Corrosion Resistance of Hard Coat Anodized AA 6061 in Citric–Sulfuric Solutions

Miramontes, José Ángel Cabral; Gaona-Tiburcio, C.; Estupiñán-López, Francisco; Lara-Banda, María; Zambrano‐Robledo, Patricia del Carmen; Nieves-Mendoza, Demetrio; Maldonado-Bandala, Erick; Chacón-Nava, J.G.; Almeraya-Calderón, Facundo

doi:10.3390/coatings10060601

Cited by 19 publications

(22 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Cyclic potentiodynamic polarization (CPP) and electrochemical noise (EN) measurements were conducted at room temperature using a Gill-AC potentiostat/galvanostat/ZRA (Zero Resistance Ammeter) from ACM Instruments (Manchester, UK) in 3.5 wt % NaCl and H 2 SO 4 solutions, with the latter reagent used to simulate acid rain conditions. A conventional three-electrode cell configuration was used for electrochemical corrosion studies, which consisted of a working electrode, WE (Titanium and its alloys), a reference electrode, RE (saturated calomel electrode (SCE), and a counter electrode, CE (platinum mesh) [57,58]. Corrosion tests were realized in triplicate.…”

Section: Electrochemical Measurementsmentioning

confidence: 99%

Electrochemical Corrosion of Titanium and Titanium Alloys Anodized in H2SO4 and H3PO4 Solutions

et al. 2022

Self Cite

View full text Add to dashboard Cite

Titanium and its alloys have superior electrochemical properties compared to other alloy systems due to the formation of a protective TiO2 film on metal surfaces. The ability to generate the protective oxide layer will depend upon the type of alloy to be used. The aim of this work was to characterize the electrochemical corrosion behavior of titanium Ti-CP2 and alloys Ti-6Al-2Sn-4Zr-2Mo, Ti-6Al-4V, and Ti Beta-C. Samples were anodized in 1 M H2SO4 and H3PO4 solutions with a current density of 0.025 A/cm2. Electrochemical tests on anodized alloys were carried out using a three-electrode cell and exposed in two electrolytes, i.e., 3.5% wt. NaCl and 3.5% wt. H2SO4 solutions at room temperature. Scanning electron microscopy (SEM) was used to observe the morphology of anodized surfaces. The electrochemical techniques used were cyclic potentiodynamic polarization (CPP) and electrochemical noise (EN), based on the ASTM-G61 and G199 standards. Regarding EN, two methods of data analysis were used: the frequency domain (power spectral density, PSD) and time-frequency domain (discrete wavelet transform). For non-anodized alloys, the results by CCP and EN indicate icorr values of ×10−6 A/cm2. However, under anodizing conditions, the icorr values vary from ×10−7 to ×10−9 A/cm2. The PSD Ψ0 values are higher for non-anodized alloys, while in anodized conditions, the values range from −138/−122 dBi (A2·Hz−1)1/2 to −131/−180 dBi (A2·Hz−1)1/2. Furthermore, the results indicated that the alloys anodized in the H3PO4 bath showed an electrochemical behavior that can be associated with a more homogeneous passive layer when exposed to the 3.5% wt. NaCl electrolyte. Alloys containing more beta-phase stabilizers formed a less homogeneous anodized layer. These alloys are widely used in aeronautical applications; thus, it is essential that these alloys have excellent corrosion performance in chloride and acid rain environments.

show abstract

Section: Electrochemical Measurementsmentioning

confidence: 99%

Electrochemical Corrosion of Titanium and Titanium Alloys Anodized in H2SO4 and H3PO4 Solutions

et al. 2022

Self Cite

View full text Add to dashboard Cite

show abstract

“…All oxide layers exhibited porous structures. Alumina layers were usually formed in a hexagonal structure in a highly ordered honeycomb [4]. However, when alumina layers were hydrated the thin 'cornflake' structure would be formed at the surface of the oxide layer [17].…”

Section: Resultsmentioning

confidence: 99%

“…In detail, it was found that possible cathodic reactions to form the oxide layer in the acid sulfuric bath would be done as follows [2,4,27],…”

Section: Eds Resultsmentioning

confidence: 99%

“…Chao-lei et al [3] found that with the presence of citric acid in the boric acid bath, alumina layers would be precipitated in the crystalline phase. Cabral-Miramontes et al [4] characterized hard oxide layers fabricated in a citric/sulfuric acid anodizing bath. They investigated the effect of the applied current density of the anodizing bath on the electrochemical behavior of oxide layers.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effect of lemon juice as an eco-friendly additive on the microstructure and corrosion properties of anodized alumina layers

hasanpoor

Azadi²,

Mohri³

2022

Surf. Topogr.: Metrol. Prop.

View full text Add to dashboard Cite

The challenge of anodizing processes is to decrease the chromate compounds or other poisonous materials from the anodizing bath in a way that the performance of oxide layers does not change. Therefore, in this study, a new anodizing bath was developed to create the alumina layers. The new bath contained an H2SO4 solution with an eco-friendly additive. This additive was lemon juice (which contained natural citric acid) at various concentrations (0.3 to 2.5 vol%). Field-emission scanning electron microscopy (FESEM) was used to investigate the microstructural evaluations. Tafel polarization and electrochemical impedance spectroscopy (EIS) were also utilized to study the corrosion behavior of the alumina layers on aluminum substrates. The obtained results depicted that the presence of the bio-additive in the anodizing bath caused a reduction in corrosion rates of alumina layers by approximately 90.2 to 100% compared to the layer manufactured without additive. EIS measurements showed an increase in impedance of modified alumina layers by approximately 46-71 % in 0.6 M NaCl solution. Optimum corrosion properties were related to the modified alumina layer when the additive concentration in the anodizing bath was approximately 1.8 vol%. Since it contained low porosity with a value of 3.8% and a thick barrier layer with a thickness of 21 nm.

show abstract

“…Some authors have found that the Warburg impedance in this type of material may be since the porous layer with high thicknesses becomes brittle and initially allows the ions to pass quickly. However, when they penetrate and reach the barrier layer, they make it difficult to continue penetrating and continue to accumulate [83]. The Warburg element controls the reaction rate through the diffusion of oxidizing and reducing species to and from the metal substrate.…”

Section: Cyclic Potentiodynamic Polarization (Cpp)mentioning

confidence: 99%

Citric Acid as an Alternative to Sulfuric Acid for the Hard-Anodizing of AA6061

Miramontes

Almeraya-Calderón

López

et al. 2021

Metals

Self Cite

View full text Add to dashboard Cite

Hard-anodized is a widely used method in the aeronautical sector to improve aluminum alloys abrasion and corrosion resistance. Aim of this work was to characterize the mechanical properties and resistance hard-anodized aluminum 6061 in citric acid solution as a replacement sulfuric acid solution were investigated. Aluminum alloy 6061 was used as the base material to produce the hard anodizing; this process was carried out in a citric and sulfuric acid solution, applying current densities 3 and 4.5 A/cm2 and subsequently exposed to 3.5 wt. % NaCl solution. Microstructure and mechanical properties of the anodizing material were characterized by scanning electron microscopy (SEM) and Vickers microhardness (HV). Corrosion behavior of the hard-anodized material it was carried out with electrochemical techniques as cyclic potentiodynamic polarization (CPP) and electrochemical impedance spectroscopy (EIS) respectively. Results obtained indicated that all samples anodized in citric acid solution showed negative hysteresis and lower corrosion current density (1 × 10−10 A/cm2), indicating generalized corrosion on the material surface. EIS results show that anodizing in citric acid solution and a current density of 4.5 A/dm2 provides better corrosion protection than a sulfuric acid solution.

show abstract

Corrosion Resistance of Hard Coat Anodized AA 6061 in Citric–Sulfuric Solutions

Cited by 19 publications

References 49 publications

Electrochemical Corrosion of Titanium and Titanium Alloys Anodized in H2SO4 and H3PO4 Solutions

Electrochemical Corrosion of Titanium and Titanium Alloys Anodized in H2SO4 and H3PO4 Solutions

Effect of lemon juice as an eco-friendly additive on the microstructure and corrosion properties of anodized alumina layers

Citric Acid as an Alternative to Sulfuric Acid for the Hard-Anodizing of AA6061

Contact Info

Product

Resources

About