Analysis of the degradation process and electrochemical behaviour of AZ31 magnesium alloy in artificial saliva




Artificial saliva, AZ31, Degradation rate, EIS, HF treatment, Polarisation curves, Polarisation resistance


This work applies a combination of immersion tests, surface analysis techniques, and electrochem­ical methods to characterise the degradation process of AZ31 magnesium alloy when it is exposed to artificial saliva for 28 days. The surface of the alloy was evaluated in two conditions: bare and with an MgF2 layer. This conversion layer was formed by soaking AZ31 in hydrofluoric acid (HF). SEM images revealed differences in the corrosion attack of the two surface conditions, specifically in the vicinity of Al-Mn intermetallic particles. Both EDS and XPS analysis indicated that the composition of the corrosion layers formed during immersion tests corresponds mainly to Mg(OH)2 and Ca10(PO4)6(OH)2 for the bare sample, whereas for the treated surface the principal corrosion product was MgCO3. The polarisation resistance (Rp) value estimated from EIS experi­ments was two orders of magnitude higher for the HF-treated samples than that of the bare samples. In addi­tion, the corrosion rate (CR) calculated from the potentiodynamic polarisation (PDP) curves was lower for the HF-treated surface than for that of the bare AZ31 surface. All results indicate that the HF-treatment on AZ31 magnesium alloy surface improves significantly its corrosion resistance in artificial saliva.


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Asgari, M., Hang, R., Wang, C., Yu, Z., Li, Z., Xiao, Y. (2018). Biodegradable Metallic Wires in Dental and Orthopedic Applications: A Review. Metals 8 (4), 212.

ASTM G1-03 (2017). Standard Practice for Preparing, Clean­ing, and Evaluating Corrosion Test Specimens. ASTM International, West Conshohocken, PA, USA.

ASTM G102-89 (2015). Standard Practice for Calculation of Cor­rosion Rates and Related Information from Electrochemical Measurements. ASTM International, West Conshohocken, PA, USA.

Carboneras, M., Iglesias, C., Perez-Maceda, B., del Valle, J., García-Alonso, M., Alobera, M., Clemente, C., Rubio, J., Escudero, M., Lozano, R. (2011). Corrosion behaviour and in vitro/in vivo biocompatibility of surface-modified AZ31 alloy. Rev. Metal. 47 (3), 212-223.

Chaturvedi, T. (2009). An overview of the corrosion aspect of dental implants (Titanium and its alloys). Indian J. Dent. Res. 20 (1), 91-98. PMid:19336868

Curioni, M., Scenini, F., Monetta, T., Bellucci, F. (2015). Cor­relation between electrochemical impedance measure­ments and corrosion rate of magnesium investigated by real-time hydrogen measurement and optical imaging. Electrochim. Acta 166, 372-384.

Da Conceicao, T., Scharnagl, N., Blawert, C., Dietzel, W., Kainer, K. (2010). Surface modification of magnesium alloy AZ31 by hydrofluoric acid treatment and its effect on the corrosion behaviour. Thin Solid Films 518 (18), 5209-5218.

Delgado, M.C., García-Galvan, F.R., Barranco, V., Batlle, S.F. (2017). A Measuring Approach to Assess the Corrosion Rate of Magnesium Alloys Using Electrochemical Impedance Spectroscopy. In Magnesium Alloys. Aliofkhazraei M. (Ed), IntechOpen, 130-159.

Echavarria, A., Arroyave, C. (2003). Electrochemical assess­ment of some titanium and stainless steel impact dental alloys. Rev. Metal. 39 (Nº Extra), 174-181.

Eisenburger, M., Addy, M., Hughes, J., Shellis, R. (2001). Effect of time on the remineralisation of enamel by synthetic saliva after citric acid erosion. Caries Res. 35 (3), 211-215. PMid:11385202

ISO 16428 (2005). Implants for surgery - Test solutions and environmental conditions for static and dynamic corrosion tests on implantable materials and medical devices. Inter­national Organization for Standarization, Switzerland.

Mena-Morcillo, E., Veleva, L.P., Wipf, D.O. (2018). Multi-scale monitoring the first stages of electrochemical behav­ior of AZ31B magnesium alloy in simulated body fluid. J. Electrochem. Soc. 165 (11), C749-C755.

Moulder, J., Stickle, W., Sobol, P., Bomben, K. (1992). Hand­book of X-ray photoelectron spectroscopy. Perkin-Elmer Corporation, Minnesota, USA.

Murray, J., Moran, P., Gileadi, E. (1988). Utilization of the spe­cific pseudocapacitance for determination of the area of corroding steel surfaces. Corrosion 44 (8), 533-538.

Poinern, G.E.J., Brundavanam, S., Fawcett, D. (2012). Bio­medical magnesium alloys: a review of material properties, surface modifications and potential as a biodegradable orthopaedic implant. Am. J. Biomed. Eng. 2 (6), 218-240.

Renita, D., Rajendran, S., Chattree, A. (2016). Influence of Arti­ficial Saliva on the Corrosion Behavior of Dental Alloys: A review. Indian J. Adv. Chem. Sci. 4 (4), 478-483.

Riaz, U., Shabib, I., Haider, W. (2018). The current trends of Mg alloys in biomedical applications-A review. J. Biomed. Mater. Res., Part B 107 (6), 1-27. PMid:30536973

Wen, C., Guan, S., Peng, L., Ren, C., Wang, X., Hu, Z. (2009). Characterization and degradation behavior of AZ31 alloy surface modified by bone-like hydroxyapatite for implant applications. Appl. Surf. Sci. 255 (13-14), 6433-6438.



How to Cite

Mena-Morcillo, E., Veleva, L., & Espadas-Herrera, L. J. (2020). Analysis of the degradation process and electrochemical behaviour of AZ31 magnesium alloy in artificial saliva. Revista De Metalurgia, 56(2), e166.