Corrosion resistance of Mg–5Al–xSr alloys

Nam, Nguyễn Đăng; Kim, W.C.; Kim, Jae Gyoon; Shin, Kwang Seon; Jung, Heechul

doi:10.1016/j.jallcom.2011.01.187

Cited by 38 publications

(18 citation statements)

References 76 publications

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“…The addition of excessive Sr to Mg alloys led to rough grain boundaries which accelerate the degradation of Mg alloys. Although studies [9][10][11]13,14,16,17] found that Sr has significant influence on the degradation, Li et al [11] demonstrated that Mg alloys with an addition of 2% Sr exhibited relatively lower degradation rate compared with other Mg-Zr-Sr alloys, which is in good agreement with the results reported in Gu et al's study. [10] In order to systematically investigate the effects of Sr on the degradation behavior of Mg alloys, as-cast Mg5ZrxSr (x ¼ 0, 2, 5%) and their T4-treated alloys (solution heat treatment) were prepared in this study.…”

Section: Introductionsupporting

confidence: 69%

“…In fact, Sr-containing phases may exhibit complicated influence on the corrosion of Mg alloys, particularly for ternary alloys with multiple element additions such as Mg5AlxSr alloys. [16] Four phases were found in this series of alloys including AlSr, Al 4 Sr, Mg 17 Sr 2 , and Mg 17 Al 12 . The increment of Sr-containing phases resulted in a decrease in the amount of Mg 17 Al 12 in the Mg alloy, leading to a reduction in bio-corrosion rate of the Mg alloys in simulated body fluid (SBF).…”

Section: Introductionmentioning

confidence: 73%

“…[1][2][3] Mg and its alloys are lightweight but their mechanical properties are similar to those of natural bone; in particular, their Young's moduli (41-45 GPa) are closer to that of human bone (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) GPa) than those of titanium (110-117 GPa), Cr-based alloys (%230 GPa) and stainless steel (190)(191)(192)(193)(194)(195)(196)(197)(198)(199)(200)(201)(202)(203)(204)(205), which minimizes or even eliminates stress shielding. [4] After implantation, the released Mg ions may stimulate the growth of bone tissue.…”

Section: Introductionmentioning

confidence: 99%

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Effects of Mg₁₇Sr₂ Phase on the Bio‐Corrosion Behavior of Mg–Zr–Sr Alloys

Ding

Wen

2015

Adv Eng Mater

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The effect of the second phase Mg 17 Sr 2 on the biocorrosion behavior of Mg5ZrxSr (x ¼ 0, 2, 5 wt%) alloys before and after solution treatment was investigated. Electrochemical impedance spectroscopy, cathodic polarization and hydrogen evolution were used to evaluate the biocorrosion of Mg5ZrxSr. We found that Mg 17 Sr 2 precipitated on boundary zones and enhanced the galvanic effect, leading to a severer corrosion of the Mg matrix adjacent to Mg 17 Sr 2 . The corrosion subsequently spread gradually from the regions adjacent to the Mg 17 Sr 2 to the central Mg matrix. However, a high volume fraction of Mg 17 Sr 2 could also form a continuous network, isolate the Mg matrix and act as a barrier of corrosion.

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Section: Introductionsupporting

confidence: 69%

Section: Introductionmentioning

confidence: 73%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effects of Mg₁₇Sr₂ Phase on the Bio‐Corrosion Behavior of Mg–Zr–Sr Alloys

Ding

Wen

2015

Adv Eng Mater

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“…In addition, the XRD patterns (Fig. 56 Nam et al 58 also found that the addition of Sr to a base material of Mg5Al had a significant effect on the grain boundaries, corrosion resistance, and surface film, and contributed to the formation of a hydroxide protective film on the Mg alloy. These findings imply that Mg(OH) 2 on the surface of Mg-Zr-Sr alloys dissolves gradually, and it only provides partial protection for Mg-Zr-Sr alloys in SBF.…”

Section: Effects Of the Surface Layer On The Degradation Behavior Of mentioning

confidence: 95%

Effects of zirconium and strontium on the biocorrosion of Mg–Zr–Sr alloys for biodegradable implant applications

Ding

Lin³

et al. 2015

J. Mater. Chem. B

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The successful applications of magnesium (Mg) alloys as biodegradable orthopedic implants are mainly restricted due to their rapid degradation rate in the physiological environment, leading to a loss of mechanical integrity. This study systematically investigated the degradation behaviors of novel Mg-Zr-Sr alloys using electrochemical techniques, hydrogen evolution, and weight loss in simulated body fluid (SBF). The microstructure and degradation behaviors of the alloys were characterized using optical microscopy, XRD, SEM, and EDX. The results indicate that Zr and Sr concentrations in Mg alloys strongly affected the degradation rate of the alloys in SBF. A high concentration of 5 wt% Zr led to acceleration of anodic dissolution, which significantly decreased the biocorrosion resistance of the alloys and their biocompatibility. A high volume fraction of Mg 17 Sr 2 phases due to the addition of excessive Sr (over 5 wt%) resulted in enhanced galvanic effects between the Mg matrix and Mg 17 Sr 2 phases, which reduced the biocorrosion resistance. The average Sr release rate is approximately 0.15 mg L À1 day À1 , which is much lower than the body burden and proves its good biocompatibility. A new biocorrosion model has been established to illustrate the degradation of alloys and the formation of degradation products on the surface of the alloys. It can be concluded that the optimal concentration of Zr and Sr is less than 2 wt% for as-cast Mg-Zr-Sr alloys used as biodegradable orthopedic implants. Fig. 16 Schematic model for biocorrosion propagation of Mg-Zr-Sr alloys in SBF: (a) dissolution of the Mg matrix due to galvanic effects; (b) the partially protective film of Mg(OH) 2 ; (c) dissolution of Mg(OH) 2 due to deterioration by Cl À ; (d) formation of HA; (e) corrosive residues escaping from the Mg matrix.

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“…For example, the AZ91D alloy tends to lose its creep strength above 150 • C [4]. So, it loses commercial value in application when it is used as structural parts at 150 • C. Therefore, one of the most important investigations on magnesium alloys is to develop an alloy which can be economically applied at the temperatures up to 200 • C [5,6].…”

Section: Introductionmentioning

confidence: 99%