纳米SiO2改性环氧涂层的防腐性能

用电化学阻抗谱法(EIS)研究纳米SiO2改性环氧涂层在3.5%NaCl(质量分数)水溶液中的腐蚀规律,结合电容法和重量法分析改性涂层的吸水行为.结果表明,添加纳米SiO2可明显改善涂层的防腐性能,添加质量分数为2%时防腐性能最好.H2O在不同PVC(pigment volume concentration)环氧涂层中传输的起始阶段满足Fick第二扩散定律.纳米SiO2虽可与环氧树脂发生物理化学键合,填充涂层孔隙,但超过临界添加量时纳米粒子团聚作用又使涂层缺陷增多,防腐性能降低.

ANTI-CORROSION PROPERTIES OF EPOXY COATINGS MODIFIED BY NANO-SiO2

Electrochemical impedance spectroscopy (EIS) was employed to investigate the corrosion regulations of nano-SiO_2 modified epoxy coatings on carbon steel in 3.5 mass% NaCl solution, coupled with capacitance and gravimetric methods. The water uptake behavior of modified coatings was analysed. Four systems were studied, which are clear coating and three pigmented coatings (with 1%,2%,3% mass percentage nano-SiO_2). The EIS results showed that nano-SiO_2 particle could improve the anti-corrosion performance of the coatings, and the optimal additions is 2%. The results obtained by capacitance and gravimetric methods showed that the diffusion process of water through epoxy coatings with different PVC(pigment volume concentration) followed the second Fick diffusion law in the initial period. Adding the nano-SiO_2 into epoxy coatings can act effectively. The positive one is attributed to the reaction between nano powder and epoxy resin, which improve the barrier effectiveness of coatings. The negative one is to increase the number of pores in the coatings when the adding amount is beyond the critical pigment volume concentration.