高速列车用不饱和聚酯腻子的耐蚀性和老化机理

Corrosion Resistance and Aging Mechanism of Unsaturated Polyester Putty for High-Speed Train

利用电化学阻抗谱、湿热老化等方法研究了不饱和聚酯腻子的耐蚀性和老化机理。结果表明:在3.5%NaCl溶液中浸泡6 h后,腐蚀溶液便渗入腻子/铝合金界面,并发生电化学腐蚀,不饱和聚酯腻子阻抗下降明显,防护能力下降较快;在湿热老化过程中,不饱和聚酯腻子光泽和色差逐渐增加,表面随着树脂的老化和降解变得光滑且局部产生空洞;不饱和聚酯腻子在老化初期存在着后固化现象;老化和降解更容易在芳香酯的位置发生。

The corrosion resistance and aging mechanism of unsaturated polyester putty were investigated using electrochemical impedance spectroscopy and accelerated hydrothermal aging test.The results show that the electrolyte solution penetrated into the putty/aluminum alloy interface and electrochemical corrosion occurred after immersing in 3.5 wt.%NaCl solution for 6 hours.The impedance of unsaturated polyester putty decreased significantly and the protection ability of unsaturated polyester putty decreased rapidly.In the process of hydrothermal aging,the surface of unsaturated polyester putty became smooth with the aging and degradation of resin.The aging and degradation of resin also caused localized holes on the surface of unsaturated polyester putty,and the gloss and color difference increased gradually.Unsaturated polyester putty had post-curing phenomenon at the initial stage of aging,and aging and degradation were more prone to occur at the position of aromatic ester.