferrite and HRB335 is pearlite. Q235 is more susceptible to chloride ions leading to pit-ting than HRB335. The polarization curves show that the breakdown potential of the passive film in saturated Ca(OH)2 solution containing 0.4 M NaCl is 0 V for Q235 and 0.34 V for HRB335. The Mott-Schottky analyses show that passive films formed on Q235 and HRB335 in saturated Ca(OH)2 solution containing chloride ions behave like an n-type semiconductor. The passive film formed on Q235 has a higher donor density, which explains why Q235 is more susceptible to pitting than HRB335.
Keywords
Pitting susceptibility; Carbon steel; Phase structure; Polarization curve; Electrochemical impedance spectroscopy; Mott-Schottky
Hrčak ID:
96897
URI
Publication date:
6.2.2013.
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