Corrosion Behavior of AA 1100 Anodized in Gallic-Sulfuric Acid Solution

Abstract

Sulfuric acid anodization is one of the common methods used to improve corrosion resistance of aluminum alloys. Organic acids can be added to the sulfuric acid electrolyte in order to improve the properties of the anodized aluminum produced. In this study, the use of gallic acid as an additive to the sulfuric acid anodization of AA1100 was explored. The effect of varying anodization current density and gallic acid concentration on the properties of anodized aluminum samples was observed using electrochemical impedance spectroscopy, linear polarization, and scanning electron microscopy. It was observed that the corrosion resistance of samples anodized in gallic-sulfuric acid solution at 10 mA·cm−2 is lower than samples anodized in sulfuric acid. It was also observed that higher anodization current density can lead to lower corrosion resistances for aluminum samples anodized in gallic-sulfuric acid solution. However, samples anodized at 5 mA·cm−2 and at a gallic acid concentration of 5 g·L−1 showed better corrosion performance than the samples anodized in sulfuric acid only. This suggests that the use of low amounts of gallic acid as an additive for sulfuric acid anodization can lead to better corrosion resistances for anodized aluminum.

Progress of research on gallic acid in corrosion inhibition and rust removal protection of metals

“…Adding nanomaterials to coatings is a relatively mature method to enhance the performance of the coating (Albrecht and Schneider, 1999). Nanomaterials can effectively fill the micropores and gaps of the coating and have the advantages of high specific surface area and small size, which can improve the compactness of the coating and prolong the penetration path of the corrosive medium between the coating and the substrate, to achieve the purpose of improving the physical barrier ability (Nagaraja et al , 2012; Mopon et al , 2021; Ostovari et al , 2009). In addition, many nanomaterials (such as metal oxides) have excellent mechanical stability, which can make up for the shortcomings of insufficient strength, poor continuity and poor wear resistance of coatings (Gao et al , 2018).…”

“…Gallic acid is involved in metal protection as a raw material for the synthesis of one of the resin coatings. A common synthetic reaction is the ester exchange reaction: gallic acid exchanges with ester groups in the polymer to form new ester bonds and release small molecules that trigger the lengthening and cross-linking of polymer chains, the ester bonds formed to enhance the strength, chemical resistance and oxidation resistance of the coating (Proenca et al , 2022; Tan et al , 2020; Mopon et al , 2021). Researchers have explored a variety of resin systems, such as epoxy resins, polyesters, polyurethanes and acrylics.…”

Using modern concepts in the design of extrusion dies to improve the mechanical extrusion and fatigue properties for AA1100

“…The Corrosion resistance for anodized samples in gallic-sulfuric Solution with 10 mA-cm -2 was less than that of anodized Samples in sulfuric acid. Also it was noted that corrosion resistances of anodized samples with gallic-sulfuric solution will decrease with increasing the adonization current density [2,3].…”

Incorporation of Ions into Nanostructured Anodic Oxides—Mechanism and Functionalities

“…Further development of more reliable tools is necessary for studying the initiation and evolution of the pores' arrangement throughout the anodization [46]. Researchers are still exploring novel anodization regimes and new electrolytes [47,48] or combining various electrolytes to improve the quality of the formed oxides [49]. Challenges associated with the anodization of items with sharp edges made of aluminum and its alloys [50] as well as scaling-up of the process are still being studied [51].…”