Investigation and enhancement of the biocompatibilityof cocralsi shape memory alloy

Current study investigates the biocompatibility of a novel CoCrAlSi shape memory alloy for orthopedic implant applications. The alloy was fabricated by vacuum induction melting and characterized using SEM, XRD, and XPS. A silver thin film, about 1000 nm thick, was deposited by physical vapor deposition to improve corrosion resistance. The silver coated samples were tested in phosphate-buffered saline (PBS) under body-like conditions. Ion release was measured with ICP-MS and compared to values reported in the literature. The Ag coating significantly reduced Co and Cr release, with decreases up to 84.6% and 51.6%, respectively, after 28 days of immersion. However, the absolute values of Co and Cr remained above safe biological thresholds. The silver layer itself showed an initial burst release that decreased over time, while surface analysis confirmed the formation of protective oxide films. These results suggest that Ag thin films can improve corrosion behavior and support the potential use of CoCrAlSi alloys in biomedical implants, but further optimization of coating thickness and ion release control is required.