Biodegradation of Mg-14Li alloy in simulated body fluid: A proof-of-concept study
High corrosion kinetics and localised corrosion progress are the primary concerns arising from the clinical implementation of magnesium (Mg) based implantable devices. In this study, a binary Mg-lithium (Li) alloy consisting a record high Li content of 14% (in weight) was employed as model material...
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KeAi Communications Co., Ltd.
2018-03-01
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| Series: | Bioactive Materials |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2452199X17300804 |
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| author | Xiao-Bo Chen Chuanqiang Li Daokui Xu |
| author_facet | Xiao-Bo Chen Chuanqiang Li Daokui Xu |
| author_sort | Xiao-Bo Chen |
| collection | DOAJ |
| description | High corrosion kinetics and localised corrosion progress are the primary concerns arising from the clinical implementation of magnesium (Mg) based implantable devices. In this study, a binary Mg-lithium (Li) alloy consisting a record high Li content of 14% (in weight) was employed as model material aiming to yield homogenous and slow corrosion behaviour in a simulated body fluid, i.e. minimum essential medium (MEM), in comparison to that of generic Mg alloy AZ31 and biocompatible Mg-0.5Zn-0.5Ca counterparts. Scanning electron microscopy examination reveals single-phase microstructural characteristics of Mg-14Li (β-Li), whilst the presence of insoluble phases, cathodic to α-Mg matrix, in AZ31 and Mg-0.5Zn-0.5Ca. Though slight differences exist in the corrosion kinetics of all the specimens over a short-term time scale (no longer than 60 min), as indicated by potentiodynamic polarisation and electrochemical impedance spectroscopy, profound variations are apparent in terms of immersion tests, i.e. mass loss and hydrogen evolution measurements (up to 7 days). Cross-sectional micrographs unveil severe pitting corrosion in AZ31 and Mg-0.5Zn-0.5Ca, but not the case for Mg-14Li. X-ray diffraction patterns and X-ray photoelectron spectroscopy confirm that a compact film (25 μm in thickness) consisting of lithium carbonate (Li2CO3) and calcium hydroxide was generated on the surface of Mg-14Li in MEM, which contributes greatly to its low corrosion rate. It is proposed therefore that the single-phase structure and formation of protective and defect-free Li2CO3 film give rise to the controlled and homogenous corrosion behaviour of Mg-14Li in MEM, providing new insights for the exploration of biodegradable Mg materials. |
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| format | Article |
| id | doaj.art-3eba5f02860b465f9c03f16197b4df6f |
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| language | English |
| last_indexed | 2024-04-24T08:14:47Z |
| publishDate | 2018-03-01 |
| publisher | KeAi Communications Co., Ltd. |
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| series | Bioactive Materials |
| spelling | doaj.art-3eba5f02860b465f9c03f16197b4df6f2024-04-17T04:17:23ZengKeAi Communications Co., Ltd.Bioactive Materials2452-199X2018-03-013111011710.1016/j.bioactmat.2017.08.002Biodegradation of Mg-14Li alloy in simulated body fluid: A proof-of-concept studyXiao-Bo Chen0Chuanqiang Li1Daokui Xu2School of Engineering, College of Science, Engineering and Health, RMIT University, Carlton, VIC 3053, AustraliaDepartment of Materials Science and Engineering, Monash University, Clayton, 3800, VIC, AustraliaKey Laboratory of Nuclear Materials and Safety Assessment, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, ChinaHigh corrosion kinetics and localised corrosion progress are the primary concerns arising from the clinical implementation of magnesium (Mg) based implantable devices. In this study, a binary Mg-lithium (Li) alloy consisting a record high Li content of 14% (in weight) was employed as model material aiming to yield homogenous and slow corrosion behaviour in a simulated body fluid, i.e. minimum essential medium (MEM), in comparison to that of generic Mg alloy AZ31 and biocompatible Mg-0.5Zn-0.5Ca counterparts. Scanning electron microscopy examination reveals single-phase microstructural characteristics of Mg-14Li (β-Li), whilst the presence of insoluble phases, cathodic to α-Mg matrix, in AZ31 and Mg-0.5Zn-0.5Ca. Though slight differences exist in the corrosion kinetics of all the specimens over a short-term time scale (no longer than 60 min), as indicated by potentiodynamic polarisation and electrochemical impedance spectroscopy, profound variations are apparent in terms of immersion tests, i.e. mass loss and hydrogen evolution measurements (up to 7 days). Cross-sectional micrographs unveil severe pitting corrosion in AZ31 and Mg-0.5Zn-0.5Ca, but not the case for Mg-14Li. X-ray diffraction patterns and X-ray photoelectron spectroscopy confirm that a compact film (25 μm in thickness) consisting of lithium carbonate (Li2CO3) and calcium hydroxide was generated on the surface of Mg-14Li in MEM, which contributes greatly to its low corrosion rate. It is proposed therefore that the single-phase structure and formation of protective and defect-free Li2CO3 film give rise to the controlled and homogenous corrosion behaviour of Mg-14Li in MEM, providing new insights for the exploration of biodegradable Mg materials.http://www.sciencedirect.com/science/article/pii/S2452199X17300804Biodegradable materialsMagnesium-lithium alloysMEMSEMPotentiodynamic polarisation |
| spellingShingle | Xiao-Bo Chen Chuanqiang Li Daokui Xu Biodegradation of Mg-14Li alloy in simulated body fluid: A proof-of-concept study Bioactive Materials Biodegradable materials Magnesium-lithium alloys MEM SEM Potentiodynamic polarisation |
| title | Biodegradation of Mg-14Li alloy in simulated body fluid: A proof-of-concept study |
| title_full | Biodegradation of Mg-14Li alloy in simulated body fluid: A proof-of-concept study |
| title_fullStr | Biodegradation of Mg-14Li alloy in simulated body fluid: A proof-of-concept study |
| title_full_unstemmed | Biodegradation of Mg-14Li alloy in simulated body fluid: A proof-of-concept study |
| title_short | Biodegradation of Mg-14Li alloy in simulated body fluid: A proof-of-concept study |
| title_sort | biodegradation of mg 14li alloy in simulated body fluid a proof of concept study |
| topic | Biodegradable materials Magnesium-lithium alloys MEM SEM Potentiodynamic polarisation |
| url | http://www.sciencedirect.com/science/article/pii/S2452199X17300804 |
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