Enhanced mechanical properties and increased corrosion resistance of a biodegradable magnesium alloy by plasma electrolytic oxidation (PEO)

White, Leon; Koo, Youngmi; Neralla, Sudheer; Sankar, Jagannathan; Yun, Yeoheung

doi:10.1016/j.mseb.2016.02.005

Cited by 80 publications

(44 citation statements)

References 41 publications

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“…For this reason, surface tratments are needed in order to improve the surface properties and thereby extend the use of magnesium and its alloys. Various processes, such as electrodepostion [5][6][7], electroless coating [8][9][10][11][12], conversion coating [13][14][15], microarcoxidation [16,17], gas-phase deposition [18,19], surface laser modification [20], and the combination of two or more of the mentioned approaches, have been used to improve the surface performance of the alloys; among these, electroless Ni-P plating offers the possibility of generating uniform, crack-free, and well-adhered coatings, without the need of an external power source [21,22].…”

Section: Introductionmentioning

confidence: 99%

Study of the formation of alkaline electroless Ni-P coating on magnesium and AZ31B magnesium alloy

Zuleta

Correa

Castaño

et al. 2017

Surface and Coatings Technology

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In this work, alkaline electroless Ni-P coatings were directly formed on commercial purity magnesium and AZ31B magnesium alloy substrates using a process that avoided the use of Cr(VI) compounds. The study focused on two aspects of coating formation: (i) the effect of the substrate roughness on the kinetics of the electroless Ni-P deposition process on magnesium; (ii) the morphological and chemical evolution of the coating on both magnesium and the AZ31B alloy. For these purposes, gravimetric measurements, scanning electron microscopy (SEM), X-ray diffraction (XRD), Rutherford backscattering spectrometry (RBS) and open-circuit potential (OCP) measurements were employed. It is shown that a relatively rough substrate promotes the rapid formation of the Ni-P coating on the substrate surface in comparison with smoother substrates. Furthermore, the presence of fluoride ions derived from the NH 4 HF 2 reagent in the electroless Ni-P plating bath leads to formation of MgF 2 a few seconds after immersion in the bath; the MgF 2 . Subsequently, crystals of NaMgF 3 , with a cubic morphology, are developed, which later become embedded in the Ni-P matrix. The presence of fluorine species passivates the substrate during coating formation and hence restricts the decomposition of the electroless Ni-P plating bath, which can occur due to release of Mg 2+ ions. Finally, according to gravimetric measurements, SEM and XRD, the plating process is initially faster on magnesium than on the alloy.

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Section: Introductionmentioning

confidence: 99%

Study of the formation of alkaline electroless Ni-P coating on magnesium and AZ31B magnesium alloy

Zuleta

Correa

Castaño

et al. 2017

Surface and Coatings Technology

View full text Add to dashboard Cite

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“…4b). ZE41B also gradually degraded over 90 days but AZ31B degraded fast at the initial stage and leveled off for both with/without stressed samples [9,33]. There was a report that the ultimate tensile strength (UTS), yield strength (YS) and elongation (EL) of the Mg-2Zn-0.8Zr samples with immersion decreased rapidly at first and then decreased slowly [11].…”

Section: Resultsmentioning

confidence: 99%

A study of long-term static load on degradation and mechanical integrity of Mg alloys-based biodegradable metals

Koo

Jang

Yun

2017

Materials Science and Engineering: B

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Predicting degradation behavior of biodegradable metals in vivo is crucial for the clinical success of medical devices. This paper reports on the effect of long-term static stress on degradation of magnesium alloys and further changes in mechanical integrity. AZ31B (H24) and ZE41A (T5) alloys were tested to evaluate stress corrosion cracking (SCC) in a physiological solution for 30 days and 90 days (ASTM G39 testing standard). Scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDX) and micro-computed tomography (micro-CT) were used to characterize surface morphology and micro-structure of degraded alloys. The results show the different mechanisms of stress corrosion cracking for AZ31B (transgranular stress corrosion cracking, TGSCC) and ZE41A (intergranular stress corrosion cracking, IGSCC). AZ31B was more susceptible to stress corrosion cracking under a long term static load than ZE41A. In conclusion, we observed that long-term static loading accelerated crack propagation, leading to the loss of mechanical integrity.

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“…Moreover, surface properties such as pore size, porosity, permeability, and physical/chemical properties not only impact cell proliferation but also can control the direction of cell growth, which has been demonstrated in an artificial nerve guide conduit . It is also well established that the wettability of a solid surface could be altered as a function of surface roughness and structure . A considerable amount of research has been directed toward examining the relationship between surface structure and cell adhesion as achieved using electrospinning or sculpture on films, with the findings that slight changes in the surface can result in enormous differences in cell adhesion .…”

Section: Discussionmentioning

confidence: 99%

Control of weft yarn or density improves biocompatibility of PET small diameter artificial blood vessels

Guan

et al. 2017

J Biomed Mater Res

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Polyethylene glycol terephthalate (PET) fabrics with woven structures have proved to be quite effective for use on large diameter artificial blood vessels. However, their use within small-diameter artificial blood vessels has been associated with poor long-term patency, a problem resulting from slow endothelialization on PET and an over hyperplasia of smooth muscle cells. Previous research from our laboratory has revealed that ICAM-1 can be used as a marker to investigate cell adhesion, an effect which was closely associated with cell behavior on the surface of polycaprolactone (PCL) films. Moreover, we found that the coarseness or pore size of the surface exerts considerable influence on cell adhesion and proliferation on PCL films. In this study, we successfully fabricated six types of PET woven fabrics with varying gradients of tightness and porosities. Levels of ICAM-1 expression (membrane ICAM-1 & soluble ICAM-1) were then determined in these woven fabrics. Our results show that increased levels of mICAM-1 and decreased levels of sICAM-1 expression were obtained in HUVECs seeded on these six samples. These findings indicate that cell adhesion and proliferation on fabric surfaces were strongly influenced by their structural parameters, in particular the initial adhesion between the cell and fabric surface. In addition, we also found that extracellular matrix adhesion tends to prefer flat and tight surfaces, which promotes cell-cell and cell-matrix interactions, as well as the endothelialization on the surface of PET fabrics. These findings provide some novel insights with regard to the design and application of small-diameter artificial blood vessels. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 954-964, 2018.

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Enhanced mechanical properties and increased corrosion resistance of a biodegradable magnesium alloy by plasma electrolytic oxidation (PEO)

Cited by 80 publications

References 41 publications

Study of the formation of alkaline electroless Ni-P coating on magnesium and AZ31B magnesium alloy

Study of the formation of alkaline electroless Ni-P coating on magnesium and AZ31B magnesium alloy

A study of long-term static load on degradation and mechanical integrity of Mg alloys-based biodegradable metals

Control of weft yarn or density improves biocompatibility of PET small diameter artificial blood vessels

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