Anodizing of AA2024 Aluminum–Copper Alloy in Citric-Sulfuric Acid Solution: Effect of Current Density on Corrosion Resistance
Source abstract
Abstract
Al–Cu alloys are widely used as a structural material in the manufacture of commercial aircraft due to their high mechanical properties such as hardness, strength, low density, and tolerance to fatigue damage and corrosion. One of the main problems of these Al–Cu alloy systems is their low corrosion resistance. The purpose of this study is to analyze the influence of anodizing parameters on aluminum–copper alloy (AA 2024) using a bath of citric-sulfuric acid with different anodizing current densities on the thickness, microhardness, and corrosion resistance of the anodized layer. Hard anodizing is performed on AA 2024 Al–Cu alloy in mixtures of solutions composed of citric and sulfuric acid at different concentrations for 60 min and using current densities (i) of 0.03, 0.045, and 0.06 A/cm2. Scanning electron microscopy (SEM) was used to analyze the surface morphology and thickness of the anodized layer. The mechanical properties of the hard anodized material are evaluated using the Vickers hardness test. The electrochemical techniques use cyclic potentiodynamic polarization curves (CPPC) according to ASTM-G6 and electrochemical impedance spectroscopy (EIS) according to ASTM-G61 and ASTM-G106, respectively, in the electrolyte of NaCl at 3.5 wt. % as a simulation of the marine atmosphere. The results indicate that corrosion resistance anodizing in citric-sulfuric acid solutions with a current density of 0.06 A/cm2 is the best with a corrosion current density (jcorr) of 1.29 × 10−8 A/cm2. It is possible to produce hard anodizing with citric and sulfuric acid solutions that exhibit mechanical properties and corrosion resistance similar or superior to conventional sulfuric acid anodizing.
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Research context
OpenAlex topics: Anodic Oxide Films and Nanostructures · Concrete Corrosion and Durability · Aluminum Alloy Microstructure Properties
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
Affiliations
Universidad Autónoma de Nuevo León, Centro de Investigación e Innovación en Ingeniería Aeronáutica (CIIIA), FIME, San Nicolás de los Garza 66455, Mexico
Facultad de Ingeniería Civil, Universidad Veracruzana, Xalapa 91000, Mexico
Área Académica de Ingeniería y Arquitectura, Universidad Autónoma del Estado de Hidalgo, Carretera Pachuca-Tulancingo Km. 4.5., Pachuca 42082, Mexico
Funding
Universidad Autónoma de Nuevo León (UANL)
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