Jump to ContentJump to Main Navigation
Show Summary Details
More options …

BioNanoMaterials

Editor-in-Chief: Jockenhoevel, Stefan / Stiesch, Meike / Barcikowski, Stephan / Sternberg, Katrin

Editorial Board Member: Muellen, Klaus / Weitschies, Werner / Liefeith, Klaus / Boccaccini, Aldo R. / Williams, J. Koudy / O'Brien, Fergal J. / Kellomäki, Minna

4 Issues per year


CiteScore 2016: 0.59

SCImago Journal Rank (SJR) 2016: 0.241
Source Normalized Impact per Paper (SNIP) 2016: 0.172

Open Access
Online
ISSN
2193-066X
See all formats and pricing
More options …
Volume 17, Issue 3-4 (Sep 2016)

Issues

Investigating the effect of salicylate salt in enhancing the corrosion resistance of AZ91 magnesium alloy for biomedical applications

Adel Francis
  • Department of Advanced Materials, Central Metallurgical R and D Institute (CMRDI), P. O. Box 87, Helwan, Cairo, Egypt
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
/ Sannakaisa Virtanen
  • Corresponding author
  • Institute of Surface Science and Corrosion, Department of Materials Science and Engineering, University of Erlangen-Nuremberg, 91058 Erlangen, Germany
  • Email
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
/ Metehan C. Turhan
  • Institute of Surface Science and Corrosion, Department of Materials Science and Engineering, University of Erlangen-Nuremberg, 91058 Erlangen, Germany
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
/ Aldo R. Boccaccini
  • Corresponding author
  • Institute of Biomaterials, Department of Materials Science and Engineering, University of Erlangen-Nuremberg, Cauerstrasse 6, 91058 Erlangen, Germany
  • Email
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
Published Online: 2015-08-13 | DOI: https://doi.org/10.1515/bnm-2015-0008

Abstract

The pretreatment process plays a vital role in the development of a robust protective layer on magnesium alloys. This work presents a novel insight into the pretreatment of magnesium alloy AZ91 in alkaline silicate solution by anodic oxidation in the presence of C7H5NaO3 (sodium salicylate) to enhance surface resistance and introduce a passive biolayer. The electrochemical corrosion behavior of protective layers prepared at different voltages was evaluated by electrochemical impedance spectroscopy (EIS) in SBF solution. The Nyquist impedance plots for anodized films, which consist of a mixture of magnesium silicate and salicylate, indicate a significant corrosion protection ability of the layers formed under optimized conditions; an increase of the real impedance from the value of ~2 kΩ.cm2 for the bare alloy surface to about 10–12 kΩ.cm2 for the anodized film can be observed. The results indicate that surface modification by anodizing in silicate electrolyte in the presence of sodium salicylate is an alternative pretreatment to improve the corrosion resistance of AZ91.

Keywords: electrochemical impedance spectroscopy; magnesium and magnesium alloys; pretreatment and corrosion protection; salicylate salts

Introduction

Development of biomedical magnesium implants, which have suitable mechanical properties and additionally safely degrade in vivo, opens an avenue for the fabrication of future biodegradable metallic implants. For many years, metallic materials including stainless steel, cobalt-chromium, and titanium alloys have been the primary biomaterials used for load-bearing applications. Considering the release of undesired metallic ions and potential allergic reactions when these metallic alloy implants come in contact with surrounding body tissues and fluids, magnesium alloys are being suggested as promising biodegradable materials for temporary implants, to overcome the limitations and long-term drawbacks of the conventional (permanent) metallic materials being used [1]. In addition, the elastic modulus of Mg has been reported as 45 GPa [2], which is far closer to the elastic modulus of human bone, in comparison to that of unalloyed commercially titanium, stainless steel, cobalt, and platinum alloys, which lie between 103 and 107 GPa [3], [4], 193, 195–210, and 147 GPa respectively [5]. Magnesium is a candidate for orthopedic applications and for bone tissue regeneration approaches [6]. However, the excessive corrosion rate of Mg alloys in physiological environment and the release of hydrogen gas during degradation represents a current limitation for clinical application of Mg and its alloys [7]. Therefore, reducing the corrosion rate of magnesium is the most appropriate strategy which can be achieved with the use of different approaches including alloying [8], [9], [10], [11], [12], [13], [14], [15], surface treatment/coating [16], [17], [18], [19], [20], [21], [22], [23], [24], [25], [26], [27] and mechanical processing such as squeeze casting, hot rolling, equal-channel angular pressing (ECAP), cyclic extrusion and compression, and double extrusion [28], [29], [30], [31], [32]. Surface treatment or deposition of a coating is considered as a viable approach to improve the corrosion resistance and to pride an appropriate surface for better bone bonding and cell growth on Mg and Mg alloys [26], [33]. The various aspects of surface modification methods and protective coatings on Mg and its alloys have been reviewed [18], [26], [27].

The challenge is to develop appropriate coatings or protective layers that would delay the rate of corrosion attack of Mg being at the same time biocompatible. Organic-based coatings appear as one of the most interesting options, as they offer protection against corrosion together with other functions such as drug delivery or functionalisation ability involving organic bio-molecules [26], [34], [35], [36]. For instance, corrosion tests performed in NaCl solution on Mg-6Zn substrates coated by polylactic glycolacid (PLGA) showed reduced degradation rate due to the presence of the biopolymer coating [37]. Following the same study, Chen et al. [38] successfully prepared polycaprolactone (PCL) as well as polylactic acid (PLA) coatings on the surface of pure magnesium. Corrosion studies in SBF solution including static polarization and dynamic immersion tests showed slightly improved corrosion resistance due to the interaction between substrate and polymer coating. Recently, Degner et al. [39] deposited a corrosion-resistant biodegradable polymer film of polycaprolactone (PCL) in different concentrations by spin coating. In the same context, the corrosion behavior of dip-coated magnesium alloys with PCL and PEI has been evaluated by Wong et al. [40] and Conceicao et al. [41], respectively.

However, Xu and his co-authors [42] introduced a two-step coating approach adopting a preliminary PEO treatment of the alloy WE42 followed by dropping organic phases (cross-linked gelatin/PLGA-particles solution) onto the surface. There was no significant difference between the corrosion resistance after PEO treatment and after the entire two-step processes.

Considering the two aspects of appropriate protective layer and biocompatibility, the present work presents a preliminary study on the pretreatment/coating of magnesium alloy AZ91 in alkaline silicate solution by anodic oxidation in the presence of sodium salicylate to introduce a protective coating with uniform coverage for the application of magnesium alloys in biodegradable implants. It is also of special interest to determine the role of salicylate in improving the corrosion behavior of Mg alloys and its reaction with silicates and magnesium alloys. Salicylates are compounds derived from salicylic acid, which has been used as a common painkiller and to reduce fever and inflammation for centuries. Clinical studies have shown the anti-aging benefits of sodium salicylate in human skin [43]. Salicylate and its derivatives [44], [45] have been regarded as one of the most interesting pharmacologic compounds with many undisclosed therapeutic properties. Sodium salicylate (NaSAL) could also represent a powerful antidote to be used against paraquat (PQ) poisonings. Moreover, the presence of the salicylate molecule in many commercial drugs [46], and its complexation ability with metallic ions and metal surfaces [47] is an interesting topic which deserves a deep research. The usage of salicylate as passivating agent for copper alloys has already been discussed [48], [49]. In a study on the role of salicylate ions in the anodic behavior of copper, Cascalheira et al. [50] observed the formation of Cu(II)-salicylate film at the electrode surface which contributes to its passivation. They also determined the oxidation peak of salicylate at around 1V. For the Mg alloy AZ91, it has been demonstrated that release of salicylate as dopant in polypyrrole coatings can function as inhibitor for the Mg alloy [51]. As limited work has been published regarding the surface pretreatment/coating of Mg alloys by organic molecules, it is interesting to explore the use of salicylate as passivating agent that leads to the delay of corrosion attack for Mg. The use of salicylate in the present work can only be fully justified if high quality corrosion-resistant coatings can be achieved, which might be able to compete with current organic or bioactive materials for biomedical applications.

Experimental

As-received Mg alloy samples (AZ91) were used as substrates. They were cut into 20×20 mm2 pieces and used as deposition substrates during surface treatment. The AZ91 substrate was ground with silicon carbide paper (Grade P 1200), rinsed, cleaned with ethanol by ultrasonication, and dried in nitrogen at room temperature. Pretreatment of AZ91D was performed in an electrolyte of sodium hydroxide, sodium silicate and sodium salicylate (a 200 mL solution containing 0.25 M NaOH, 0.1 M Na2SiO3 and 0.026 M C7H5NaO3) and carried out at various voltages. Figure 1 illustrates the set-up experiment for the anodic spark oxidation. The corrosion studies on coated and uncoated samples were performed using electrochemical impedance spectroscopy (EIS) technique (Autolab PGSTAT 30). The electrochemical cell consisted of three electrode set-up, in which the particular Mg alloy samples act as working electrode. A platinum sheet was used as counter electrode and a Ag/AgCl with 3 M KCl was used as reference electrode. As electrolyte a physiological simulated body solution (SBF) was prepared according to the recipe of SBF5 by Müller and Müller [52]. The pH of the solution was maintained at 7.4, and the temperature was kept at 37°C using a water bath. Open circuit potential (OCP) was monitored continuously for 30 min until the steady state was reached. During EIS experiments, a sinusoidal perturbation of ±10 mV for 10 points per decade in a frequency range between 100 kHz and 10 mHz was used. The surfaces of coatings were characterized using optical microscopy. Infrared spectrum of the anodized film on AZ91 MG alloy was performed with a Bruker Fourier Transform Infrared spectrometer (FTIR). The range from 4000 to 400 cm−1 was scanned.

The experimental laboratory set-up for the anodic oxidation process.
Figure 1:

The experimental laboratory set-up for the anodic oxidation process.

Results and discussion

There is an increasing need for assessing the corrosion resistance of coated magnesium alloys under physiological environment. Anodization presents one possible coating route, and has been previously explored also for Mg alloys [18], [19], [21], [22], [25], [27], [53]. In the present study, anodization using a new type of electrolyte was investigated. It should be pointed out that a pretreatment coating or a pretreatment followed by another bioactive coating can effectively prevent corrosion and provide a passive layer between the metal and the physiological environment. The coating bath for anodizing is a novel alkaline electrolyte (NaOH+Na2SiO3)+C7H5NaO3 (organic material). Figure 2 displays the deposition current as a function of deposition time at different voltages. At start, the deposition current decreased drastically in a short time after applying 4 and 10V, and then reached a steady level as the deposition progressed. Experimentally, anodizing can be performed either under voltage or current controlled conditions. Under voltage control, the current drops with treatment time as the insulating oxide film is growing. However, the situation was completely reversed at 5 and 7 V; this may be due to the reaction between the Mg substrate and the electrolyte that leads to the formation of a steady protective layer on the Mg substrate.

Deposition current as a function of deposition time at different anodizing voltages 4–10 V on AZ91.
Figure 2:

Deposition current as a function of deposition time at different anodizing voltages 4–10 V on AZ91.

The pretreatment leads to a modification of the macro-structural morphology of the Mg alloy as shown in Figure 3. It is clear that pretreatments changed the macroscopic color of the surface and almost covered the whole substrate of the magnesium alloy.

Surface microscopic photographs (50 μm) of AZ91 pieces after different pre-treatments: A) bare alloy, B) at 4 V for 10 min, C) at 5 V for 10 min, D) 7 V at 10 min, and E) 10 V at 10 min.
Figure 3:

Surface microscopic photographs (50 μm) of AZ91 pieces after different pre-treatments: A) bare alloy, B) at 4 V for 10 min, C) at 5 V for 10 min, D) 7 V at 10 min, and E) 10 V at 10 min.

Figure 4 demonstrates the Nyquist plots which depict the imaginary impedance, which is indicative of the capacitive and inductive character, vs. the real impedance. It is apparent from these plots that anodization at 4 and 7 Volt leads to coatings with the best corrosion resistance in physiological solution, reaching an impedance value up to 10 and 12 kΩ. The existence of a pseudoinductive loop which appears as scattered points at low frequency can be attributed to relaxation processes corresponding to nucleation of corrosion pits [54]. However, the EIS spectrum of the layer formed by anodizing at 7V for 5 min shows the best corrosion resistance without any sign of the inductive loop, additionally indicating a good protection performance. From the comparison of results at different voltages and pretreatment durations up to 10 min with and without sodium salicylate, it can be concluded that the pretreatment in the presence of salicylate passivates the alloy surface in the course of anodizing, and thus increases its resistance and leads to the formation of an effective barrier against corrosion of the alloy. The lowest impedance values at 10 V in comparison to the other applied voltages might be due to the deterioration of the coating layers or the presence of defects, possibly generated during interactions of the silicate/hydroxide/salicylate solutions with magnesium alloy at this relatively high voltage.

Nyquist plots recorded for the AZ91 magnesium alloy before (bare alloy) and after anodizing in the presence and absence of salicylate at different voltages for different pre-treatment. The anodization time for No Sali is 3 min.
Figure 4:

Nyquist plots recorded for the AZ91 magnesium alloy before (bare alloy) and after anodizing in the presence and absence of salicylate at different voltages for different pre-treatment. The anodization time for No Sali is 3 min.

The anodized film formed over AZ91 Mg alloy was analyzed using IR spectroscopy, Figure 5, and the obtained spectrum confirmed the presence of both magnesium silicate and salicylate. The band at 1650 cm−1 is attributed to the characteristic stretching frequency of C=O in Mg-salicylate salt. The broad band at around 1400 cm−1 is due to C-O stretching in Mg-salicylate [55]. The peak around 856 cm−1 is due to MgO. Magnesium silicate shows a strong vibrational band at 1020 cm−1 which is due to the Si-O-Si symmetrical and asymmetrical stretching vibrations [56]. The sharp band at around 3700 is attributed to the O-H stretching [57]. However, the band at 2360 and the striations between 1450 and 1600 cm−1 might be associated with the bending vibration of Si-O, stretching vibration of Mg-O, and bending vibration of Si-O-Mg.

FTIR spectrum of anodized film obtained at 5 V for 3 min (the bands are explained in the text).
Figure 5:

FTIR spectrum of anodized film obtained at 5 V for 3 min (the bands are explained in the text).

In order to compare the current results with previous studies in the literature, we consider the real impedance at which the imaginary part vanishes for the capacitive part to be the charge transfer resistance (Rt), and regard it as a measure of corrosion resistance [58]. For example, Ye et al. [59] found that the Rt value of bioactive glass–ceramic coated AZ31 Mg substrate has a value of 2.51 kΩ.cm2 in comparison to the uncoated alloy (0.8 kΩ.cm2). Some authors [60] showed that a 5 min MAO coated bio-compatible magnesium alloy had better corrosion resistance (≤0.477 kΩ.cm2) after immersion in SBF solution for different durations up to 7 days. On the other hand, Wang et al. [61] have suggested that dicalcium phosphate hydrate-polycaprolactone (DCPD-PCL) composite coatings are a promising choice in comparison to DCPD alone to protect the Mg-Zn alloy. The real impedance (Zre) of the DCPD-PCL coated Mg-Zn alloy reached about 3000 Ω, approximately 4 times as large as that of the DCPD coated sample. Earlier research [62] has investigated the biodegradable behavior of HA coating on AZ91D magnesium alloy. The EIS plot showed that the capacitance loop diameter of the HA coating was larger than that of the magnesium alloy substrate but still the real impedance was less than 3000 Ω. In prior studies, Chiu et al. [63] demonstrated that the EIS of fluoride conversion coating on biodegradable Mg implants showed a polarization resistance of 5.2 kΩ.cm2.

Therefore, the coating presented here represents an effective and innovative way to improve the corrosion resistance of magnesium alloys using salicylate as electrolyte. The coated AZ91 substrates exhibited the best corrosion resistance during electrochemical tests in SBF, which was demonstrated by the larger value of the real impedance in comparison to data from the literature dealing with one-step, two-step and even layer-by-layer coatings.

The preliminary measurements presented in this paper indicate the potential of the one step pre-treatment/coating route of anodic oxidation in the presence of sodium salicylate to enhance the corrosion resistance of magnesium alloys. To the authors’ knowledge, the corrosion behavior of the anodized films over AZ91 in the presence of salicylate salt has not been studied before. Further experiments are required, however, to assess quantitatively and biologically the biocorrosion rate and mechanisms of the Mg alloy (AZ91).

Conclusions

Anodizing in the presence of a mixture of silicate electrolyte and sodium salicylate generates a protective coating film on AZ91 magnesium substrates. The effect of the coating was analyzed using optical microscopy and EIS. The improved corrosion resistance of anodized films is attributed to the structure modification with formation of both magnesium silicate and salicylate layer which form a coating that acts as an effective barrier to SBF. FTIR confirmed the presence of both magnesium silicate and salicylate as robust films formed on the magnesium alloy.

Acknowledgments

A. Francis is grateful to the Alexander von Humboldt foundation and DAAD for support in the form of research stays in 2014 and 2011. A. Francis extends his gratitude to all the colleagues at the Institute of Biomaterials and at the Institute of Surface Science and Corrosion at the University of Erlangen-Nuremberg.

References

  • 1.

    Martinez Sanchez AH, Luthringer BJ, Feyerabend F, Willumeit R. Mg and Mg alloys: How comparable are in vitro and in vivo corrosion rates? A review. Acta Biomater 2015;13:16–31. Google Scholar

  • 2.

    Zeng R, Dietzel W, Witte F, Hort N, Blawert C. Progress and challenge for magnesium alloys as biomaterials. Adv Eng Mater 2008;10:B3–14. Google Scholar

  • 3.

    International A. Standard specification for unalloyed Titanium, for surgical implant applications (UNS R50250, UNS R50400, UNS R50550, UNS R50700). ASTM F67-06 Medical Device Standards and Implant Standards. Google Scholar

  • 4.

    Elias C, Lima J, Valiev R, Meyers M. Biomedical applications of titanium and its alloys. J Miner Met Mater Soc 2008;60: 46–9. Google Scholar

  • 5.

    Black J. Orthopaedic biomaterials in research and practice. New York: Churchill Livingstone, 1988. Google Scholar

  • 6.

    Staiger M, Pietak A, Huadmai J, Dias G. Magnesium and its alloys as orthopedic biomaterials: a review. Biomaterials 2006;27:1728–34. Google Scholar

  • 7.

    Li Z, Gu X, Lou S, Zheng Y. The development of binary Mg-Ca alloys for use as biodegradable materials within bone. Biomaterials 2008;29:1329–44. Google Scholar

  • 8.

    Yang L, Huang Y, Feyerabend F, Willumeit R, Mendis C, Kainer KU, et al. Microstructure, mechanical and corrosion properties of Mg-Dy-Gd-Zr alloys for medical applications. Acta Biomater 2013;9:8499–508. Google Scholar

  • 9.

    Kim WC, Kim JG, Lee JY, Seok HK. Influence of Ca on the corrosion properties of magnesium for biomaterials. Mater Lett 2008;62:4146–8. Google Scholar

  • 10.

    Bobby Kannan M, Singh Raman RK. In vitro degradation and mechanical integrity of calcium-containing magnesium alloys in modified-simulated body fluid. Biomaterials 2008;29:2306–14. Google Scholar

  • 11.

    Du H, Wei Z, Liu X, Zhang E. Effects of Zn on the microstructure, mechanical property and bio-corrosion property of Mg-3Ca alloys for biomedical application. Mater Chem Phys 2011;125:568–75. Google Scholar

  • 12.

    He Y, Tao H, Zhang Y, Jiang Y, Zhang S, Zhao C, et al. Biocompatibility of bio-Mg-Zn alloy within bone with heart, liver, kidney and spleen. Chinese Sci Bull 2009;54:484–91. Google Scholar

  • 13.

    Zhang S, Zhang X, Zhao C, Li J, Song Y, Xie C, et al. Research on an Mg-Zn alloy as a degradable biomaterial. Acta Biomater 2010;6:626–40. Google Scholar

  • 14.

    Zhang B, Hou Y, Wang X, Wang Y, Geng L. Mechanical properties, degradation performance and cytotoxicity of Mg-Zn-Ca biomedical alloys with different compositions. Mater Sci Eng C 2011;31:1667–73. Google Scholar

  • 15.

    Datta MK, Chou DT, Hong D, Saha P, Chung SJ, Lee B, et al. Structure and thermal stability of biodegradable Mg-Zn-Ca based amorphous alloys synthesized by mechanical alloying. Mater Sci Eng B 2011;176:1637–43. Google Scholar

  • 16.

    Kuwahara H, Al-Abdullat Y, Mazaki N, Tsutsumi S, Aizawa T. Precipitation of magnesium apatite on pure magnesium surface during immersing in Hank’s solution. Mater Trans 2001;42:1317–21. Google Scholar

  • 17.

    Li L, Gao J, Wang Y. Evaluation of cyto-toxicity and corrosion behavior of alkali-heat-treated magnesium in simulated body fluid. Surf Coat Technol 2004;185:92–8. Google Scholar

  • 18.

    Blawert C, Dietzel W, Ghali E, Song G. Anodizing treatments for magnesium alloys and their effect on corrosion resistance in various environments. Adv Eng Mater 2006;8:511–33. Google Scholar

  • 19.

    Kim YK, Lee MH, Nepane Prasad M, Park IS, Lee MH, Seol KW, et al. Surface characteristics of magnesium alloys treated by anodic oxidation using pulse power. Adv Mater Res 2008;47–50:1290–3. Google Scholar

  • 20.

    Xu L, Yamamoto A. Characteristics and cytocompatibility of biodegradable polymer film on magnesium by spin coating. Colloid Surface B 2012;93:67–74. Google Scholar

  • 21.

    Zozulin AJ, Bartak DE. Anodized coatings for magnesium alloys. Met Finish 1994;92:39–44. Google Scholar

  • 22.

    Guo HF, An MZ, Huo HB, Xu S, Wu LJ. Microstructure characteristic of ceramic coatings fabricated on magnesium alloys by micro-arc oxidation in alkaline silicate solutions. Appl Surf Sci 2006;252:7911–6. Google Scholar

  • 23.

    Yao ZP, Li LL, Liu XR, Jiang ZH. Preparation of ceramic conversion layers containing Ca and P on AZ91D Mg alloys by plasma electrolytic oxidation. Surf Eng 2010;26:317–20. Google Scholar

  • 24.

    Gu Y, Chen CF, Bandopadhyay S, Ning C, Zhang Y, Guo Y. Corrosion mechanism and model of pulsed DC microarc oxidation treated AZ31 alloy in simulated body fluid. Appl Surf Sci 2012;258:6116–26. Google Scholar

  • 25.

    Arrabal R, Mota JM, Criado A, Pardo A, Mohedano M, Matykina E. Assessment of duplex coating combining plasma electrolytic oxidation and polymer layer on AZ31 magnesium alloy. Surf Coat Technol 2012;206:4692–703. Google Scholar

  • 26.

    Hornberger H, Virtanen S, Boccaccini AR. Biomedical coatings on magnesium alloys – A review. Acta Biomater 2012;8: 2442–55. Google Scholar

  • 27.

    Wang J, Tang J, Zhang P, Li Y, Wang J, Lai Y, et al. Surface modification of magnesium alloys developed for bioabsorbable orthopedic implants: a general review. J Biomed Mater Res B 2012;100:1691–701. Google Scholar

  • 28.

    Zhang X, Yuan G, Mao L, Niu J, Fu P, Ding W. Effects of extrusion and heat treatment on the mechanical properties and biocorrosion behaviors of a Mg-Nd-Zn-Zr alloy. J Mech Behav Biomed Mater 2012;7:77–86. Google Scholar

  • 29.

    Zhang X, Yuan G, Niu J, Fu P, Ding W. Microstructure, mechanical properties, biocorrosion behavior, and cytotoxicity of as extruded Mg-Nd-Zn-Zr alloy with different extrusion ratios. J Mech Behav Biomed Mater 2012;9:153–62. Google Scholar

  • 30.

    Wang H, Estrin Y, Zúberová Z. Bio-corrosion of a magnesium alloy with different processing histories. Mater Lett 2008;62:2476–9. Google Scholar

  • 31.

    Gu XN, Li N, Zheng YF, Kang F, Wang JT, Ruan L. In vitro study on equal channel angular pressing AZ31 magnesium alloy with and without back pressure. Mater Sci Eng B 2011;176:1802–6. Google Scholar

  • 32.

    Zhang X, Wang Z, Yuan G, Xue Y. Improvement of mechanical properties and corrosion resistance of biodegradable Mg–Nd–Zn–Zr alloys by double extrusion. Mater Sci Eng B 2012;177:1113–9. Google Scholar

  • 33.

    Sankara Narayanan TS, Song Park IL, Ho Lee M. Strategies to improve the corrosion resistance of microarc oxidation (MAO) coated magnesium alloys for degradable implants: Prospects and challenges. Prog Mater Sci 2014;60:1–71. Google Scholar

  • 34.

    Bertsch T, Borck A. Biocorrodible metallic implant having a coating or cavity filling made of gelatin. Biotronik: assignee, Patent US 2008/0058923A1. 

  • 35.

    Borck A. Biocorrodible metallic implant having coating or cavity filling made of a PEG/PLGA.copolymer. Biotronik: assignee, Patent US 2008/0051872A1. 

  • 36.

    Adden N. Implant of a biocorrodable magnesium alloy and having a coating of a biocorrodable polyphosphazene. Biotronik: assignee, Patent US 2009/0048660A1. 

  • 37.

    Li JN, Cao P, Zhang XN, Zhang SX, He YH. In vitro degradation and cell attachment of a PLGA coated biodegradable Mg–6Zn based alloy. J Mater Sci 2010;45:6038–45. Google Scholar

  • 38.

    Chen Y, Song Y, Zhang S, Li J, Zhao C, Zhang X. Interaction between a high purity magnesium surface and PCL and PLA coatings during dynamic degradation. Biomed Mater 2011;6:1–8. Google Scholar

  • 39.

    Degner J, Singer F, Cordero L, Boccaccini AR, Virtanen S. Electrochemical investigations of magnesium in DMEM with biodegradable polycaprolactone coating as corrosion barrier. Appl Surf Sci 2013;282:264–70. Google Scholar

  • 40.

    Wong HM, Yeung KW, Lam KO, Tam V, Chu PK, Luk KD, et al. A biodegradable polymer-based coating to control the performance of magnesium alloy orthopaedic implants. Biomaterials 2010;31:2084–96. Google Scholar

  • 41.

    da Conceicao TF, Scharnagl N, Dietzel W, Kainer KU. Corrosion protection of magnesium AZ31 alloy using poly(ether imide) [PEI] coatings prepared by the dip coating method: Influence of solvent and substrate pre-treatment. Corros Sci 2011;53: 338–46. Google Scholar

  • 42.

    Xu X, Lu P, Guo M, Fang M. Cross-linked gelatin/nanoparticles composite coating on micro-arco xidation film for corrosion and drug release. Appl Surf Sci 2010;256:2367–71. Google Scholar

  • 43.

    Merinville E, Byrne AJ, Rawlings AV, Muggleton AJ, Laloeuf AC. Three clinical studies showing the anti-aging benefits of sodium salicylate in human skin. J Cosmet Dermatol 2010;9:174–84. Google Scholar

  • 44.

    Brunton L, Lazo J, Parker K. Goodman & Gilman’s The pharmacological basis of therapeutics. New York: McGraw Hill, 2006. Google Scholar

  • 45.

    Dinis-Oliveira RJ, Pontes H, Bastos ML, Remião F, Duarted JA, Carvalho F. An effective antidote for paraquat poisonings: the treatment with lysine acetylsalicylate. Toxicology 2009;255:187–93. Google Scholar

  • 46.

    Galvez E, Fernandez-Sanchez C, Sanz-Aparicio J, Florencio F, Fernandez-Navarro E, Bellanato J. Structural study of benzidamine salicylate in the solid state and in solution. J Pharm Sci 1992;81:94–98. Google Scholar

  • 47.

    Alvarez-Ros MC, Sanchez-Cortes S, Garcıa-Ramos JV. Vibrational study of the salicylate interaction with metallic ions and surfaces. Spectrochim Acta A 2000;56:2471–77. Google Scholar

  • 48.

    Cascalheria CA, Aeiyach S, Lacaze PC, Abrantes LM. Electrochemical synthesis and redox behavior of polypyrrole coatings on copper in salicylate aqueous solution. Electrochim Acta 2003;48:2523–9. Google Scholar

  • 49.

    Cascalheira AC, Aeiyach S, Aubard J, Lacaze P-C, Abrantes LM. Electropolymerization of pyrrole on oxidizable metals: role of salicylate Ions in the anodic behavior of Copper. Russ J Electrochem 2004;40:294–8. Google Scholar

  • 50.

    Cascalheria CA,Viana AS, Abrantes LM. In situ atomic force microscopy investigation of copper behavior and polypyrrole deposition from salicylate medium. Electrochimic Acta 2008;53;5783–8. Google Scholar

  • 51.

    Turhan MC, Rückle D, Killian MS, Jha H, Virtanen S. Corrosion behavior of polypyrrole/AZ91D in simulated body fluid solutions and its functionalization with albumin monolayers. Corrosion 2012;68:536–47. Google Scholar

  • 52.

    Müller L, Müller FA. Preparation of SBF with different HCO3-content and its influence on the composition of biomimetic apatite. Acta Biomaterialia 2006;2:181–9. Google Scholar

  • 53.

    Verdier S, Boinet M, Maximovitch S, Dalard F. Formation, structure and composition of anodic films on AM60 magnesium alloy obtained by DC plasma anodizing. Corros Sci 2005;47:1429–44. Google Scholar

  • 54.

    Cao CN, Zhang JQ. An introduction to electrochemical impedance spectroscopy. Beijing: science press, 2002. pp. 176–9. Google Scholar

  • 55.

    Srinivasan A, Ranjani P, Rajendran N. Electrochemical polymerization of pyrrole over AZ31 Mg alloy for biomedical applications. Electrochim Acta 2013;88:310–21. Google Scholar

  • 56.

    Yang H, Li S, Liang Z. Anodized oxidative electrosynthesis of magnesium silicate whiskers. Int J Electrochem Sci 2013;8:9332–7. Google Scholar

  • 57.

    Nakamoto K. Infrared spectra of inorganic and coordination compounds. New York: John Wiley, 1963. Google Scholar

  • 58.

    Hou SS, Zhang RR, Guan SK, Ren CX, Gao JH, Lu QB, et al. In vitro corrosion behavior of Ti-O film deposited on fluoride-treated Mg-Zn-Y-Nd alloy. Appl Surf Sci 2012;258:3571–7. Google Scholar

  • 59.

    Ye X, Cai S, Dou Y, Xu G, Huang K, Ren M, et al. Bioactive glass–ceramic coating for enhancing the in vitro corrosion resistance of biodegradable Mg alloy. Appl Surf Sci 2012;259:799–805. Google Scholar

  • 60.

    Liu J, Zhang W, Zhang H, Hu X, Zhang J. Effect of microarc oxidation time on electrochemical behaviors of coated bio-compatible magnesium alloy. The 1st International Joint Mini-Symposium on Advanced Coatings between Indiana University-Purdue University Indianapolis and Changwon National University Materials Today: Proceedings 1, 2014:70–81. Google Scholar

  • 61.

    Wang H, Zhao C, Chen Y, Li J, Zhang X. Electrochemical property and in vitro degradation of DCPD-PCL composite coating on the biodegradable Mg-Zn alloy. Mater Lett 2012;68:435–8. Google Scholar

  • 62.

    Song YW, Shan DY, Han EH. Electrodeposition of hydroxyapatite coating on AZ91D magnesium alloy for biomaterial application. Mater let 2008;62:3276–79. Google Scholar

  • 63.

    Chiu KY, Wong MH, Cheng FT, Man HC. Characterization and corrosion studies of fluoride conversion coating on degradable Mg Implants. Surf Coat Technol 2007;202:590–8. Google Scholar

About the article

Corresponding authors: Sannakaisa Virtanen, Institute of Surface Science and Corrosion, Department of Materials Science and Engineering, University of Erlangen-Nuremberg, 91058 Erlangen, Germany, E-mail: ; and Aldo R. Boccaccini, Institute of Biomaterials, Department of Materials Science and Engineering, University of Erlangen-Nuremberg, Cauerstrasse 6, 91058 Erlangen, Germany, E-mail:


Received: 2015-03-16

Accepted: 2015-06-23

Published Online: 2015-08-13

Published in Print: 2016-09-01


Author’s statementConflict of interest: Authors state no conflict of interest.

Materials and methodsInformed consent: Informed consent has been obtained from all individuals included in this study.

Ethical approval: The research related to human use has been complied with all the relevant national regulations, institutional policies and in accordance the tenets of the Helsinki Declaration, and has been approved by the authors’ institutional review board or equivalent committee.


Citation Information: BioNanoMaterials, ISSN (Online) 2193-066X, ISSN (Print) 2193-0651, DOI: https://doi.org/10.1515/bnm-2015-0008.

Export Citation

©2016 Walter de Gruyter GmbH, Berlin/Boston. Copyright Clearance Center

Comments (0)

Please log in or register to comment.
Log in