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High Purity Magnesium Coatings and Single Crystals for Biomedical Applications

Salunke, Pravahan Shamkant
http://rave.ohiolink.edu/etdc/view?acc_num=ucin150488269765649

Abstract Details

2017, PhD, University of Cincinnati, Engineering and Applied Science: Materials Science.
Magnesium is a promising candidate for biodegradable applications. However, the performance of magnesium based implants is hampered by fast corrosion of the implants as well as hydrogen evolution and excess alkalinity in the vicinity of the implant. Unalloyed magnesium with high purity shows higher resistance to corrosion in simulated body fluids than commercial magnesium and magnesium alloys. The experiments for preparing high purity magnesium coatings using thermal PVD system have been described. The coatings were evaluated using D.C. polarization tests, in vitro and in vitro tests. These high purity coatings lower the corrosion potential and corrosion current of bulk magnesium in simulated body fluid environment and increased cell activity was also observed near the coated surfaces of conventional implant materials. The different issues arising out of using bulk polycrystalline magnesium in the human body can be addressed by using single crystals. This document describes successful efforts to design, build, establish, test and utilize a single crystal grower using the Bridgman approach for directional solidification and study the obtained single crystals. The obtained single crystals were verified for their quality using metallography with optical microscopy, powder x-ray diffraction, laue x-ray diffraction, x-ray pole figures and micro-computed tomography The mechanical properties of single crystal magnesium were studied in comparison with polycrystalline magnesium through tensile, compressive, 3-point bend and izod tests. These tests indicated that single crystal magnesium can have high ductility. Further, the microstructure response to compressive load in two orthogonal directions was also studied by electron backscattered diffraction and x-ray pole figure analysis. It revealed incipient recrystallization at strains as low as 8 % strain during compression. The observed variation in microstructural response with the orientation allows for wide range for tailoring mechanical properties of magnesium single crystals Electrochemical D.C polarization tests were carried out on these single crystals and they showed an improvement in corrosion potential. Additionally, the response of magnesium single crystals was observed In vivo in sub cutaneous implantation in mice, ACL ring in goat and Ulna fracture model in rabbits. The in vivo tests showed favorable cell response and healthy tissue growth around the implant. Overall, the high purity magnesium coatings and magnesium single crystals reveal unique and promising properties, which can be harnessed for biomedical applications.
Vesselin Shanov, Ph.D. (Committee Chair)
Rodney Roseman, Ph.D. (Committee Member)
Mark Schulz, Ph.D. (Committee Member)
Vijay Vasudevan, Ph.D. (Committee Member)
120 p.
Materials Science
magnesium single crystal; bridgman method; physical vapor deposition; biomedical implants; ductility; etching

Recommended Citations

Citations

  • Salunke, P. S. (2017). High Purity Magnesium Coatings and Single Crystals for Biomedical Applications [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin150488269765649

    APA Style (7th edition)

  • Salunke, Pravahan. High Purity Magnesium Coatings and Single Crystals for Biomedical Applications. 2017. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin150488269765649.

    MLA Style (8th edition)

  • Salunke, Pravahan. "High Purity Magnesium Coatings and Single Crystals for Biomedical Applications." Doctoral dissertation, University of Cincinnati, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin150488269765649

    Chicago Manual of Style (17th edition)

ucin150488269765649
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© 2017, all rights reserved.
This open access ETD is published by University of Cincinnati and OhioLINK.