Accelerated corrosion of zinc, erbium and cerium co-doped Mg-alloys prepared by spark plasma sintering for bioresorbable implant applications

Abstract

Magnesium (Mg) alloys have become attractive as bioresorbable implants in recent times as they possess compatible mechanical properties with that of the cortical bone. Mechanical properties of Mg alloys can be tailored using suitable alloying elements. Bioresorption, the corrosion in the physiological condition, on the other hand, can be tailored using a variety of techniques such as alloying, melting and thermo-mechanical and cold working as well as and functionally graded coating. Powder metallurgy processes such as spark plasma sintering have gained interest for rapid consolidation of metals which were generally difficult to sinter due to excessive grain growth. In this study, we investigate the potential of a newly designed Mg alloy that is prepared by Spark Plasma Sintering (SPS). We selected the alloying elements zinc (Zn), erbium (Er) and cerium (Ce) depending on their solid solubility in Mg and the potential mechanical properties and expected biocompatibility. We carried out surface analysis using microscopy, microhardness and accelerated corrosion behaviour in simulated body fluid. A possible reason for strengthening and corrosion behaviour has been discussed in light of reduced porosity and grain size. Accelerated corrosion test and microhardness test revealed maximum corrosion rate (39%) and minimum hardness (93.87Hv) for the samples sintered at relatively lower temperature of 400 ᵒC suggesting tunability of both bioresorption and strength of these alloys by controlling density during sintering.