材料期刊网

研究了Q235钢在1 mmol/L NaCl，10 mmol/L NaSO₄和NaCO₃薄液膜下潮湿时间随温度、相对湿度和浸润时间的变化规律。采用数据挖掘中标准化技术对自变量和因变量进行预处理，提高了分析精度。通过线性模型中各自变量的权重系数研究环境控制因素对潮湿时间的影响规律和贡献份数，分析污染离子和腐蚀产物对潮湿时间的作用方式。结果表明：数据标准化技术可有效提高分析精度。 Cl^-、SO₄^2-和CO$_₃^2-三种污染离子对于材料表面潮湿时间有不同的影响模式。温度和湿度对潮湿时间的影响较大，浸润时间对潮湿时间的影响较小。浸润时间和湿度跟潮湿时间呈正相关，而温度跟潮湿时间呈负相关。在24 ℃和相对湿度为70%~80%左右(转化点)温度和相对湿度指数有显著变化。温度和相对湿度对潮湿时间的影响有明显负协同作用，强弱和模式依赖于污染离子种类和理化性质，与腐蚀产物也有密切关系。

Time of wetness (TOW) of Q235 steel covered by thin liquid layer of 1 mmol/L NaCl，10 mmol/L Na₂SO₄ and Na₂CO₃ is measured by taking consideration of three control factors, i.e. temperature (Temp), relative humility (RH) and time of immersion (TOI), as well as corrosion deposits. The standardization procedure from data mining is adopted and applied to all parameters before a linear model is introduced to correlate the TOW and its control factors. Effect and pattern of the control factors as well as corrosion deposits on TOW is studied. The result shows that the pattern of temperature and RH on TOW is greatly changed due to the involvement of Cl^-, SO₄^2- and CO₃^2-  ions compared with that without these contaminants. Depending on the chemical/physical properties of the contaminants and the composition and distribution of corrosion deposits, the contribution of temperature and RH terms to TOW could be reversed or enhanced or weakened. Specifically, the TOW behavior can be clustered into two sections with the threshold values of 24 ℃ and RH 70%~80% which is determined approximately and conclusively. In each section, the contribution of temperature and RH to TOW is changed at different levels. At the end, the synergic effect of temperature and relative humidity on TOW is found and discussed in detail including the cause of this effect and possible dependence on the contaminating ions and corrosion deposits.