青藏铁路站台雨棚钢结构防腐涂层抗老化性能研究与服役寿命预测

Study on Anti Aging Performance and Service Life Prediction of Anti-corrosion Coating for Platform Canopy Steel Structure of Qinghai-Tibet Railway

针对青藏铁路沿线强紫外线环境,对常用钢结构防腐涂层体系进行了荧光紫外线加速老化试验。通过失光率、色差、厚度损失、SEM形貌变化等老化指标,评价了涂层体系的抗紫外线老化性能,并根据环境因子量化模型和环境应力等效假设,对常用钢结构防腐涂层体系在青藏铁路的服役寿命进行预测。结果表明:荧光紫外线老化试验中醇酸体系保光性、保色性最差,厚度损失较明显;丙烯酸脂肪族聚氨酯体系具有较优的保光性、保色性,但厚度损失最明显;氟碳体系和丙烯酸聚硅氧烷体系在保光性、保色性、抗厚度损失等方面均最优;醇酸体系和丙烯酸脂肪族聚氨酯体系的主要官能团键能低于紫外线能量,其抗紫外线老化性能差;氟碳体系的C—F和丙烯酸聚硅氧烷体系的Si—O—Si的键能高于紫外线能量,其抗紫外线能力较强;采用氟碳体系或丙烯酸聚硅氧烷体系的防腐涂层服役寿命明显长于采用醇酸体系或丙烯酸脂肪族聚氨酯体系,建议青藏铁路站台雨棚钢结构采用氟碳体系或丙烯酸聚硅氧烷体系进行涂装。

In view of the strong ultraviolet environment along the Qinghai-Tibet Railway,the accelerated aging test of fluorescent ultraviolet light was carried out on the commonly used anti-corrosion coating systems for steel structures.The anti-ultraviolet aging performance of the coating system was evaluated by aging indicators such as light loss,color difference,thickness loss,SEM appearance change,etc.The service life of the commonly used steel structure anticorrosion coating system in the Qinghai-Tibet Railway was predicted according to the quantitative model of environmental factors and the assumption of environmental stress equivalence.The results showed that the alkyd system had the worst light and color retention and obvious thickness loss in the fluorescent ultraviolet light aging test.The acrylic aliphatic polyurethane system has better light and color retention,but the thickness loss is the most obvious.Fluorocarbon system and acrylic polysiloxane system are the best in light retention,color retention and thickness loss resistance.The main functional group bond energy of alkyd system and acrylic aliphatic polyurethane system is lower than the ultraviolet energy,and their ultraviolet aging resistance is poor.The bond energy of C-F in fluorocarbon system and Si—O—Si in acrylic polysiloxane system is higher than that of ultraviolet energy,and their ultraviolet resistance is stronger.The service life of the anti-corrosion coating with fluorocarbon system or acrylic polysiloxane system is significantly longer than that with alkyd system or acrylic aliphatic polyurethane system.It is recommended that the steel structure of the platform canopy of Qinghai-Tibet Railway be coated with fluorocarbon system or acrylic polysiloxane system.