Biocorrosion studies of a novel Mg70Al18Zn6Ca4Y2 low entropy multicomponent alloy in different simulated body fluids

Abstract

In the present investigation, biocorrosion behaviour of novel Mg-based multicomponent low-entropy alloy (Mg70Al18Zn6Ca4Y2 LEA), fabricated using disintegrated melt deposition technique has been evaluated. The electrochemical behaviour of this Mg LEA alloy at different simulated body fluid solutions, such as [artificial blood plasma (ABP), pH 7.4], [phosphate buffer saline (PBS), pH 7.4], [Hank’s balanced salt solution (HBSS), pH 7.4] and artificial saliva solution (ASS, pH 6.2) has been studied using Potentio-dynamic polarization test followed by qualitative analysis attained from electrochemical impedance spectroscopy (EIS). Further, the surfaces of the corroded samples were examined using scanning electron microscopy and its chemical composition were analysed using energy-dispersive X-ray spectroscopy. The results show significant passive behaviour and improved corrosion resistance for sample in ASS solution compared to the ABP, PBS and HBSS. The rank of the Mg LEA alloy based on the corrosion resistance is in the following order: ABP<HBSS<PBS<ASS. Pitting corrosion was observed in ABP, PBS and HBSS solution system. Further, EIS analysis was conducted to confirm the electrochemical behaviour of Mg-LEA alloy. Various electrochemical parameters obtained from equivalent circuit provide insights on corrosion mechanisms.