Surface Analysis of Magnesium AZ31 Samples Immersed in Various Aqueous Solutions
Abstract
Rapid degradation in body fluids is known to be the main shortcoming of the AZ31 magnesium alloy that is aimed to be controlled in this study by chemical conversion of its surface in various phosphate and chloride solutions. Deposited layers on the surface of bare alloy plates were subjected to compositional and morphological analyses to assess their performance as barriers to degradation. Also changes in the mass of the samples and pH of the solutions were monitored during 21 day immersion periods. Formations of prismatic, platelike, needlelike crystals of various compositions including calcium phosphates, magnesium phosphates, magnesium chlorides were observed by scanning electron microscopy and their atomic compositions were determined by EDX and quantitative XRD analyses. The results indicate that a layer of ceramic of various thicknesses can stably form on the base alloy by simple adsorption of the particles suspended in the solution or by nucleation and growth of the products of reactions between dissolved ions and the metal ions released from the surface. These deposition layers that are solely induced by the electrochemical potential of the species in the solution offer facile surface modification methods and novel phases to control the degradation of magnesium alloys in aggressive environments such as body fluids or marine environments.
Keywords
AZ31 magnesium alloy, Coating, Magnesium phosphates, Calcium phosphates, Phase analysis.
Project Number
Tübitak 119N759
Thanks
The authors appreciate the financial support from Scientific and Technological Research Council of Turkiye (TUBITAK) (Project No: 2020-119N759). İzmir Institute of Technology Materials Research Center staff is acknowledged for their assistance in characterizations. Doebelin.org and Crystallography Open Database (Crystallography.net) are acknowledged for sharing their XRD analysis software and database.
References
- [1] X. Li, X. Liu, S. Wu, K. W. K. Yeung, Y. Zheng, and P. K. Chu, “Design of magnesium alloys with controllable degradation for biomedical implants: From bulk to surface,” Acta Biomater., vol. 45, pp. 2–30, 2016.
- [2] Z. Ran, W. Dai, K. Xie, and Y. Hao, “Advances of biodegradable magnesiumbased implants for orthopaedics,” Life Res., vol. 5, no. 7, pp.1-12, 2022.
- [3] T. Cain, L. G. Bland, N. Birbilis, and J. R. Scully, “A compilation of corrosion potentials for magnesium alloys,” Corrosion, vol. 70, no. 10, pp. 1043–1051, 2014.
- [4] F. Witte, V. Kaese, H. Haferkamp, E. Switzer, A. Meyer-Lindenberg, C.J. Wirth, and H. Windhagen, “In vivo corrosion of four magnesium alloys and the associated bone response,” Biomaterials, vol. 26, no. 17, pp. 3557–3563, 2005.
- [5] F. Witte, N. Hort, C. Vogt, S. Cohen, K. U. Kainer, R. Willumeit, and F. Feyerabend, “Degradable biomaterials based on magnesium corrosion,” Curr. Opin. solid state Mater. Sci., vol. 12, no. 5–6, pp. 63–72, 2008.
- [6] E. Ghali, “Magnesium and magnesium alloys,” Uhlig’s Corros. Handb., pp. 809–836, 2011.
- [7] W. D. Müller, M. L. Nascimento, M. Zeddies, M. Córsico, L. M. Gassa, and M. A. F. L. de Mele, “Magnesium and its alloys as degradable biomaterials: corrosion studies using potentiodynamic and EIS electrochemical techniques,” Mater. Res., vol. 10, pp. 5–10, 2007.
- [8] Y. Xin, K. Huo, H. Tao, G. Tang, and P. K. Chu, “Influence of aggressive ions on the degradation behavior of biomedical magnesium alloy in physiological environment,” Acta Biomater., vol. 4, no. 6, 2008.
- [9] S. Seetharaman, D. Sankaranarayanan, and M. Gupta, “Magnesium-Based Temporary Implants: Potential, Current Status, Applications, and Challenges,” J. Funct. Biomater., vol. 14, no. 6, p. 324, 2023.
- [10] A. Carangelo, A. Acquesta, and T. Monetta, “Durability of AZ31 magnesium biodegradable alloys polydopamine aided. Part 2: ageing in Hank’s solution,” J. Magnes. Alloy., vol. 7, no. 2, pp. 218–226, 2019.