Abstract
En el presente trabajo se ha investigado el efecto de los elementos aleantes Zn (0,95% en masa) y Ca (0,15% en masa) en el mecanismo de degradación del Mg. Las superficies del Mg puro y de la aleación Mg-Zn-Ca han sido caracterizadas durante su exposición a la solución fisiológica de Hanks (a 37 °C) hasta siete días, utilizando las técnicas SEM-EDS y XPS. La capa formada en la superficie de la aleación contiene Ca10(PO4)6(OH)2, que puede mejorar la compatibilidad ósea. Las partículas intermetálicas compuestas de la fase Mg2Ca, así como la presencia de Zn, han promovido la formación de una capa protectora más uniforme. Las pruebas de EIS y ruido electroquímico (EN) han indicado que la resistencia a la polarización (Rp) del Mg puro es un orden de magnitud menor y la resistencia al ruido de la corriente (Rn) ≈ 5 veces menor, que los de la aleación de Mg-Zn-Ca. Los valores del índice de picadura (PI) de cada material fueron inferiores a 0,6; lo que sugiere que el ataque de corrosión no está altamente localizado. Al final de las pruebas de inmersión, la concentración de iones de Mg liberados durante la degradación ha sido ≈ 4,5 veces mayor para Mg puro (1,63 ± 0,02 mg·cm−2) que para Mg-Zn-Ca (0,35 ± 0,03 mg·cm−2). En consecuencia, la densidad de corriente de corrosión (jcorr) calculada para el Mg puro fue dos veces mayor (1,33 μA·cm−2) que la de la aleación de Mg ZX10 (0,59 μA·cm−2).
Highlights
The effect of Zn (0.95% wt.) and Ca (0.15% wt.) alloying elements on the general degradation mechanism of Mg was investigated in this work
Mg-based biomaterials have attracted an increasing interest for their application as resorbable temporary implants, owing to the combination of high strength and ductility that they exhibit, the value of Youngs modulus of Mg (40 GPa, close to cancellous bones) and their degradability in physiological medium (Zhang et al, 2011; Hänzi et al, 2012; Bohlen et al, 2015). During these materials degradation process Mg-ions are released, which are involved in various chemical reactions in the human body, as well as in the bone healing (Yamasaki et al, 2002; Zreiqat et al, 2002; Yamasaki et al, 2003; Revell et al, 2004), that may be enhanced when Mg is alloyed with Zn and Ca elements (Tapiero and Tew, 2003; Stefanidou et al, 2006)
The electrolyte employed in this study was the Hanks’ physiological solution, which was prepared with the following reagents: NaCl, NaHCO3, KCl, K2HPO4·3H2O, KH2PO4, MgSO4·7H2O, CaCl2, and ultrapure deionized water (18.2 MΩ·cm) as described elsewhere (Kuwahara et al, 2001)
Summary
The effect of Zn (0.95% wt.) and Ca (0.15% wt.) alloying elements on the general degradation mechanism of Mg was investigated in this work. Mg-based biomaterials have attracted an increasing interest for their application as resorbable temporary implants, owing to the combination of high strength and ductility that they exhibit, the value of Youngs modulus of Mg (40 GPa, close to cancellous bones) and their degradability in physiological medium (Zhang et al, 2011; Hänzi et al, 2012; Bohlen et al, 2015) During these materials degradation process Mg-ions are released, which are involved in various chemical reactions in the human body, as well as in the bone healing (Yamasaki et al, 2002; Zreiqat et al, 2002; Yamasaki et al, 2003; Revell et al, 2004), that may be enhanced when Mg is alloyed with Zn and Ca elements (Tapiero and Tew, 2003; Stefanidou et al, 2006). The electrochemical degradation behaviour of ZX10 in Hanks’ solution has not been reported yet
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
