Composite magnesium phosphate coatings for improved corrosion resistance of magnesium AZ31 alloy

Jayaraj, Jithu; Raj, S. Amruth; Srinivasan, A.; Ananthakumar, S.; Pillai, U.T.S.; Dhaipule, Nanda Gopala Krishna; Mudali, U. Kamachi

doi:10.1016/j.corsci.2016.10.010

Cited by 165 publications

(54 citation statements)

References 44 publications

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“…The not stable evolution of the R p in time can correlate with the thicker layer of corrosion products and its cracking, corrosion or remove from the samples surface, which was observed only in a minor form in the case of AZ31 magnesium alloy with the stable evolution of R p in time. The presence of inductive loop L [54,55] in the equivalent circuit implies the occurrence of pitting corrosion on the magnesium alloy's surface.…”

Section: Discussionmentioning

confidence: 99%

Influence of the Composition of the Hank’s Balanced Salt Solution on the Corrosion Behavior of AZ31 and AZ61 Magnesium Alloys

Tkácz

Doležal

Drábiková

et al. 2017

Metals

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Abstract:The electrochemical corrosion characteristics of AZ31 and AZ61 magnesium alloys were analyzed in terms of potentiodynamic tests and electrochemical impedance spectroscopy. The influence of the solution composition and material surface finish was examined also through the analysis of corrosion products created on the samples' surface after electrochemical measurements in terms of scanning electron microscopy using energy-dispersive spectroscopy. Obtained data revealed the differences in the response of the magnesium alloys to enriched Hank's Balanced Salt Solution-HBSS+ (with Mg 2+ and Ca 2+ ions) and Hank's Balanced Salt Solution-HBSS (without Mg 2+ and Ca 2+ ions). Both examined alloys exhibited better corrosion resistance from the thermodynamic and kinetic point of view in the enriched HBSS+. AZ61 magnesium alloy reached higher values of polarization resistance than AZ31 magnesium alloy in both the used corrosion solutions. Phosphate-based corrosion products were characteristic for the AZ31 and AZ61 alloys tested in the HBSS (without Mg 2+ and Ca 2+ ions). The combination of phosphate-based corrosion products and clusters of MgO and Mg(OH) 2 was typical for the surface of samples tested in the enriched HBSS+ (with Mg 2+ and Ca 2+ ions). Pitting corrosion attack was observed only in the case of enriched HBSS+.

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Section: Discussionmentioning

confidence: 99%

Influence of the Composition of the Hank’s Balanced Salt Solution on the Corrosion Behavior of AZ31 and AZ61 Magnesium Alloys

Tkácz

Doležal

Drábiková

et al. 2017

Metals

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“…The R t values of the coatings increased in the following order: C2 (1.12e 4 Ω•cm 2 ) < C0 (1.158e 4 Ω•cm 2 ) < C8 (2.541e 4 Ω•cm 2 ) < C5 (2.831e 4 Ω•cm 2 ) < C3 (3.375e 4 Ω•cm 2 ). Similarly, the value of Q is related to corrosion reaction area and low value of Q implies relatively low area of the exposed surface is corroded . The fitted values of Q dl showed decrease in the double‐layer coating capacitance in the following order: C2 (1.164e −4 S n /cm 2 ) > C0 (7.454e −5 S n /cm 2 ) > C8 (7.099e −5 S n /cm 2 ) > C5 (5.236e −5 S n /cm 2 ) > C3 (1.908e −5 S n /cm 2 ).…”

Section: Resultsmentioning

confidence: 94%

“…Generally, the time constant at high frequency corresponds to the coating capacitance and resistance of the microporous coating surface. The low‐frequency region appears due to the double‐layer coating capacitance and the corresponding polarization resistance during the corrosion process …”

Section: Resultsmentioning

confidence: 99%

“…In both circuits, R s is related to the solution resistance between the reference electrode and the work electrode, and Q c , R po , Q dl , R t , and R c represent the coating capacitance, microporous resistance, double‐layer capacitance, charge transfer resistance, and coating resistance, respectively. To obtain more precise fitting results, a constant phase element ( Q ) are used instead of capacitance . The parameter Q is represented by the following equation:

Z_{Q} = \frac{1}{Y_{0} {(j ω)}^{n}}

where Y 0 is a parameter, ω is the angular frequency, “ n ” represents the independent parameter, and j = (−1) 1/2 .…”

Section: Resultsmentioning

confidence: 99%

“…The variation in R s was mainly due to the reaction between the substrate and the ions in the electrolyte solution, which decreased the ionic concentration and thereby causing an increase in the solution resistance for coated samples. In general, the charge transfer resistance ( R t ) is correlated to the corrosion process and high R t means high resistance . The R t values of the coatings increased in the following order: C2 (1.12e 4 Ω•cm 2 ) < C0 (1.158e 4 Ω•cm 2 ) < C8 (2.541e 4 Ω•cm 2 ) < C5 (2.831e 4 Ω•cm 2 ) < C3 (3.375e 4 Ω•cm 2 ).…”

Section: Resultsmentioning

confidence: 99%

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Functionalized boron carbide for enhancement of anticorrosion performance of epoxy resin

Wang

Xie

et al. 2017

Polymers for Advanced Techs

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In this study, epoxy coatings were modified by adding various compositions of B 4 C particles. In order to achieve proper dispersion of particles in the epoxy coating and increasing chemical interactions between particles and polymeric coating, the surface of the B 4 C particles was treated with γ-(2,3-epoxypropoxy) propytrimethoxysilane (KH560). The surface modification and microstructure of B 4 C were characterized by Fourier transform infrared, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. Electrochemical impedance spectroscopy was also used to evaluate the impedance of coatings. The results revealed that the KH560 not only enhanced the interaction between B 4 C particles and epoxy resin but also exhibited a remarkable ability to improve the anticorrosion performance of epoxy resin. The epoxy coating with the 3 wt% B 4 C-KH560 particles exhibited the best anticorrosion performance, which can be attributed to the best uniform dispersion of the B 4 C-KH560 particles, and the particles effectively block the aggressive species (Cl − , O 2 , and H 2 O) from the coating.

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Robust Rare‐Earth‐Containing Superhydrophobic Coatings for Strong Protection of Magnesium and Aluminum Alloys

Liu

Lei

et al. 2018

Adv Materials Inter

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The robust rare‐earth‐containing superhydrophobic coatings are fabricated by a simple and scalable method, which includes spraying the lanthanum hydroxide sol onto metallic substrates (AZ61 Mg and 2024 Al) and then modifying the surfaces with stearic acid. The as‐prepared coatings on AZ61 Mg and 2024 Al have identical morphology and composition. Both are composed of fiber‐like La(OH)3 nanowires that cross‐link and form a network structure, which are pivotal for inducing surface superhydrophobicity with water contact angles (WCAs) as high as ≈157°. The superhydrophobic coatings demonstrate remarkable corrosion resistance as well as high chemical and mechanical stabilities. The theoretical simulation based on molecular mechanics suggests that the high stabilities mainly arise from the strong bonding between La2O3 and stearic acid molecules. The fabrication approach proposed here is hopeful to extend for large‐scale preparation of robust superhydrophobic metallic materials widely applied.

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Composite magnesium phosphate coatings for improved corrosion resistance of magnesium AZ31 alloy

Cited by 165 publications

References 44 publications

Influence of the Composition of the Hank’s Balanced Salt Solution on the Corrosion Behavior of AZ31 and AZ61 Magnesium Alloys

Influence of the Composition of the Hank’s Balanced Salt Solution on the Corrosion Behavior of AZ31 and AZ61 Magnesium Alloys

Functionalized boron carbide for enhancement of anticorrosion performance of epoxy resin

Robust Rare‐Earth‐Containing Superhydrophobic Coatings for Strong Protection of Magnesium and Aluminum Alloys

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