4. Electric Discharge Treatment of Co–Cr Alloy

This chapter provides an in-depth examination of the systematic experiments carried out on cobalt-chromium (Co–Cr) alloy substrates utilizing the electrical discharge coating (EDC) technique. The primary aim of this research is to analyze the impact of various electrical discharge machining (EDM) parameters on the surface properties, biocompatibility, and wear resistance of Co–Cr implants employed in biomedical applications. The specific alloy under investigation, ASTM F75, is widely recognized for its application in orthopedic and dental implants due to its excellent mechanical strength, durability, and inherent chemical inertness. These attributes make it suitable for long-term implantation in the human body. However, there remains a significant opportunity to enhance its surface characteristics, which in turn could optimize biological responses, including corrosion resistance, hemocompatibility, and cytocompatibility, factors that are critical in ensuring the longevity and effectiveness of implants. To achieve these goals, the research was structured around a comprehensive three-stage experimental approach. In the first stage, the baseline properties of the Co–Cr alloy were established, assessing parameters such as initial surface roughness and mechanical strength. The second stage involved the application of the EDC technique with varying EDM parameters, including discharge current, pulse duration, and electrode material, to modify the surface characteristics systematically. In the final stage, extensive evaluations of biocompatibility and wear behavior were conducted through a series of in-vitro and in-vivo tests, with the aim of determining how these modified surfaces interacted with biological tissues and fluids. This detailed exploration aims to contribute valuable insights into how optimizing the surface properties of Co–Cr alloys can lead to improved performance of biomedical implants, ultimately enhancing patient outcomes.