Experimental study of corrosion rate supplied with an ab-initio elucidation of corrosion mechanism of biodegradable implants based on Ag-doped Zn alloys

Abstract

Biodegradable Zn-based alloys hold great promise for biomedical implant applications, with the Zn-Ag-Cu alloy being particularly intriguing due to the additional antibacterial and antimicrobial properties. Here, to enhance the mechanical properties of the Zn-4%Ag-1Cu alloy, equal-channel angular pressing (ECAP) is employed, which is found to induce strain and lattice distortions leading to a grain size decrease and corrosion rate enhancement. To understand key factors of the surface degradation behavior on atomistic level, the density-functional theory (DFT)-based method was employed. Specifically, the study investigated the corrosion mechanism of the Zn-Ag-Cu alloy’s surface, providing valuable insights into the degradation behavior of Zn-Ag-Cu alloys. Both experiment and simulation reveal a higher corrosion resistance for the Zn-Ag-Cu alloys with higher Ag content that can be due to a homogeneous distribution of alloying induced stresses. The intermetallic component is shown to have the lowest degradation ability, which is important in terms of its contribution to dispersion hardening of the alloy. This work presents a comprehensive study shedding light on the corrosion rates of Zn-Ag-Cu alloys, providing essential knowledge concerning the mechanisms of the corrosion of Zn-Ag-Cu alloys, which is useful for the development of biodegradable implants with improved structural and degradation characteristics.