Tensile strength and immersion corrosion behavior of nano-ZnO, rare earth Gd reinforced Mg nanocomposites developed by novel stir ultrasonication process

This paper presents the tensile and immersion corrosion properties of Mg-Zn-0.2Gd-xZnO (x = 1, 1.5, 2 and 2.5 wt.%) alloy and nanocomposites developed by stir ultrasonication coupled with squeeze casting. The immersion corrosion tests were performed under the simulated body fluid (SBF) conditions. The microscopic measurements indicate that the examined alloys/nanocomposites exhibit a significant decrease in grain size when both alloying elements Gadolinium (Gd) and Zinc Oxide (ZnO) nanoparticles are added. The examination of the phase by XRD indicates the presence of α-Mg and Mg2Zn, Mg7Zn3 secondary phases, which act as barriers against corrosion. The study confirmed that the incorporation of nanoparticles ZnO content ranging from 1 to 2.5 wt. % leads to a notable enhancement in yield strength (140 to 230 MPa). From the immersion corrosion test, the nanocomposites with the inclusion of 2 wt. % ZnO ceramic nanoparticles resulted in the highest level of corrosion resistance with a corrosion rate of 0.049 mm per year. This nanocomposite also shows better wettability with improved hydrophilicity. The developed Mg based advanced nanocomposites have the potential to be used in load bearing implant applications as it exhibited high corrosion resistance characteristics.