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| CORROSION RATE OF CARBON STEEL UNDER LIQUID LAYER CONTAINING Cl- AND ITS CORRELATION WITH ENVIRONMENT CONTROL FACTORS |
| TANG Zilong1;2; LI Chao1; LI Hui1 |
1．School of Materials Science and Engineering; Tianjin University; Tianjin 300072
2．Tianjin Key Laboratory of Composite and Functional Materials; Tianjin University; Tianjin 300072 |
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Abstract Corrosion behavior of carbon steel under NaCl liquid layer is investigated by inductive resistance probe(IRP). Average corrosion rate over the wet period, short for IFACR, is calculated by integration filter algorithm (IFA) with controlled environment factors including time of immersion (TOI), temperature and relative humidity (RH). A data-standardization approach is proposed in order to improve the accuracy of correlation of IFACR with the 3 control factors modeled by a linear equation. Two sets of corrosion kinetics parameters, corrosion current density Icorr, polarization resistance and anodic and cathodic Tafel constants, of Q235 steel in 1，5，10 mmol/L NaCl are measured by various electrochemical techniques including polarization curve, dynamic potential scan and potential step with an intention to benefit the understanding of corrosion under thin liquid layer. The results indicate that temperature has positive correlation with IFACR and TOI and RH show negative correlation. The contribution of RH to IFACR is maximum among three control factors, TOI is minimum and temperature is in middle. A changed contribution to IFACR of the factors, around 24 ℃ and RH 70% called threshold, is identified and specified. Also, this threshold is consistent with that of TOW (Time of Wetness) measurements done previously. The roles of Cl- in the changed contribution and the specific threshold are analyzed. The detailed discussion on the dependences of IFACR and total corrosion loss on TOI, temperature and RH is presented with the help of electrochemical measurements.
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Received: 01 December 2008
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Corresponding Authors:
TANG Zilong
E-mail: zlt633@gmail.com
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(唐子龙, 李超, 曲文超等.污染离子对Q235钢潮湿时间的多因素关联性分析 [J]. 中国腐蚀 与防护学报，待发表) |
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