Cabral-Miramontes José, Almeraya-Calderón Facundo, Méndez-Ramírez Ce Tochtli, Flores-De Los Rios Juan Pablo, Maldonado-Bandala Erick, Baltazar-Zamora Miguel Ángel, Nieves-Mendoza Demetrio, Lara-Banda María, Pedraza-Basulto Gabriela, Gaona-Tiburcio Citlalli
Universidad Autónoma de Nuevo León, FIME, Centro de Investigación e Innovación en Ingeniería Aeronáutica (CIIIA), San Nicolás de los Garza 66455, Mexico.
Facultad de Ingeniería Civil, Universidad Veracruzana, Xalapa 91000, Mexico.
Materials (Basel). 2024 Aug 29;17(17):4285. doi: 10.3390/ma17174285.
Hard anodizing is used to improve the anodic films' mechanical qualities and aluminum alloys' corrosion resistance. Applications for anodic oxide coatings on aluminum alloys include the space environment. In this work, the aluminum alloys 2024-T3 (Al-Cu), 6061-T6 (Al-Mg-Si), and 7075-T6 (Al-Zn) were prepared by hard anodizing electrochemical treatment using citric and sulfur acid baths at different concentrations. The aim of the work is to observe the effect of citric acid on the microstructure of the substrate, the mechanical properties, the corrosion resistance, and the morphology of the hard anodic layers. Hard anodizing was performed on three different aluminum alloys using three citric-sulfuric acid mixtures for 60 min and using current densities of 3.0 and 4.5 A/dm. Vickers microhardness (HV) measurements and scanning electron microscopy (SEM) were utilized to determine the mechanical characteristics and microstructure of the hard anodizing material, and electrochemical techniques to understand the corrosion kinetics. The result indicates that the aluminum alloy 6061-T6 (Al-Mg-Si) has the maximum hard-coat thickness and hardness. The oxidation of Zn and Mg during the anodizing process found in the 7075-T6 (Al-Zn) alloy promotes oxide formation. Because of the high copper concentration, the oxide layer that forms on the 2024-T6 (Al-Cu) Al alloy has the lowest thickness, hardness, and corrosion resistance. Citric and sulfuric acid solutions can be used to provide hard anodizing in a variety of aluminum alloys that have corrosion resistance and mechanical qualities on par with or better than traditional sulfuric acid anodizing.
硬质阳极氧化用于提高阳极氧化膜的机械性能和铝合金的耐腐蚀性。铝合金阳极氧化涂层的应用包括空间环境。在这项工作中，通过在不同浓度的柠檬酸和硫酸浴中进行硬质阳极氧化电化学处理，制备了2024-T3（Al-Cu）、6061-T6（Al-Mg-Si）和7075-T6（Al-Zn）铝合金。这项工作的目的是观察柠檬酸对基体微观结构、机械性能、耐腐蚀性以及硬质阳极氧化层形态的影响。使用三种柠檬酸 - 硫酸混合物对三种不同的铝合金进行60分钟的硬质阳极氧化处理，电流密度分别为3.0和4.5 A/dm²。利用维氏显微硬度（HV）测量和扫描电子显微镜（SEM）来确定硬质阳极氧化材料的机械特性和微观结构，并采用电化学技术来了解腐蚀动力学。结果表明，6061-T6（Al-Mg-Si）铝合金具有最大的硬涂层厚度和硬度。在7075-T6（Al-Zn）合金的阳极氧化过程中发现的Zn和Mg的氧化促进了氧化物的形成。由于铜浓度高，在2024-T6（Al-Cu）铝合金上形成的氧化层厚度、硬度和耐腐蚀性最低。柠檬酸和硫酸溶液可用于在各种铝合金中进行硬质阳极氧化，这些铝合金具有与传统硫酸阳极氧化相当或更好的耐腐蚀性和机械性能。
