Sintering Behaviour, Graded Microstructure and Corrosion Performance of Sintered Fe-Mn Biomaterials

• Published in: International journal of electrochemical science 2015-11, Vol.10 (11), p.9256-9268
• Main Authors: Kupková, Miriam, Hrubovčáková, Monika, Kupka, Martin, Oriňáková, Renáta, Turoňová, Andrea Morovská
• Format: Article
• Language: English
• Subjects: biodegradable Fe-Mn sintered materials; corrosion; fractal dimension; OCP
• ISSN: 1452-3981; 1452-3981
• DOI: 10.1016/S1452-3981(23)11175-8

This article discusses the corrosion of sintered Fe-Mn alloys, as influenced by spatial variability in microstructure and composition. Materials of interest were manufactured by mixing an iron powder with 25, 30 and 35wt.% of manganese powder, pressing the mixtures in a die and sintering. Particles that the sintered materials were comprised of possessed ferritic/martensitic core regions and austenitic pheripheries. While the thickness of austenite shell seemed to increase with increasing Mn content for Fe-25Mn and Fe-30Mn materials, it appeared to fall to its lowest value for the Fe-35Mn material. The corrosion potential of a material exposed to Hank's solution increased with increasing Mn content for Mn-poorer materials but fell to its lowest value for the Mn-richest material. The fractal dimension of an electrochemical noise generated in corroding material was much lower than 1.5 for Mn-poorer materials but increased to the "white noise" value of 1.5 for the Mn-richest material. Corrosion rates of all materials were higher than those reported for homogeneous Fe-Mn alloys. It was concluded that while the Mn-richest material was very likely undergoing general corrosion, Mn-poorer materials suffered from galvanic interaction between particle cores and pheripheries and their corrosion was dominated by localized events.