在酒石酸-硫酸溶液中阳极氧化AA2099-T8铝锂合金获得阳极氧化膜,并采用新型绿色封闭工艺对阳极氧化膜进行封孔处理。采用场发射扫描电镜观察阳极氧化膜封孔前后的显微形貌,通过开路电位、动电位极化、电化学阻抗谱及中性盐雾实验研究氧化膜封孔前后的耐腐蚀性能。结果表明:采用酒石酸-硫酸阳极氧化处理能在AA2099-T8铝锂合金表面生成一层均匀、致密的氧化膜,采用新型封闭工艺可在常温下有效封闭氧化膜孔隙;阳极氧化和封孔处理均能提高合金的抗腐蚀能力,但单纯的阳极氧化对合金耐腐蚀性能的提高有限,而阳极氧化+封孔处理能显著提高合金的耐腐蚀性能。
AA2099-T8 aluminum-lithium alloy was anodized in tartaric-sulfuric acid solution to obtain the anodic films, and then the resultant anodic films were sealed by a novel, environmentally friendly sealing process. The morphology of the anodic films before and after sealing was examined using field emission gun scanning electron microscope (FEG-SEM). The corrosion resistance of the anodic films with and without sealing was investigated through open circuit potential measurement, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and neural salt spray test (NSST). The results show that, a uniform and compact anodic film forms on the alloy in tartaric-sulfuric acid solution and the film can be effectively sealed at room temperature by novel sealing process. The improvement of corrosion resistance by the anodic films alone is limited while anodizing and sealing can significantly improve the corrosion resistance of the alloy.