采用盐雾和盐水浸泡加速实验,结合ATR-FTIR,SEM,AFM表面分析技术及EIS电化学分析技术,考察纳米CeO_2作为涂层颜料对聚氨酯涂层防腐性能的影响。结果表明,添加纳米CeO_2能改善涂层的防腐性能,延缓聚氨酯涂层的阻抗衰减进程,但同时会削弱涂层在金属基体上的附着力。当添加量较低时(≤0.5%,质量分数),由于H_2O和侵蚀性离子渗入聚氨酯层,纳米CeO_2水解流失,导致涂层阻抗谱随时间降低较快;当添加量达到1.0%时,涂层阻抗在较长时间内保持较高值,这可能是由于纳米CeO_2在涂层微孔中发生水解膨胀,压缩了孔隙通道,同时Ce(Ⅲ,Ⅳ)迁移到铝合金/涂层界面,抑制了腐蚀活性位点,因而减缓了阻抗的衰减进程。然而,在盐雾实验后期,CeO_2进一步水解会导致Ce~(4+)的溶解流失,造成微孔隙的再次疏通和涂层阻抗的快速下降。过量添加(>1.0%)还会削弱涂层在铝合金基体上的附着力。长期浸泡实验结果表明:添加1.0%CeO_2可基本实现Ce~(4+)溶解和流失的平衡,增强聚氨酯涂层的防腐性能。 The effects of nano-CeO 2 as coating pigment on the anticorrosive properties of polyurethane coatings were investigated by accelerated experiments with salt spray and brine immersion, combined with ATR-FTIR, SEM, AFM surface analysis and EIS electrochemical analysis. The results show that adding nano-CeO_2 can improve the anticorrosive property of the coating and retard the process of impedance decay of the polyurethane coating, but at the same time it will weaken the adhesion of the coating to the metal matrix. When the addition amount is lower (≤0.5%, mass fraction), the impedance spectrum of the coating decreases rapidly with time due to the infiltration of H_2O and corrosive ions into the polyurethane layer and the hydrolysis and loss of CeO_2. When the addition amount reaches 1.0% The impedance of the layer remained high for a long time. This may be due to the hydrolysis and expansion of nano-CeO 2 in the micro-pores of the coating and the compression of the pore channels, and the migration of Ce (Ⅲ, Ⅳ) to the aluminum alloy / coating interface, Corrosion of the active site, thus slowing the attenuation of the impedance process. However, after the salt spray experiment, further hydrolysis of CeO 2 led to the dissolution loss of Ce 4+, leading to the reopening of microporosity and the rapid decrease of coating resistance. Excessive addition (> 1.0%) also weakens the adhesion of the coating to the aluminum alloy substrate. The results of long-term immersion experiments showed that the addition of 1.0% CeO 2 can basically achieve the balance of dissolution and loss of Ce 4+, and enhance the anticorrosion performance of polyurethane coating.