Surface Modifications of the Mg Alloy by Self-Assembled Monolayers of Fatty Acids

Metikoš‐Huković, Mirjana; Babić, Ranko; Rončević, Ivana Škugor; Grubač, Zoran

doi:10.1149/1.3692438

Cited by 3 publications

(5 citation statements)

References 29 publications

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“…Data show that the AZ91D alloy exhibits significantly higher corrosion resistance than pure magnesium (R p ≈ 1 k cm 2 ). 43 The AZ91D alloy has a two phase microstructure typically consisting of a matrix of α grains with the β phase (the intermetallic Mg 17 Al 12 ) along the α grain boundaries. 31 The β-phase is cathodic with respect to the matrix α phase and exhibits a passive behavior over a wider pH range than either of its components Al and Mg.…”

Section: Resultsmentioning

confidence: 99%

“…18,47 The values obtained are significantly higher (30-40%) than those obtained with the SAMs self-assembled during a shorter period of time (2 h) indicating that the self-assembly of carboxylic acids is a slow process. 43 The numerical values of R p were used to calculate the protection efficiency (PE%) of modified surface layers according to the expression:…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Surface Modification of Biodegradable Magnesium Alloys

Grubač¹,

Rončević²,

Metikoš‐Huković³

et al. 2012

J. Electrochem. Soc.

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The use of self-assembling monolayers (SAM) of long chain carboxylic acids has a potential for designing specific interface architectures in degradable implants technology. In this paper, the native and anodically formed oxide films on the Mg-alloy (AZ91D) surface were modified with the SAMs of palmitic acid (PA) and stearic acid (SA) to protect the alloy degradation in a physiological solution. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) were used to evaluate chemical composition, bonding modes of acids to the substrate, and structural properties (ordering and close-packing) of the surface layers. The results obtained by electrochemical impedance spectroscopy (EIS) have shown a beneficial effect of anodization and especially of the oxide layer modification by forming SAMs of PA and SA on the corrosion properties of AZ91D alloy in physiological solutions.Magnesium and its alloys are ideal structural materials for the lightweight engineering applications due to their remarkable properties such as low density, high specific strength, high thermal conductivity, and electromagnetic interference resistance. But so far, their application has been limited mostly due to the poor corrosion and wear resistance. 1 As a potential biodegradable implant material, magnesium shows many advantages over current metallic materials as well as biodegradable polymeric and ceramic materials because it is an essential element and in the human body its concentration is high . 1-3 However, in a solution containing Cl − ions like body fluids magnesium and its alloys easily corrode, and their successful application as degradable orthopedic implants has been mainly inhibited due to the high degradation rates and a consequent loss of the mechanical integrity. 2-6 Various surface treatments have been applied to Mg and its alloys to improve their corrosion resistance and the lifetime of implants including anodization, 7, 8 deposition of chemical conversion layers, 9 treatments based on the sol-gel application, 10 and the surface modification by formation of SAMs of long-chain carboxylic acids. 11, 12 The chemisorption of saturated long-chain (C 16 , C 18 ) carboxylic acids has been also studied on many surfaces such as aluminum oxide, 13-15 iron, 16, 17 zinc, 17 and steel. 18 As endogenous compounds and the main components of fats, fatty acids are very biocompatible substances. According to the Food and Agriculture Organization of the United Nations (FAO) recommendation, the intake of saturated fatty acids by adults should not exceed 10% of the total energy consumption. 19 However; the results on the interaction of carboxylic acids with the magnesium/AZ91D alloy surface are not consistent. While the theoretical studies predict that the most stable adsorbed configuration is one in which the carboxyl group is attached by its each oxygen atom to two separate magnesium ions, 20 the experimental results have confirmed the existence of monodentate bonding, 11 and even the electrostatic attraction of magne...

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Surface Modification of Biodegradable Magnesium Alloys

Grubač¹,

Rončević²,

Metikoš‐Huković³

et al. 2012

J. Electrochem. Soc.

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“…The third parallel R 3 -CPE 3 combination represents carboxylic acid SAM (Figure 3). 27 The constant phase element (CPE) was used instead of capacitance because the associated distribution of time constants provides an improved fit. 28 Its impedance is equal to Z(CPE) = [(Q(jω) n ] −1 ; where Q is the constant, ω is the angular frequency, and n is the CPE power.…”

Section: Eis Measurements -Phosphonic Acids Sammentioning

confidence: 99%

“…The presence of these peaks and the lack of peaks corresponding to the ν(C=O) stretching and C-O-H stretching indicate that the carboxylic head group is attached to the surface layer in a bidentate configuration. 27,45,46 (4) For anions, A is a large negative number consequently, η is also quite large. Because it's known that the hardness is independent of charge the approximation can be made for a number of ions of interest.…”

Section: Ftir Characterizationmentioning

confidence: 99%

Surface Modifications of the Biodegradable Magnesium Based Implants with Self-Assembled Monolayers Formed by T-BAG Method

Rončević¹,

Vladislavić²,

Buzuk³

2018

ACSi

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In this paper, magnesium based materials (Mg and Mg-alloy (AZ91D)) were surface modified using various organic acids (carboxylic and phosphonic), in order to improve corrosion resistance and enhance theirs biocompatibility. Formations of surface layer were performed by tethering by aggregation and growth (T-BAG) method. Organization and bond mode of these layers were examined by Fourier transform infrared spectroscopy (FTIR). Additionally, semiempirical quantum molecular modeling calculation methods were used for getting insight into their structural and electronic properties, as also as corrosion resistance in the physiological solution (Hanks' solution). Corrosion resistance of modified materials were investigated by electrochemical impedance spectroscopy (EIS) in the physiological solution (Hanks' solution) and obtained results reveal a beneficial effect of the modification by forming organic acids self-assembled monolayer (SAM) on the corrosion properties of magnesium based materials, especially layers of octadecylphosphonic acid. The maximum corrosion inhibition efficiency of 87% for magnesium and of 93% for Mg-alloy (AZ91D) are achieved by the formation of octadecylphosphonic acid (ODPA) SAM.

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“…The environmental toxicity of organic corrosion inhibitors has prompted the search for green corrosion inhibitors since they are biodegradable and do not contain heavy metals or other toxic compounds [1]. Metal protection vis these organic inhibitors comes from the fact that they adsorb on the metal surface to form a protective layer against corrosive species in the media [4][5][6]. The efficiency of an inhibitor depends on many factors, such as the nature of the metal surface, the type of corrosive media and the chemical structure of the inhibitor.…”

Section: Introductionmentioning

confidence: 99%

Corrosion protection of tin by some carboxylic acids in sodium chloride solution

Rončević

Vladislavić

Buzuk

et al. 2020

Maced. J. Chem. Chem. Eng.

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Tin is a moderately corrosion resistant material that is widely used in tinplate for food beverages. However, despite its excellent corrosion resistance, the presence of oxidizing agents enhances tin dissolution. Dissolution of metallic tin, especially from the inside of a can body into the food content has a major influence on the food quality and may cause toxicological effects. To overcome the problem, different chemical compounds are added. The most utilized inhibitors in the food industry are nitrites and nitrates well-known as hazardous to health. The present study aimed to investigate the influence of carboxylic acids on the corrosion resistance of tin since they are present in fruit juices and different foodstuffs. The corrosion protection efficiency of the carboxylate coatings was investigated in a sodium chloride solution using electrochemical and spectroscopic techniques. The structural characteristics of the surface coatings were investigated using the FTIR spectroscopy and optical microscope.

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Surface Modifications of the Mg Alloy by Self-Assembled Monolayers of Fatty Acids

Cited by 3 publications

References 29 publications

Surface Modification of Biodegradable Magnesium Alloys

Surface Modification of Biodegradable Magnesium Alloys

Surface Modifications of the Biodegradable Magnesium Based Implants with Self-Assembled Monolayers Formed by T-BAG Method

Corrosion protection of tin by some carboxylic acids in sodium chloride solution

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