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Microstructure analysis and corrosion behavior of biodegradable Mg-Ca implant alloys

The calcium content in binary Mg-xCa alloys affects the microstructure, corrosion and solidification behavior of the alloys. In this study, binary Mg-xCa alloys with various Ca contents from 0.5 to 10wt.% were produced by casting process. Microstructural evolutions were characterized by optical micr...

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Main Authors:	Rad, H. R. B., Idris, Mohd. Hasbullah, Abdul Kadir, Mohammed Rafiq, Farahany, S.
Format:	Article
Published:	Elsevier Ltd. 2012
Subjects:	TJ Mechanical engineering and machinery
Online Access:	http://eprints.utm.my/id/eprint/29299/ http://dx.doi.org/10.1016/j.matdes.2011.06.057
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spelling	my.utm.292992019-03-25T08:06:49Z http://eprints.utm.my/id/eprint/29299/ Microstructure analysis and corrosion behavior of biodegradable Mg-Ca implant alloys Rad, H. R. B. Idris, Mohd. Hasbullah Abdul Kadir, Mohammed Rafiq Farahany, S. TJ Mechanical engineering and machinery The calcium content in binary Mg-xCa alloys affects the microstructure, corrosion and solidification behavior of the alloys. In this study, binary Mg-xCa alloys with various Ca contents from 0.5 to 10wt.% were produced by casting process. Microstructural evolutions were characterized by optical microscopy, X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy. Solidification behavior was assessed via two thermocouple thermal analysis method. The corrosion resistance was examined in vitro by potentiodynamic polarization and immersion test in Kokubo solution at room temperature. The results revealed that the grain size and dendrite cell size decreased significantly with rising Ca content, whilst the content of Mg2Ca intermetallic phase in grain boundaries increased with increasing Ca content. Potentiodynamic polarization tests in simulated body fluid (SBF) indicated that corrosion rates of Mg-xCa alloy increased significantly with rising Ca content. Immersion tests in Kokubo solution also showed that dissolution rate of Mg-xCa alloy increased with increasing Mg2Ca content which lead to an increase in pH value. It was observed that corrosion damage in specimens with lower Ca content was more moderate and uniform than higher Ca content. Thermal analysis results showed that the fraction of primary a-Mg at dendrite coherency point (faDCP) decreased with increasing Ca content but the liquid fraction fL increased causing the rise in eutectic Mg2Ca intermetallic phase in grain boundaries, thus increasing the corrosion rate. Our analyses showed that Mg-0.5Ca alloy is a promising alloy to be used as biodegradable implants. Elsevier Ltd. 2012-01 Article PeerReviewed Rad, H. R. B. and Idris, Mohd. Hasbullah and Abdul Kadir, Mohammed Rafiq and Farahany, S. (2012) Microstructure analysis and corrosion behavior of biodegradable Mg-Ca implant alloys. Materials and Design, 33 (1). pp. 88-97. ISSN 0264-1275 http://dx.doi.org/10.1016/j.matdes.2011.06.057 DOI:10.1016/j.matdes.2011.06.057
institution	Universiti Teknologi Malaysia
building	UTM Library
collection	Institutional Repository
continent	Asia
country	Malaysia
content_provider	Universiti Teknologi Malaysia
content_source	UTM Institutional Repository
url_provider	http://eprints.utm.my/
topic	TJ Mechanical engineering and machinery
spellingShingle	TJ Mechanical engineering and machinery Rad, H. R. B. Idris, Mohd. Hasbullah Abdul Kadir, Mohammed Rafiq Farahany, S. Microstructure analysis and corrosion behavior of biodegradable Mg-Ca implant alloys
description	The calcium content in binary Mg-xCa alloys affects the microstructure, corrosion and solidification behavior of the alloys. In this study, binary Mg-xCa alloys with various Ca contents from 0.5 to 10wt.% were produced by casting process. Microstructural evolutions were characterized by optical microscopy, X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy. Solidification behavior was assessed via two thermocouple thermal analysis method. The corrosion resistance was examined in vitro by potentiodynamic polarization and immersion test in Kokubo solution at room temperature. The results revealed that the grain size and dendrite cell size decreased significantly with rising Ca content, whilst the content of Mg2Ca intermetallic phase in grain boundaries increased with increasing Ca content. Potentiodynamic polarization tests in simulated body fluid (SBF) indicated that corrosion rates of Mg-xCa alloy increased significantly with rising Ca content. Immersion tests in Kokubo solution also showed that dissolution rate of Mg-xCa alloy increased with increasing Mg2Ca content which lead to an increase in pH value. It was observed that corrosion damage in specimens with lower Ca content was more moderate and uniform than higher Ca content. Thermal analysis results showed that the fraction of primary a-Mg at dendrite coherency point (faDCP) decreased with increasing Ca content but the liquid fraction fL increased causing the rise in eutectic Mg2Ca intermetallic phase in grain boundaries, thus increasing the corrosion rate. Our analyses showed that Mg-0.5Ca alloy is a promising alloy to be used as biodegradable implants.
format	Article
author	Rad, H. R. B. Idris, Mohd. Hasbullah Abdul Kadir, Mohammed Rafiq Farahany, S.
author_facet	Rad, H. R. B. Idris, Mohd. Hasbullah Abdul Kadir, Mohammed Rafiq Farahany, S.
author_sort	Rad, H. R. B.
title	Microstructure analysis and corrosion behavior of biodegradable Mg-Ca implant alloys
title_short	Microstructure analysis and corrosion behavior of biodegradable Mg-Ca implant alloys
title_full	Microstructure analysis and corrosion behavior of biodegradable Mg-Ca implant alloys
title_fullStr	Microstructure analysis and corrosion behavior of biodegradable Mg-Ca implant alloys
title_full_unstemmed	Microstructure analysis and corrosion behavior of biodegradable Mg-Ca implant alloys
title_sort	microstructure analysis and corrosion behavior of biodegradable mg-ca implant alloys
publisher	Elsevier Ltd.
publishDate	2012
url	http://eprints.utm.my/id/eprint/29299/ http://dx.doi.org/10.1016/j.matdes.2011.06.057
_version_	1643648270686224384
score	13.211869

Microstructure analysis and corrosion behavior of biodegradable Mg-Ca implant alloys

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