用磁阻探头技术研究1 mmol/L NaCl液膜下碳钢腐蚀行为的磁信号特征，以IFA (Integration Filter Algorithm)算法计算潮湿时间内平均腐蚀速率。提出多因素关联分析的数据标准化方案，并根据线性模型分析平均腐蚀速率随浸润时间、温度和相对湿度的变化关系。用多种电化学技术研究Q235钢在1 mmol/L、\linebreak5 mmol/L及10 mmol/L的NaCl溶液中的腐蚀动力学，计算自腐蚀电流和极化阻力等电化学参数。结果表明，浸润时间和相对湿度(RH)跟平均腐蚀速率呈负相关；温度跟平均腐蚀速率呈正相关。各因素对潮湿期平均腐蚀速率影响的大小次序是相对湿度>温度>浸润时间。温度和相对湿度分别在24 ℃和RH70%左右对平均腐蚀速率的影响存在转折点。
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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