材料期刊网

目的：基于灰色系统理论预测模型建立涂层腐蚀寿命的预测模型,利用该模型计算不同厚度的无溶剂环氧煤焦沥青涂层在滨海氯盐土模拟液中的涂层寿命。方法采用电化学方法,测定不同厚度无溶剂环氧煤焦沥青涂层涂覆的碳钢在滨海氯盐土模拟液中的交流阻抗值。基于灰色系统理论GM(1,1)模型将滨海氯盐土模拟液中测试的无溶剂环氧煤焦沥青涂料的低频阻抗模值和浸渍时间关系,建立涂层腐蚀寿命的预测模型。结果三种不同厚度无溶剂环氧煤焦沥涂层试样在侵蚀性溶液中浸泡240 d时,低频阻抗模值仍保持在8.3×108Ω·cm2以上,应用预测公式计算的滨海氯盐土模拟液中三种无溶剂环氧煤焦沥涂层低频阻抗模值的实测值与预测值的相对误差小于6.0%,C<0.35,P=1,该模型的预测精度好。涂层厚度为200μm的无溶剂环氧煤焦沥青层预测寿命t=781 d,涂层从浸泡初期阶段进入中期阶段。随着涂层厚度的增加,涂层寿命愈长,当涂层厚度为600μm时,其预测寿命达到2926 d。结论所建涂层腐蚀寿命的预测模型表现出较好的拟合精度和预测可靠度。

Objective To set up the life prediction model of the coating based on the grey theory and use the model to calculate the coating life of the solvent-free coal tar epoxy coating with different thicknesses in coastal chloride salt soil simulation. Methods By electrochemical methods, the electrochemical impedance spectroscopy of carbon steel with the solvent-free coal tar epoxy coating of different thicknesses in the simulated solution of coastal chloride salt soil was obtained. Based on the GM(1,1) model of grey theory and the relationship between the low frequency impedance modulus value and the immersion time, the prediction model of the impedance modulus at the low frequency for the coating was established in the simulated solution of coastal chloride salt soil. Results The low-frequency impedance modulus value still remained above 8. 3×108Ω·cm2, when the coatings with three different thicknesses were immersed in corrosive solution for 240 d. Applying the prediction calculation formula, the relative error was less than 6. 0% between measured and predicted modulus values of low-frequency impedance of the three kinds of coating in the simula-tion solution of coastal chlorine saline soil, C<0. 35, P=1, and the prediction accuracy of the model was good. The life prediction of the solvent-free coal tar epoxy coating with the thickness of 200μm in coastal chloride salt soil simulation was 781 days, and the coating was changed from the initial stage of immersion into the middle stage. With the increase of coating thickness, the coating life was longer, and the predicted life reached 2926 days when the coating thickness was 600μm. Conclusion The corrosion model for life prediction showed good fitting precision and prediction reliability.