Biodegradable Iron-Based Materials—What Was Done and What More Can Be Done?

Iron, while attracting less attention than magnesium and zinc, is still one of the best candidates for biodegradable metal stents thanks its biocompatibility, great elastic moduli and high strength. Due to the low corrosion rate, and thus slow biodegradation, iron stents have still not been put into use. While these problems have still not been fully resolved, many studies have been published that propose different approaches to the issues. This brief overview report summarises the latest developments in the field of biodegradable iron-based stents and presents some techniques that can accelerate their biocorrosion rate. Basic data related to iron metabolism and its biocompatibility, the mechanism of the corrosion process, as well as a critical look at the rate of degradation of iron-based systems obtained by several different methods are included. All this illustrates as the title says, what was done within the topic of biodegradable iron-based materials and what more can be done.

Degradation and Corrosion of Biodegradable Metal Zn-xCa

Zn-based biodegradable metals (BMs) are considered as new potential in osteosynthetic implant devices. In this study Ca, which acts as an essential element in the human body, is used to improve the rate of Zn degradation and corrosion. The alloy was synthesized using the powder metallurgy method with two different processes: cold pressing followed by sintering (CP-S) and hot isostatic pressing (HIP). Microstructure properties, as well as in vitro degradation and corrosion were studied to determine the effect of adding Ca. Variations in the sample consist of Zn-0.5Ca, Zn-1Ca, Zn-1.5Ca and Zn-2Ca. The results and analysis of test data show that the addition of Ca increases the rate of corrosion and degradation of the materials. Better bonding and microstructure properties are obtained in Zn-2Ca samples which form CaZn13 phases and small porosity. As for the HIP process, a better microstructure is obtained compared to CP-S.