In Vitro Biodegradation and Mechanical Properties of Mg-Zn Alloy and Mg-Zn-Hydroxyapatite Composite Produced by Mechanical Alloying for Potential Application in Bone Repair

Abstract

A biodegradable Mg-6.5 wt pct Zn (Mg-Zn) alloy and Mg-6.5 wt pct Zn reinforced with 10 wt pct hydroxyapatite (HA) composite were prepared by mechanical milling. In vitro biodegradation activity as a function of immersion time was performed in Hank’s balanced salt solution (HBSS). The dissolution of Mg ions (Mg2+) decreased from 75.74 µg/ml of pure Mg to 59.24 µg/ml and 46.88 µg/ml corresponding to the Mg-Zn alloy and Mg-Zn/HA composite, respectively. This finding indicates the progressive effect of HA followed by the Zn addition in decelerating the degradation rate of Mg. More positive corrosion potential of Mg-6.5 wt pct Zn alloy (− 1.5015 V) and Mg-Zn/10 wt pct HA composite (− 1.4647 V) than that of pure Mg (− 1.6972 V) suggested that the Mg-Zn/10 wt pct HA composite exhibited the highest corrosion resistance in the bioenvironment. The compressive strength values after 7 days of immersion in HBSS of the Mg-Zn alloy and Mg-Zn/HA composite are 230.64 and 278.46 MPa, respectively, and these are considerably higher compared to the compressive strength of the cortical bone (100 to 230 MPa).