The Microstructure and the Electrochemical Behavior of Cobalt Chromium Molybdenum Alloys from Retrieved Hip Implants

Because of their excellent mechanical, tribological, and electrochemical properties, Cobalt Chromium Molybdenum alloys have been used as the material for both the stem and head of modular hip implants. Corrosion is one mechanism by which metal debris, from these implants, is generated, which can lead to adverse events that requires revision surgery. Manufacturing process such as wrought, as-cast, and powder metallurgy influences the microstructure, material properties, and performance of these implants The current research focuses on analyzing the microstructure of CoCrMo alloys from retrieved hip implants with optical and scanning electron microscopy. Additionally, energy disperse spectroscopy was utilized to determine weight composition of cobalt, chromium, and molybdenum in solution. Potentiodynamic polarization was used as an accelerated corrosion testing method to determine the electrochemical behavior of the different microstructures. In agreement with prior literature, it was found that Low Carbon Wrought CoCrMo Alloys have the best corrosion resistance properties