Effects of Nb and Mo Alloying Elements on the Corrosion Characteristics of Sintered Cobalt-Chromium Alloys in Hanks Solution for Biomedical Application

Abstract This study investigates the influence of molybdenum and niobium on the corrosion characteristics of spark plasma-sintered cobalt–chromium (Co–Cr) in Hank’s solution for their biocompatibility for potential biomedical applications using spark plasma sintering (SPS). The results indicated that the Co–Cr binary alloy was highly susceptible to corrosion in the Hanks solution due to its low corrosion potential and high current density. Compared to Co–Cr–7Mo, the ternary compositions of Co–Cr–5Mo and Co–Cr–6Mo exhibited a somewhat higher susceptibility to corrosion more than 10%, showing a high corrosion potential and current density. While the Co–Cr–3Mo–3Nb composition had a high current density and a negative corrosion potential. The Co–Cr–2.5Mo–2.5Nb composition was only moderately susceptible to passive corrosion. The highest corrosion resistance was found in the Co–Cr–3.5Mo–3.5Nb alloy, indicating that uniform corrosion may occur in this alloy, albeit slowly. This study explores the impact of Nb and Mo on the corrosion resistance of sintered cobalt-chromium alloys in a biologically relevant environment. Hence, it is noteworthy that the development of next-generation biomaterials and medical devices depends on this breakthrough in surface functionalization.