Effect of exposure time in a physiological environment on the corrosion rate of ultrafine-grained Zn-Fe-Mg alloy

The development of novel bioresorbable materials for medical use has been a topic of interest for the scientific community in recent years. Many research groups have focused on zinc-based materials due to their favorable biocompatibility and moderate rate of degradation in the body. When selecting a suitable material and assessing its corrosion rate, the research methodology employed is critical, as it directly influences the performance and conclusions regarding the suitability of the material as a bioresorbable implant. For bioresorbable materials, tests are conducted by immersing test specimens in the physiological environment, with the temperature and composition of the solution playing a significant role in the outcomes. The most straightforward method for evaluating corrosion characteristics is the gravimetric method, which relies on accurately measuring the weight of the sample before and after exposure. In this study, the influence of exposure time on the corrosion resistance of UFG Zn-1 %Fe-1 %Mg zinc alloy is investigated, as well as a comparative analysis of the outcomes of immersion tests conducted with different exposure times, including intermittent and long-term exposure times. As a result of the studies conducted, the experimental dependence of the corrosion rate on the exposure time of Zn-1 %Fe-1 %Mg alloy samples with an ultrafine-grained (UFG) structure in Ringer’s solution was obtained and analyzed. Within the framework of microstructural analysis using electron microscopy, common features and differences were identified, as well as mechanisms of corrosion propagation in UFG samples under intermittent and prolonged testing regimes. It was shown that in UFG samples, the corrosion process occurs in areas with a relatively small grain size. It was established that the results of estimating the corrosion rate in the UFG alloy under the two regimes differed by 2.5 times, depending on the frequency of cleaning the samples from corrosion products. Furthermore, it was demonstrated that the corrosion rate decreased when the holding time was increased up to 60 days, regardless of the testing methodology.

1. Russian Science Foundation - 23-29-00667