Metal Dissolution and Oxide Formation Mechanisms of Heat-Treated Additively Manufactured Co28Cr6Mo in Amino Acid, Protein, and Simulated Inflammatory Environments for Biomedical Applications

• Applicant: Dr.-Ing. René Daniel Pütz
• Subject Area: Biomaterials
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 581145531

Metallic implants significantly improve patients’ quality of life by relieving pain and restoring joint function. However, failures still occur due to mechanical stress, corrosion, and chemical reactions related to wear particles and ion release. CoCrMo alloys are among the most widely used materials for hip and knee prostheses due to their high strength, wear resistance, and corrosion protection ensured by a passive oxide layer. Nevertheless, long-term (tribo)corrosion can lead to the release of nanoparticles and metal ions, which can trigger inflammatory responses and weaken the implant longevity. Additive manufacturing (AM), particularly Laser Powder Bed Fusion (LPBF), enables the production of patient-specific CoCrMo implants with refined microstructures and improved properties compared with conventional manufacturing. The LPBF process controls microstructural features such as grain size, phase distribution, and residual stresses that strongly influence corrosion and wear performance. Post-process heat treatments adjust the ratio of γ-(fcc) to ε-(hcp) phases, promote the formation of intermetallic precipitates and carbides, reduce residual stresses, and facilitate grain growth, allowing targeted control of mechanical and electrochemical stability. Despite growing research, systematic studies on how different heat treatments affect corrosion mechanisms in AM-produced CoCrMo alloys remain limited. Moreover, complex physiological conditions containing organic species such as amino acids and proteins are often neglected, even though they strongly alter surface reactions. Protein adsorption may stabilize the passive film or accelerate dissolution by forming metal–protein complexes, depending on protein type and concentration. This project investigates LPBF-fabricated Co28Cr6Mo after various heat treatments in simulated physiological media containing amino acids, proteins, and oxidizing agents (H₂O₂) to simulate inflammatory conditions. Electrochemical testing, trace metal release analysis, and surface characterization will be used to correlate microstructure, passivation behavior, and corrosion mechanisms. In addition, tribocorrosion interactions will be analyzed to evaluate how proteins influence the formation and protective role of tribolayers during sliding contact. The results will advance understanding of structure–property relationships and contribute to developing advanced CoCrMo implants.

• DFG Programme: Fellowship
• International Connection: Canada
• Host: Professorin Dr. Yolanda Hedberg